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  • Artikel: DFG Deutsche Nationallizenzen  (642)
  • 1995-1999  (642)
  • 1975-1979
  • 1970-1974
  • 1920-1924
  • 1820-1829
  • 1997  (642)
  • Inorganic Chemistry  (608)
  • Electron microscopy
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  • Artikel: DFG Deutsche Nationallizenzen  (642)
Materialart
Erscheinungszeitraum
  • 1995-1999  (642)
  • 1975-1979
  • 1970-1974
  • 1920-1924
  • 1820-1829
Jahr
Schlagwörter
  • 1
    Digitale Medien
    Digitale Medien
    Renewing olfactory receptor neurons in goldfish do not require contact with the olfactory bulb to develop normal chemical responsiveness (1997)
    Springer
    Journal of comparative physiology 181 (1997), S. 425-437 
    Details
    ISSN: 1432-1351
    Schlagwort(e): Key words Olfactory receptor cells ; Olfactory bulbectomy ; Olfactory axotomy ; Electrophysiology ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract This study investigated whether contact with the olfactory bulb was necessary for developing and renewing olfactory receptor neurons (ORNs) to attain normal odorant responsiveness, and whether the anatomical and functional recoveries of the olfactory epithelium were similar in both bulbectomized (BE) and bilaterally axotomized (AX) preparations. In vivo electrophysiological recordings were obtained in response to amino acids, a bile acid [taurolithocholic acid sulfate(TLCS)] and a pheromonal odorant [17α, 20β,-dihydroxy-4-pregnen-3-one (17,20P)] from sexually immature goldfish. Both transmission and scanning electron microscopy indicated that the olfactory epithelium degenerated in BE and AX goldfish. Within 1–2 weeks subsequent to the respective surgeries, responses to high concentrations (〉0.1 mmol · l−1) of the more stimulatory amino acids remained, whereas responses were no longer obtainable to TLCS and 17,20P. At 4 weeks, responses to amino acid stimuli recovered to control levels, while responses to TLCS and 17,20P were minimal. By 7 weeks post bilateral axotomy, the olfactory epithelium recovered to a condition similar to control sensory epithelium; however, the rate of degeneration and proliferation of receptor neurons in BE preparations appeared to remain in balance, thus blocking further recovery of the olfactory epithelium. At 7 weeks post surgery, odorant responses of AX and BE goldfish to TLCS and 17,20P were still recovering.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003590050126
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  • 2
    Digitale Medien
    Digitale Medien
    Cytodifferentiation of atypical adenomatous hyperplasia and bronchioloalveolar lung carcinoma: immunohistochemical and ultrastructural studies (1997)
    Springer
    Virchows Archiv 431 (1997), S. 415-424 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Key words Bronchioloalveolar lung carcinoma ; Atypical adenomatous hyperplasia ; Surfactant apoprotein ; Urine protein 1 ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  We used immunohistochemistry and electron microscopy to evaluate the differentiation of cells comprising atypical adenomatous hyperplasia (AAH; n = 26), early bronchioloalveolar lung carcinoma (BAC; n = 11), and overt BAC (n = 16), which are assumed to constitute a continuous spectrum of developmental steps of BAC. Surfactant apoprotein (SAP), a marker for type 2 alveolar cells, was expressed in cells from all the lesions of AAH, early BAC, and overt BAC. However, the proportion of SAP-positive cells decreased and their distribution became more heterogeneous with advancing lesion grade. Urine protein 1, which is identical to the Clara cell-specific 10 kDa protein, was expressed in 70% of overt BAC, whereas only 20% of early BAC showed weak reactivity and none of AAH lesions showed any reactivity at all. Ultrastructurally, type 2 alveolar cell differentiation was predominant among cells from AAH and early BAC. Our results suggest that precursor cells of BAC differentiate predominantly towards type 2 alveolar cells. Cells comprising overt BAC retain this differentiation phenotype, but to a reduced extent. In contrast, concomitantly with progression, cells with Clara cell differentiation emerge and their proportion increases. Such phenotypic changes may reflect metaplasia occurring in tumour cells during the development of BAC.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004280050118
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  • 3
    Digitale Medien
    Digitale Medien
    Adenovirus-induced liver necrosis in a case of AIDS (1997)
    Springer
    Virchows Archiv 431 (1997), S. 469-472 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Key words Adenovirus ; Liver pathology ; Electron microscopy ; AIDS
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Adenovirus-induced liver necrosis is rare. Before the era of AIDS (acquired immunodeficiency syndrome) this entity was seen predominantly in infants suffering from inborn immunodeficiency syndromes or from iatrogenic immunosuppression because of bone marrow or liver transplantation. Here, we report a case of a 30-year-old woman with AIDS who developed fever and rapidly progressing liver failure. A frozen section from a needle biopsy of the liver allowed a quick diagnosis of viral liver necrosis. The light-microscopic and electron microscopic aspects were typical of adenovirus infection and should be known to the surgical pathologist. The diagnosis was confirmed by immunohistochemistry and DNA hybridization analysis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004280050125
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  • 4
    Digitale Medien
    Digitale Medien
    Argyrophilic tau-positive twisted and non-twisted tubules in astrocytic processes in brains of Alzheimer-type dementia: an electron microscopical study (1997)
    Springer
    Acta neuropathologica 95 (1997), S. 28-39 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Key words Astrocytes ; Alzheimer-type dementia ; Electron microscopy ; Glial fibrillary tangles ; Tau protein
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract This report concerns pathological astrocytic tubular structures (astrocytic tubules, As-Tbs) that coexist with glial filaments in astrocytic processes in brains with presenile-onset Alzheimer-type dementia. The formation of As-Tbs appears to be related to the duration of disease and the intensity of Alzheimer histopathology. In three cases in which the disease was of extremely long duration, As-Tbs were found in the frontal and temporal neocortices, the temporal pole and the hippocampus using electron microscopy, whereas they were not found in two cases with a long, but not extremely long, illness duration. As-Tbs were almost exclusively found in the highly devastated neuropil, and we could not find them in regions of moderate neuronal degeneration despite intensive inspection. As reported previously, some As-Tbs was seen adjacent to extracellular neurofibrillary tangles (NFTs) and in perivascular astrocytes. Our novel finding is that they can exist independently from these, in the highly devastated neuropil. Two types of As-Tbs were observed, twisted tubules with periodic constrictions at 50- to 80-nm intervals and non-twisted tubules where no constrictions were seen but which had a 15-nm fuzzy outer contour. They were positively stained by anti-human tau antibody, an antibody that does not recognize extracellular NFTs. Thus, it is most likely that As-Tbs are not the sequestration of extracellular NFTs, and that they are of astrocytic origin. Moreover, As-Tbs showed argyrophilia. As-Tbs appear indistinguishable from dystrophic neurites under the light microscope. The present data suggest that they may be more widely distributed in the damaged cerebral neuropil than previously thought.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004010050762
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  • 5
    Digitale Medien
    Digitale Medien
    Scots pine needle injuries at subarctic industrial sites (1997)
    Springer
    Trees 11 (1997), S. 378-387 
    Details
    ISSN: 0931-1890
    Schlagwort(e): Key words Pinus sylvestris (L.) ; Electron microscopy ; Heavy metals ; Multi-stress-symptoms ; SO2
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract  Injuries to needles of Scots pines (Pinus sylvestris L.) growing in nutrient-poor soils on the Kola Peninsula collected in April 1991 were studied on a gradient of increasing distances (10 – 115 km) from the Monchegorsk nickel smelter, Russia, which emits SO2, Ni and Cu. The condition of the mesophyll cells was quantified from needles of the two latest age classes using a light and an electron microscope. The damage to the ultrastructure consisted of multistress symptoms caused by excess sulphur, heavy metals, frost, acidic precipitation and ozone. Injuries were most commonly manifested in the form of dark, irregularly shaped chloroplasts with protrusions and light thylakoids and plastoglobuli. These symptoms gradually disappeared with increasing distance and decreasing deposition rate. Concentrations of sulphur, copper and nickel decreased towards more distant sites where normal levels of the latter two elements were reached. Sulphur concentrations remained above background throughout the distance gradient. In the closest plots to the smelter area, cell collapse under the stomata and epidermis related to acute SO2 and heavy metal effects was found, whereas further away symptoms were more diverse, pointing towards the effects of ozone, acidic deposition and thereby decreased frost tolerance. The additive multistress symptoms were clearly seen in the area up to 40 km from the smelter where needle Cu concentration was above 110 ppm, Ni concentration above 39 ppm and S concentration above 1343 ppm.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004680050099
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  • 6
    Digitale Medien
    Digitale Medien
    Phenotypic variability of CADASIL and novel morphologic findings (1997)
    Springer
    Acta neuropathologica 94 (1997), S. 247-254 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Key words CADASIL ; Electron microscopy ; Granular osmiophilic material ; αB crystallin ; Heat ; shock proteins
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a non-arterio-atherosclerotic, non-amyloidotic arteriopathy affecting preferentially the small arteries and arterioles of the brain. The morphologic hallmark is the presence of a characteristic granular alteration of the arterial media that ultrastructurally corresponds to the accumulation of electron-dense material surrounding the smooth muscle cells. Although the presence of this granular osmiophilic material (GOM) was originally described as limited to brain vessels, identical electron microscopic findings have been demonstrated in the media of peripheral tissue arteries, allowing for a pathologic diagnosis of the disease by a simple skin, muscle or nerve biopsy. We report some atypical features identified in our CADASIL patients that broaden the phenotypic expression of this disease. Firstly, we identified a cortical infarct in an otherwise typical CADASIL patient. Secondly, we observed GOM in skin arteries of a 30-year-old man with hemiplegic migraine, the son of a woman who had died with CADASIL. This confirms that it may be possible to diagnose the disease at a preclinical stage by the ultrastructural evaluation of peripheral tissue biopsy material, particularly for individuals for whom there is a supporting family history. Thirdly, ultrastructural examination of the skin, and subcutaneous and striated muscle of an unrelated and apparently sporadic patient with neuropathologic and neuroradiologic evidence of CADASIL in meningeal and cerebral vessels failed to reveal diagnostic lesions in peripheral arteries. Thus, the possibility of a false-negative pathologic diagnosis in patients with a clinicoradiologic diagnosis of CADASIL, if one relies solely on a peripheral tissue biopsy, does exist. Additionally, we have identified heat shock proteins (Hsp70 and αB crystallin) and ubiquitin in the vascular myocytes of affected arteries. αB crystallin also seemed to be deposited extracellularly, which suggests that GOM also might be immunoreactive for αB crystallin.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004010050700
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  • 7
    Digitale Medien
    Digitale Medien
    Density and fine structure of peripheral nerves in various skin lesions of atopic dermatitis (1997)
    Springer
    Archives of dermatological research 289 (1997), S. 125-131 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Key words Atopic dermatitis ; Peripheral nerve ;   ; Electron microscopy ; Protein gene product ; Substance P
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The density and fine structure of the peripheral nerve system in various skin lesions of 64 patients with atopic dermatitis (AD) was quantitatively analyzed by immunohistochemical staining with antibodies directed against protein gene product (PGP) and substance P (SP). The density of PGP-positive peripheral nerves was 2.5 × 10 3 μm 2 /Δs (Δs = 0.24 mm 2 selected area) in early acute lesions, 3.8 × 10 3 μm 2 /Δs in subacute lesions, 4.9 × 10 3 μm 2 /Δs in lichenified lesions and 7.1 × 10 3 μm 2 /Δs in prurigo lesions of AD. The density of nerve fibers in subacute, lichenified and prurigo lesions was significantly higher than in uninvolved skin of AD patients (2.0 × 10 3 μm 2 /Δs). Electron microscopically, bulging of axons with many mitochondria and a loss of their surrounding sheath of Schwann cells suggests that the free nerve endings in skin lesions of AD are in an active state of excitation. Many pinocytotic vesicles in the periphery of basal keratinocytes facing nerve endings which contained many neurovesicles suggests reciprocal effects between keratinocytes and nerve endings. The number of SP-positive nerve fibers in AD lesions was far less than one-tenth of the number of PGP-positive nerve fibers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004030050167
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  • 8
    Digitale Medien
    Digitale Medien
    Effects of brefeldin-A and monensin on organelle distribution and morphology in the preimplantation mouse embryo (1997)
    Springer
    Development genes and evolution 206 (1997), S. 503-514 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Key words Preimplantation mouse embryo ; Brefeldin-A ; Monensin ; Golgi ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  The intracellular trafficking of integral membrane and secreted proteins is likely to be a key element involved in the morphogenesis and differentiation of the early mammalian embryo. In this study, we used transmission electron microscopy (TEM) to analyse the effects of brefeldin-A (BFA) and monensin, well known inhibitors of vesicular protein trafficking in somatic cells, on the structure of preimplantation mouse embryos. Both BFA and monensin distinctively altered the morphology of Golgi compartments in the blastomeres of treated morulae. BFA-treated morulae lacked recognizable Golgi complexes but possessed heterogeneous organelle clusters consisting of an abundance of smooth tubular and vesicular membrane compartments in addition to mitochondria, endosomes and lysosomes. Treatment of morulae with monensin was associated with swelling of Golgi compartments in addition to altering the morphology of mitochondria, lysosomes and the plasma membrane. BFA, and to a lesser extent monensin, inhibited cytokinesis as evidenced by the detection of binucleate blastomeres. In addition, BFA induced morulae to decompact. These latter effects have not been reported previously for these agents in mammalian somatic cell lines or other vertebrate or invertebrate embryos. These results provide the first demonstration of the structural effects of BFA and monensin on cells of the early mammalian embryo, some of which are consistent with the known actions of these agents on components of the vesicular protein trafficking system in mammalian somatic cells. This information serves as a foundation for the further use of these agents in studies of vesicular protein trafficking as an agent of preimplantation morphogenesis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004270050081
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  • 9
    Digitale Medien
    Digitale Medien
    Komibinierte neuronale und endokrine Tumoren der Sellaregion (1997)
    Springer
    Der Pathologe 18 (1997), S. 419-424 
    Details
    ISSN: 1432-1963
    Schlagwort(e): Schlüsselwörter Gangliozytom ; Gangliogliom ; Hypophysenadenom ; Immunhistologie ; Ultrastruktur ; Key words Gangliocytoma ; Ganglioglioma ; Pituitary adenoma ; Immunohistochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Gangliocytomas or gangliogliomas of the sellar region are very rare tumors. In a great proportion of those cases an adenoma of the anterior pituitary develops from the cell type that is hyperstimulated by the releasing hormone produced from the gangliocytoma. Five GHRH secreting gangliocytomas are reported. Four of these were localized adjacent to a GH secreting adenoma. In one case, no adenoma tissue was found beside the ganglicytoma. As only the adenomas can secrete GH, the adenomas and not the gangliocytomas are directly responsible for acromegaly so that such an adenoma has to be present in cases of acromegaly. A CRH secreting gangliocytoma was combined with an ACTH cell adenoma that had induced Cushing’s disease. A ganglioglioma of the posterior pituitary had led to an inappropriate secretion of Vasopressin. The morphology of the different tumors is presented.
    Notizen: Zusammenfassung Intraselläre Gangliozytome/Gangliogliome sind sehr seltene Tumoren, die in einem Großteil der Fälle ein Hypophysenadenom aus dem Zelltyp heraus entstehen lassen, der durch das gebildete Releasinghormon überstimuliert wird. Es wird über 5 GHRH-bildende Gangliozytome berichtet, von denen 4 einem STH-bildenden Hypophysenadenom benachbart waren. Ein Fall enthielt keine Adenomanteile. Diese müssen in Anbetracht der klinisch vorhandenen Akromegalie aber vorhanden sein, da nur das jeweilige Adenom, nicht aber die Gangliozytome für die Überfunktion unmittelbar verantwortlich sind. Ein CRH-bildendes Gangliozytom war mit einem zum Morbus Cushing führenden ACTH-Zelladenom kombiniert. Ein Gangliogliom des Hinterlappens hatte zu einer inadäquaten Vasopressinsekretion Anlaß gegeben. Die Morphologie der Tumoren wird dargelegt.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002920050236
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  • 10
    Digitale Medien
    Digitale Medien
    Ultrastructural subtypes of glutamate-immunoreactive terminals on rat trigeminal motoneurones and their relationships with GABA-immunoreactive terminals (1997)
    Springer
    Experimental brain research 114 (1997), S. 99-116 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Key words Synapse ; Axo-axonic synaptic contacts ; Trigeminal motor nucleus ; Immunogold ; Electron microscopy ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Electron-microscopic immunolabelling methods were used to study the relationships between glutamate-immunoreactive and γ-aminobutyric acid (GABA)-immunoreactive synapses on trigeminal motoneurones labelled by the retrograde transport of horseradish peroxidase. Serial sections were cut through the motor nucleus, alternate sections were incubated with antibodies to glutamate and GABA, and the immunopositive nerve terminal profiles were recognized using a quantitative, postembedding immunogold method. Boutons exhibiting high levels of glutamate immunoreactivity and GABA-immunoreactive boutons both formed axo-dendritic and axo-somatic synaptic contacts on labelled motoneurones. Boutons strongly immunopositive for glutamate were not immunopositive for GABA, and vice versa. Strongly glutamate immunoreactive boutons received axo-axonic synaptic contacts but did not form such contacts, while GABA-immunoreactive boutons formed axo-axonic synapses but did not receive them. The presynaptic elements at all axo-axonic synapses on to glutamate-immunoreactive boutons sampled were GABA-immunopositive. These data provide ultrastructural evidence in support of the roles of glutamate and GABA as transmitters at synapses on trigeminal motoneurones, and for presynaptic control of transmission at glutamatergic synapses by GABA acting at receptors at axo-axonic synapses. The vast majority (more than 90%) of strongly glutamate immunoreactive boutons contained spherical synaptic vesicles, in contrast to GABA-immunoreactive boutons, which contained pleomorphic vesicles. Most of the glutamate-immunoreactive boutons (67%) formed asymmetrical synaptic active zones, many of which (47% of total) were associated with subsynaptic dense ”Taxi” bodies (T-terminals), while a smaller population of boutons (21%) formed symmetrical synapses, and a few (11%) made synapses associated with subsynaptic cisternae (C-terminals). The heterogeneity of active zone ultrastructure of boutons identified as being glutamatergic on the basis of their high levels of immunolabelling is discussed in relation to possible differences in co-transmitters released, origins of the synaptic input or post-synaptic receptor subtypes activated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/PL00005627
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  • 11
    Digitale Medien
    Digitale Medien
    Type III Ehlers-Danlos syndrome and pregnancy (1997)
    Springer
    Archives of gynecology and obstetrics 261 (1997), S. 39-43 
    Details
    ISSN: 1432-0711
    Schlagwort(e): Key words: Ehlers-Danlos type III ; Pregnancy ; Electron microscopy ; Prenatal diagnosis ; Premature rupture of membranes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract. We report a case of type III Ehlers-Danlos syndrome with a favourable outcome. We review the literature and do not consider that pregnancy in patients with type III Ehlers-Danlos Syndrome represents a high risk situation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004040050196
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  • 12
    Digitale Medien
    Digitale Medien
    Light and electron microscopic investigation of the process of healing of the naevus of Ota by Q-switched alexandrite laser irradiation (1997)
    Springer
    Virchows Archiv 431 (1997), S. 63-71 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Key words Naevus of Ota ; Q-switched alexandrite laser ; Light microscopy ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Melanocytes in the naevus of Ota were destroyed by irradiation using the Q-switched alexandrite laser. This laser is highly selective and highly absorbed by melanosomes. Other cells and tissue components of the dermis remained almost intact. Melanosomes were vaporized or fragmented to subelectron microscopical size, or degenerated. If the irradiated energy was sufficient, melanocytes vanished and large vacuoles several times the size of dermal melanocytes formed at the sites. If it was too weak, dermal melanocytes were also vaporized, but vacuoles formed within them. Nuclei were no longer discernible. Following irradiation macrophages infiltrated the irradiated areas and scavenged degenerated melanosomes and cellular debris. Thus, discoloration of the skin was markedly reduced. Although a few melanocytes and melanophages remained, pigmentation cleared to a satisfactory level. Melanocytes and keratinocytes were also injured in the epidermis; however, the epidermis recovered completely. No scarring was observed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004280050070
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  • 13
    Digitale Medien
    Digitale Medien
    Neuropeptide Y-immunoreactive intracardiac neurones, granule-containing cells and nerves associated with ganglia and blood vessels in rat and guinea-pig heart (1997)
    Springer
    Cell & tissue research 289 (1997), S. 445-454 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Intracardiac neurones ; Innervation ; Heart ; Neuropeptide Y ; Immunocytochemistry ; Electron microscopy ; Rat (Sprague Dawley) ; Guinea-pig (Dunkin Hartley)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. Intrinsic neuropeptide Y-containing neurones in rat and guinea-pig hearts were studied at the ultrastructural level by the pre-embedding peroxidase-antiperoxidase immunocytochemical technique. Intracardiac neuronal cell bodies were often weakly or moderately immunostained, and the labelling was usually pronounced in the Golgi complex, multivesicular bodies, some cisterns of granular endoplasmic reticulum and large granular vesicles. Neuropeptide Y-immunoreactive nerve fibres were also observed in association with intracardiac neurones. A subpopulation of neuropeptide Y-immunoreactive granule-containing cells in the rat heart are described for the first time and were very heavily labelled; other granule-containing cells were non-immunoreactive, but were contacted by neuropeptide Y-containing nerves. Preterminal regions of nerve fibres that were located in nerve bundles were only weakly neuropeptide Y-immunoreactive, in contrast to the heavy labelling observed in varicosities that contained many synaptic vesicles. Many neuropeptide Y-immunoreactive nerve fibres were associated with the coronary vasculature and were particularly prominent in the walls of small arteries and arterioles where labelled nerve varicosities were present close to the smooth muscle cells. Immunoreactive nerves were also seen in the myocardium, usually near to capillaries. In axonal varicosities, the central core of large granular vesicles was immunolabelled, and electron-dense immunoreactive material outlined the membranes of small and large clear vesicles. The significance of neuropeptide Y-immunoreactive intracardiac neurones and granule-containing cells and the origin of associated labelled nerve fibres in the heart are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410050890
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  • 14
    Digitale Medien
    Digitale Medien
    Immuno-electron microscopy reveals that the excitotoxin quinolinate is associated with the plasma membrane in human peripheral blood monocytes/macrophages (1997)
    Springer
    Cell & tissue research 290 (1997), S. 633-639 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Quinolinic acid ; Interferon-γ ; Kynurenine ; Electron microscopy ; Immunocytochemistry ; Excitotoxicity ; Human
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract.  Quinolinate (QUIN), a tryptophan-derived excitotoxin, was localized ultrastructurally in human peripheral blood monocytes/macrophages (MØ) by immuno-electron microscopy. A combined carbodiimide/glutaraldehyde/paraformaldehyde-based fixation procedure was developed for optimal retention of QUIN in the cell as well as minimal loss of ultrastructure; a silver-enhanced colloidal gold detection system was used for electron-microscopic analysis. Gold particles representing QUIN immunoreactivity were associated with the inner side of the plasma membrane in normal MØ. The number of gold particles increased significantly when QUIN levels were elevated by treatment with its precursor kynurenine, but location of the gold particles remained essentially the same under this condition. Treatment with interferon-γ increased the number of Golgi bodies, vacuoles and pseudopodia, reflecting the activated state of the cell. Significantly increased numbers of gold particles representing QUIN were detectable in approximately the same location as in the case of kynurenine treatment. Combined treatment with kynurenine and interferon-γ maximally increased the number of gold particles at the periphery of the cell. The pseudopodia were intensely stained with gold particles, while they were not detectable in the inner part of the cytoplasm or in any other organelle even under this activated condition. The significance of the specific location of QUIN revealed in the present study and its relation to the release and subsequent actions of QUIN are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410050969
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  • 15
    Digitale Medien
    Digitale Medien
    Synaptic exocytosis of dense-core vesicles in blue crab (Callinectes sapidus) stomach muscles (1997)
    Springer
    Cell & tissue research 289 (1997), S. 517-526 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Neuromuscular junction ; Synaptic vesicles ; Vesicle fusion ; Electron microscopy ; Callinectes sapidus (Crustacea)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. Neuromuscular terminals of a single motoneuron to four muscles (CPV7a, GM5a, CV2, and CV3) in the stomach of the blue crab Callinectes sapidus showed structural evidence for the exocytotic release of dense-core vesicles exclusively at synapses. The primary evidence was the appearance of dense cores in the synaptic cleft, accompanied by indentations of the presynaptic or postsynaptic membrane. In their simplest form, these consisted of an omega-shaped figure of the presynaptic membrane enclosing one dense core, denoting release of a single dense-core vesicle. A larger indentation of the presynaptic membrane enclosing several dense cores denoted multiple release. A more complex form of multiple release was where the presynaptic membrane was normal, but the postsynaptic membrane elaborated into a sac projecting into the granular sarcoplasm and filled with dense cores. The postsynaptic sac in some instances was compressed into a thin, fingerlike extension, which lacked dense cores and, at its distal end, separated into small cisternae, suggesting a mechanism for membrane recycling. Profiles depicting single and multiple releases of dense-core vesicles were found more frequently at neuromuscular terminals that release relatively large amounts of transmitter with a single stimulus, such as CV2 and CV3, compared to those releasing smaller amounts, such as CPV7a and GM5a. The disparity in release sites among the four muscles of this single motor unit and the fact that many of the multiple-release figures were closely adjacent to the active zones for transmitter release suggest a possible modulatory role for dense-core vesicles in synaptic transmission. Such modulation may be long lasting, as implied by the postsynaptic sacs, which may permit prolonged release of the contents of their dense cores into the synaptic cleft. This is in keeping with the functional role of these stomach muscles, which is to be continuously active for long periods of time.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410050897
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  • 16
    Digitale Medien
    Digitale Medien
    Immunoreactive excitatory amino acids in the parietal eye of lizards, a comparison with the pineal organ and retina (1997)
    Springer
    Cell & tissue research 287 (1997), S. 275-283 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Parietal eye ; Pineal organ ; Retina ; Glutamate ; Aspartate ; Immunocytochemistry ; Electron microscopy ; Lacerta muralis ; Lacerta agilis ; Lacerta viridis (Lacertilia)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. The fine structure of the organ and the localization of the excitatory amino acids glutamate and aspartate were studied in the parietal eye of lizards by postembedding immunoelectron microscopy. The parietal eye contains cone photoreceptor cells, secondary neurons, and ependymal and lens cells. The photoreceptors form long inner and outer segments, some of them being paired as ”twin-photoreceptors” by zonulae adherentes. Perikarya of neurons bear sensory cilia (containing 9×2+0 pairs of tubules) extending into the intercellular space. No neurohormonal terminals are present in the parietal eye. A higher immunoreactivity to glutamate than to aspartate is found in the photoreceptors and in the secondary neurons of the parietal eye. Glutamate immunogold labeling is more intense in the axonal processes of photoreceptors and neurons and in most of the nerve fibers of the parietal nerve running to the brain stem. Weak aspartate and glutamate immunoreactivity can be detected in the ependymal and lens cells. A similar distribution of immunoreactive amino acids is found in the photoreceptors, secondary neurons, and ependymal glial elements of the pineal organ, and retina of the lateral eye of the same animals. Immunoreactive glutamate accumulates in the axons of photoreceptors and secondary neurons of the parietal eye suggesting that this excitatory amino acid acts as a synaptic mediator in the neural efferentation of the organ. Thus, the efferent light-conducting pathway of the parietal organ is similar to that of the pineal organ and lateral eye retina. As the Mullerian cells of the retina, the ependymal and lens cells of the parietal eye and the ependymal-glial cells of the pineal organ may play a role in the metabolism and/or elimination of excitatory amino acids released by photoreceptors.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410050752
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  • 17
    Digitale Medien
    Digitale Medien
    Expression of basic fibroblast growth factor-like immunoreactivity in the nuclei of regenerating hepatocytes (1997)
    Springer
    Cell & tissue research 288 (1997), S. 517-527 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Liver ; Subcellular fractions ; Immunohistochemistry ; Electron microscopy ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. This study, utilizing rats subjected to two-thirds partial hepatectomy or sham operation, was designed (1) to investigate the content of basic fibroblast growth factor (bFGF) in the subcellular fractions of regenerating and sham-operated rat livers by immunoblot experiments and enzyme-linked immunosorbent assay (ELISA), (2) to show that bFGF immunoreactivity and proliferating cell nuclear antigen (PCNA) immunoreactivity are markers for hepatocellular mitosis before and after partial hepatectomy, and (3) to observe the location and fine structure of the bFGF immunoreaction within the regenerating liver with special attention to bFGF immunoreactivity in the nuclei of regenerating hepatocytes. Immunoblot experiments and ELISA showed a transient increase in high-molecular-weight forms of bFGF in the nuclear subcellular fraction of regenerating liver 48 h after partial hepatectomy. By light microscopy, bFGF and PCNA immunoreactivities were detected in the nuclei of regenerating hepatocytes. Electron microscopy demonstrated bFGF-like immunoreactivity mainly in the nuclear euchromatin and rarely in the heterochromatin or nucleoli of regenerating hepatocytes. The transient increase in high-molecular-weight forms of bFGF in the nuclear euchromatin of regenerating hepatocytes, together with the concomitant expression of PCNA in the regenerating liver, suggests an important role of the high-molecular-weight forms of bFGF in hepatocyte proliferation and/or mitosis, although authentic bFGF with a molecular form of 18 kDa is not considered to be involved in hepatic regeneration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410050837
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  • 18
    Digitale Medien
    Digitale Medien
    Osmoregulatory mutants that affect the function of the contractile vacuole inChlamydomonas reinhardtii (1997)
    Springer
    Protoplasma 200 (1997), S. 99-111 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Chlamydomonas reinhardtii ; Contractile vacuole ; Electron microscopy ; Videomicroscopy ; Osmoregulation ; Osmoregulatory mutants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Four independent osmoregulatory mutants,osml, osm3,osm4, and osm7, were isolated on the basis of their requirement for growth medium of high osmotic strength. In normal low-osmoticstrength medium, in contrast to wild-type cells, the mutants grow poorly or not at all; in distilled water mutant cells are immobilized and eventually swell and burst. The mutants were examined by ordinary brightfield and phase-contrast microscopy, videomicroscopy, and electron microscopy. The four mutants showed different defects in the contractile vacuole (CV) cycle. Timing of various stages of the CV cycle showed thatosm1 was affected primarily in the early stage of the cycle when the CV begins to grow,osm3 primarily in midcycle when vacuoles fuse to form the CV proper,osm7 at a late stage of the cycle at docking and fusion of the CV with the plasma membrane, andosm4 during contraction of the CV. At the electron microscopic level, in dilute medium, mutant cells by comparison with wild-type cells had large autophagosomes, swollen mitochondria, and dilated ER cisternae. Although electron microscopy showed general abnormalities of the contractile vacuoles consistent with the videomicroscopic observations of living cells, no obvious vacuole membrane abnormalities were seen which would explain the mutational defects. The mutations help define the separate processes that contribute to the coordinated CV cycle inChlamydomonas, and open the way to eventual isolation of some of the genes responsible for CV function.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01280738
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  • 19
    Digitale Medien
    Digitale Medien
    Structure and behavior of contractile vacuoles inChlamydomonas reinhardtii (1997)
    Springer
    Protoplasma 198 (1997), S. 73-84 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Chlamydomonas reinhardtii ; Contractile vacuole ; Osmoregulation ; Videomicroscopy ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The contractile vacuole (CV) cycle ofChlamydomonas reinhardtii has been investigated by videomicroscopy and electron microscopy. Correlation of the two kinds of observation indicates that the total cycle (15 s under the hypo-osmotic conditions used for videomicroscopy) can be divided into early, middle, and late stages. In the early stage (early diastole, about 3 s long) numerous small vesicles about 70–120 nm in diameter are present. In the middle stage (mid-diastole, about 6 s long), the vesicles appear to fuse with one another to form the contractile vacuole proper. In the late stage (late diastole, also about 6 s long), the CV increases in diameter by the continued fusion of small vesicles with the vacuole, and makes contact with the plasma membrane. The CV then rapidly decreases in size (systole, about 0.2 s). In isosmotic media, CVs do not appear to be functioning; under these conditions, the CV regions contain numerous small vesicles typical of the earliest stage of diastole. Fine structure observations have provided no evidence for a two-component CV system such as has been observed in some other cell types. Electron microscopy of cryofixed and freeze-substituted cells suggests that the irregularity of the profiles of larger vesicles and vacuoles and some other morphological details seen in conventionally fixed cells may be shrinkage artefacts. This study thus defines some of the membrane events in the normal contractile vacuole cycle ofChlamydomonas, and provides a morphological and temporal basis for the study of membrane fusion and fluid transport across membranes in a cell favorable for genetic analysis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01282133
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  • 20
    Digitale Medien
    Digitale Medien
    Selective UV-induced damage to short-wavelength receptor cells in the butterflyPapilio xuthus (1997)
    Springer
    Protoplasma 200 (1997), S. 112-115 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Electron microscopy ; UV-induced cell damage ; Photoreceptor ; Eye ; Lepidoptera
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A technique that allows the specific inactivation of short-wavelength-sensitive photoreceptive cells has been needed for a long time. Such a technique could be useful in studies on the role(s) of UV-receptors in circadian rhythmicity, recognition of floral patterns, homing behaviour, and mate selection in arthropods. We provide ultrastructural evidence that short-wavelength receptor cells can be selectively damaged without affecting other spectral-cell types. Since the method does not require the killing of the experimental animal, the latter can be used in behavioural or other follow-up tests.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01280739
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  • 21
    Digitale Medien
    Digitale Medien
    Electron microscopic and immunomorphological investigations on the mucosa of the human paranasal sinuses (1997)
    Springer
    European archives of oto-rhino-laryngology and head & neck 254 (1997), S. 230-235 
    Details
    ISSN: 1434-4726
    Schlagwort(e): Paranasal sinus mucosa ; Collagen type VII ; Subepithelial connective tissue ; Electron microscopy ; Immunofluorescence microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The morphology of the mucosa from the human paranasal sinuses was investigated by electron microscopy. A total of 27 specimens was taken from 11 patients following midfacial fractures. All tissue samples were biopsied during surgery after informed consent had been given. In accordance with light microscopic investigations, the mucosa represented a highly prismatic epithelium consisting of kinocilia-carrying and mucus-producing (goblet) cells. Other cell types, such as those occurring in the respiratory epithelium of other areas, could not be demonstrated. Electron microscopic and immunomorphological investigations revealed collagen type VII beneath the lamina densa of the basal lamina. According to findings obtained to date, this collagen type accompanies only a multilayered epithelium. Another peculiarity was the small number of basophils and eosinophils. Pronounced acute reactions of the mucosa in this area cannot be expected, which is in contrast to that of the nasal mucosa.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00874094
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  • 22
    Digitale Medien
    Digitale Medien
    Ultrastructural findings of the macula utriculi in a case of a petrous apex cholesteatoma: a comparison with findings in a patient with an acoustic neuroma (1997)
    Springer
    European archives of oto-rhino-laryngology and head & neck 254 (1997), S. 255-258 
    Details
    ISSN: 1434-4726
    Schlagwort(e): Electron microscopy ; Inner ear ; Utricle ; Cholesteatoma ; Acoustic neuroma
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The morphological characteristics of the vestibular sensory cells of the macula utriculi obtained during surgery in a patient with a petrous apex cholesteatoma were examined using scanning and transmission electron microscopy. Findings were compared to cells studied in a patient with acoustic neuroma. Scanning electron microscopy showed that compared to the apparently normal cells in the acoustic neuroma case, most sensory cells in the cholesteatoma case had large cuticular plates, irregular locations of cilia and no clear polarizations. Supporting cells showed profuse short microvilli on the whole surface. With transmission electron photomicrographs, type I hair cells were not seen and certain morphological changes were observed in type-1I-like cells and supporting cells. We presume that the degenerative changes in the vestibular epithelia were due to circulatory disturbances and/or direct pressure applied to the vestibular nerve at the internal auditory canal, with subsequent involvement of the macula utriculi.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00874100
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  • 23
    Digitale Medien
    Digitale Medien
    Electron microscopic localization of nitric oxide I synthase in the organ of Corti of the guinea pig (1997)
    Springer
    European archives of oto-rhino-laryngology and head & neck 254 (1997), S. 396-400 
    Details
    ISSN: 1434-4726
    Schlagwort(e): Guinea pig hair cells ; Electron microscopy ; Immunocytochemistry ; Nitric oxide synthase ; Sound transduction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Nitric oxide synthase (NOS) activity has been detected previously in the mammalian cochlea at a light microscopic level. Here we present results of electron microscopic analysis for post-embedding immunoreactivity of neural-type NOS I in the cochlea of the guinea pig. Strong enzyme immunoreactivity was identified in the cytoplasm of inner and outer hair cells. Gold-labeled NOS I antibodies were mainly located in electron-dense areas of the cytoplasm, whereas electron-lucent regions of the receptor cells were nearly free from any immunoreactivity. In both types of hair cells anti-NOS I antibodies were also visible in the cuticular plates, hair bundles and nuclei. Further ultrastructural analysis revealed that the submembranous cisternae of the outer hair cells were nearly free from any reaction product, demonstrating that the whole cytoplasm of this hair cell was not immunoreactive. Other NOS I immunoreactivity was identified in the cuticular plates of the inner and outer pillar cells and in the cytoskeletal elements located in the apical parts of Deiter cells, forming the lamina reticularis or in cytoskeletal-containing regions in basal Deiter cells. Anti-NOS antibodies were visible in the nuclei of various cell types. Our findings suggest that nitric oxide produced by NO I synthase in the organ of Corti may act as a modulator of hair cell physiology during the processes of signal transduction with frequence selectivity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01642558
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  • 24
    Digitale Medien
    Digitale Medien
    Immunohistochemical and electron microscopical characterization of stromal cells in nasopharyngeal angiofibromas (1997)
    Springer
    European archives of oto-rhino-laryngology and head & neck 254 (1997), S. 196-199 
    Details
    ISSN: 1434-4726
    Schlagwort(e): Nasopharyngeal angiofibroma ; Ultrastructure ; Myofibroblast ; Immunohistochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Twenty-eight cases of nasopharyngeal angiofibroma were studied immunohistochemically for cytoskeletal phenotyping of stromal cells. Electron microscopy was also used to study the ultrastructure of five of the tumors. All typical stromal cells showed intensive immunostaining for vimentin, but were negative for smooth muscle actin and desmin. Ultrastructurally, most of these cells appeared to be exclusively fibroblasts. However, in some areas stromal cells were seen that morphologically resembled myofibroblasts by their shapes and arrangement, and were characterized by the coexpression of vimentin and smooth muscle actin. Electron microscopy confirmed their myofibroblastic nature. The present study showed that the typical stromal cells in nasopharyngeal angiofibromas were fibroblasts and not myofibroblasts. In these tumors myofibroblasts occurred only focally, in connection with fibrotic areas and exclusively as a vimentin+/actin+ cytoskeletal phenotype. This indicates that myofibroblasts are not primary stromal tumor cells in nasopharyngeal angiofibromas, but occur due to regressive changes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00879273
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  • 25
    Digitale Medien
    Digitale Medien
    Hydrogen Bonding and Conformational Analysis of Chelate-Stabilized Alkoxopalladium(II) Complexes Derived from Amino Alcohol Ligands (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 35-44 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Alkoxopalladium(II) ; Conformational analysis ; Hydrogen bonding ; Two-dimensional and cage structures ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reaction of palladium acetate with two equivalents of di- and triethanolamines RN(CH2CH2OH)2 in the presence of a base affords the new chelate-stabilized alkoxo Pd(II) complexes [Pd(OCH2CH2N(R)CH2CH2OH)2] [R = Me (1), Et (2), n-Bu (3), benzyl (4) or CH2CH2OH (5)]. These N,O-ligated complexes are isolated in high yield as yellow, crystalline solids and are thermally stable despite the presence of several β-hydrogen atoms in the ligand system. Both complexes possess a square-planar palladium coordination geometry with the two oxygen atoms positioned mutually trans. The most notable difference in the molecular structures is that 1 forms a two dimensional network of intermolecular O-H≡O hydrogen bonds, whereas 5 forms intramolecular O-H⃛O hydrogen bonds, which cage the palladium center. In solution 1-4 exist as a diastereoisomeric mixture (a racemic enantiomeric pair SNSN, RNRN and a mesomeric form RNSN) in a 1:1 molar ratio, and this ratio is independent of temperature in nonalcoholic solvents, When complexes 1-4 are dissolved in protic solvents (e.g. MeOH) the diastereomeric excess is temperature-dependent due to an exchange process between the meso diastereoisomer and the (racemic) enantiomeric pair. Thermodynamic parameters for this process in a mixture of MeOH-toluene have been determined with NMR and show this process to be influenced by the steric nature of the alkyl substituent (R) on nitrogen. A conformational analysis based on 1H-NMR coupling constants within the N,O-chelate ring of complexes 1-4 provides details on the solution structure of the ring in both diastereoisomers.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300106
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  • 26
    Digitale Medien
    Digitale Medien
    Synthesis of Functionalized Carbamates through a Palladium-Catalyzed Reductive Carbonylation of Substituted Nitrobenzenes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 13-22 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Carbamates ; Catalysis ; Substituted nitrobenzenes ; Palladium ; Reductive carbonylation ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The palladium-catalyzed reductive carbonylation of ortho and para-substituted nitrobenzenes has proven to be an attractive route for the synthesis of functionalized carbamates. For the Pd(1, 10-phenanthroline)2(triflate)2 catalyst system, the scope of the reaction has been studied. Substrates with electron-donating substituents at the para position were found to decrease the catalytic activity, most probably as a result of their relatively low oxidizing capacity. the selectivity towards the desired carbamate, however, was increased for these substrates. Under the influence of electron-withdrawing substituents the azoxybenzene and azobenzene derivatives became important side products. Introduction of large steric hindrance at the ortho position of the nitro substrates gave rise to an interesting side reaction, viz. methoxylation of the aromatic ring. The methoxylation reaction appeared to occur on an intermediate species in the catalytic cycle. Several functionalities have shown to be resistant to the reaction conditions required for the conversion ot the nitro group. Especially with 4-nitrobenzoic acid, an extremely high activity and selectivity was found, thus yielding a very convenient synthesis for N-protected amines containing carboxylic acid function.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300104
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  • 27
    Digitale Medien
    Digitale Medien
    Dimeric Silver(I) Complexes of Some Isothiazole-Based LigandsDedicated to Prof. Dr. Rolf Gleiter on the occasion of this 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 95-100 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Isothiazole complexes ; Dinuclear silver(I) complexes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A series of isothiazole-based potential ligands bearing substituents with additional donor sites in the 5-position of the heterocycle was synthesized [3-Me-5-R-C3HNS; R = CH=N(CH2)2py (1), CH=NCH2py (2), CH2N(CH2CH2NEt2)2 (4), (CH2)2SMe (5)]. Upon reaction with AgO3SCF3 they formed complexes [(1)AgOSO2CF3]2 (6), [(2)AgOSO2CF3]2 (7), [(4)Ag]2+2(O3SCF-3)2 (8) and [(5)AgOSO2CF3]2 (9), respectively. 6, 8 and 9 were shown by X-ray structural analyses to consist of dimeric units L2Ag2+2, either discrete (8), coordinated by terminal CF3SO-3 units (6). In 8 and 9 the isothiazole moiety is bonded to the metal center via the ring-N. The coordination potential of the isothiazole heterocycle is discussed.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300115
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  • 28
    Digitale Medien
    Digitale Medien
    Synthesis and Structure of Binuclear Single-Bridged Bis[(phosphane)gold(I)]halogenonium Complexes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 115-118 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Gold complexes ; Bromonium complex ; Halogenonium complex ; Halogen, two-coordinate ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Reactions of (R3P)AuX (X = Cl, Br, I) with [(R3P)Au]+ BF-4 obtained from (R3P)AuCl and AgBF4 in tetrahydrofuran, lead to cationic binuclear gold(I) complexes of the general formula ([(R3P)Au]2X}+ BF-4. A number of chloro- (R = Ph, o-Tol, Mes, Bzl, Et), bromo- (R = Ph, o-Tol, Mes) and iodo-bridged (R = Ph, Mes) complexes of this type have been isolated and identified on the basis of their analytical and spectroscopic data. The crystal structure of bis[(triphenylphosphane)gold(I)]bromonium tetrafluoroborate was determined by single-crystal X-ray diffraction. The cations contain two-coordinate bromine atoms with an Au-Br-Au angle of 96.83(3)°.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300119
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  • 29
    Digitale Medien
    Digitale Medien
    A Specific Route to Enantiomerically Pure Asymmetric (η6-Arene)(η4-1,5-cyclooctadiene)Ru(0) ComplexesDedicated to Professor Rolf Gleiter on the occassion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 123-130 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Arene complexes ; Ruthenium compounds ; Electrophilic substitution ; Lithiation ; Catalysis ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Chiral or achiral (arene)(COD)Ru complexes can be made by replacing the η6-ligands of (η4-1,5-COD)(η6-1,3,5-cyclooctatriene)Ru (1) or (η4-1,5-COD)(η6-naphthalene)Ru (2) by a suitable arene. This well known reaction has been extended to mono- and dibromoarenes and we report a novel route to substituted (arene)(COD)Ru species, utilizing (bromoarene)-(COD)Ru as starting materials. These facilitate a rapid bromine-lithium exchange reaction with nBuLi at low temperatures and the lithiated species react readily with alkyl chloroformates as electrophiles. By using chiral electrophiles [alkyl = (-)-menthyl] enantiomerically pure or diastereomeric complexes containing CO2R* groups are formed, depending on the symmetry of the original complex. A diastereomeric 1:1 mixture was separated by recrystallization. All (arene)-(COD)Ru complexes tested so far are useful as catalysts for the hydrogenation of simple alkenes at room temperature.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300121
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  • 30
    Digitale Medien
    Digitale Medien
    Recent Advances in C-F Bond Activation (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 145-154 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Fluorocarbons ; C-F bond activation ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The main reaction pathways which lead to the breaking of C-F bonds in perfluoroalkanes and -arenes are discussed. Emphasis is placed on recent developments and on the mechanistic patterns that emerge.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300203
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  • 31
    Digitale Medien
    Digitale Medien
    Metal Atoms in the Synthesis of Metal Clusters, VIII.On the Reaction of Sterically Demanding Cyclopentadiene Ligands with Cobalt Atoms: Synthesis, Crystal Structure, Spectroscopic Behavior, and Reactivity of Di-, Tri- and Tetranuclear Hydrido Clusters of CobaltDedicated to Professor IV Siehert on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 161-170 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The metal-vapor reactions of Co atoms with 1,3-tBu2CpH (1a), 1,3-tBu2CpH (1a), 1,2,4-tBu3CpH (1b) and EtMe4CpH (1c) are described. With 1a the two mononuclear complexes [(η5-tBu2Cp) (η4-tBu2-1,3-cyclopentadiene)Co] (2a) and [(η5-tBu2Cp)2Co] (3a) were isolated, together with the dinuclear cobalt cluster [{(η5-tBu2Cp)Co}2H3] (4a) and trace amounts of the tetranuclear cluster [{(η5-tBu2Cp)CoH}4] (5a). The molecular structures of 3a and 4a were determined by X-ray diffraction. Reaction of 1b with Co atoms afforded a single product, the dinuclear cluster [{(η5-tBu3Cp)Co}2H3] (4b), whose molecular structure was determined by single-crystal X-ray diffraction. Both, 4a and 4b exhibit extremely short Co-Co distances [2.244(1) (4a) and 2.242(1) Å (4b)], as found for the Me5Cp analog [{(η5-Me5Cp)Co}2H3] (4c). Reaction of an isomeric mixture of Me4EtCpH (1c) with Co atoms furnished the mononuclear sandwich [ (η5-Me4EtCp)(η4-Me4Et-1,3- cyclopentadiene)Co] (2b), the trinuclear hydridocobalt cluster [{(η5-Me4EtCp)Co}3H4] (6a) and the tetranuclear hydridocobalt cluster [{(η5-Me4EtCp)Co}4H4] (5c). The molecular structure of 5c was determined by X-ray crystallography and revealed a tetrahedral arrangement of the cobalt atoms. The electrochemical behavior of the dinuclear complexes 4a-4c was studied by cyclic voltammetry. Reversible redox couples were found for all three compounds, with a correlation between the degree of alkyl substitution and their respective cathodic shifts. Compounds 4a and 4b react with CO to yield the mononuclear and dinuclear complexes [ (η5- CpR)Co(CO)2] (R=1,3-tBu2, 1,2,4-tBu3) (7a and 7b) as well as [{(η5-CpR)CO}2(CO)2] (8a and 8b). Reaction of the trinuclear hydridocobalt cluster 6a and its Me5Cp analog 6b with AgBF4 in the presence of PEt3 yielded the heteronuclear clusters [{η5-Me4CPR)Co}3AgP(Et)3H4]+[BF4]- (R=Et, Me) (9a and 9b). 9a was structurally characterized by X-ray crystallography.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300205
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  • 32
    Digitale Medien
    Digitale Medien
    Generation and Synthetic Application of Metallated Methyl Isopropenyl Ether, A Substitute for Acetone Enolate (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 45-48 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Metallated methyl isopropenyl ether ; Tetrahydrofurans ; 1-Oxabicyclo[4.3.0]heptanes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Methyl isopropenyl ether (1) has been metallated at low temperature with a 1:1 molar mixture of n-BuLi/t-BuOK in THF-hexane, and subsequently functionalized with a variety of electrophilic reagents. At temperatures higher than - 30°C, the metallated methyl isopropenyl ether (2) decomposes with formation of allene. When the suspension of 2 is allowed to warm up to room temperature in the presence of an additional equivalent of n-BuLi, the intermediary allene is converted into 1-propynyllithium (2c), which reacts with propylthiocyanate to give 1-propylthio-1-propyne (4). Some of the functionalization products were subjected to acidic hydrolysis affording the expected methyl ketones.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300107
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  • 33
    Digitale Medien
    Digitale Medien
    Asymmetric Catalysis, 105Part 104: Ref.. Stereoselective Hydrogenation of Folic Acid with Immobilized Optically Active Rhodium(I)/Diphosphane Catalysts (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 55-62 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Diastereoselective hydrogenation ; Folic acid ; Immobilized optically active rhodium(I)/diphosphane catalysts ; Leucovorin ; HPLC analysis of 5-formyltetrahydrofolic acid derivatives ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: For the hydrogenation of the C=N bonds in the pyrazine ring of the vitamin folic acid (1) optically active rhodium(I)/diphosphane complexes immobilized on supports such as silica gel or Al2O3 were used. The reduction was carried out at 50 bar hydrogen pressure in an aqueous solution buffered to pH 7. Thus, 5,6,7,8-tetrahydrofolic acid (2) was obtained which contains a new asymmetric center at C-6 of the pterine system. Therefore, in combination with the (S) configuration of the natural L-glutamic acid part of the molecule two diastereomers with (6S,S) and (6R,S) configuration arise. The relatively unstable tetrahydrofolic acid (2) was converted into its 5-formyl derivative folinic acid (4) by treatment with methyl formate/formic acid in a 5:1 mixture of DMSO/pyridine. The Ca salt of folinic acid (4) is the widely used drug leucovorin. The diastereomers were separated by silica gel HPLC. To the column bovine serum albumine (BSA) is covalently bound. With optically active rhodium(I)/diphosphane catalysts, immobilized on silica gel supports, a diastereoselectivity of up to 90% could be achieved in the hydrogenation of folic acid (1).
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300109
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  • 34
    Digitale Medien
    Digitale Medien
    Hexahydro-closo-hexaborane as a Ligand in Coordination Compounds: Syntheses and Crystal Structures of [M2(μ-bis-η3-B6H6)(PPh3)2] )M = Cu, Au) (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 405-408 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Hexahydro-closo-hexaborates ; Boron ; Bridging ligands ; NMR spectroscopy ; Gold ; Copper ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: By reaction of (PPh3)3 CuCl and PPh3AuCl with [B6H6]2- in organic media, dinuclear complexes are formed containing the hexaborate as a bridging ligand coordinated to the metal centers by opposite B3 facets of the B6 cluster in a trihapto mode. This is verified by single-crystal X-ray structural analysis of the isotypical (Paā) compounds [Cu2μ-bis-η3-B6H6)(PPh3)2] (1) and [Au2(μ-bis-η3-B6H6)(PPh3)2)] (2) which showed the metal centers to be very close to the B3 plane [1.92 (1), 2.10 (2) Å. The 11B NMR spectra of the two compounds feature doublets, at δ= -15.32 in 1 and at -11.51 in 2, which are significantly shifted downfield in comparison to [B6H6]2- (δ= -17.2).
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300315
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  • 35
    Digitale Medien
    Digitale Medien
    Crown Thioether Chemistry: Novel Silver(I) Complexes of 1,3-Dithiole-Annelated 1,4,7-Trithiacyclononane (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 425-429 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Silver complexes ; Crown compounds ; Thioethers ; 1,3-Dithioles ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The coordination chemistry of two crown thioethers 2,5,8,10,12-pentathiabicyclo[7.3.0]dodeca-1)9)-ene-11-thione (L) and -11-one (L') with Ag1 has been investigated by structural methods. Both thioethers act as tridentate ligands coordinating the silver ion in a trigonal fashion. In the case L, the 11- thione sulfur is coordinated additionally by another silver ion, to yield a polymeric chain with a distorted-tetrahedral geometry about the metal ion. Despite differing only in its carbonyl chalcogen, L' forms six-coordinated, monomeric complexes.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300319
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  • 36
    Digitale Medien
    Digitale Medien
    Unsymmetric Dinucleating Ligands for Metallobiosite Modelling (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 433-442 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Metallobiosites ; Metalloproteins ; Metalloenzymes ; Dinucleating ligands ; Transition metals ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Awareness of the asymmetric nature of numerous dinuclear metallobiosites and of the ability of the individual metal ions to have quite distinct roles in the functioning of the metalloenzyme concerned has led to a search for carefully designed unsymmetric dinucleating ligands that will give dinuclear complexes capable of acting as models for the metallobiosites. This review surveys progress made in the design and synthesis of complexes capable of serving as models for donor atom, coordination number and geometric asymmetries found at dinuclear metal centres.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300402
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  • 37
    Digitale Medien
    Digitale Medien
    Chemie polyfunktioneller Moleküle, 125Part 124: Ref. Synthese und Kristallstruktur von N,N,N′,N“,N-Pentamethyl-diethylentriamin-cokoordiniertem Kalium-bis(diphenylphosphanyl)amidHerrn Prof. Dr. Gerhard Herberich zum 60. Geburtstage gewidmet. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 141-144 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Alkali metal organophosphanylamide ; Carbon-potassium bonding ; Phosphazane ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The metalation of bis(diphenylphosphanyl)amine [HN-(PPh2)2,1 with KOtBu at 95°C in toluene affords a pale yellow precipitate of potassium bis(diphenylphosphanyl)amide (3a). On addition of liquid N,N,N′,N“,N“-pentamethyldiethylenetriamine (PMDTA, 4) the precipitate dissolves in toluene at 115°C to give a yellow solution, from which yellow-green blocks of [(Ph2P)2NK·PMDTA] (3b) are obtained. X-ray analysis reveals that the coordination sphere of potassium consists of the chelating triamine ligand and [N(PPh2)2]- as N-donor as well as η1 and η2 C-donor with two phenyl fragments. No phosphorus coordination of [N(PPh2)2]- is observed.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300124
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  • 38
    Digitale Medien
    Digitale Medien
    Organophosphorus Compounds, 114. Tetracyclic Phosphorus-Aluminium-Carbon Compounds - Synthesis by Cooligomerization of Kinetically Stabilized Phosphaalkynes with Trialkylaluminium CompoundsDedicated to Professor Michael Hanack on the occasion of his 65th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 255-259 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Phosphaalkynes ; Triorganoaluminium compounds ; Cooligomerization ; Cage compounds ; Aluminium compounds ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: When the trialkylaluminium reagents 5 are allowed to react with phosphaalkynes 4 in n-pentane, a highly selective phosphaalkyne cyclotrimerization with incorporation of two organometallic units occurs (→ 6). The tetracyclooctane derivatives 6a-e represent the first examples of phosphorus-aluminium-carbon cage compounds. The polycyclic products 6 are able to function as ligands in transition-metal complexes (→ 7), which is illustrated by the reactions of 6b, c with nonacarbonyldiiron and pentacarbonyl(tetrahydrofuran)tungsten, respectively.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300219
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  • 39
    Digitale Medien
    Digitale Medien
    On the Ligating Properties of Sulfonate and Perchlorate Anions Towards Zinc (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 283-289 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Zinc ; Sulfonate ligands ; Perchlorates ; Coordination modes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Attempts are reported to incorporate sulfonate and perchlorate anions as ligands in zinc complexes of tripodal ligands. Using tris(benzimidazolylmethyl)amine (BIMA) only the aqua complexes [ (BIMA)Zn-OH2](RSO3)(ClO4) and [(BIMA)Zn-OH2](RSO3)2(R=CH3, CF3, p-tolyl) were accessible. Using substituted pyrazolylborates (Tp*), the same three sulfonate anions were found to be ligands in the complexes Tp*Zn-OSO2R. Spectroscopic evidence for perchlorate coordination in Tp*ZnClO4 · 2 DMSO conflicts with crystallograpic evidence against it in Tp*ZnClO4 · pyridine. The crystal structures of [(BIMA)Zn-OH2](CH3SO3)2, TpCum,MeZn-OS02CH3, TPtBu,MeZn-OSO2C6H4-p-CH3, and [TpCum,MeZn · NC5H5]ClO4 were determined.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300223
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  • 40
    Digitale Medien
    Digitale Medien
    Multiple Bonds Between Main-Group Elements and Transition Metals, CLXIV. Alkylrhenium(VI) Oxides-Synthesis and Characterization (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 295-298 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Rhenium ; Oxides ; Alkyl ligands ; Dirhenium compounds ; Metal-metal interactions ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Most alkylrhenium(VII) oxides, e.g. ((cyclo)-C3H5)Re03 (2) are rather sensitive to temperature and moisture with the prominent exception of methyltrioxorhenium (1). The corresponding alkylrhenium(VI) oxides of formula [RR′(O)- Re(μ-O)]2 [R=R′=(cyclo)-C3H5 (3), iPr (4); R=CH3, R′=C2H5 (5), R=CH3, R′=iPr (6)] are much more stable in this regard. They can be handled in air at room temperature. They were synthesized from Re207 and dialkylzinc precursors, fully characterized and are available in much higher yields than their ReVII congeners. Mixed tetraalkyltetraoxodirhenium(VI) complexes (R # R′) synthesized from 1 and dialkylzinc compounds form as a mixture of cis/trans isomers. They are oily liquids at room temperature. The Re=O and Re-Re stretching force constants as a measure of the bond strengths, were determined from IR and Raman data.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300225
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  • 41
    Digitale Medien
    Digitale Medien
    Hydroxy- and Carboxy-Substituted Allylsilanes: A Simple and Stereoselective Method of Preparation (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 335-340 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Allylsilanes ; Superbases ; Metalations ; Stereoselectivity ; Cyclizations ; Silicon ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: When treated with two equivalents of a butyllithium/potassium tert-butoxide mixture, terminal olefins carrying unprotected hydroxy or carboxy groups generate allylmetal intermediates which can be trapped with chlorotrimethylsilane to afford functionalized (Z)-2-alkenyltrimethylsilanes. One equivalent of the superbasic reagent suffices if the unsaturated alcohols are first protected as acetals before being subjected to the metalation/silylation/hydrolysis sequence.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300306
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  • 42
    Digitale Medien
    Digitale Medien
    Preparation, Properties, and Reactions, of Metal-Containing Heterocycles, XCVIPart XCV: E. Lindner, E. Bosch, R. Fawzi, M. Steimann, H.A. Mayer, K. Gierling, Chem. Ber. 1996, 129, 945-951.. Mono-, Di- and Trinuclear Metallacycloalkanes of the Iron-TriadDedicated to Professor Wolfgang Beck on the occasion of his 65th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 347-356 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Metallacycloalkanes ; Metallacycloalkenes ; Osmium ; Iron ; Cyclic ketones ; Metallacycles ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reaction of the bis(triflates) [F3CSO3-(CH)m-O3SCF3] [m = 5-10, 12, 14, 16 (1a-i) with Na2[Os(CO)4] in dimethyl either affords the osmacycloalkanes 2a, 2b and 2f-i (m = 5, 6, 10, 12, 14, 16), diosmacycloalkanes 3a-i (m = 5-10, 12, 14, 16), and triosmacycloalkanes 4a-i (m = 5-10, 12, 14, 16). The structure of 3f was investigated by an X-ray structural analysis. This 22-membered disomacycle crystallizes in the space group Pā with Z = 1. If the unsaturated cis-4-octen-1,8-diyl bis(trifluoromethanesulfonate) (5) is treated with Na2[Os(CO)4] the diosmacyclooctadeca-5,14-diene 6 is obtained. By treating the bis(triflates) 1a, b with Na2[Fe(CO)4] the corresponding ferracycloalkanes are formed only in situ. Insertion of carbon monoxide into the M-C σ bonds leads to the cyclic ketones 7a, d and to the diketone 8d.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300308
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  • 43
    Digitale Medien
    Digitale Medien
    Enantioselective Catalysis, XIIIPart XII: U. Nagel, J. Leipold, Chem. Ber., 1996, 129815-821.. Preparative and Structural Chemistry of Chiral 3-(Diphenylphosphanyl)-pyrrolidiens and Their Palladium(II) Complexes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 385-398 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Pyrrolidinephosphanes ; 3-Hydroxypyrrolidine ; 3-Diphenylphosphanylpyronlidine ; Salt effects ; Polymorphism ; Homogeneous catalysis ; Palladium ; Asymmetric catalysis ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The preparation of both enantiomers of 3-diphenylphosphanulpyrrolidiine (2) and several N-substituted derivatives together with two PdIi complexes of this ligand is reported. Form L-malic acid and L-hydroxyproline both enantiomers of 3-hydroxypyrrolidine are prepared without any problems due to epimerization. KPPh2 in the presence of LiCl is shown to be the most effective reagent for the synthesis of 2. The reported X-ray structure determination sof Pdl2 complexes show a rather rigid bicyclic hetero-norbornane skeleton. The flexibility of the other parts of the molecules is obvious in several polymorphs revealed by this method. This polymorphism is additionally investigated by a 31P-CP-MAS study. From solution 1-, 13C- and 31P-NMR studies it is concluded that the bicyclic hetero-norbornane skeleton is retained in solution.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300313
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  • 44
    Digitale Medien
    Digitale Medien
    Reactions of Silicon-Silicon Bonds, VIFor part V, see ref.[1].. Reductive Trichloroslilylation Reactions Leading to Alkyl- and Dialkylaminobis(trichlorosilyl)phosphanesDedicated to Professor Walter Siebert on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 377-384 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Trichlorosilylation ; Dichlorophosphanes ; Silylphosphanes ; Amino(silyl)phosphanes ; Silicon /Reductions ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Reactions of hexachlorodisilane and of trichlorosilane/triethylamine with alkyl-and dialkylaminodichlorophosphanes RPCl2 1a-i [R = iPr: a; (Me3Si)2CH: b; R=1-adamantly: c: R=tBu: d; R=Et2N: e; R=iPr2M: f] furnish bis(trichlorosilyl)-phosphanes RP(SiCl3)2 3a-f. However, when less bulky substituents are attached to the phosphorus atom, so that there is little steric crowding, the double reductive silylations leading from 1 to 3 are accompanied by side reactions and decomposition of 3. Therefore, only 3b, 3c, 3d, and 3f wre isolated in a pure state. These compounds are more readily prepared by the; trichlorosilane/triethylamine method. 1H-, 31P- and 29Si-Nmr spectra confirm their constitution. The structure of solid 3f, the first aminobis(trichlorosilyl)phosphane, was determined by X-ray crystallography. 3f contains a phosphorus atom in a pyramidal environment surrounded by two silicon atoms and a planar nitrogen atom of the diisopropylamino group.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300312
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  • 45
    Digitale Medien
    Digitale Medien
    Formation of the Digallium Compound [(C5C6)2N3](R)Ga-Ga(R)[N3(C6H5)2] with Two Bis(trimethylsilyl)methyl Groups and Two Terminal Chelating Diphenyltriazenido Ligands (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 417-420 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Gallium ; Low-valent compounds ; Gallium-gallium bond ; Terminal triphenytriazenido ligand ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Tetrakis[bis(trimethylsilyl)methyl]digallane (4) 1 reacts with 1,3-diphenyltriazene to yield two compounds, which were both characterized by a crystal structure determination. The gallium-gallium bond is retained in the yellow derivate [(H5C6)2N3](R)Ga-Ga(R)[N3(C6H5)2 2 [R = CH(SiMe3)2], which is formed by a ligand exchange reaction and shows two terminal chelating triazenido ligands besides two bis(trimethylsilyl)methyl groups; the Ga—Ga bond length is 245.79(6) pm. The second product is the orange dialkyl(diphenyltriazenido)gallium derivative R2Ga[N3(C6H5)2] 3, where the triazene has reacted as an oxidant by the cleavage of the Ga—Ga bond and probably by release of elemental hydrogen.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300317
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  • 46
    Digitale Medien
    Digitale Medien
    The Electronic Structure of [Te15Br4][MoOBr4]2 and Some General Aspects of Bonding in “Classical” and Hypervalent Tellurium Halides (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 463-472 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Hypervalent compounds ; Tellurium ; Polycations ; Molecular Orbital Theory ; Band structure ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Approximate MO and band structure calculation are used to analyze the bonding in the recently synthesized paramagnetic, semiconducting phase [Te15Br4]2+. The [Te15Br4]2+ chains are very similar to those in the tellurium subhalide Te2Br. The electronic structure and bonding within these chains is analysed and the possibility of hypervalency in both [Te15Br4][MoOBr4]2 and Te2Br is discussed. The bonding in the classically hypervalent molecule TeBr42- and a model Te3Br24- is compared to that of the infinite system. Our calculations indicate that both [Te15Br4][MoOBr4]2 and Te2Br contain weakly hypervalent Te atoms and that the interesting electronic properties of [Te15Br4][MoOBr4]2 arise within the distinct sublattices, which do not interact significantly.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300405
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  • 47
    Digitale Medien
    Digitale Medien
    Heterobimetallic Complexes with a Propynylidene C3-Bridge: General Synthetic Routes to Bimetallic Ethynylcarbene Complexes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 479-488 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Heterobimetallic complexes ; Carbene complexes ; Alkynes ; Coupling reaction ; Bridging ligands ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Sequential reaction of the dimethylamino(trimethylsilylethylnyl)carbene complexes [(CO)5M'=C(NMe2)C≡CSiMe3] [M' = W (1a)] with KF/THFMeOH, nBuLi and transition metal halides, [XMLn], affords heterobimetallic propynyliden complexes of the type [(CO)5M'=C(N-Me2)C≡CMLn] [MLn = Ni(PPh3) Cp (4a, b). Ni(PMe2Ph)2- {Mes) (Mes=2,4,6-C6H2Me3) (5a), Rh(CO)(PPh3)2 (6a), Fe(CO)2Cp (7a,b)]. In contrast, reaction of 1a with MeLi · LiBr and [IFe(CO)2Cp] yields the novel N-metallated complex [(CO)5W=C{N(ME)Fe(CO)2Cp}C≡CSiMe3] (8a). The complexes [(CO)5M'=C(NMe2)C≡CMLn=Fe(CO)2Cp (7a, b), Ru(CO)2Cp (10a,b), Ru(CO)(PPh3)Cp (11a), Mn(CO)5 (12a), Re(CO)5 (13a)] are accessible by Pd-catalyzed coupling of the C-stannylated carbene complexes [(CO)5M'=C-(NMe2)C≡CSnBu3] (9a, b) with [XMLn]. The related monomethylaminocarbene complexes [(CO)5M'=C(NHMe)C≡ CSnBu3] (16a, b), obtained by stannylation of [(C))5M'=C(NHMe)C=CH] (15a, B) with Bu3SnNEt2, react with [IFe(CO)2Cp] to give the bimetallic complexes [(CO)5M'=C(NHMe)C≡CFe(CO)2Cp] (17a, b). The complexes 4a, 5a, 7a and 10a were characterized by X-ray structural analysis. The spectroscopic and structural data suggest that the two metal centers in 4-7, 10-13, and 17 interact only weakly.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300407
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  • 48
    Digitale Medien
    Digitale Medien
    Synthesis and Molecular Structure of a Rhenium Complex Derived from 8a-Amino-6-methyl-ergolineDedicated to Professor Roland Mayer on the occasion of his 70th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 839-841 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Rhenium ; Technetium ; 8a-Amino-6-methyl-ergoline ; Chelates ; Structure elucidation ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Current research in radiopharmaceutical chemistry is aimed at the design of technetium-based receptor-binding radiotracers because of the excellent nuclide properties of the isotope 99mTc. Tc tracers and the corresponding complexes of rhenium, as the inactive surrogate of Tc, are required to imitate organic agonists or antagonists of the receptor. We have started studies with ergolines, which are known to be dopamine substitutes. The present report deals with the functionalization of 8α-amino-6-methyl-ergoline (2) with a 2-mercaptoacetyl group, and the subsequent synthesis of the first rhenium complex containing a pendent ergoline moiety [Re- O(SSS)(RS)] (HSSSH = HS-CH2CH2-S-CH2CH2-SH and RSH = 8a-amino-N-(2-mercaptoacetyl)-6-methyl-ergoline) (4). The molecular structure of the rhenium complex was determined by X-ray crystal structure analysis.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300705
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  • 49
    Digitale Medien
    Digitale Medien
    Aminotroponimines as Ligands for Yttrium and Lanthanide Complexes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 859-862 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Yttrium ; Lanthanum ; Samarium ; Lanthanides ; Aminotroponiminate ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reaction of N-isopropyl-2-(isopropylamino)troponimine, [(i-Pr)2ATI]H, with KH in THF affords [(i-Pr)2ATI]K. This is a useful starting material for the preparation of the mono-, bis- and tris-substituted compounds [[i-Pr)2ATI]YCl2-(THF)2}2, [(i-Pr)2ATI2Y[O(2,6,t-Bu2C6H3)] and [(i-Pr)2-ATI]3Ln (Ln = Y, La, Sm), which can be obtained from ([i-Pr)2ATI]K and LnX3 and LnX3 (X = Cl, I), or Y[O(2,6-t-BuC6H3)]3. All compounds have been characterized by spectroscopic methods. The monosubstituted yttrium complex {[(i-Pr)2ATI]YCl2(THF)2}2 has also been investigated by single crystal X-ray diffraction.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300708
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  • 50
    Digitale Medien
    Digitale Medien
    C-H Bond Activation of Simple Alkenes with (C5H5)CO Fragments: Preparation, Molecular Structure, and Dynamical Behaviour of Tri- and Tetranuclear Cyclopentadienylcobalt Cluster complexes with μ-Cycloalkyne Ligands (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 593-603 
    Details
    ISSN: 0009-2940
    Schlagwort(e): C-H activation ; Alkyne complexes ; Cyclopentadienyl cobalt ; Fluxionality ; Hydrido complexes ; Clusters ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Vicinal C-H bonds of the cycloalkenes CnH2n (n = 5-8) were activated upon treatment under mild conditions with reactive sources of the (C5H5)CO fragment. With [C5H5)CO(C2H4)2] (2a), the trinuclear cluster complexes [H2((C5H5)CO)3(μ3-C2(CH2)n-2)] (5a: n = 5; 5c: n = 5d: n = 8) were formed. Using the more reactive [(C5H5)2Co]/K, 5a-5dwere obtained, along with small amounts of the tetranuclear [{(C5H5)CO}4r{μ4-C2(CH2)n-2}] (8a-c: n = 5-7). X-ray structure analyses of 5c, d and 8b, c were performed. A μ-‖ (orμ3-η1:η2:η1) coordination of the cycloalkyne ligands was found in the trinuclear cluster complexes. The tetranuclear 8b, c had the cycloalkynes quadruply bridging (μ4-η1:η2:η2:η1_ a butterfly arrangement of the metal atoms. The acetylenic carbon-carbon bonds are considerably lengthened upon coordination [1.392(4), 1.398(3) å in 5c d; 1.464(8), 1.499(5) Å in 8b, c]. Three dynamic processes - alkyne “walk” on top of the CO3 triangle, μ2-hydride migration, and μ2/μ3-hydride exchange - are operational in the trinuclear 5a-d. Dynamic NMR data for 5a are consistent with a “windshield-wiper” mechanism for the alkyne migration. Hydride exchange is associated with a higher energy barrier, and is probably and independent dynamic process.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300510
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  • 51
    Digitale Medien
    Digitale Medien
    Organoamido- and Aryloxolanthanoids, 15Part 14: Ref. [1a].. Organometallic Compounds of the Lanthanoids, 116Part 115: Ref. [1b].. Syntheses of Low Coordination Number Divalent Lanthanoid Organoamide Complexes, and the X-ray Crystal Structures of Bis[(N-2,6-diisopropylphenyl)(N-trimethylsilyl)amido]bi(tetrahydrofuran)samarium(II)and -ytterbium(II) (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 409-415 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Mercury ; Lanthanides ; Lanthanoid(II) complexes ; (N-2,6-Diisopropylphenyl)(N-trimethylsily)amide complexes ; Bis(trimethylsilyl)amide complexes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The Mercury(II) amide complex Hg[N(SiMe3)(2,6-iPr2C6H3)]2 (1) was prepared by reaction of HgBr2 with Li[N(SiMe3) 2,6-iPr2C6H3)] in diethyl ether solvent. Redox transmetallation reactions of 1 with elemental samarium, europium or ytterbium in THF solvent (THF = tetrahydrofuran), generated the novel divalent complexes Ln[N(SiMe3)(2,6-iPr2C6H3]2(THF)2 with Ln = Sm (2), Eu (3) and Yb (4). 4 was also synthesized by reaction of elemental ytterbium, HgPh2 and HN(SiMe3)(2,6-Me3)2]2(THF)2 [Ln = Sm (5), Yb (6)] by reaction of the metals with HgPh2 and HN(SiMe3)2. Thermal desolvation of 4 under high vacuum gave Yb(N)(SiMe3)2,6-iPr2C6H3)]2 (THF) (7), whereas under identical conditions 6 yielded the solvent-free complex [Yb[N{SiMe3)2]2]2. (8). The new compounds 1-4 and 7 are hydrocarbon soluble and 171Yb-NMR spectra were recorded for 4, 6, 7 and 8. X-ray crystal structure determinations of 2 and 4 revealed four-coordinate, distorted tetrahedral metal environments augmented by weak Ln…ipso-C(aryl) interactions.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300316
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  • 52
    Digitale Medien
    Digitale Medien
    Synthesis and Structure of 2,2′ -Boryl-, Germyl-Silyl-, and Stannyl-Substituted 1,1′ -Binaphthyl SystemsDedicated to Professor Hans Paulsen on the occasion of his 75th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 923-932 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Biaryls ; Boron ; Chirality ; Cooperative Effects ; Lewis acids ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A number of Lewis acid binaphthyl systems, substituted in 2-or 2,2′-position, are synthesized by lithiation of 2,2′-dibromo-1,l ′-binaphthyl (5), followed by addition of various electrophiles. Stepwise lithiation and subsequent borylation with trimethyl borate leads to the bromoboronic acid 6, which can be stabilized by esterification with pinacol giving 7. By increasing the reaction mixture to 2 equiv. of n-butyllithium and 2 equiv. of methyl borate the path to the binaphthylmonoboronic acid ester 9 is opened up. A further increase in the quantity of electrophile also leads to the binaphthylbisboronic acid ester 12. The 2,2′-disubstituted silyl, germyl, and stannyl derivatives 13a-15a are accessible in good yields. Treatment with boron halides leads exclusively to methyl/halogen exchange, giving the bidentate Lewis acids 13b-15b, the former of which can be bridged by oxygen.Only in case of the bis(tributylstannyl)binaphthyl 16a does ipso substitution occur in the presence of boron trichloride, giving the bis(dichloroboryl)-substituted binaphthyl 16b which can then be hydrolysed to 11. The structures of the majority of the compounds were investigated by X-ray diffraction. In case of the 2,2′-disubstituted compounds 13a-15a the naphthyl groups are orientated perpendicular to each other. The intra- and intermolecular interactions are dominated by this binaphthyl system. In case of the oxygenbridged compounds 13c and 14c the angle between the naphthyl planes decreases to about 70°. This also has an effect on the packing of the molecule; in this instance the orientation of two naphthyl in neighbouring molecules is nearly parallel. The structure of the diboronic acid is dominated by intra- and intermolecular hydrogen bonding.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300718
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  • 53
    Digitale Medien
    Digitale Medien
    Temperature-dependent Ring-Opening and -Closure of a Cyclic Phosphane-BoraneDedicated to Professor Gottfried Huttner on the occasion of his 65th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 951-954 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Phosphane-boranes ; Medium-sized rings ; Ring opening and closure ; Temperature-dependent NMR studies ; Phosphorus ; Boron ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A phosphane-borane (3) with the P-B bond integrated into a seven-membered ring was prepared from 4-pentenyl-diphenylphosphane (4) by hydroboration using 9-borabicyclononane (9-BBN). The product was confirmed to have a ring structure in the solid state by single crystal X-ray diffraction. The P-B distance of 2.057(2) Å is indicative of a standard donor-acceptor bond similar to the type found in homologous five- and six-membered rings. The room-temperature 31P-NMR signal of the compound in various solvents (δ ≈ - 15) is not compatible with the cyclic structure and suggests that ring opening occurs as the compound is dissolved. Variable-temperature NMR work corroborated this assumption, and the enthalpy of ring closure was determined to be ΔH = -30.5(4) kJmol-l. In CD2C12 at -90°C, δ31P is shifted to +3.5 ppm to low field, suggesting virtually complete ring closure under these conditions.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300722
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  • 54
    Digitale Medien
    Digitale Medien
    The Coordination Chemistry of Fluorocarbons: Group-I and Group- II Metal Ion Complexes of Fluoro Macrocycles (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 963-968 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Fluorine ; Macrocycles ; Complexes ; Sodium ; Barium ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Two new fluoro macrocycles BenzoFN2O3 and F(N2O2)2C2H4 were synthesized in the reactions of 1,3-bis(bromomethyl)-2-fluorobenzene with benzo-diaza-15-crown-5 and 1,2-bis(diaza-12-crown-4)ethane, respectively, in 30% yield each. Close CF...metal ion interactions in the respective alkaline metal complexes in solution are evidenced by characteristic shifts of the 19F-NMR resonances of up to δ = 18.7 relative to the free ligand and by a decrease of the 1J(CF) coupling constant of up to 20 Hz, which is most pronounced in BenzoFN2O3 · Li+ and F(N2O2)2C2H4 · K+. In BenzoFN2O3· Li+ a1J(19F-7Li) of 15.5 Hz was observed, which is indicative very close CF...Li+ interactions in solution. In the X-ray crystal structures of BenzoFN2O3 · Na+ [CF⃛Na+ 246.8(2) pm], 26-fluoro-4,7,13,16-tetraoxa-1, 10-diazatricyclo[ 8.8.7.1 20,24 ] - hexacosa-20,22,24(26)triene · Na+ (CF⃛Na+ 267.1(2) pm) and 21 -fluoro-3,6,9,12,15,18-hexaoxabicyclo[ 18.3.1 1,20]heneicosa- l(24),20,22-triene. Ba2+ [CF⃛Ba2+ 299.0(3) pm] short CF⃛metal interactions were found. Such close CF⃛metal ion interactions do not result in a lengthening of the C-F bonds, which is not a sign of weak CF⃛metal ion interactions, since a Cambridge Structural Database search revealed that a shortening of the C-O bond length is also not observed in crown ether complexes of alkaline metals.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300725
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  • 55
    Digitale Medien
    Digitale Medien
    Organophosphorus Compounds, 118Part 2: 117: Ref1. Reactions of 1-Chloro-1H-phosphirenes with Nucleophiles (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 711-723 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Phosphorus heterocycles ; 1H-Phosphirenes ; Nucleophilic substitution reactions at 1H-phosphirenes ; Metal-complexation of functionalized 1H-phosphirenes ; Carbonyl complexes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The halogen atoms in the 1-chloro-1H-phosphirenes, 5a-c, are easily substituted on reaction with organolithium and Grignard reagents, 14a-p, with formation of the corresponding O-, N-, C-, Si-, and Ge-substituted 1H-phosphirenes, 15a-t. C1/H exchange reactions also occur on reaction with lithium metal hydrides (5a → 17). Furthermore, substitution reactions are also realized with the alkali metal borates, 18a-g (→19a-g); the same is true for reactions with trimethylsilyl cyanide and azide (→22a-d). Some of the substitution products have been characterized in the form of their metal complexes, 16, 23, 24, and 25.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300607
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  • 56
    Digitale Medien
    Digitale Medien
    Synthesis of Germatranyl Derivatives of Esters of Carboxylic Acids via Organometallic (Si, Ge, Sn) Reagents (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 739-746 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Germatranes ; Organotrihalogenogermanes ; Organometallic (Si, Ge, Sn) reagents ; Transmetallation ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Trialkylstannyl esters of tris(2-hydroxyalkyl)amines, N(CH2CHROSnAlk3)3 (9-11 (R = H, Me; Alk = Et, Bu), react with X3GeC(R1)(R2)COOR3 (12-17) (X = Cl or Br; R1, R2=H, Me, Ph, SiMe3, COOEt; R3=Me, Et) to give esters of α-germatranylcarboxylic acids, N(CH2CHRO)3GeC(R1)(R2)-COOR3 (1-8), in high yields. The synthesis of esters 12-17 is reported. Esters of α-germatranyldiphenylacetic acid 24 and 25 can be obtained by treatment of diphenylketene with Et3SnOMe to give in situ Et3SnC(Ph2)COOMe (23), followed by reaction with GeCl4 to give in situ Cl3GeC(Ph2)COOMe (22 and further reactions with 9 or 11, respectively. Reduction of germatrane 6 with LiAlH4 in diethyl ether leads to cleavage of the germanium-carbon bond with subsequent formation of (2-hydroxyethyl)trimethylsilane. The crystal structures of 3, 6 and 7 are reported. 1-Acyloxygermatranes 26 and 27 are obtained by treatment of 1-methoxygermatrane (28) with diphenyl- and dichloroacetic acid, respectively.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300611
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  • 57
    Digitale Medien
    Digitale Medien
    Base-Induced Synthesis of a Tetrastannatriazabicyclo[3.1.1]heptane from Tris)dimethylchlorostannyl)amineDedicated to Professor W. Sieber on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 765-769 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Tin - Nitrogen cage compounds ; Sn—X—Sn intramolecular bridges ; Distannylamine pyridine adduct ; Tin ; Moessbauer spectroscopy ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Tris(dimethylchlorostannyl)amine (2a) reacts with pyridine in a 3:4 molar ratio to produce the tin-nitrogen containing bicyclo[3.1.1]heptane (3) with elimination of the adduct Me2SnCl2·2 py. Treatment of the distannylamine 2,6-[Pr2H3N(SnMe2Cl)2 (4) with pyridine, however, leads to the formation of the 1:1 pyridine adduct 4 and this can be regarded as a model to explain the route to 3. The molecular structures of 3 and 5 were determined by multinuclear magnetic resonance spectroscopy in solution, as well as by X-ray structure analysis of their crystals. Typical structural features for both compounds are intramolecular Sn—X—Sn bridges. Support for the structures comes from MS fragmentation patterns, IR spectra, and the Mössbauer spectra.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300615
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  • 58
    Digitale Medien
    Digitale Medien
    Thermal Reactions of 5-Alkylidene-4,5-dihydro-3H-1,2,4(λ3)-diazaphospholes (4-Phosphapyrazolines) - A Route to Various P—Heterocycles and to 2-PhosphabutadienesDedicated to Professor M. Hanack on the occasion of his 65th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 779-788 
    Details
    ISSN: 0009-2940
    Schlagwort(e): 1,2,4-Diazaphospholes ; Phosphiranes, alkylidene- ; 2-Phosphabutadienes ; Phosphorus heterocycles ; pyrazolines, thermolysis ; Rearrangements ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The 5-alkylidene-4,5-dihydro-3H-1,2,4(λ3)-diazaphospholes (4-phosphapyrazolines) are thermally much more stable than related compounds without the exocyclic double bond. Thermolysis reactions typically occur in the range 110-150°C in toluene solution, and different, mostly competing, reaction pathways are observed. Thermal extrusion of nitrogen from 8a-g gives rise to β-phosphanaylsiloxyalkenes 10, benzo[c]-phosphole derivatives 11, 14 and 115, (β-siloxyalkylidene)-Phosphiranes 12, and dihydro-1,3-oxaphospholes 13. The thermolysis of 5-alkylidene-4,5-dihydro-4-trimethylsilyl-3-trimethylsilyloxy-3H-1,2,4-dizaphospholes 17 afforded three products, including the highly substituted and stable 2-phosphabutadienes 18 formed by nitrogen extrusion and rearrangement. Finally, the 4-chloro-3-trimethylsilyloxy-substituted heterocycle 21 was transformed at 170°C into 4H-1,2,4-diazaphosphole 23. The structures of 13c and 18a were determined by single-crystal X-ray diffraction.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300617
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  • 59
    Digitale Medien
    Digitale Medien
    Reaction of 1,3-Dialkyl-4,5-dimethylimidazol-2-ylidenes with 2-Bromo-2,3-dihydro-1H-1,3,2-diazaboroles (Alkyl=iPr and tBu)Dedicated to professor Adolf Zschunke on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 705-710 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Boron ; Diazaboroles ; Carbenes ; Heterocycles ; Imidazoles ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 2-Bromo-2,3-dihydro-1H-1,3,2-diazaboroles (3a-c) were synthesized by cyclocondensation of dilithiated 1,4-diazabutadienes (5a-c) with boron tribromide in hexane. 3a was also obtained by sodium amalgam reduction was conducted in ether solvents, diboroxane (2) resulted as the main product. Compound 3a and 1,3-dialkyl-4,5-dimethylimidazol2-ylidenes (6a, b) underwent halide displacement to afford the borolylimidazolium salts 7a, b. Compounds 2, 3a-c, and 7a, b were characterized by elemental analyses and spectroscopic methods (1H, 11B, 13C NMR; Ir; MS). The molecular structures of 2 and 7a were established by single-crystal X-ray diffraction analyses.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300606
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  • 60
    Digitale Medien
    Digitale Medien
    Well-Defined Metallodendrimers by Site-Specific Complexation (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 725-728 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Dendrimers ; Metal complexes ; Nanostructures ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Strong multiple complexation of transition metal ions, Cu(II), Zn(II) and Ni(II) with different generations of well-defined poly(propylene imine) dendrimers as multi(tridentate) ligands has been used to construct nanoscopic assemblies of defined structure and size incorporating a distinct number of metal ions from 2 up to 32.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300608
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  • 61
    Digitale Medien
    Digitale Medien
    Compounds of Germanium and Tin, 2lPart 20: Ref.[1]. A Tetraaryldigermene with a Short Germanium-Germanium Double Bond and a Nearly Planar Environment of Both Germanium AtomsDedicated to Professor Hans Bürger on the occasion of his 6oth birthday (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 735-738 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Germanium ; Digermenes ; Tin ; Germylenes ; Stannylenes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Treatment of GeCl2 · dioxane with the Grignard reagent RMgBr (R=2-tBu-4,5,6-Me3C6H) furnishes the tetraaryldigermene R2Ge=GeR2 (8). X-ray structure-analysis of 8 reveals a short Ge=Ge double bond, a nearly planar environment of both germanium atoms and extremely widened C—Ge—C angles of 128°. In solution, 8 dissociates into two germylene molecules R2Ge, which can be trapped with oxygen or by [4+1] cycloaddition reactions with 1,4-dihetero-1,3-dienes. A similar cycloadduct of a stannylene wa obtained by thermolysis of (R′2Sn)3 (R′=2,4,6-iPr3C6H2), in the presence of a 1,4-diazabutadiene and characterized by an X-ray structure-analysis.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300610
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  • 62
    Digitale Medien
    Digitale Medien
    Synthesis and Crystal Structure of tert-Butylamino)di-tert-butyl)siliceniotrichloroaluminate, (Me3C)2Si=NCMe3·AlCl3, and Dimethylazomethine-Aluminium Trichloride, Me2C=NH·AlCl3Dedicated to Prof. A. Meller on the occasion of his 65th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 753-755 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Silicenium ion ; Iminosilane ; Aluminate ; Silicon ; Aluminium ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Lithiated text-butylaminolfluorosilanes react with aluminum trichloride in ether, eliminating LiF to give AlCl3 adducts of iminosilanes  -  aminosiliceniotrichloroaluminates {R2Si-NCMe3·AlCl3}, which thermally form the dimethylazomethine- aluminium trichloride, Me2C=NH·AlCl3.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300613
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  • 63
    Digitale Medien
    Digitale Medien
    Sulfur Compounds, 199Part 198: R. Steudel, Y Drozdova, K. Miaskiewicz, R. H. Hertwig, W. Koch, J Am. Chem. Soc. 1997, 119, 1990.. Novel Titanocene Thiolato Complexes and Their Application in Preparing New Sulfur-Containing Heterocycles (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 757-764 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Titanocene complexes ; S ligands ; Organic polysulfanes ; Ligand transfer reactions ; Sulfur heterocycles ; Chalcogens ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Treatment of Cp2Ti(CO)2 (3) with the di- and polysulfanes 1,2,4-(CH2)2S3, C4S6 (9), C,7H10S3 (11), 1,2,4,6-(CH2)3S4 (16), C6H10S6(19), and S6 affords the titanocene chelate complexes Cp2TiS3(CH2)2 (8), (Cp2Ti)2C4S6 (10), Cp2TiS3C7H10 (13), Cp2TiS2C7H10 (14), Cp2TiS4(CH2)3 (17), Cp,2TiS6C6H6H10 (20), and Cp2TiS8 (23). 14 is also obtained from Cp2TiCl2 (1) and the geminal dithiol of norbornene. The analogous reaction with the dithiol of dicyclopentadiene yields Cp2TiS2C10H12 (15). In ligand transfer reactions, 8 reacts with SCl2 to give 1,2,3,5-tetrathiane (25), 10 provides 9 on reaction with Cl2, 13 when treated with S2Cl2 affords C7H10S5 (12), 15 reacts with S2Cl2Cl2 to give C10H12S4. 17 and SCl2 yield 1,2,3,5,7-pentathiepane (18), 20 is converted to C6H10S7 (22) on reaction with SCl2, and 23 yields S10 and 1,2,-C6H4(SCl)2, respectively. With phosgene, thiophosgene, and thionyl chloride, compound 15 yields the corresponding dithiocarbonate 26, the trithiocarbonate 27 and the trisulfane 2-oxide 28. The structure of 27 was determined by X-ray crystallography.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300614
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  • 64
    Digitale Medien
    Digitale Medien
    Synthesis of a Bisdienophilic Phthalocyanine and of Precursors for Repetitive Diels-Alder Reactions Based on Hemiporphyrazines and Phthalocyanines (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 801-806 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Unsymmetrical phthalocyanines ; Hemiporphyrazines ; Macrocyclic bisdienes and bisdienophiles ; Diels-Alder reactions ; Ladder polymers ; Cycloaddition ; Macrocycles ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The specific synthesis of a metal-free bisdienophilic phthalocyanine 193, suitable for repetitive Diels-Alder reactions, is reported. This was achieved by condensation of 191,3,3-trichloro-6/7-nitroioindolenine (191) and 4,9-dibutoxy-2,3,5,8-tetrahydro-1,3-diimino-1H-5,8-epoxybenz[f]isoindoline (2). The ability of 3 to undergo Diels-Alder reactions was tested by reaction with an excess of 1,2,3,4-tetraphenylcyclopentadienone (5). Experimental data of the hemiporphyrazines 9, 10, and 11, which can be used as precursors for the synthesis of ladder polymers, are also given in the Experimental Section.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300620
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  • 65
    Digitale Medien
    Digitale Medien
    Pseudoelement Compounds, XPart IX: Ref. Synthesis and Crystal Structure of New Complexes of the Type trans-[Pt(H)X(PPh3)2 with Cyanamide and Cyanomethanide LigandsDedicated to Professor S. Engels on the occasion of his 65th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1007-1012 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Platinum ; Nitrocyanamide ; Nitrosodicyanomethanide ; 1,1,3, 3-Tetracyano-2-azapropenide ; 1,1,2,3,3-Pentacyanopropenide ; Hydrido complexes ; Coordination modes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The new coordination compounds trans-[Pt(H)X(PPh3)2] with NCN- and C(CN)2-functionalized anions (X- = [N(O)C(CN)2]-, [NO2NCN]-, [N{C(CN)2}2]-, [NCC{C-(CN)2}2]-, have been characterized by 1H-, 31P-, 13C-NMR, and IR spectroscopy and elemental analyses the crystal structures of trans-[Pt(H)N(O)C(CN)2(PPh3)2], trans- [Pt(H)N{C(CN)2}2(PPh3)2], and trans-[Pt(H)NCC{C(CN)2}2-(PPh3)2) have been determined by X-ray diffraction. Remarkably, [N(O)C(CN)2]- is coordinated through the central nitrogen atom, while [N{C(CN)2}2]- and [NCC(C(CN)2]2]- are bonded through terminal nitrogen atoms of a C(CN)2 unit.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300730
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  • 66
    Digitale Medien
    Digitale Medien
    New Coupling Reactions and Phosphorylations Using Organozinc Reagents (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1021-1027 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Zinc ; Chirality ; Cross-coupling ; Phosphorylations ; Catalysis ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: This Microreview on the chemistry of organozinc reagents starts by briefly showing the methods of preparation of organozinc compounds and then discusses the considerable synthetic utility of zinc organometallics for the formation of new carbon-carbon bonds in the presence of transition-metal catalysts. Finally, the use of organozinc chemistry for the preparation of polyfunctional and chiral phosphanes is described.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300802
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  • 67
    Digitale Medien
    Digitale Medien
    Synthesis and Structures of Bis(tetramethylipiperidino)aluminum Halides-X-ray Crystal Structures of tmp2AlX (X = Cl, Br, I) and [tmp2A1(μ-F)l2 (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1047-1052 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Bis(tetramethylipiperidino)aluminum halides ; Alkoxy((tetramethylpiperidino)aluminum halides ; 27Al-NMR spectra ; Aluminum ; Amides ; Synthetic methods ; Bridging ligands ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: N-Lithio-2,2,6,6-tetramethylpiperidine [Li(tmp)] reacts with AlX3 (X = Cl, Br) in diethyl ether/ n-hexane solution to generate the products of substitution and ether cleavage, [tmpAl(X)(μ-OEt)], (la, X = Cl; 1b, X = Br). However, when the reaction is allowed to proceed in n-hexane alone, an almost quantitative yield of compounds tmp2AlX (2a, X = Cl; 2b, X = Br; 2c, X = I) is obtained. According to 27AI-NMR spectroscopy, mass spectroscopy, cryoscopy, and X-ray crystal structure determinations, these compounds are monomeric in the solid state, in solution, and in the gas phase. 2b reacts with AgBF4 yielding the fluoride-bridged dimer (tmp2AlF), 2d, as shown by X-ray crystal structure determination.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300805
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  • 68
    Digitale Medien
    Digitale Medien
    Synthesis, Structure, and Dynamic Behavior of (μ-Aldimido)(μ-η1: η2-alkyne)- biszirconocene Cation Complexes That Contain Planar-Tetracoordinate Carbon (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1069-1077 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Planar-tetracoordinate carbon ; Dynamic organometallic systems, μ-alkyne complexes ; π-Agostic systems ; Zirconium ; Metallocenes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The benzonitrile hydrozirconation product Cp2ZrCl(N—CHPh) 8 was treated with propynyl lithium to yield the (propynyl)(benzaldimido)ZrCp; complex 9. Subsequent treatment with trityl tetraphenylborate generated [Cp2Zr(C—C—CH3)-BPh-4] that instantaneously added to 9 to eventually form the (μ-aldimido)(μ-η1:η2-hexadiyne)ZrCp2 cation 11. The X-ray crystal structure analysis showed that 11 contains a planar-tetracoordinate carbon atom that is stabilized by forming a three-center-two-electron bond with the two adjacent metal atoms. Similarly, complex 9 reacted with [Cp2Zr(CH3)+CH3B(C6F5)3 1 to yield the planar-tetracoordinate carbon containing (μ-aldimido)(μ-η1:η2-2-butyne) Cp; cation 12. Both complexes 11 and 12 exhibit dynamic NMR spectra due to their rapid reorganization of the dimetallabicyclic frameworks (ΔG* = 10 kcal mol-1) in addition to an anchimerically assisted C—N bond rotation (ΔG* =15 kcal mol-1).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300808
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  • 69
    Digitale Medien
    Digitale Medien
    Isolation and Characterization of a Porphinatomanganese(IV) Complex from the Reaction of Dichloro Monoxide with 5,10,15,20-Tetrakis-(2,6-dichloropheny)porphinatomanganese(III) Chloride [Mn(EDCPP)CI] (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1099-1103 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Porphyrinatomanganese(IV) ; Monooxygenase model ; Dichloro monoxide ; Catalytic alkene epoxidation ; Catalytic alkane oxygenation ; Catalytic alkane chlorination ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The isolation at -78°C and characterization of the novel crystalline reactive porphinatomanganese(IV) complex Mn-(TDCPP)(OCl)2 (5) is described. 5 is compared with the porphinatomanganese(IV) complexes Mn(TDCPP)(C6H5IOCl)2 (2), Mn(TDCPP)(C6F510C1)CI (3) and Mn(TDCPP)(OCH3)2, (4). The stoichiometric reaction of 5 with triphenylphosphane yields 2.5 equivalents of triphenylphosphane oxide and 1.0 equivalent of Mn(TDCPP)Cl (1). Complex 5 epoxidizes stilbene, and oxygenates and chlorinates cyclohexane.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300811
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  • 70
    Digitale Medien
    Digitale Medien
    Synthesis and Structure of Allenyl-Substituted η6-Benzene(tricarbonyl)-chromium Complexes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1135-1139 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Arene complexes ; Chromium ; Allenes ; Rearrangements ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The Cr(CO)3-complexed η6-phenylpropargylic alcohols 3 react in a displacement rearrangement with thionyl chloride or chlorodiphenylphosphane to give the chloro- or phosphoryl allenyl substituted η6-phenyl complexes 4 and 6, respectively. In the X-ray crystal structure of the novel organometallic allenic derivatives 4b and 6b the vicinal chloro or phosphoryl substituent and the benzene(tricarbonyl)chromium fragment are arranged coplanarily. Palladium/copper-catalyzed couplings of the chloroallene 4b with terminal alkynes disclose a facile access to ynallene derivatives 8, novel carbon-rich organometallic π-systems.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300816
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  • 71
    Digitale Medien
    Digitale Medien
    Raman and Infrared Spectra and Quantum Chemical Calculations for Trichlorophosphoranylidenesulfamoyl Chloride, CISO2N=PCI3 (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1141-1145 
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    ISSN: 0009-2940
    Schlagwort(e): Trichlorophosphoranylidenesulfamoyl chloride ; Vibrational spectroscopy ; Conformational properties ; Quantum chemical calculations ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Raman (3500-50 cm-l) and infrared (4000-400 cm-l) spectra of the title compound, ClSO2N=PCl3, were recorded for the solid and liquid phase. Additionally, the Raman spectrum of the compound dissolved in CCl4 was obtained and qualitative depolarization values were determined. The spectra of the liquid and solid phase were interpreted in terms of the existence of only one conformation possessing C1 symmetry, as predicted by quantum chemical calculations. A complete vibrational assignment is proposed based on the relative intensities, on group frequencies along with support from the normal coordinate analysis. The experimental fundamental vibrational modes are compared to those obtained from theoretical approaches employing the ab initio MP2/6-31G* method and a density functional approximation (B3PW91/6-31G*).
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300817
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  • 72
    Digitale Medien
    Digitale Medien
    Ab Initio Studies on Disubstituted closo-Icosahedral Heteroboranes, X2B10H10 [X = CH, SiH, N, P, and Sb] (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1147-1150 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Icosahedral heteroboranes ; Ab initio calculation ; Bonding models ; Aromaticity ; Nucleus Independent Chemical Shift [NICS] ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Ab initio theoretical studies on X2B10H10 (X = CH, SiH, N, P and Sb) have been done for all the three possible isomers. Unlike lower-vertex heteroboranes, all the hetero derivatives have shown similar trends in the relative stabilities, the 1,12-isomer being more stable followed by 1,7- and 1,2-isomers, except for N and Sb. No conventional 1,2-isomer for N could be found. Instead, a new nido isomer which is 18.1 kcal/mol higher in energy than the most stable isomer has been located. Any hetero group substitution to icosahedral R12H122- is found to be thermodynamically destabilizing. However, the Nucleus Independent Chemical Shift criterion shows that all compounds, except for 8, have similar aromaticity.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300818
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  • 73
    Digitale Medien
    Digitale Medien
    The Molecular Structures of Triaminosilanes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1159-1166 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Aminosilantes ; Structure elucidation ; Molecular conformations ; Configuration determination ; Nitrogen Planarity/Silanes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The structural chemistry of a series of triaminosilanes XSi(NR2)3 has been investigated in order to determine the ground-state configuration and conformation of these molecules. Theoretical studies and analogy with the isoelectronic XP(NR2)3 (X = CH2, O, Se, NSiMe3 etc.) and P(NR2)3 molecules suggest structures of Cs or C3 symmetry, with small energy differences between them. The molecular structure of HSi(NMe2)3 (1) has been determined by a single-crystal X-ray diffraction study at low temperature. Surprisingly, the molecules have a non-standard conformation with an irregular orientation of the three NMe2 groups. The hydrido-, chloro-, methyl-, and vinyltris(morpholino)silanes XSi[N(CH2CH2)2O]3 (X = H, Cl, Me, Vi; 2-5) were prepared from the corresponding chlorosilanes and morpholine (2, 3) or lithium morpholide (4,5). Their variable-temperature NMR spectra were studied and the molecular structures determined by single crystal X-ray diffraction. Compound 2 has a molecular geometry approaching mirror symmetry with one morpholino group significantly different from the other two. This structure resembles that of isoelectronic tris(amino)phosphines. Compounds 3-5 have structures with a propeller-like arrangement of the three morpholino rings approaching C3 symmetry for this part of the molecules. The chloro compound 3 shows the shortest Si-N bond lengths (average 1.690 Å), followed by 2 (1.708Å),5 (1.709Å) and 4 (l.712Å). The configuration of all nitrogen atoms is almost planar, with sums of the angles close to 360°, and the morpholino rings adopt a chair conformation. According to the solution NMR spectra the ring inversion is slow at low temperature, but the rings rotate freely about the Si-N bonds on the NMR time scale. The molecular structures are discussed in terms of steric and electronic effects of the substituents. Other model compounds, including (Me2N)3SiC6H4-4-Br (6), MeSi[N(CH2CH2)2NMe]3 (7) and PhSi[N(CH2)4]3 (8), could not be crystallized, but were characterized by their analytical and spectroscopic data.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300820
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  • 74
    Digitale Medien
    Digitale Medien
    A Monomeric Bis(arena)lead(II) Complex with a Plumbocene-like Bent Sandwich Structural Unit  -  Structure of [Pb(1,2-C6H4Me2)2(AlCl4)2Dedicated to Professor C. G. Kreiter on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1731-1732 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Lead ; Tetrachloroaluminate ; Arenes ; o-Xylene ; Bis(arene) Complexes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Bis(o-xylene)lead(II) bis(tetrachloroaluminate), obtained from lead(II) chloride and aluminium trichloride in o-xylene, has been shown by X-ray crystallography to be a mononuclear lead complex with point group symmetry C2 The two aromatic ligands are arranged similarly to those in monomeric plumbocene. The coordination sphere is completed by two bidentate AlCl4-ions. The lead center uses about a quarter of its bonding capability for each of the four ligands
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971301204
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  • 75
    Digitale Medien
    Digitale Medien
    Titanium and Zirconium Complexes Containing a Novel Dianionic Trifunctional Amido Ligand (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1751-1759 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Amido complexes ; Titanium ; Zirconium ; Alkylmetal compounds ; Amido complexes ; Titanium ; Zirconium ; Alkylmetal compounds ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The novel tridentate diamidoamine ligands [RC(2C5H4N)(CH2NSiMe3)2)2- (R = H, CH3) have been synthesized and coordinated to TiIV giving the pentacoordinate complexes [MX2(RC(2-C5H4N)(CH2NSiMe3)2}] (M = Ti, Zr; X = Cl, Br). The crystal structure analysis of [TiBr2{HC(2-C5H4N)(CH2)2}] (M = Ti, Zr; X = Cl, Br). The crystal structure analysis of [TiBr2{HC(2-C5H4N)(CH2NSiMe3))] (10b) confirmed the involvement of the pyridyl function in the coordination to the meta centre occupying an apical position in the trigonal bipyramidal ligand polyhedron. alkylation of [TiCl2{H3CC(2-C5H4N)(CH2NSiMe3)2)] (12a) with one or two molar equivalents of [RMgCl](R = PhCH2, Me3SiC2) yielded the mono- and dialkyl complexes [TiClR{H3CC(2-C5H4N)(CH2NSiMe3)2)] and [TiR2(H3CC(2-C5H4N)(CH2NSiMe3)2)] and [TiR2(H3CC(2-C5H4N)(CH2NSiMe3)2}] in good yields. Depending on the steric demand of the alkyl group coordination or decoordination of the pyridyl group leads to four- or five-coordinate species. A crystal structure analysis of the pentacoordinate complex [TiCl(CH2SiMe3){H3CC(2-C5H4N)(CH2NSiMe3)2}] (16) was carried out.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971301208
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  • 76
    Digitale Medien
    Digitale Medien
    Masthead (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997) 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971301101
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  • 77
    Digitale Medien
    Digitale Medien
    Cobalt Phthalocyanine Derivatives Supported on TiO2 by Sol-Gel Processing. Part 1: Preparation and Microstructure (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1585-1589 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Phthalocyanines ; Sol-gel processes ; Titanium alkoxides ; Supported catalysts ; Heterogenous catalysis ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Cobalt(II) 2,9,16,23-tetrasulphophthalocyanine and cobalt(II) 2,9,16,23-tetra(chlorosulphonyl)phthalocyanine were supported on TiO2 by reaction of the phthalocyanines with Ti(OR)4 followed by sol-gel synthesis. The thus obtained solid materials are stable in sulfide-containing media and are therefore suitable as catalysts for HS oxidation. The structure of the samples was characterized by electron microscopy diffraction. The morphology of the matrix strongly depends on the cobalt phthalocyanine derivative. The pathalocyanines in the titania matrices are monomeric or dimeric depending both on the type of substituents of the CoPc derivative and on the titanium alkoxide used as precursors.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971301106
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  • 78
    Digitale Medien
    Digitale Medien
    Reversible Rearrangements of Chlorophosphane-Dichlorogermylene Ylides to Trichlorogermylphosphanes  -  Structure Determination of a Tetranuclear Bis(chlorophosphane)bis(trichlorogermylphosphane) Silver Bromide Complex (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1619-1623 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Dichlorogermylene ; Trichlorogermylphosphanes ; Insertion ; Silver bromide complex ; Carbene homologues ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Chlorophosphanes RR'PCl (1a: R,R' = 1b: R = tBu, R' = iPr, 1c: R = iPr, R' = Et2N, 1d: R = Et2N react with the dichlorogermylene dioxane complex 2 furnishing trichlorogermylphosphanes RR'PGeCl3 4a-d. In the cases of 1c/4c and 1d/4d the insertion reaction remain incomplete; similarly, 4a always contains, shortly after isolation in pure state, small amounts of 1a that can be detected by NMR. A provided by the reaction of trichlorosilylphosphane tBu(Et2N)PSiCl3 (5d) with GeCl4. The alkyl(dialkylamino) trichlorogermylphosphane 4d exists only in an equilibrium with chlorophosphane 1d, which coordinates GeCl2 leading to the dichlorogermylene complex 3d. A 1:1 mixture of 4a with 1a is formed by the novel cleavage (“chlorogermylation”) of the P-P bond of tetraisopropyldiphosphane with germanium tetrachloride. Di-tert-butyl(trichlorogermyl)phosphane 4e (R, R' = tBu) reacts with silver bromide providing a crystalline silver complex 7. A structure determination by X-ray diffraction reveals that 7 is [Ag4Br4(tBu2PCl)2(tBu2PGeCl3)2]. 2C7H8. Two of the Ag atoms of the cubane-like (AgBr)4 core of 7 are coordinated by chlorophosphane 1e, the other two by trichlorogermylphosphane 4e.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971301110
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  • 79
    Digitale Medien
    Digitale Medien
    Formation of the Cationic [(2-Aminoethenyl)carbine]iron Complexes by Treatment of (2-Methoxyethenyl)carbene Complexes with Primary Amines:Synthesis and Characterisation (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1647-1654 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Iron ; Carbene complexes ; (2-Methoxythenyl)methoxycarbene complexes ; Aminolysis ; (2-Aminoethenyl) methoxycarbene complexes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Cationic (2-methoxyethenyl)methoxycarbene iron complexes 2, [Cp(CO)2Fe(C(OMe)CH=CR(OMe))+][PF6-], are obtained by the addition of methanol to the corresponding (alkynyl)-methoxycarbene complexes 1, [Cp(CO)2Fe(C(OMe)C≡CR)+][PF6-]. Primary amines, H2NR', react with these 1,3-dimethoxy-substituted (alkenyl)carbene complexes, 2, through an addition/elimination process to yield cationic (2-aminoethenyl)methoxycarbene iron complexes, 3, [Cp(CO)2Fe(C(OMe)CH=CR(NHR'))+][PF6-] in an isolated yield of 71-90%. The complexes 3a-c were characterized by X-ray structural analyses. Thus, previously isolated products, from the reaction, of the (alkynyl)methoxycarbene complexes 1a and 1c, with aniline at room temperature, are assigned to the structures 3c and 3e. The spectroscopic and structural data obtained are discussed.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971301115
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  • 80
    Digitale Medien
    Digitale Medien
    1-Hexene Hydroformylation with the Rhodium (I) Triphosphane Complex [Rh(CO){PhP(CH2CH2PPh2)2}]PF6: An In Situ Study Using High-Pressure NMR Spectroscopy (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1633-1641 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Hydroformylation ; High-pressure NMR ; Homogeneous catalysis ; Rhodium ; Polyphosphane ligands ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The rhodium-catalyzed hydroformylation of 1-hexene in THF with the linear triphosphane PhP(CH2CH2PPh2)2 [PP,] has been studied both in situ and in high-pressure autoclaves. Sapphire NMR tubes with titanium valves have proved useful for studying the in situ reactions under conditions of relatively high syngas pressure (30-90 atm H,/CO) and temperature (60-100 C). Under conditions conducive to effective hydroformylation, the catalyst precursor [ (PP,)Rh(CO)]+ is quantitatively converted to the dicarbonyl [ (PP,)Rh(CO),]+, which is also the termination product of the catalysis. Irrespective of the syngas composition and of the total pressure, the dicarbonyl complex is the only phosphorus-containing species detectable on the NMR time-scale during the course of the isomerization and hydroformylation of the alkene. The PP2-Rh catalytic system exhibits some peculiar features that may be summarized as follows. (i) Very high partial pressures of CO (120 atm) neither inhibit the hydroformylation nor affect the n/i selectivity; (ii) alkene hydrogenation occurs neither at very high partial pressures of H, (120 atm) nor in the absence of added CO; (iii) the isomerization rate is slightly faster than that of hydroformylation; (iv) terminal and internal alkenes (2-, 3-hexenes) are hydroformylated with comparable rates. Various control experiments have been carried out using in-situ NMR, as well as batch experiments under different reaction conditions or with different catalyst precursors. Despite these extensive studies, unambiguous conclusions about the catalysis mechanism have not been reached. In particular, the possibility that different catalysts may be operative depending on the reaction conditions cannot be ruled out. The hydroformylation results rule out the involvement of phosphane-free “Rh-CO” catalysts, even under conditions of very high partial pressure of CO, and point to “(PP,)Rh(CO),” catalysts with small steric hindrance over the whole range of syngas pressures investigated.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971301113
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  • 81
    Digitale Medien
    Digitale Medien
    Masthead (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997) 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971301201
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  • 82
    Digitale Medien
    Digitale Medien
    Coordination Chemistry of PentahalocyclopentadienylsThis article is dedicated to Professor Wolfgang Beck on the occasion of his 65th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1721-1730 
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    ISSN: 0009-2940
    Schlagwort(e): Perhalometallocenes ; Cylopentadienes ; Perhalogenated ; Halogen-metal exchange reactions ; Sandwich complexes ; Ligand effects ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The coordination chemistry of perhalocyclopentadienyl ligands, first developed in the early 1970's as a part of a research program directed towards the synthesis of oxidation-resistant fuel additives, has been revived in the last ten years. This renewed interest stems from the discovery that the coordinated cyclopentadienyl ligand allows multiple functionalizations. Thus, the high versatility of this important class of ligands can be broadened even further, which may be important with regard to industrial applications of metallocenes.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971301203
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  • 83
    Digitale Medien
    Digitale Medien
    Density Functional Studies on Amino-Substituted Methane and Silane (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1745-1749 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Density functional calculations ; Tetra(amino)methane ; Tetra(amino)silane ; Transition states ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: In all-electron density functional calculations on mono- and tetraaminosubstituted methane and silane the coordination around the nitrogen center is found, in complete agreement with experiment, to be less pyramidal in the silicon compounds. The calculated barrier to inversion at nitrogen is only 0.6 kcal/mol in silylamine, while in methylamine it is 5.5 kcal/mol. The larger flexibility is attributed to the greater ionic character of the Si-N bond compared to that of the C-N bond. In tetra(amino)methane, inversion of one amino group leads to a local minimum (calculated inversion barrier: 6.4 kcal/mol), while a corresponding structure (or barrier) does not exist for the silicon compound. Due to the steric influence of the amino groups, the barrier to rotation around the C-N bond is larger in the tetrasubstituted compound (6.4 kcal/mol compared to 2.3 kcal/mol in methylamine). While the average binding energy of the amino groups is similar in both tetra(amino)compounds, the binding energy of the fourth ligand is about 25% larger in the silicon compound for both homolytic and heterolytic bond cleavage. This difference arises from the relative stabilization of the tri(amino)-methyl species, due to some n contribution to the C-N bond.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971301207
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  • 84
    Digitale Medien
    Digitale Medien
    Phosphanyl-Substituted Phosphaferrocenes as p,p-Chelate Ligands (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1771-1776 
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    ISSN: 0009-2940
    Schlagwort(e): Chelates ; P ligands ; Phosphaferrocene ; Carbonyl complexes ; Heterocycles ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Dicyclohexyl-acid diphenylphosphanyl-substituted phosphaferrocenes 2 and 3 were synthesized by substitution of the amino group in 2-dimethylaminomethyl-3,4,-dimethylphosphaferrocene 1 · Homologization of 2-formyl-3,4-dimethylphosphaferrocene 4 by one CH2 unit via Wittig olefination provided access to the phosphanylethyl derivative 9. Ligands 2, 3 and 9 formed P, P-chelate complexes with tetracarbonyl metal fragments in good yield. X-ray crystal structure determinations were carried out for the five-ring chelate complex 2. Mo(CO)4 (≡ l0), and the six-ring chelate complex 9 . Mo(CO)4, (≡ 13).
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971301211
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  • 85
    Digitale Medien
    Digitale Medien
    A Structural Study of Selenobenzamides: Crystal Structures and Dynamic 13C NMR (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 49-54 
    Details
    ISSN: 0009-2940
    Schlagwort(e): 4-(p-Bromoselenobenzoyl)morpholine ; 4-[(p-(Dimethylamino)selenobenzoyl]morpholine ; Hindered rotation ; Hammett treatment ; Selenoamides ; Amides ; Selenium compounds ; Structure elucidation ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The solid-state structures of (p-bromoselenobenzoyl)morpholine (2a) and [p-(dimethylamino)selenobenzoyl]morpholine (2b) were determined by X-ray diffraction. Both molecules show a flat selenoamide group. The larger contribution of resonance stabilization by the aromatic ring carrying the p-dimethylamino substituent is reflected by the smaller interplanar angle Θ between the aromatic ring and the selenoamide group [53.3(1)° vs. 81.1(1)°] and by the shorter length of the C=Se bond [1.824(5) Å vs. 1.840(3) Å]. The Gibbs free energy of activation of C-N bond rotation (ΔG≠rot) of five p-substituted (selenobenzoyl)morpholines was determined by dynamic 13C NMR. The activation barriers were found to range from 61.6 kJ/mol (X = NNMe2) to 75.1 kJ/mol (X = H). The ΔG≠rot values of the corresponding (thiobenzoyl)morpholines were found to be from 3.2 kJ/mol (X = NMe2) to 5.0 kJ/mol (X = H) lower. In both cases, ΔG≠rot showed an excellent linear Hammett correlation with s̰+p.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300108
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  • 86
    Digitale Medien
    Digitale Medien
    A Theoretical Investigation of Cycloadditions of Hydrogen Isocyanide to CH2=X and PH=X Dipolarophiles (X = CH2, NH, O, SiH2, PH, S)We dedicate this paper to the memory of our friend and colleague, Prof. Dr. Gerrit L'Abbé, who untimely passed away on August 27, 1996. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 69-76 
    Details
    ISSN: 0009-2940
    Schlagwort(e): [2 + 1] Cycloadditions ; Hydrogen cyanide ; Phosphorus dipolarophiles ; Three-membered rings ; Calculations, ab initio ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: We performed a systematic investigation of [2 + 1] cycloadditions of HN≡C to dipolarophiles of the type CH2=X and PH=X with X=CH2, NH, O, SiH2, PH, and S, as well as HN=NH and H2Si=SiH2. Ab initio MO calculations at the QCISD(T)/6-311G(d,p)/MP2/6-31G(d,p)+ZPE level were applied to construct the minimum-energy reaction pathways. Calculated results concerning the regiochemistry of the approaches and the stereochemistry of the product formation were analyzed in relation with established concepts such as frontier orbital, net charge distribution and stereoelectronic effect. For some systems, up to four distinct transition structures for cycloaddition were found. In general, there is a certain similarity between the behavior of both C and P series of dipolarophiles. The characteristics of the transition structures can be, in most cases, recovered by using qualitative concepts. The [2 + 1] cycloadditions are highly regioselective and stereospecific. Silicon-containing dipolarophiles are particularly attractive as they exhibit very small energy barriers to addition to isocyanides.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300111
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  • 87
    Digitale Medien
    Digitale Medien
    Triphenylphosphonio-Substituted 1,2,3,4-Triazaphospholes and 1,2,4-Diazaphospholes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 89-94 
    Details
    ISSN: 0009-2940
    Schlagwort(e): (Triphenylphosphonio)phosphaethyne ; Azides ; [3 + 2] Cycloadditions ; Phosphonio-1,2,3,4-triazaphospholes ; Diphosphonio-1,2,4-diazahospholes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Several products resulting from the condensation of the bis-(trimethylsilyl)ylide 1 with PCl3 serve as synthetic equivalents of a phosphoniophosphaethyne. Cycloaddition reactions with azides lead to phosphonio-1,2,3,4-triazaphosphole cations 5, 7 and to the zwitterionic phosphonio-1,2,3,4-triazaphospholide 6. The latter readily undergoes a cycloreversion yielding a phosphoranediyl diazomethane 12 as intermediate. Its cycloaddition affords the diphosphonio-1,2,4-diazaphosholide chloride 9a as the final product. 9a is a remarkably stable and unreactive derivative of the two-coordinate phosphorus. By HCL it is protonated at a nitrogen atom to give dication without any tendency to associate with the chloride counterions.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300114
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  • 88
    Digitale Medien
    Digitale Medien
    Tris(phenylthiomethyl)phosphane Sulfide and Selenide, (PhSCH2)3PX (X = S, Se), as Ambidentate Ligand Systems in Copper(I) Complexes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 105-110 
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    ISSN: 0009-2940
    Schlagwort(e): Sulfides ; Selenides ; Copper complexes ; Ambidentate ligands ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Triphenylphosphite has been converted into tris(phenylthiomethyl)phosphane (1) by reaction with LiCH2SPh/DABCO, and subsequently into the corresponding sulfide (2) and selenide (3) by treatment with elemental sulfur or selenium, respectively. Ligands 2 and 3 react with copper(I) halides CuX (X = Cl, Br, I) in polar organic solvents to give either 1:1 (X = Cl: 4, 7, X = Br: 5, 8 ) or 1:2 complexes (X = Br: 9, X = I: 6, 10). The crystal structures of five of these complexes have been determined by single crystal X-ray diffraction studies. All compounds of the type [(PhSCH2)3P=S/Se]CuX (X = Cl, Br) form centrosymmetrical dinuclear complexes featuring a four-membered ring core Cu2[S/Se], fused to two five-membered rings Cu[S/Se]PCS through common trans edges. Only one of the three phenyl-thiomethyl functions is involved in coordination to a metal center. The compound [(PhSCH2)3P=S](CuI)2 (6) is associated into a centrosymmetrical tetranuclear complex containing two four-membered rings (ICu2S) bridged via iodine atoms in 1,3-cis positions. The ligand is found to employ two of its PhSCH2 functions for metal coordination, giving rise to two five-membered rings fused to the four-membered rings via neighbouring edges. In all cases, therefore, the P=S/Se functions of the ligands are the preferred donor sites, which are used for the building of bridgehead structural units of polynuclear complexes.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300117
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  • 89
    Digitale Medien
    Digitale Medien
    Bildung und Charakterisierung des Dinatrium-tetraphosphendiids (tBu3Si)NaP-P=P-PNa(SitBu3) und seines Dimeren (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 135-140 
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    ISSN: 0009-2940
    Schlagwort(e): Synthesis ; Phosphorus ; Supersilyloligophosphides ; Crystal structure ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Reaction of P4 in THF or DME with 2 R*Na (R* = SitBu3) at -78°C leads quantitatively to deep red THF or DME adducts of R*NaP-P=P-PNaR* (3). According to 31P NMR, the P4 skeleton 3 is cis-configurated. On the other hand, reaction of P4 in TBME with 2 R*Na at -78°C leads quantitatively to (R*NaP)4 (4), a [2+2] cycloadduct of 3, the Na4P8 skeleton of which according to X-ray structure analysis forms a double cube with four P atoms in the second layer and two P and two Na atoms in alternating positions in the first and in the third layer (the Na atoms are coordinated with donors). By resolving the THF adduct 3 in TBME (the TBME adduct of 4 in THF) the compound 4 (the compound 3) is rapidly formed under reversal of the P-P=P-P configuration by way of [2+2] cycloaddition (by way of [2+2] cycloreversion). 3 and 4 are sensitive to oxidation and to protolysis. With TCNE, 3 is oxidized to R*2P4 (bicyclic P4 skeleton), with CF3SO3H, 3 may be transformed into R*3P5Na2 X 4 THF or in (R*P3)3 and R*PH2.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300123
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  • 90
    Digitale Medien
    Digitale Medien
    Cyclopentadienyl Ring Metathesis with Organocalcium and Organopotassium Compounds (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 155-159 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Cyclopentadienes ; Metathesis ; Potassium ; Calcium ; Main-group elements ; Sandwich complexes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Cyclopentadienyl ring metathesis occurs between [Ca(C5Me5)2] and [Ln(C5H5)3] complexes in toluene to generate the mixed ring compounds [Ln(C5Me5)2(C2H5)] (Ln=1-La, 1-Nd). 1-Nd has been characterized with X-ray diffraction as a sterically crowded monomer. Only one ring is exchanged between [Ca(C5Me5)2(thf)x] and [La(C5H5)3(thf)x] in toluene to yield [La(C5Me5)C5H5)2 (thf)] (2). In reaction with [M(C5H5)2] (M=Sn, Pb, Mn), [Ca(C5M5)2(thf)x] yields the corresponding [M(C5Me5)2] complexes. K[C5Me5] reacts with [La(C5H5)3(thf)], [Sn(C5H5)2] and [Pb[C5H5)2] in toluene to yield the ring-exchanged products 2, [Sn(C5Me5)2], and [Pb(C5Me5)2], respectively.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300204
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  • 91
    Digitale Medien
    Digitale Medien
    Sterically Shielded Titanocene Enolates - Synthesis, Structure and Their Exceptional Stability towards Hydrolysis (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 195-199 
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    ISSN: 0009-2940
    Schlagwort(e): Titanium ; Enolates ; Kinetics ; Enols ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reaction of various sterically congested sodium enolates, generated by quantitative deprotonation of stable enols (of diphenylacetaldehyde in the case of 5), with dichlorotitanocene afforded a series of novel titanium enolates 1-5. The crystal structure of 1 could be determined. Due to the considerable steric shielding of the β,β-diaryl moiety, all the titanium enolates exhibit an oustanding stability towards hydrolysis, which increases with the higher steric demand of the substitutents at the C-C double bond. The kinetics of the hydrolysis, which is pseudo-first-order in THF/water (1 : 1) and acetonitrile/water (1 : 1), was investigated by UV spectroscopy. The pseudo-first-order rate constants measured in these solvent mixtures are in the range 6.4 · 10-4 s-1 〈 k1 〈 1.1 · 10-3 s-1. For comparison, the hydrolysis of 6, which should exhibit the usual sensitivity of titanium enolates towards hydrolysis, is about 1000 times faster.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300209
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  • 92
    Digitale Medien
    Digitale Medien
    (Triphenylphosphane)gold(I) Scrambling in a Hexanuclear Complex of Phenylene-1,2-bis(phosphane) (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 217-219 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Gold compounds ; (Phosphane)gold(I) complexes ; Clusters ; P Ligands ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Phenylene-1,2-bis(phosphane) reacts with two mole-equivalents of tris[(triphenylphosphane)gold(I)]oxonium tetrafluoroborate in dichloromethane at -78°C to give high yields of a hexanuclear complex {C6H4]P(AuPPh3)3]2}2+ · 2 BF-4 (1). The variable-temperature 31P{1H}-NMR spectra of the product in CD2Cl2 at - 80°C are compatible with a static structure featuring three Ph3PAu units associated with each of the two C6H4P2 phosphide functions, as derived from a clear doublet/quartet pattern. At 50°C in CDCl3, however, there is rapid intramolecular scrambling of these Ph3PAu units, which gives rise to a triplet/septet pattern with the J(P,P) value reduced to exactly one half of the value at the low temperature limit.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300212
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  • 93
    Digitale Medien
    Digitale Medien
    Synthesis and Properties of New Mixed-Halide Derivatives of Iron-Sulfide Dimers-Crystal Structure of (Et4N)2[Fe2S2Cl2Br2] (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 235-239 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Iron-sulfur cluster ; Mixed halide ligands ; Magnetic properties ; Clusters ; Iron compounds ; Sulfur compounds ; Halogen compounds ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The synthesis and characterization of the new mixed-halide clusters (Et4N)2[Fe2S2Cl4-nBrn] (n=2, 3), together with an improved synthesis of (Et4N)2[Fe2S2Br4] and the crystal and molecular structure of (Et4N)2[F2S2Cl2Br2], are reported here. The structure consists of [Fe2S2Cl2Br2] dianions, with a pseudo-tetrahedral symmetry around each iron atom. A disorder problem precludes precise identification of the locations of the chloride and bromide ligands. A syn (or anti) conformation is however considered to be most likely, for steric hindrance reasons and on the basis of Mössbauer data. The Mössbauer, magnetic susceptibility, cyclic voltammetry and UV/Vis properties of the new clusters remain similar to those of the parent single-type halide clusters. These new clusters are interesting precursors for complexes with mixed thiolate and non-thiolate coordination at the iron sites.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300216
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  • 94
    Digitale Medien
    Digitale Medien
    Cyclic Aryleneazachalcogenes, X. Synthesis, Molecular Structure and Photoelectron Spectrum of 6,7,8,9-Tetrafluoro-1,3,5,2,4-benzotrithiadiazepine and Attempted Syntheses of Related Larger Size Heterocycles[1] (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 247-253 
    Details
    ISSN: 0009-2940
    Schlagwort(e): 6,7,8,9-Tetrafluoro-1,3,5,2,4-benzotrithiadiazepine ; 1,2,3,4-Tetrafluoro-5,6-bis(1-trimethylsilyl-2,4-dithia-1,3-diaza-1,2-butadien-4-yl)benzene ; Photoelectron spectroscopy ; Semiempirical calculations ; Nitrogen heterocycles ; Sulfur heterocycles ; Fluorine compounds ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The 14π-electron title compound 7 has been synthesized by two different ring-closure approaches. Its structure has been determined by X-ray diffraction to be planar within ±0.018 Å. The He(I) photoelectron spectrum of the title compound is assigned by Koopmans' correlation with PM3 eigenvalues based on the structural data, and by the π-perfluoro effect observed. The π-system can be rationalized y heteroatom first-order perturbation, which reduces the cycli π-delocalization. Replacement of the four fluorine substituents by hydrogen affects neither the long-wavelength absorption band in the UV/Vis spectrum nor the δ15N shift in the 15N-NMR spectrum. The synthesis of 20π-electron heterocycles related to the title compound has been attempted.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300218
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  • 95
    Digitale Medien
    Digitale Medien
    Tertiary Phosphane-Diiodine Compounds: Are They Molcular Adducts or Iodophosphonium Iodides? (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 299-305 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Iodine ; Phosphorus ; Charge transfer ; NMR spectroscopy ; Raman spectroscopy ; Structure elucidation ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The solid-state and solution structures of Ph3P · I2 have been studied in detail by electronic, 31P{1H}-NMR and Raman spectroscopy as well as conductometric measurements. When 1 : 1 ratios of triphenylphosphane and diiodine are mixed in dichloroethane, the molecular adduct is shown to exist also in solution. On the basis of the overall results, this molecular adduct is best described as a charge-transfer complex of the donor I- with the acceptor Ph3PI+, rather than the charge-transfer complex of the donor Ph3P with the acceptor I2 or the ionic species [Ph3PI]I as previously proposed. When higher diiodine to triphenylphosphane ratios are used, the Ph3P · I2 adduct dissociates to give Ph3PI+ and I3- or I5- depending on the diiodine excess. Previously reported solution data, which were ascribed to the ionic form of the adduct, are instead in agreement with hydrolysis products (Ph3PO, PH3POH+) of the very reactive adduct, formed in the presence of traces of water.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300226
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  • 96
    Digitale Medien
    Digitale Medien
    Tris(dimethylamino)phosphane as a New Ligand in Gold(I) Chemistry: Synthesis and Crystal Structures of [(Me2N)3P]AuCl, {[(Me2N)3PAu]3O}+BF4-, {[Me2N)3PAu]3NP(NMe2)32+ {BF-4}2 and the Precursor Molecule (Me2N)3PNSiMe3 (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 323-328 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Gold ; Phosphanes ; Phosphaneimines ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: [Tris(dimethylamino)phosphane]gold(I) chloride, μ-tris-{[tris(dimethylamino)phosphane]gold(I)}oxonium tetrafluoroborate, {μ3-tris(dimethylamino)phosphaneimidotris[tris(dimethylamino)phosphane]gold(I)}(2+) bis(tetrafluoroborate) and N-trimethylsilyltris(dimethylamino)phosphaneimine were prepared using modifications of established procedures. Their structures were determined in single-crystal X-ray diffraction studies. The ligand (Me2N)3P, here introduced into gold(I) chemistry for the first time, lends high stability to these compounds through efficient steric shielding of the reaction sites and through a balanced electronic substituent effect. The structural details of the (Mr2N)3P groups are of current interest because of the unusual nonequivalent configuration of the nitrogen atoms in the dimethylamino groups. This behaviour has been observed for most of the (Me2N)3P units in the compounds studied in this work.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300304
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  • 97
    Digitale Medien
    Digitale Medien
    Technetium and Rhenium Complexes with Thioether Ligands, 5. Synthesis and Structural Characterization of Neutral Oxorhenium(V) Complexes with Tridentate Dithioethers (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 357-362 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Rhenium complexes ; Technetium complexes ; Radiopharmaceuticals ; Dithioether ligands ; Dithiaalcohols ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Neutral oxorhenium(V) complexes of the general formula ReO(L)Cl2 are obtained by reaction of [ReO4]- or [ReOCl4]- with functionalized dithiaalcohols (L) containing the donor atom sequences S, S, O- and S, O-, S. Ligand exchange reaction of [ReOCl4]- with HO(CH2)2S(CH2)2S(CH2)2O (R = H, Et ) leads to the formation of ReOCl2[O(CH2)2S(CH2)2-S(CH2)2OEt] (1b). Reduction of [ReO4]- with a 1:1 mixture of concentrated HCl and glacial acetic acid in the presence of nBuSCH2- CH(OH)CH2S-nBu yield ReOCl2[OCH(CH2S-nBu)2) (4). X-ray structure analysis of 1a, 1b and 4 shows distorted octahedral coordination with the chlorine and sulfur atoms in the equatorial plane. The oxygen of the hydroxyl group coordinates in a trans position with respect to the Re=O core. 1a reacts with an excess of acetyl chloride in an unexpected way, resulting in cleavage of the trans Re-O bond and acylation of both of the hydroxyl groups to form the μ-oxo bridged complex [ReOCl2{CH3COO{CH2)2S(CH2)2PPC-CH3}}2O (3).
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300309
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  • 98
    Digitale Medien
    Digitale Medien
    Synthesis and Properties of Me2Ge-Bridged Arenes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 421-424 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Macrocycles ; Germanium ; UV/Vis spectroscopy ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Linear and cyclic oligomers of Me2Ge-bridged π-systems have been obtained by the reaction of carbo- and heterocyclic anions and dianions with Me2GeCl2. The spectroscopic properties of the new compounds are compared with analogous carbon- and Me2Si-bridged π-systems.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300318
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  • 99
    Digitale Medien
    Digitale Medien
    P/O Ligand Systems: Synthesis, Reactivity, and Structure of Tertiary o-Phosphanylphenol Derivatives (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 431-431 
    Details
    ISSN: 0009-2940
    Schlagwort(e): o-Phosphanylphenols ; P,O hybrid ligands ; P asymmetry ; C,O-dilithium reagents ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300320
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  • 100
    Digitale Medien
    Digitale Medien
    Masthead (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997) 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300401
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