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  • 1965-1969  (107)
  • 1920-1924
  • 1968  (107)
  • Analytical Chemistry and Spectroscopy  (92)
  • Electron microscopy  (15)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 127 (1968), S. 154-164 
    ISSN: 1432-0568
    Keywords: Collagen ; Connective tissue ; Electron microscopy ; Polarization microscopy ; Tendons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The correlation of the mechanical properties and the morphological behaviour of collagenous tissue during strain was investigated. Relaxed and strained tendons were examined by incidental and transmitted polarized light microscopy and electron microscopy. It was concluded that the wavy pattern seen at the seminicroscopic level of the collagen fibers vanished at relatively low loads. The direction of birefringence in transmitted light microscopy varied in the relaxed preparations but became even in the strained. The electron microscopy showed that the fibrils had the same periodicity as calculated from X-ray diffraction patterns of moist collagen, i.e. 680 Å, and that straining increased the period lengths of some fibrils. The correlation of these findings to a mechanical analogy of the tissue was discussed.
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  • 2
    ISSN: 1432-0533
    Keywords: Electron microscopy ; Skeletal muscle ; Ring fibers (Ringbinden) ; Sarcoplasmic masses ; Sarcomere fragmentation ; Myofilaments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Dans diverses conditions habituellement pathologiques, la fibre musculaire peut comporter une zone périphérique nettement individualisée et contenant des formations filamentaires dont la disposition spatiale est anormale. Les auteurs analysent les aspects ultrastructuraux de trois types de telles formations filamentaires périphériques: 1. lesfibrilles annulaires, bien visibles en microscopie optique; la microscopie électronique permet d'établir leur structure myofibrillaire normale, la fréquence des aspects complexes d'entretissage entre ces myofibrilles et les myofibrilles de disposition longitudinale; 2. lesmasses latérales dites “sarcoplasmiques” en microscopie optique, dont l'analyse en microscopie électronique permet d'établir la richesse fréquente en formations myofilamentaires disposées de façon anarchique; 3. lesempilements de fragments de sarcomère selon les différents plans de l'espace, qui ne peuvent être mis en évidence en microscopie optique, et n'apparaissent clairement qu'en microscopie électronique. L'étude ultrastructurale permet de récuser le caractère artificiel de ces différents aspects, souvent envisagé en microscopie optique, d'insister sur le caractère topographique limité le plus souvent à la périphérie de la fibre de telles altérations, et sur la fréquence de l'association de ces différentes anomalies entre elles. Cette étude apporte en outre des arguments en faveur de la nature dégénérative de ces aspects. Ces anomalies ne sont spécifiques d'aucune affection musculaire particulière, mais les auteurs les ont rencontrées cependant avec un maximum de fréquence dans les dystrophies musculaires progressives.
    Notes: Summary In various—usually pathologic—conditions the muscle fibre may show a distinct peripheral zone containing abnormally arranged filamentous formations. The authors have analysed the ultrastructural aspects of three types of such peripheral filamentous formations: 1.ring-shaped fibrils clearly visible under the light microscope; in these cases the electron microscope reveals their normal myofibrillar structure as well as the high incidence of complex formations resulting from the intertwining of such myofibrils and longitudinally disposed ones; 2. so-called“sarcoplasmic” lateral masses under light microscopy; in these cases the electron microscope shows a wealth of irregularly disposed myofilamentous formations; and 3.accumulations of sarcomere fragments at different spatial levels, which may be distinguished only under the electron microscope but not by light microscopy. The ultrastructural study permits the authors to disprove the artificial character of these different aspects—an assumption frequently made on the basis of light-microscopic findings—, to insist on the fact that such alterations are mostly limited topographically to the periphery of the fibre, and to stress that these different anomalies are often associated with one another. The study has furthermore furnished considerable evidence in favour of the degenerative nature of the forms under consideration. The anomalies in question are not specific to any one muscular affection; however they have been found most frequently in progressive muscular dystrophy.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 10 (1968), S. 336-346 
    ISSN: 1432-0533
    Keywords: Electron microscopy ; Rat brain, new born ; Porencephalic cyst ; Brain injury ; Glial reactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Stichverletzung des Gehirns neugeborener Ratten erzeugte regelmäßig eine Defekthöhle, deren Begrenzung zuerst aus einer Schicht fibrillärer Astrocyten mit vielen dünnen Cytoplasmafortsätzen bestand. Während der 2. und 3. Woche wurde die Astrocytenschicht lockerer und durch eine Basalmembran abgegrenzt, die gewöhnlich in Verbindung mit einer darüberliegenden Schicht von Pia-ähnlichen Zellen stand, Erst hernach ähnelte die Feinstruktur der Defektwand jener der Heldschen “Membrana gliae accessoria” für die differenzierte Struktur vorbehalten bleiben und nicht zur Bezeichung der frühen Astrocytenbegrenzung verwendet werden sollte. Keine dichte Glia-oder Bindegewebsnarbe, wie im Erwachsenengehirn üblich, wurde gefunden. Die Makrophagen verschwinden vor der 3. Woche, anstelle monatelang wie beim Erwachsenen zu verweilen. Das Vorhandensein oder Fehlen von Narbenbildung und Makrophagen dürfte nur das Alter, in dem die Verletzung erfolgte, widerspiegeln und daher für die Unterscheidung zwischen Mißbildungs-und Verletzungsdefekten unverläßlich sein.
    Notes: Summary Needle injury of the newborn rat brain resulted regularly in cavity formation, the lining of which at first consisted of a layer of fibrous astrocytes with many thin cytoplasmic projections. Between the second and third weeks the astrocytic surface became smoother and was lined by a basement membrane, usually in association with an overlying layer of pia-like cells. Only after this time did the fine structure of the cavity wall resemble that of Held's membrana gliae limitans superficialis. It is, therefore, suggested that Spatz's “membrana gliae limitans accessoria” be reserved for this differentiated structure and not used to identify the earlier astrocytic lining. No dense glial or connective tissue scarring, as usually seen in the adult brain, was found. Macrophages disappear before the third week, rather than persisting for months, as in the adult. The presence or absence of scar formation and macrophages may only reflect the age at which the injury occurred and may, therefore, be unreliable in distinguishing between cavities due to malformation and to injury.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 10 (1968), S. 17-25 
    ISSN: 1432-0533
    Keywords: Myelinated CNS axons ; Axoplasm ; Tubular structures ; Axonal reactive changes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Eine honigwabenartige tubuläre Anordnung wurde in stark myelinisierten Axonen gefunden. Sie wurde im Kleinhirn einer offenbar gesunden Ratte und eines Schimpansen mit Kuru-ähnlichen Symptomen beobachtet. Sie fand sich ferner in der Großhirnrnde einer Maus mit einem intracerebralen Tumorimplantat. Eine verbindliche Ursache konnte nicht aufgedeckt werden. Es wird jedoch angenommen, daß diese Struktur eine spezifische axonale Reaktion auf eine mögliche Vielfalt von noch unbekannten Bedingungen entspricht.
    Notes: Summary A honeycomb-like tubular array was observed in heavily myelinated axons. It was observed in the cerebellum of an apparently normal rat and a chimpanzee with “Kurulike” symptoms. It was also found in the cerebral cortex of a mouse that had had a intracerebral tumor implant. A common underlying etiology could not be found. It is suggested, however, that this structure represents a specific axonal response to perhaps a variety of as yet unknown conditions.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 10 (1968), S. 132-142 
    ISSN: 1432-0533
    Keywords: Myoclonus body disease ; Lafora bodies ; Electron microscopy ; Corpora amylacea ; Unverricht-Lundborg disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Les auteurs analysent l'ultra-structure des corps de Lafora à propos d'une biopsie cérébrale pratiquée dans une maladie d'Unverricht-Lundborg caractéristique. La surcharge observée dans les périkaryons neuronaux et dans les prolongements dendroaxonaux, au niveau des synapses, comporte des structures filamenteuses hélicoïdales de 75 Å d'épaisseur, correspondant à des macro-molécules protéiques complexes, des corpuscules denses de 150 à 300 Å et une matrice finement granuleuse. Les corps de Lafora, dépourvus de membrane propre, correspondent à une sécrétion anormale ou à une transformation d'organites cellulaires. Des relations de continuité existent entre les filaments et les ribosomes ergastoplasmiques. Les auteurs soulignent les relations unissant corps de Lafora et corps amylacés. Ils discutent leur morphologie et la comparent à celle de plusieurs structures pathologiques connues d'aspect fibrillaire.
    Notes: Summary The authors analyse the Lafora bodies' ultra-structure about a cerebral biopsy in a typic case of Unverricht-Lundborg disease. This obvious storage is noticed in the nerve cells perikarya, dendro-axonal processes and synapses; it appears to be compound of helicoïdal, filamentous, 75 Å wide profiles corresponding to complex proteic macro-molecules, 150–300 Å wide densities and slightly granulous matrix. The Lafora bodies without any limiting membran correspond to a pathologic neuro-secretion or to changes of cytoplasmic organites. Some continuity is seen between filaments and ribosomes. The authors emphazise the relations connecting Lafora bodies and corpora amylacea. Their morphology is discussed and compared with that of several pathologic fibrillar structures.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 10 (1968), S. 263-272 
    ISSN: 1432-0533
    Keywords: Hypertensive encephalopathy ; Ischemic-anoxic encephalopathy ; Edema anoxic ; Electron microscopy ; Astrocytic swelling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wurden elektronenmikroskopische Untersuchungen am Gehirn von Katzen bei akuter Hypertonie, die durch wechselnde Kompression der absteigenden Aorta erzeugt wurde, ausgeführt. Die ultrastrukturellen Veränderungen umfaßten Schwellung der Astrocytenausläufer, Erweiterung des endoplasmatischen Reticulums, und geringe Erweiterung des Extracellulärraumes des Gehirnmarks. Manchmal wurde auch Schwellung der Mitochondrien mit Zerstörung der Cristae beobachtet. Der Extracellulärraum der Gehirnrinde zeigte keine Erweiterung. Die Veränderungen in der Ultrastruktur des Zentralnervensystems werden im Hinblick auf die Pathogenese der hypertonischen Encephalopathie diskutiert.
    Notes: Summary Electron microscopic examinations were carried out in the brains of cats with acute arterial hypertension produced by intermittent compression of the descending aorta. The ultrastructural changes included swelling of the astrocytic processes, dilatation of the endoplasmic reticulum, and slight enlargement of the extracellular space of the white matter. Swelling of the mitochondria with disruption of the cristae was sometimes observed. The extracellular space of the gray matter showed no expansion. The changes in the ultrastructure of the central nervous system in hypertensive and ischemic encephalopathy were found to be very similar. This finding is discussed with special regard to the pathogenesis of acute hypertensive encephalopathy.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 10 (1968), S. 308-323 
    ISSN: 1432-0533
    Keywords: Experimental brain tumors ; Virus with brain tumors ; Electron microscopy ; Histochemistry ; Hydrocarbon (crystalls), oncogenic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Krebserzeugende Kohlenwasserstoffe wurden in Gehirn und Muskel von C3H Mäusen implantiert. Dabei konnten virusähnliche, cylindrisch geformte Partikel in den präcarcinomatösen Läsionen nachgewiesen werden. Die filamentartigen Stäbchen wurden nur im Cytoplasma von solchen Zellen beobachtet, die phagocytiertes Carcinogen enthielten. Die meisten Zellen, in denen diese Viruspartikel nachzuweisen waren, wurden als Makrophagen angesehen und es wird angenommen, daß sie mesenchymaler Herkunft sind. Der genaue Mechanismus, durch den die krebserzeugende Wirkung der Kohlenwasserstoffe zur Bildung von Viruspartikel führt, ist nicht klar, aber offensichtlich ist das endoplasmatische Reticulum beteiligt. Viele Partikel konnten innerhalb der Cisternen beobachtet werden; dabei wurde ihre äußere Hülle von der Membran des endoplasmatischen Reticulums gebildet. Gelegentlich wurden die Viruspartikel auch zwischen den zwei Membranen der Kernhülle beobachtet. Die Bedeutung dieser Partikel in Beziehung zu den Tumoren ist unbestimmt. Die Möglichkeit besteht, daß sie eine unreife oder unvollendete Form darstellen und daß zusätzliche Faktoren erforderlich sind, um ihre krebserzeugende Wirkung hervorzubringen.
    Notes: Summary Carcinogenic hydrocarbons were implanted into brain and muscle of C3H mice. Virus-like particles of cylindrical form were demonstrated in the precancerous lesions. These filamentous rods were observed only within the cytoplasm of those cells which contained phagocytosed carcinogen. The majority of reactive cells containing the virus-like particles were identified as macrophages, and are thought to be mesenchymal in origin. The precise mechanism by which the carcinogenic effect results in the formation of virus-like particles is not clear, but evidently involves the endoplasmic reticulum. Many of the particles were found within the cisternae, and their outer shells were derived from the membranous component of the endoplasmic reticulum. Occasionally, they were seen between the two membranes of the nuclear envelope. The significance of these particles in relationship to tumors is not certain. The possibility exists that they represent immature or incomplete forms and that additional factors may be necessary to prove them oncogenic.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 10 (1968), S. 324-335 
    ISSN: 1432-0533
    Keywords: Electron microscopy ; Rat brain, new born ; Brain injury ; Brain edema ; Extracellular space
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Reaktion des Gehirns neugeborener Ratten auf Stichverletzung wurde elektronenmikroskopisch untersucht. Die wenigen im Neugeborenenhirn vorhandenen protoplasmatischen Astrocyten erschienen an der Reaktion unbeteiligt. Hingegen erwies sich der Extracellularraum durch Anhäufung von Ödemflüssigkeit erweitert. Die Mikrogliazellen reagieren bemerkenswert schnell; viele, ganze Zellen sowie Myelinfiguren und Fetttröpfchen enthaltende Makrophagen werden schon 24 Stunden nach der Verletzung gefunden. Eine dichte Glia- oder Bindegewebsnarbe bildet sich nicht. Diese Reaktionen sind von denen für das reife Hirngwebe charakteristischen durchaus verschieden; mögliche Erklärungen für diese Unterschiede werden erörtert.
    Notes: Summary The reaction of the newborn rat brain following needle injury has been studied electron microscopically. Very few protoplasmic astrocytes are present in the newborn brain, and they do not appear to participate in the reaction. Instead, the extracellular space appears to be widened by an accumulation of oedema fluid. The microglial cells react remarkably rapidly; many macrophages containing whole cells as well as myelin figures and lipid droplets are found within 24 hours after the injury. At no time does a dense glial or connective tissue scar form. These reactions are quite different from those characteristic of mature brain tissue, and possible explanations for these differences are discussed.
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  • 9
    ISSN: 1432-0533
    Keywords: Hypocupremia, experimental ; Vascular pathology ; Basal brain arteries ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Kaninchen wurden in utero und post partum unter Entzug von Kupfer aus der Nahrung aufgezogen (die Nahrung enthielt nur 0,60 p.p.m. Kupfer). Eine Gruppe von Kontrolltieren wurde ebenfalls untersucht. Bei der post partum-Gruppe der Kaninchen dauerten die Versuche 2 Monate. Am Ende der 7. Woche wurden petechiale Blutungen in den Ohren beobachtet. Angiographisch wurden Gefäße des Kopfes und Nackens untersucht. Einige Dilatationen und Ungleichheiten wurden beobachtet. Bei zwei Tieren wurden Herzrisse festgestellt. Innerhalb von 2 Monaten wurden alle Tiere getötet und seziert. Es wurden Darmblutungen festgestellt. In der linken Niere einer der kupferarmen Kaninchen wurde eine cystenartige Bildung gefunden. Dieser Befund mag ein zufälliger gewesen sein. Das Herz, Cervicalgefäße und basale Hirngefäße wurden licht- und elektronenmikroskopisch untersucht. Anhäufungen von Fibroblasten, dissektive Blutungen und Defekte oder Brüche in Muskel- und elastischen Geweben wurden beobachtet. An den fibrösen Stellen wurde eine Anhäufung von neutral-rotem Material gefunden. Die Folgen des Entzugs von Kupfer aus der Nahrung waren somit Veränderungen des Herzens, muskulärer und elastischer Schichten der Cervicalgefäße und basalen Hirngefäße.
    Notes: Summary Rabbits were reared in utero and post partum under hypocupremic conditions (the diet containing only 0.60 p.p.m. copper). A control series was investigated as well. For the post partum series of rabbits the experiments lasted 2 months. At the end of the 7 th week petechial hemorrhages were observed in the ears. Angiography was carried out and cervical and head vessels were studied. Some vessel dilatations and unevennesses were observed. One animal died of heart rupture and another collapsed as a consequence of intramural bleeding in the ventricular wall. Within about two months all the animals were killed and autopsied. Intestinal bleedings were observed. A cystlike structure was found in a kidney of one hypocupremic rabbit. This finding may have been coincidental. The hearts and cervical and basal cerebral vessels were investigated by light and electron microscopy. Fibroblast accumulation, dissecting hemorrhages and defects or breaks in muscular and elastic tissue were observed. At the sites of fibrosis, accumulation of a neutral red-positive material was found. At the ultrastructural level lipids could be identified. Deprivation of dietary copper thus resulted in changes of the heart and muscularis and elastica layers of cervical and basal cerebral vessels of rabbits.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 10 (1968), S. 218-241 
    ISSN: 1432-0533
    Keywords: Myotonic dystrophy ; Sarcoplasmic masses ; Striated annulets (Ringbinden) ; Muscle fiber ; Electron microscopy ; Phase microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Das Biopsiematerial von drei Patienten mit unterschiedlichen klinischen und pathologischen Stadien der myotonischen Dystrophie wurde phasenkontrast-und elektronenmikroskopisch untersucht. Beim 1. und 2. Fall waren “sarkoplasmatische Massen” und “Ringbinden” besonders zahlreich, während sie beim 3. Fall mit klinisch erheblich fortgeschrittener Muskelatrophie nur ausnahmsweise vorkamen. Elektronenmikroskopisch erschienen fast alle Elemente der Muskelfasern, zumindest an einigen Stellen, von dem atrophischen oder dystrophischen Prozeß betroffen: Myofilamente, Z-Streifen, Triaden, Kerne, Mitochondrien und Sarkolemm. Außerdem fanden sich cytoplasmatische Cysten, multilamellierte Körperchen, zahlreiche Lipofuscingranula und verschiedene andere abnorme Strukturen. Besonders kennzeichnend für die Erkrankung waren die “sarkoplasmatischen Massen”, die mit variablen Mengen von fehlorientierten Myofilamenten, aber auch von anderen Komponenten der Muskelzelle ausgefüllt waren. Die Ringbinden wurden von fehlorientierten Myofibrillen gebildet, indem sie meist kreisförmig die im Zentrum normal ausgerichteten Myofibrillen umschlossen. Einzelne Veränderungen, die bisher weder bei der myotonischen Dystrophie noch in irgendeiner anderen Muskelkrankheit nachgewiesen worden sind, konnten in leicht dystrophischen wie auch in hochgradig atrophischen Fasern nachgewiesen und identifiziert werden: Große homogene Lacunen, die sich vom sarkoplasmatischen Reticulum herleiten und eigenartige geometrische Anordnungen der terminalen Cisternen. Der Ursprung bestimmter anderer Strukturen blieb unklar. In unserem Material fanden sich keine segmentalen Nekrosen, so daß sich die Relation des dystrophischen Prozesses zur Zenkerschen Degeneration und zur Atrophie, den nach histologischen Untersuchungen wesentlichsten Befunden bei der Steinertschen Erkrankung, nicht eindeutig bestimmen ließ.
    Notes: Summary Biopsies from three patients with different clinical and pathological stages of myotonic dystrophy were studied by phase and electron microscopy. Large sarcoplasmic masses and spiral annulets were prominent in Cases 1 and 2 while in Case 3, featured clinically by atrophic weakness, they were infrequent. In the latter the residual fibers were either large and dystrophic or small and atrophic. Electron microscopically, nearly all components of the muscle cell, in places, were involved in the dystrophic or atrophic process, such as myofilaments, Z discs, triads, nucleic, mitochondria, and the sarcolemma. In addition, cytoplasmic cysts, multilammellated bodies, and lipofuscin granules were observed. The most characteristic feature of the disease were sarcoplasmic masses, filled with varying amounts of disoriented myofilaments and other sarcoplasmic components. Disoriented myofibrils often encircled the remaining core of normal myofibrils, thus forming the striated annulets (Ringbinden). Several other abnormalities, not previously reported in myotonic dystrophy or any other myopathy, were identified in slightly dystrophic as well as in severaly atrophic fibers. These were large, homogenous lacunes derived from the sarcoplasmic reticulum and peculiar geometric arrangements of terminal cisternae. The origin of some other structures remains obscure. The relation of the dystrophic process to segmental degeneration and atrophy, the principal histologic findings in Steinert's disease, is unsettled since segmental necrosis was not observed in our samples for phase and electron microscopy.
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  • 11
    ISSN: 1432-0533
    Keywords: Nuclear inclusion body ; Herpes-virus-infection ; Immunology ; Electron microscopy ; Nuclear metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es werden die pathologischen Befunde bei einem 28 jährigen, schwachsinnigen Patienten beschrieben, der seit früher Kindheit progressive Spastizität und Ataxie zeigte. In Gehirn und allen anderen Organen wurden weitverbreitet eosinophile, intranucleäre Einschlußkörperchen, zugleich mit größeren, intensiver gefärbten, globulären Ablagerungen, gefunden. Corpus striatum, innere Kapsel, Pallidum und Thalamus waren besonders schwer betroffen. Die globulären Ablagerungen hatten sich wahrscheinlich aus vergrößerten, intranucleären Einschlußkörperchen entwickelt. Färberisch und histochemisch gaben beide Strukturen eine positive Reaktion für Protein. Entzündliche Reaktionen waren nicht vorhanden. Die Elektronmikroskopie zeigte, daß die intranucleären Einschlußkörperchen und die globulären Ablagerungen aus homogenem, feinkörnigem Material bestanden. Im Innern einer solchen Ablagerung in der inneren Kapsel wurden virusähnliche Partikel gesehen, die entweder unregelmäßig verteilt oder kristallartig angeordnet waren. Die Partikel sahen denen der Herpesvirusgruppe ähnlich. Es wird die Möglichkeit diskutiert, ob diese Veränderungen den Endzustand einer alten, generalisierten Herpesvirusinfektion darstellen, die entweder in früher Kindheit, zur Zeit der Geburt oder im Uterus stattgefunden hatte. Um den einzigartigen morphologischen Befund zu erklären, wird die Hypothese aufgestellt, daß entweder eine primäre immunologische Unzulänglichkeit vorlag oder daß eine Virusinfektion stattfand, bevor eine immunologische Kompetenz erworben war. Es wird kurz auf die zweite Möglichkeit hingewiesen, daß der Prozeß eine primäre, das Kernprotein beeinflussende Stoffwechselkrankheit darstellen könnte.
    Notes: Summary The pathologic findings are described in a mentally-retarded 28-year old man with progressive spasticity and ataxia since childhood. They consisted in the widespread presence, throughout the brain and visceral organs, of eosinophilic intranuclear inclusions, with the association of larger, more intensely staining globular bodies. The corpora striata, internal capsule, pallida and thalami were the most severely affected. The globular bodies seemed to be derived from the enlargement of the intranuclear inclusions: both gave the tinctorial and histochemical reactions for protein. There was no evidence of inflammation. Electron microscopy showed that the intranuclear inclusions and the globular bodies were composed of homogeneous finely granular material. In one such mass, in the internal capsule, virus-like particles, both randomly distributed and arranged in crystalline arrays, were seen. The particles resembled those of the herpesvirus group. The possibility is discussed that these alterations may present the residuum of an old generalized herpesvirus infection which could have been incurred in early life, at birth, or in utero. The hypothesis of a primary immunologic deficiency, or of a viral infection having occurred before the acquisition of immunologic competence, is advanced in order to account for the unique morphologic features. The alternative suggestion of a primary metabolic disorder affecting nuclear protein is briefly considered.
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  • 12
    ISSN: 1432-0533
    Keywords: Inclusion body, intranuclear ; Leucoencephalitis, subacute sclerotizing ; Electron microscopy ; Microtubuli (ultrastructural) ; Myxovirus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Ein klinisch-biologisch völlig typischer Fall von SSLE wurde enzymhistochemisch und elektronenoptisch untersucht. Enzymhistochemisch erwiesen sich die Läsionen als unspezifisch. Die nachgewiesenen Zunahme der oxydativen Enzyme ist identisch mit jener, die man bei allen reaktiven Makro- und Mikrogliosen beobachtet. Elektronenoptisch fanden sich keine intranucleären Einschlüsse aus Mikrotubuli von 170 bis 230 Å Durchmesser, deren Morphologie an gewisse Myxoviren erinnert. Andererseits bot dieser Fall auch lichtoptisch keine sicher nachweisbaren Kerneinschlüsse vom Typ Cowdry A, die bei SSLE nicht obligat sind. Die von einem Verfasser erstmals beobachteten mikrotubulären Einschlüsse erscheinen als das am meisten spezifische ultrastrukturelle Element der SSLE. Hingegen fanden sich bei der vorliegenden Beobachtung intracytoplasmatische Partikeln von virusähnlichem Aussehen, die vonGonatas bei SSLE und von den Verfassern bei entzündlicher diffuser Sklerose Typ Schilder beschrieben wurden. Gegenwärtig ergibt sich der Eindruck, daß diese Partikeln nicht spezifisch sind und ihre Deutung als virale Elemente größter Vorsicht bedarf. Es könnte sich um Sekretgranula in der Glia unter bestimmten pathologischen Bedingungen handeln, oder aber um phagocytierte Partikeln, die beispielsweise aus dem Myelin stammen.
    Notes: Summary Enzyme histochemical as well as electron microscopic studies were made in a typical case of SSLE. From the enzyme histochemical point of view the lesions were not specific, and the observed increase of oxydative enzymes is identical with that found in every reactive macro- and microgliosis. No intranuclear inclusions of microtubuli with a diameter of 170–230 Å resembling certain mixoviruses could be demonstrated by electron microscopy. By light microscopy, nuclear inclusions of the Cowdry type could not be demonstrated neither; however, they are not always found in SSLE. The microtubuli inclusions, observed for the first time by one of us, seem to be the most specific element in SSLE. On the other hand, the intracytoplasmatical particles with a virus-like aspect which have been described byGonatas in SSLE and by ourselves in periaxial diffuse encephalitis of the Schilder type were also found in the present case. Our impression is that these particles are nonspecific and great caution has to take place in classifying them as viral elements. They might be secretory granules arising in the glia in certain pathological conditions, or perhaps phagocyted particles, possibly stemming from myelin.
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  • 13
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    Springer
    Acta neuropathologica 10 (1968), S. 279-294 
    ISSN: 1432-0533
    Keywords: Neurofibromas ; von Recklinghausen's disease ; Neurinomas (or schwannomas) ; Electron microscopy ; Peripheral nervous tumors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé L'examen en microscopie optique et électronique de 6 neurofibromes prélevés chirurgicalement chez des patients atteints de maladie de Recklinghausen autorise un certain nombre de conclusions: l'ultrastructure des neurofibromes est faite de 2 types de cellules (cellules de Schwann et fibroblastes) dispersées au sein d'un espace extra-cellulaire contenant de nombreuses fibres de collagène. Des axones myélinisés et amyéliniques sont présents; l'aspect ultrastructural de 3 neurinomes de l'acoustique a été comparé à celui des neurofibromes et apparaît comme différent. Les neurinomes sont faits d'un seul type cellulaire (très probablement cellule de Schwann), le collagène y est beaucoup moins abondant, les axones absents. Quelques déductions pathogéniques et nosologiques sont proposées.
    Notes: Summary Six neurofibromas from patients with von Recklinghausen's disease have been examined by light and electron microscopy: 2 types of cells have been found (Schwann cells and fibroblasts) scattered in extracellular spaces rich in collagen fibers. Myelinated and nonmyelinated axons were observed. These data have been compared with other ones collected from 3 acoustic neurinomas. These latter contained only one cellular type (very likely to be Schwann cell), much less collagen and no axon at all. A pathogenic and nosologic discussion is given.
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  • 14
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    Springer
    Experimental brain research 6 (1968), S. 89-99 
    ISSN: 1432-1106
    Keywords: Substantia gelatinosa ; Dorsal root fibers ; Light microscopy ; Electron microscopy ; Operated rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The terminal degeneration in the substantia gelatinosa of the rat was studied with the Fink-Heimer silver technique following dorsal root section. Providing the survival time of the animal was in the range of 1–4 days, a massive degeneration was seen in lamina I, II and III of Rexed. The light microscope findings were corroborated by electronmicroscopic observations of degenerating boutons. Spinal cord material examined with silver methods one week after dorsal root section showed few signs of degeneration in the substantia gelatinosa. Although a significant dorsal root distribution to the substantia gelatinosa was found also in the cat, the terminal degeneration in lamina II showed considerable regional variations in this species.
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  • 15
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    Springer
    Clinical and experimental medicine 148 (1968), S. 255-274 
    ISSN: 1591-9528
    Keywords: Adipose tissue ; Fat cells ; Isolated fat cells ; Electron microscopy ; Ultrastructure ; Tissu adipeux ; Cellules adipeuses isolées ; Microscopie électronique ; Ultrastructure ; Fixation de tissus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Au cours de ces dernières années, la recherche biochimique au niveau du tissu adipeux a pris un très grand développement. La technique d'isolement des cellules adipeuses a beaucoup contribué à accroître la connaissance de leur métabolisme, rendant plus nécessaire encore l'étude des corrélations existant entre les données biochimiques et l'aspect ultrastructural. Ce travail porte sur la préparation de ce matériel pour l'observation au microscope électronique. Les cellules adipeuses sont des «gouttes» lipidiques recouvertes d'une fine couche de cytoplasme. La fragilité qui en résulte nécessite une préparation particulière: 1. les cellules doivent être maniées avec précaution tout au long de la préparation; 2. il faut fixer très peu de cellules à la fois; 3. cette fixation requiert une concentration élevée d'osmium, sans quoi les lipides de la cellule restent partiellement solubles dans les solvants employés pour la déshydratation. Il faut admettre que l'osmium modifie les propriétés de solubilité des triglycérides, probablement de par sa fixation au niveau des doubles liaisons, ou en facilitant une liaison en chaîne unissant les triglycérides entre eux par l'intermédiaire des doubles liaisons de leurs acides gras; 4. l'enrobage peut être fait au Vestopal ou à l'Epon, ce dernier étant techniquement plus maniable. Isolées, les cellules adipeuses sont semblables aux cellules fixéesin situ. Les cellules adipeuses présentent une particularité: la gouttelette lipidique est isolée du cytoplasme par une membrane elle-même doublée du côté cytoplasmique par des saccules du reticulum endoplasmique lisse disposés parallèlement à elle.
    Notes: Summary During these past years, an increasing attention has been paid to the biochemical aspects of metabolic regulation in adipose tissue. An important advance has been that of the availability of a technique for the isolation of adipose cells without contamination by any other cellular component. As yet, morphological investigations have not kept up with biochemical ones, and little is known about the ultrastructural aspects of isolated adipose cells. The present study describes the precautions required during the preparation of isolated adipose cells for study with the electron microscope. These cells are lipid “droplets” surrounded by an extremely thin cytoplasmatic layer and their fragility requires special precautions: 1. the cells must be carefully handled at all stages of preparation, avoiding mechanic or chemical trauma; 2. only small numbers of cells should be processed at any one time; 3. fixation requires a relatively high concentration of osmium to prevent continued partial solubility of the triglycerides in the solvents used for dehydration. It would seem that osmium modifies the solubility of triglycerides, probably through reaction at the level of the double bonds, perhaps facilitating cross-linkage between triglycerides at the level of the double bonds of the fatty acids involved; 4. either Vestopal or Epon can be used for embedding, Epon being somewhat easier to handle technically. Isolated adipose cells resemble in most aspects cells fixedin situ, while presenting one added particularity. In the isolated, spherical fat cell, the fat droplet is isolated from the cytoplasm by a membrane, which is itself associated with numerous saccules of smooth endoplasmic reticulum along the cytoplasmic surface of the membrane.
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  • 16
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    Biological Mass Spectrometry 1 (1968), S. 61-70 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectral fragmentations of stereoisomeric cyclohexane-1,2-diols, p-menthane-2,3-diols, 1-hydroxycarvomenthols and 4-hydroxymenthols are discussed.
    Additional Material: 4 Ill.
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  • 17
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    Biological Mass Spectrometry 1 (1968), S. 127-137 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Examination of a large number of spectra indicates that bis-unsaturated compounds commonly undergo a skeletal rearrangement in which part or all or the bridging moiety is eliminated, often with concomitant loss of hydrogen atoms. The spectra of labeled azobenzene, diphenyl sulfide, and their p,p′-dimethyl derivatives show that scrambling of hydrogen atoms precedes or accompanies such rearrangements, in contrast to the loss of a p-methyl group from the latter derivatives. These results are rationalized in terms of the radical site formed on one unsaturated functional group attacking the polarizable π-electrons of the other unsaturated group.
    Additional Material: 3 Tab.
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  • 18
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    Biological Mass Spectrometry 1 (1968), S. 87-113 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The thermal excitation energy of molecules greatly influences multistep degradation reactions of aliphatic compounds in the mass spectrometer. Molecules very often obtain their thermal excitation energy only within the ion source by wall collisions. Since it is not usually possible to keep the ion source temperature entirely constant the peak intensities in the spectra of one and the same compound differ considerably. Attention should be paid to this fact in the preparation of mass spectra collections.Multistep degradation reactions may be influenced by reduction of the electron energy and the ion source temperature such that only primary degradation products are preferentially formed. The interpretation of such spectra is easier. This technique was used to study the fragmentation reactions of bi-functional aliphatic compounds. It was shown that nearly all fragments can be deduced from molecular ion species, ionized at one or other functional group. Depending on the amount of fragments produced by ionization at the functional group it is possible to compare the iniluence of the various substituents on the fragmentation, and to rank them according to their increasing influence on the fragmentation as shown:
    Notes: Die thermische Anregungsenergie der Moleküle beeinflußt mehrstufige Abbaureaktionen aliphatischer Verbindungen im massenspektrometer sehr stark. Thermische Anregung erhalten die Moleküle vielfach erst durch Wandstöße in der Ionenquelle. Da in den Wenigsten Fällen die Ionenquellentemperature völlig konstant gehalten werden kann, unterscheiden sich Spektren ein und derselben Verbindung oft in ihren Intensitätwerten voneinander. Diesem Umstand sollte bei der Anlage von Spektrensammlungen Rechnung getragen werden.Durch Erniedrigung von Elektronenenergie und Ionenquellentemperatur lassen sich mehrstufige Abbaureaktionen os lenken, daß vorzugsweise nur primäre Spaltprodukte entstehen. Die Spektren werden dadurch qualitativ besser auswertbar. Bie Anwendung dieses Verfahrens auf bifunktionelle aliphatische Verbindungen Können nahezu sämtliche Spaltstücke ovn Molekülionenspezies abgeleitet werden, die an der einen oder anderen funktionellen Gruppe ionisiert wurden. Je nach der Mange der durch Ionisation an einer der Gruppen entstandenen Fragmente kann man daher den Einfluß der Substituenten miteinander vergleichen und diese nach steigender Einflußnahme auf die Bruchstückbildung in einer Reihen anordnen. Es ergibt sich danach etwa die folgende Reihung:
    Additional Material: 16 Ill.
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  • 19
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    Biological Mass Spectrometry 1 (1968), S. 151-166 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of the different forms of vitamin B6, some metabolites and antimetabolites, and some analogs are reported. The free bases are suitable for study, but the 5-phosphates are not sufficiently volatile. The hydrochloride salts dissociate thermally in the inlet system into the free base and HCl and give the spectrum of the free base with the spectrum of HCL superimposed on it. The compounds studied are: pyridoxol, pyridoxamine and pyridoxal, which are different forms of vitamin B6; 4-pyridoxic acid and its lactone, 5-pyridoxic acid lactone, isopyridoxal, 5-formyl-3-hydroxy-2-methylpyridine-4-carboxylic acid, and 3-hydroxy-2-methylpyridine-4,5-dicarboxylic acid, which are vitamin B6 metabolites; α4-and α5-deoxypyridoxol, 3-deoxypyridoxol, and 4- and 5- norpyridoxol, which are antimetabolites and analogs of vitamin B6.
    Additional Material: 14 Ill.
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  • 20
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    Biological Mass Spectrometry 1 (1968), S. 167-168 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new type of ion detector has been developed that can be made to operate in two ways. It can detect all ions, or it can be made to detect only those within a preselected energy range. Its use on a mass spectrometer to examine the metastable spectra of cis- and trans-butenes is described.
    Additional Material: 2 Tab.
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  • 21
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    Biological Mass Spectrometry 1 (1968), S. 169-187 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of guanidine and ten of its derivatives have been studied under both high and low resolution conditions. Evidence was detected for the migration of methyl groups, the formation of intermediate three-membered ring structures and decompositions involving expulsion of N. with release of kinetic energy.
    Additional Material: 13 Ill.
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  • 22
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    Biological Mass Spectrometry 1 (1968), S. 199-204 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three isomeric compounds, I, II and III, were prepared and their mass spectra recorded. Comparisons of the spectra showed that the fragmentation of I proceeds only by way of II, and that II itself is transformed in part to III upon electron impact. It is suggested that selective ionization of each one of the two isolated functional groups in II may afford two isomeric radical ions, IIa and IIb. A possible interrelation to the photochemistry of these compounds is also discussed.
    Additional Material: 3 Ill.
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  • 23
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of three methoxypulvic dilactones, four methyl esters of methoxypulvic acids and five methyl ethers of pulvic acid derivatives have been measured and rationalised employing accurate mass measurements and metastable peak assignments to substantiate the proposed fragmentations and rearrangements. In particular, the mass spectral differences and similarities between the isomeric methoxypulvic dilactones, between their methanolysis products and between the isomeric methyl ethers, are rationalised.
    Additional Material: 10 Ill.
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  • 24
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of twenty three azetidines and seventeen 2-azetidinones are reported and discussed. The majority of spectra contain molecular ions. Fragmentation modes are largely dependent upon the substitution pattern and involve specific cleavage of the four-membered ring. Several hydrogen rearrangement reactions occur, and in some cases, cis and trans isomers may be distinguished by large differences in the relative abundances of certain fragment ions.
    Additional Material: 16 Ill.
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  • 25
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The formation of 1,1-dimethoxy-alkyl rearrangement ions in the mass spectra of methyl ethers of linear diols, 1,2,3-triols and of derivatives of pentaglycerol and pentaerythritol has been investigated by deuterium labelling and mass measurements. Methoxy group migrations do not occur, or at least only to a small amount, in the mass spectra of the diol-dimethyl ethers. The mass spectra of methyl ethers of 1,2,3-triols exhibit characteristic peaks of the rearrangement ions +CH(OCH3)2 and +CR(OCH3)2. These ions arise by a 1,3-migration of a methoxy group, probably during a one step degradation of the molecular ion to give a molecule methyl alkenyl ether and a H-atom or alkyl radical as neutral fragments. Large peaks of the rearrangement ion +CH(OCH3)2 are observed in the mass spectra of compounds of the following type: A radical ion, formed by loss of HY from the molecular ion, rearranges by methoxy group migration in the mass spectra of these substances. Rearrangement by migration of hydroxy and acetoxy groups are also observed, but no migration of a Cl-atom.
    Notes: Die Bildung von 1,1-Dimethoxyalky-umlagerungsionen in den Massenspektren der Metyläther von linearen Diolen, 1,2,3-Triolen und Derivaten der verzweigten Polyole Pentaglycerin und Pentaerythrit wird mit Hilfe von Markierungen mit Deuterium und Massefeinbestimmungen untersucht. Methoxygruppenwanderungen treten in den Massenspektren der Dioldimethyläther nicht oder nur in sehr geringem Ausmaß auf. Die Massenspektren der 1,2,3-Trioltrimethyläther besizen aber charakteristische Peaks der umlagerungsionen +CH(OCH3)2 und +CR(OCH3)2. Diese Ionen entstehen durch eine 1,3-Wanderung einer Methoxygruppe, wahrscheinlich bei einem einstufigen Zerfall der Molekül-Ionen unter Bildung von Methyl-alkenyl-äther und H-Atom bzw. Alkylradikal als neutrale Fragmente. Gorße Peaks der Umlagerungsionen +CH(OCH3)2 werden in den Massenspektren von Verbindungen des Typs gefunde. Bei diesen Verbindungen wandert eine Methoxygruppe beim weiteren Zerfall von Radikal-Ionen, die durch Abspaltung von HY aus den Molekül-Ionen entstehen. Wanderungen von Hydroxy- und Acetoxy-Gruppen werden ebenfalls beobachtet, aber keine Wanderung von Cl-Atomen.
    Additional Material: 14 Ill.
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  • 26
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of tetronic acid and of a number of its derivatives are recorded and discussed. Where necessary, the composition of the fragment ions has been checked by high resolution mass measurements. Fragmentation of the molecular ion is explained in terms of the rupture of a bond attached to C-4, and the predominant routes for many of the compounds can be explained on the basis of two schemes, the first involving preliminary ketonisation of the molecular ion, followed by elimination of carbon monoxide, the second involving rupture of the C-4—R3 bond prior to elimination of carbon monoxide. Special structural features, however, provide alternative routes.
    Additional Material: 6 Ill.
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  • 27
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    Biological Mass Spectrometry 1 (1968), S. 617-626 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The mass spectra of secondary vinylcarbinols of the structure R—CH(OH)—CH=CH2 show the same fragments as those of the isomeric ethylketones R—CO—C2H5. This is the result of a rearrangement of the molecular ions of the vinylcarbinols to molecular ions of the ethylketones before fragmentation occurs. Compounds of the two classes differ only slightly from one another in the intensity values.
    Notes: Die Massenspektren sekundärer des Typs R—CH(OH)—CH=CH2 zeigen die gleichen Bruchstücke wie die der isomeren Äthylketone R—CO—C2H5. Dies ist auf eine Umlagerung der Molekülionen der Vinylcarbinole in solche der Äthylktone vor Eintritt der Bruchstückbildung zurückzuführen. Die Massenspektren beider Verbindungsklassen unterscheiden sich nur geringfügig in den Intensitätswerten.
    Additional Material: 12 Ill.
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  • 28
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Some esters of γ, δ-unsaturated or β-arylsubstituted acids undergo a peculiar transformation under electron-impact including an elimination of the alcohol residue as a radical R. with the following loss of the ketene molecule. One of the oxygen atoms of the carbonyl group enters an ion which is formed from an unsaturated part of the molecule. The possible mechanism of this reaction and the influence of structural modifications on the course of this process are discussed.
    Additional Material: 2 Ill.
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  • 29
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    Biological Mass Spectrometry 1 (1968), S. 915-917 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron-impact induced loss of CO2 from phthalanil and 4-phthalimidobiphenyl is paralleled by the formation of large amounts of CO2 on pyrolysis. CO is also a major pyrolysis product, but the loss of CO from these compounds under electron-impact is not an important fragmentation process.The mass spectra of meta and para-chlorophthalanils show prominent [M — CO2] peaks but the corresponding peak for the ortho isomer is of relatively low intensity. CO and CO2 are the principal gaseous products of the thermal decomposition of o-chlorophthalanil.
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  • 30
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    Biological Mass Spectrometry 1 (1968), S. 1-1 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 31
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In spite of previous extensive studies on the mass spectrometry of alkyl cyanides, no good mechanistic insight has as yet been gained into the behavior of straight chain alky1 cyanides. For this reason the possible origins for the principal ions in the mass spectrum of a typical alkyl cyanide (n-hexyl cyanide) have been determined using high resolution mass spectrometry anddeuterium labeling of every carbon atom. The results lead to the conclusion that most of the typical fragmentation processes of n-alkyl cyanides proceed through cyclic intermediates.
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  • 32
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of nine bridged polycyclic chlorinated pesticidal compounds have been investigated, and fragmentation modes to account for the more abundant ions are postulated. The principal features of the spectra are ions corresponding to a set of retro-Diels-Alder decompositions, ions resulting from successive losses of Cl, HCl, or both, ions produced by combinations of a retro-Diels-Alder process with a preliminary or subsequent loss of Cl or HCl, and ions whose processes of formation more specifically involve the epoxide group.
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  • 33
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    Biological Mass Spectrometry 1 (1968), S. xi 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 34
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    Biological Mass Spectrometry 1 (1968), S. 425-445 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An investigation of the mass spectra of substituted benzophenones has shown that a number of rearrangement processes are operative. The rearrangements have been shown to involve solely the ortho-substituents to the carbonyl group and in many cases the carbonyl oxygen atom itself participates in the processes. Deuterium labelling experiments combined with data obtained from accurate mass and metastable analysis have enabled the probable mechanisms of rearrangement and fragmentation to be elucidated. An understanding of these processes should greatly assist in the location of substituents in unknown benzophenones.
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  • 35
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    Biological Mass Spectrometry 1 (1968), S. 459-465 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of B substituted 2,5-dimethyl cyclotetrazenoboranes have been studied. The compounds Me2N4BD, Me2N4BEt, Me2N4BVi, Me2N4BCl and Me2N4BBr give confirmatory evidence that loss of N2+H. from the system occurs by loss of H from the side chain and that the B—R bond is very stable under electron impact conditions. Fragmentation proceeds in a similar fashion to that of the 2,5-dimethyl substituted compounds with H bonded to the boron atom.
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  • 36
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    Biological Mass Spectrometry 1 (1968) 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 37
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    Biological Mass Spectrometry 1 (1968), S. 487-502 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 38
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mass spectra of trimethylsilyl (TMS) derivatives of long chain dicarboxylic acids, hydroxy acids, cyano acids, and terminal diols, dithiols and diamines have been examined. A number of fragmentation pathways involving rearrangement of partial or intact TMS groups between the termini or remote points in the chain have been determined, using deuterium and carbon-13 labeling, and high resolution mass spectrometry. Knowledge of the occurrence of functional group migrations of this type is essential to the correct interpretation of mass spectra of TMS derivatives, which are now in wide use in mass spectrometry and gas chromatography. These data in addition provide further evidence for the general ability of remote functional groups to interact, by winding or coiling of long chains. A number of interesting doubly-charged ions are reported, in which the charges are reported, in which the charges are located at opposite ends of long chains, and for which no singly-charged counterparts are observed.
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  • 39
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    Biological Mass Spectrometry 1 (1968), S. 703-712 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of mono- and di-substituted alkyl and aryl imidazolines have been measured and the spectra analysed with the aid of deuterium labelling and high resolution techiques.In contrast to the fragmentation of thiazolines, all principal fragments of the imidazoline ring contain one nitrogen with or without hydrogen migration. In the case of 2,4-disubstituted imidazolines, the presence of two tautomeric molecular ions are suggested.
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  • 40
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    Biological Mass Spectrometry 1 (1968), S. 741-743 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 41
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    Biological Mass Spectrometry 1 (1968), S. 761-775 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of two fungal metabolites, aspertetronin A and B, have been examined in conjunction with a series of tetronic acids and related compounds, and as a result the major modes of fragmentation of the tetronic acid ring system have been determined. Several substituent dependent rearrangements have also been recognised during this investigation which should prove useful in the structural elucidation of unknown compounds.
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  • 42
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    Biological Mass Spectrometry 1 (1968), S. 417-423 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The most prominent ion in the mass spectra of C6F5CH2X (X = H, Br, CH:CH2, COCl, and CH2C6F5) is C7F5H2+, formulated as the pentafluorotropylium cation. This ion is also found, in an amount comparable to the parent ion, in the spectrum of (C6F5)2CH2. The heptafluorotropylium cation is found similarly in the spectrum of C6F5CF3. The mass spectra of (C6F5)2CHBr and [(C6H5)2CH]2 exhibit an ion C13F10H+ as the base peak, which is probably a pentafluorophenylpentafluorotropylium cation.The alcohol (C6F5)2CHOH shows loss of C6F5, followed by 2H, as a major breakdown pathway.The mode of formation, and the subsequent fragmentation, of the major ions in these spectra, are discussed.
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  • 43
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    Biological Mass Spectrometry 1 (1968), S. 447-458 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An investigation of the mass spectra of a number of substituted diphenyl ethers has shown that the major fragment ions are commonly due to cleavage of the molecule into the two benzene ‘half’ fragments although in many cases the molecular ion is the most abundant species observed.Little evidence is seen of M—CO or M—CHO peaks in these molecules but a large number of different rearrangement processes have been observed which involve ortho-substituents. These rearrangement ions, although in some cases not very abundant, can be diagnostic in the problem of locating substituents in the diphenyl ether nucleus.
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  • 44
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    Biological Mass Spectrometry 1 (1968), S. 483-485 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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  • 45
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    Biological Mass Spectrometry 1 (1968), S. 467-481 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of a series of isatin, oxindole and 2-oxo-3-indolyl derivatives have been investigated using high resolution and deuterium labelling techniques. The fragmentations involve the sequential loss of a number of neutral molecules and the results show that the concept of charge localisation can be applied with success to explain the fragmentation processes even in these polyheteroatom species.
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  • 46
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    Biological Mass Spectrometry 1 (1968) 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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  • 47
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of nineteen aliphatic 1,2-glycols containing a variety of substituents have been recorded and mechanistic rationalizations are presented for the more important degradation processes observed. Fragmentation of the hydroxylated carbon-carbon bond in these compounds occurred to an appreciable degree often accompanied by the transfer of a hydroxylic hydrogen atom.
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  • 48
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The bitter compounds isolated from the species Simaroubaceae represent a new family of degraded triterpenoids. Ailanthone, glaucarubolone and chaparrinone having a C20 skeleton belong to this family and their structures were previously determined. Mass spectra of these compounds and some of their derivatives have now been studied in detail and the results obtained are discussed in this communication. The observed fragmentation pattern is characteristic of the structural features of this group of compounds.
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  • 49
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    Biological Mass Spectrometry 1 (1968), S. 891-898 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The mass spectra of trimethylalkoxy silanes (CH3)3Si—O—(CH2)n—CH3 (n = 0-8) and (CH3)3Si—O—(CH2)n—CH(CH3)2 (n = 0-3) have been investigated and most of the fragmentations, induced by electron-impact, have been identified by metastable ions. The fragmentation mechanisms of trimethylpentoxysilane, established by Diekman, Thomson and Djerassi, are also observed in the mass spectra of these trimethylalkoxy silanes. Characteristic features of these reactions in the mass spectra of compounds with smaller and longer alkoxy groups, together with some additional fragmentations, are discussed.
    Notes: Es werden die Massenspektren von Trimethylaklkoxysilanen dr Typen (CH3)3Si—O—(CH2)n—CH3 (n = 0-8) und (CH3)3Si—O—(CH2)n—CH(CH3)2 (n = 0-3) wiedergegeben und die meisten Abbaureaktionen der Verbindungen bei Elektronenstoß durch metastabile Ionen belegt. Die von Diekman, Thomoson und Djerassi für Trimethypentoxysilane angegebenen Zerallsmechanisman laufen auch bei den untersuchten Substanzen ab. Es werden Besonderheiten beim Ablauf dieser Reaktionen bei Trimethylalkoxsilanen mit längerer und kürzerer Alkoxykette diskutiert und einige weitere Zerfallsreaktionen mitgeteilt.
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  • 50
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Après avoir identifié les impuretés qui accompagnent l'o-terphényle (I) marqué au 13C en position 2, c'est-à-dire, o-xenylcyclohexanol (II), o-xenylcyclohexène (III), hexahydrotriphénylène (IV) et o-xenylcyclohexane on a étudié la fragmentation des molécules I, II et IV, sous impact électronique, en tirant profit du marquage de ces molécules par le 13C.L'étude, par spectrométrje de masse, a été effectuée sur un instrument AEI MS9 pour ce qui regarde la composition atomique des ions principaux et sur un MAT CH-4 pour les déterminations quantitatives des espèces 12C et 13C, à basse énergie, en admettant une sensibilité égale.Le marquage par 13C de la position 2 dans I n'a pas encore mis clairement en évidence le réarrangement de cette molécule en une structure phénanthrénique après ouverture d'un noyau benzènique, comme le prévoyait une hypothèse formulée antérieurement à ce travail.La molécule II se fragmente suivant deux voies: I'une est formée d'une suite de fragments hydrocarbonés, produits à partir du pic moléculaire par perte de H2O et l'ature, d'une suite de fragments qui contiennent l'unique atome d'oxygène de la molécule. La différence dans le processus de fragmentation des deus séries s'explique par le fait que la perte d'une molécule d'eau, à partir de la molécule, stabilise les 2 atomes de carbone adjacents au C porteur du groupe - OH, le titre en 13C du fragment hydrocarboné en C15 étant relativement plus élevé que celui du fragment oxygéné à nombre égal d'atomes de C.Le marquage par 13C de la molécule IV montre comment se fait la rupture du cycle saturé sous bombardement électronique, le premier atome de C enlevé étant le plus proche du cycle centra.
    Notes: After identification of the impurities, separated from synthesized orthoterphenyl (I) labelled in position 2 with 13C, i.e. o-xenylcyclohexanol (II), o-xenylcyclohexene (III), hexahydrotriphenylene (IV) and o-xenylcyclohexane (V), the fragmentation processes under electron-impact of molecules I, II and IV have been studied, advantage being taken of their 13C labelling.Mass spectrometric studies were carried out on an AEI MS-9 for determination of the atomic composition of the main ions and on a MAT CH-4 instrument for quantitative determination of 12C and 13C species, at low energy, assuming an equal sensitivity.The 13C labelling of position 2 in I, has not yet given clear evidence of a formerly assumed rearrangement into phenanthrenic structure after ring opening.The fragmentation of molecule II occurs in two ways, i.e. into a series of hydrocarbon fragments, produced from the molecular ion by loss of H2O or into fragments still containing the oxygen atom. The difference between the fragmentation processes of the two series depends on the fact that the loss of H2O from the molecule stabilizes the two carbon atoms adjacent to the C carrying the hydroxyl group. This is shown by the relatively higher 13C content of the hydrocarbon fragment in C15 compared with that of the equivalent oxygenated fragment.The labelling in IV shows how the rupture of the saturated ring occurs under electron-impact, the first C removed being the one nearest to the central ring.
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  • 51
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    Biological Mass Spectrometry 1 (1968), S. 503-517 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of a series of alicyclic fluorocarbon complexes of manganese, rhenium, iron and ruthenium are described and discussed. It is shown that the breakdown of these complexes after ionization depends on the nature of the metal, and of the other groups attached to the metal. Effects due to elimination of metal halides, formation of metal fluoride ions, and ligand transfer reactions are found, and result in significant differences in the fragmentation patterns of the complexes from those of the parent fluorocarbons.
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  • 52
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    Biological Mass Spectrometry 1 (1968), S. 563-566 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass-spectral behaviour of long-chain aliphatic primary alcohols of the normal, iso-and anteiso-series have been discussed. The mass-spectral fragmentation of individual alcoholic types have been found to be structurally specific. The mass spectra of some deuterio derivatives have shown, however, the complicated nature of the fragmentation processes.
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  • 53
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    Biological Mass Spectrometry 1 (1968) 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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  • 54
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    Biological Mass Spectrometry 1 (1968), S. 583-592 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Skeletal rearrangement processes of the general type \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm ABC}^{\mathop {\rm + }\limits_{\rm .} } {\rm } \to {\rm AC}^{\mathop {\rm + }\limits_{\rm .} } {\rm + B} $\end{document} in which HCN is eliminated and also bond-forming reactions involving intramolecular aromatic substitution occur in aromatic azines upon electron impact. In addition, hydrogen rearrangements can lead to abundant benzonitrile and benzalimine molecular ions and their substituted analogues. The abundant [M—1] ions are predominantly formed by loss of the methine hydrogen preceded by complete scrambling of the aromatic and methine hydrogens. The similarities between the processes occurring in azines and those in anils, both in their normal bond cleavages and in some bond-forming reactions are emphasized.
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  • 55
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    Biological Mass Spectrometry 1 (1968), S. 613-615 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Migration of the heteroatom substituent is an important feature in the mass spectra of β-chloro- and β-hydroxy-ethyl aryl sulphones. In these compounds the migratory aptitude of the heteroatoms appears to be greater than that of the hydrogen atoms.
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  • 56
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    Biological Mass Spectrometry 1 (1968), S. 627-632 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The fact that some αβ-unsaturated alcohols give mass spectra that bear some similarity with the corresponding saturated ketones is discussed, and the double hydrogen transfer necessary to accommodate this is examined by deuterium labelling.
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  • 57
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    Topics: Chemistry and Pharmacology
    Notes: The mass spectral fragmentation of thiosemicarbazone derivatives of some typical aliphatic, alicyclic and aromatic aldehydes and ketones has been rationalized using high resolution mass spectrometry supplemented by deuterium labeling. Thiosemicarbazone derivatives of carbonyl compounds yield mass spectra which have little in common with those generated by their semicarbazone analogs.
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  • 58
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    Biological Mass Spectrometry 1 (1968), S. 739-740 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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  • 59
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    Biological Mass Spectrometry 1 (1968), S. 713-737 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Fragmentation under electron impact of phenylhydrazones of aromatic aldehydes and ketones, of nitrostilbenes, nitrobenzalacetophenones and analogous compounds is determined by intramolecular oxidation reactions. Oxygen transfer from the o-nitrogroup on to the hydrazon- or stilbene-double bond is taking place; degradation of the resulting rearrangement products provides some of the most characteristic features in the mass spectra of such compounds. The spectra of 20 out of 40 compounds investigated are presented and discussed. Several other rearrangement reactions are observed. An additional conjugated double bond in the hydrazone chain completely changes the reactivity under electron impact. Even saturated substituents (cyclopropyl) can be drastically affected in their mode of fragmentation by an o-substituted nitrogroup.
    Notes: Die Fragmentierung von Nitrophenylhydrazonen aromatischer Aldehyde und Ketone, von Nitrostillbenen, Nitrobenzalacetophenonen und analogen Verbindungen unter Elektronenbeschuss wird entscheidend durch intramolekulare Oxidationsreaktionen beeinflusst, sofern sich eine Nitrogruppe in o-Stellung zum ungesättigten substituenten befindet. Es findet eine Sauerstoffübertragung von der o-Nitrogruppe auf die Hydrazon- oder Stilbendoppelbindung statt; ein wesentlicher Teil der charakterisierenden Fragmente in den Massenspektren dieser Verbindungen stammt aus dem Zerfall dieser Sauerstoffübertragungsprodukte. 20 Spektren von 40 untersuchten Verbindungen werden präsentiert und diskutiert. Eine Reihe weiterer umlagerungsreaktionen werden beobahtet. Eine konjugierte zusätzliche Dopplbindung in der Hydrazonkette ändert die Reaktivität der Verbindung vollsändig. auch die Fragmentierung gesättigter Substituenten (Cyclopropyl) kann durch eine o-Nitrogruppe entscheidend beeinflusst werden.
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  • 60
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In comparing N-acetylmorpholine to closely related systems, two major differences in fragmentation are observed. M-15 and M-43 fragments, although quite common to such systems, are unusual with respect to their genesis. Formation of the M-15 fragment by loss of C-3 instead of the anticipitated loss of C-2 or C-8 is evident from shifts in the spectra of deuterated analogs. The M-43 species arises from total loss of the N-acyl substituent rather than the usual two-step loss of ketene plus a ring hydrogen. These data are presented in support of mechanistic rationale involving radical induced ring contraction to a common intermediate molecular ion. Techniques of high resolution mass spectrometry and isotope labeling have been employed to substantiate certain mechanistic details.
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  • 61
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    Biological Mass Spectrometry 1 (1968) 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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  • 62
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    Biological Mass Spectrometry 1 (1968), S. 47-60 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The field ionization and electron impact mass spectra of some monoterpenes are compared. Some general rules applicable also to other substances are derived, summarizing the new structural information that can be obtained by combination of field ionization and electron impact data. The general conclusions are: (1) By comparison of FI and EI mass spectra one can recognize which of the most intense peaks in the EI mass spectra are originating from rearrangement or multistip dissociation processes on the one hand, or from simple direct bond rupture on the other hand. (2) The molecular weight of each substance containing C, H, O, N atoms (or some of them) can be determined unambiguously by field ionization, even if there is no parent peak detectable by electron impact. (3) Extremely strong metastable peaks in the FI mass spectrum are indicative of the splitting off of a polar group from a highly branched carbon atom, under rearrangement of the molecular ion. (4) Ions of about double the molecular weight are often found in the FI mass spectra if the molecule contains carbonyl or hydroxyl groups, or conjugated multiple bonds in aliphatic compounds.
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  • 63
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    Biological Mass Spectrometry 1 (1968), S. 115-126 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of a series of metal complexes of dibenzoylmethane have been rationalized. The paths of novel rearrangement reactions involving both hydrogen and oxygen migration may differ according to the type of metal atom in the complex. Further examples are proposed of the effect of metal valency changes in ion reactions.
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  • 64
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This book has been written with the intention of enabling the organic chemist to endeavor to interpret his own mass spectra and to decide whether mass spectrometry would be useful for his specific problems. Besides a description of experimental techniques the main body of the oeuvre consists of a thorough discussion of fragmentation processes triggered by various structural elements, followed by selected examples from miscellaneous classes of natural products. Of special value is a chapter on structure elucidation of unknown compounds. Each section also offers an ample list of literature references. The present book can be highly recommended as an introduction to organic mass spectrometry, yet it will prove useful also for those advanced in this art.
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  • 65
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    Biological Mass Spectrometry 1 (1968), S. 273-278 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of 1-phenylanthra-9,10-quinone and 20 substituted l-phenylanthraquinones having alkyl methoxyl, nitro and halogen substituents in the o-, m- and p-positions of the phenyl ring have been measured. The spectra are discussed with particular reference to the loss from the molecular ion of a hydrogen atom and of the substituent.
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  • 66
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    Biological Mass Spectrometry 1 (1968), S. 31-46 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 6 Ill.
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    Biological Mass Spectrometry 1 (1968), S. 13-29 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of a variety of alkyl and aryl oxazoles have been determined and the spectra analyzed with the aid of deuterium labelling and high resolution mass spectrometry. In contrast to the corresponding benzenoid compounds, the mass spectra of isomeric alkyl oxazoles are distinctive and in this respect are akin to those of the corresponding pyridines. Further analogy to the pyridines is suggested by the unfavorable nature of a carbonium ion adjacent to the 2-position and this effect may be used to locate alkyl substituents attached to the oxazole nucleus. The loss of carbon monoxide from the molecular ions of 2,5-disubstituted oxazoles probably occurs with ring opening and migration of the C-5 substituent (e.g.Br) to the C-4 position.
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    Biological Mass Spectrometry 1 (1968), S. 191-198 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectrum of 1-(2-thienyl) hexane-1-13C is reported. The principal fragmentation routes ofthe parent ion are delineated. Beta cleavage of the alkyl chain predominates, and the label retention indicates that the alpha carbon atom remains with the charged ring moiety. A substantial part of the m/e 97 ion undergoes a ring expansion to a six membered ring. A small amount of alpha cleavage of the alkyl chain occurs with the expected loss of the label. Further fragmentation of the ions from initial alpha or beta cleavage produces similar fragment ions. It is noted that many of the neutral particles lost in the formation of the fragment ions are typical of those encountered in the alkylbenzenes or other aromatic ion systems.
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  • 69
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    Biological Mass Spectrometry 1 (1968), S. 215-229 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A variety of metal-complexes with Corrin-type macrocyclic ligands and synthetic precursors thereof are investigated by mass spectrometry. Analytical results are obtained from thermal reactions in the inlet system and from electron-impact-induced fragmentations. The former yield information concerning identity of small ligands in octahedral Co(III)-complexes, of anions in complex-salts and the possibility of thermal cyclisation of open ligands, the latter provide molecular weights, a means of type analysis and theoretically interesting modes of fragmentation. An unprecedented subsequent loss of up to seven methyl-groups is observed. Different fragmentation-mechanisms and the possible influence of metal-valency-changes and even- or odd-electron-ion-features are discussed. Some of the metals like Zn and Na seem to be able to form different types of metal-ligand-bonds.
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  • 70
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    Biological Mass Spectrometry 1 (1968), S. 397-402 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Competing primary reactions by which 1-tetralone loses C2H4 and CO give rise to a doublet at mass 118 in the high-resolution mass spectrum corresponding to 96·4% C8H6O+ and 3·6% C9H10+, respectively. Study of the remainder of the spectrum however, suggests that these intensities constitute a poor measure of the relative importance of the two reaction paths. The C9H10+ ion evidently degrades more readily than C8H6O+, since an estimated 26% of the ions arising in these paths involve primary loss of CO. This estimate is supported by voltage dependence of the intensity distribution between the members of the doublet. As ionizing voltage is decreased, the intensity distribution is constant to about 20 volts, but between 20 and 10 volts the value for C9H10+ rises smoothly from about 3.5% to about 25%.
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  • 71
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    Biological Mass Spectrometry 1 (1968), S. 403-416 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectral fragmentations of the saturated five-, six- and seven-membered ring ethers have been determined by studying their site-specifically deuterated analogues by both high and low-resolution mass spectrometry.The initial processes, governing the fragmentations of the cyclic ethers are shown to be identical with the well-known processes of linear nonbranched ethers, i.e. predominant α-fisson in the lower members and predominant carbon-oxygen fisson with charge retention on the carbon atom in the higher members.
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  • 72
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    Biological Mass Spectrometry 1 (1968), S. 835-846 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of (π-C5H5)2Ti(C6F5)X (X = Cl and C6F5), C6F5Re(CO)5, RfFe(CO)2(π-C5H5) (Rf = C6F5, 4-HC6F4, and three isomeric H2C6F3), and C6F5Ru(CO)2(π-C5H5) are compared to those of C6F5X (X = F, Cl, Br, I) and the three isomers of C6F4H2. Significant differences occur, apparently depending on the relative thermodynamic stabilities of the various fragments which may be formed. Comparison of the mass spectra of pentafluorophenyl- and pentafluorobicyclo[2.2.0]hexa-2,5-dien-2-yl-Re(CO)5 show that similar ions are produced by both complexes, perhaps because of thermal isomerisation before ionisation.
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  • 73
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    Biological Mass Spectrometry 1 (1968), S. 907-909 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 74
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    Biological Mass Spectrometry 1 (1968), S. 913-914 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of esters of the general formula MeO2C·[CF2]n·CO2Me, n = 6 to 9, are reported and briefly discussed. Common features of the mass spectra are prominent peaks at [M — CO2], [M — CO2 — C2F4] and [M — CO2 — 2C2F4].
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  • 75
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    Biological Mass Spectrometry 1 (1968), S. 391-395 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Production of NO+- and NO2+- intermediate complexes formed by nitration of aromatic compounds by means of ion-molecule reactions in the gas phase were attempted. The experiments were performed with benzene, pyridine and toluene respectively and with NO+, NO2+ CH3NO2+ and CH2ONO2+ als ‘nitration’ ions. Aromatic NO+-as well as NO2+-complexes were observed with varying reaction cross-sections. The determined lower limit of bonding energy of 16 kcal/mol for to be σ-complexes. This fact was regarded as additional support for the analogy between electrophilic substitution reactions and ion-molecule reactions.
    Notes: Es wurde versucht, die bei der Nitrierung von Aromaten entstehenden NO+-bzw. NO2+-Intermediärkomplexe durch Ion-Molekül Reaktionen in der Gasphase zu erzeugen. Die utersuchungen erfolgten am Benzol. Pyridin und Toluol mit NO+, NO2+ sowie CH3NO2+ und CH2ONO2+ als ‘Nitrierungs’-Ionen. Es ließen sich sowohl aromatische NO+-Komplexe anchweisen mit wechselndem reaktionsquerschnitt. Die ermittelten unteren Grenzen der Bindungsenergien von 16 kcal/Mol für den NO+-Komplex und 29 kcal/Mol für den NO2+-Komplex legen es nahe, die nachgewiesenen Komplexe asl σ-Komplexe anzusehe, was als weiterer Hinweis für Analogie von elektrophilen Substitutionsreaktionen und Ion-Molekül-Reaktionen gewertet wird.
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  • 76
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mass spectra of 1-phenylethanol-1 and its analogues, specifically deuterated in the aliphatic chain, suggest that the [M—CH3]+ ion is represented partly by an α-hydroxybenzyl fragment. Moreover, the molecular ion loses successively - after scrambling of all hydrogen atoms, except those of CH3—a hydrogen atom and C6H6, generation the CH3CO+ ion.Diffuse peaks, found in the spectra of of 2-phenylethanol-1 and its analogues, specifically deuterated in the aliphatic chain and in the phenyl ring, show that the molecular ion loses C2H4O, possibly via a four-center mechanism, after an exchange of aromatic and hydroxylic hydrogens.Mass spectra of 1-phenylpropanol-2 and its analogues, specifically, deuterated in the aliphatic chain, demonstrate that in the molecular ion exclusively the hydroxyl hydrogen atom is transferred to one of the ortho-positions of the phenyl ring via a McLafferty rearrangement, generating the [M — C2H4O]+ ion. Furtherore, an eight-membered ring structure is proposed for the [M — CH3]+ ion to explain the loss of H2O and C2H2O from this ion after an extensive scrambling of hydrogen atoms.
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  • 77
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    Biological Mass Spectrometry 1 (1968), S. iv 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 78
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    Biological Mass Spectrometry 1 (1968), S. 527-530 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Using energetic considerations, ketonic structures are postulated for the [M—olefin]+ fragments derived from alkoxybenzenes, alkylthiobenzenes and 9-ethoxyanthracene. Experimentally determined heats of formation for the tautomeric molecular ions derived from anthrone and 9-anthrol differ by 37 Kcal. mole-1.
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  • 79
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    Biological Mass Spectrometry 1 (1968), S. 519-525 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An ‘on-line’ mass spectrometer technique which permits the examination of the effects of radiation at short times has been used to study the radiolysis of methane by reactor radiation. The mass spectrometer used was the AEI MS-10. The experiments were carried out using the UTR-100 reactor at East Kilbride and the results using highly purified methane and methane with radical scavangers are described. With pure methane at 0·25% conversion, G-values of 0·36, 0·24, 0·07 and 0·03 were calculated for C3H8, C4H10, C5H12 and C6H14 respectively. No pressure-dependent reactions were observed in the pressure range 50 to 135 torr. The effects of radical scavengers were investigated and irradiation of methane containing 1 to 2% ethylene gave G-values for C2H6, C3H8, n-C4H10, iso-C4H10, C5H12 plus C6H14, C2H2, C3H6, C4H8 and C5H10 of 1·33, 2·02, 2·03, 0·35, 0·34, 0·30, 0·37, 0·90 and 0·31. The effects of adding 1 to 2% propylene and 1 to 2% oxygen were also examined and the results are described in the paper. Experiments with smaller quantities of oxygen emphasize the importance of removing all oxygen from the system before radiolysis begins. The paper then goes on to discuss in some detail the processes involved in the radiolysis of methane and concludes with suggestions for future work.
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  • 80
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    Biological Mass Spectrometry 1 (1968), S. 543-549 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: According to Stevenson's rule, there is a possibility that the chloromethyl and bromomethyl ions in the spectra of alkylhalides may not be formed from the molecular ion by processes described by electronic ground states alone. Since ion intensities at 75 eV are generally considered to be governed by appearance potentials, the operation of Stevenson's rule should influence correlations of intensity data according to the kinetic approach to mass spectra. Deviations from linearity were obtained in correlations of CH2Br+ intensities, but not in those of CH2CL+. Stevenson's rule is of help in explaining the deviations, but by its nature it is not absolute in predicting their occurrence with certainty. Consequently caution must be exercised in the interpretation of new data, particularly for aliphatic compounds.
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  • 81
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    Biological Mass Spectrometry 1 (1968), S. 551-561 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of usnic acid, decarbousnic acid, usnetic acid and usnetol are reported and mechanistically interpreted. The mass spectra of lichexanthone and lichexanthone methyl ether were also examined, and the unusal features of the latter spectrum have been rationalized.
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  • 82
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    Biological Mass Spectrometry 1 (1968), S. 567-581 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of twenty one C-19 modified cholesteryl derivatives have been determined and compared with results for related systems. In the case when the hydrogen(s) of the C-19 group have been replaced by other groups the metastable evidence shows that in those molecules with a C-3 hydroxyl group the loss of water followed by the loss of the C-19 group gives rise to an intense ion at m/e 353, whereas the loss of the C-19 group with hydrogen transfer to the ion, followed by the loss of water gives rise to the large ion at m/e 354. In contrast in the case of the C-3 acetates the main fragmentation is the loss of acetic acid followed by the loss of the C-19 group to give the ion at m/e 353. This is rationalised on the basis of results observed in other systems. In the case of the C-3 tosylates evidence for pyrolysis before electron impact fragmentation is presented. The subsequent fragmentation of the large ions at m/e 354, 353 and other m/e values in the high mass region is shown to be in line with earlier work.
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  • 83
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The mass spectra of 15 azines and 5 phosphazines are investigated by deuterium labelling and high resolution mass measurements. Azines of aldehydes undergo a skeletal rearrangement in which HCN and (HCN + H) are eliminated from the molecular ion. Azines of ketones first eliminate an aryl or alkyl radical and then rearrange with the expulsion of CN. or (CN. + H). Analogies to the photolytic or thermal elimination of nitrogen in azines could not be detected. o,o′-Dinitrobenzaldazin undergoes a double oxygen rearrangement in which carbon dioxide is eliminated. Phosphazines show a similar behaviour under electron-impact as under pyrolytic conditions.
    Notes: Die Massenspektren von 15 Azinen sowie 5 Phosphazinen werden mittels deuterium-Markierung und exakten Massenmessungen untersucht. Azine von Aldehyden eliminieren HCN und (HCN + H) aus dem Molekülion, was mit einer Umlagerung verbunden ist. Azine von Ketonen spalten zuerst ein Aryl-bzw. Akylradikal ab und lagern sich anschliessend um unter eliminieung von CN. oder (CN. + H). Analogien zur photolytischen oder termischen Abspaltungvon Stickstoff aus Azinen wurden nicht gefunden. o, o′-Dinitro-benzaldazin erleidet unter Elektronenstoss eine doppelte Sauerstoffumlagerung, bei de CO2 eliminiert wird. Phosphazine zeigen bei Elektronenbeschuss ein ähnliches Verhalten wie bei der Thermolyse.
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  • 84
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of various ring-substituted salicylic acids and derivatives thereof have been examined. Fragmentation pathways for derivatives of salicylic acid; 3-NO2 salicylic acid; 5-I salicylic acid; 3-NO2, 5-I salicylic acid; and 3-NH2, 5-I salicylic acid are suggested. The major dissociations of these compounds are by elimination of the elements of neutral molecules, e.g. water, methanol, ketene (from the acetylated compounds) carbon monoxide, nitric oxide and nitrogen dioxide, leading to (iodo) phenoxy and (iodo) quinone type ion structures. These ions further decompose to yield the corresponding substituted cyclopentadienyl and cyclopropylium ions.
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  • 85
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    Biological Mass Spectrometry 1 (1968), S. 263-271 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of 2- and 3-phenylthiophenes and their phenyl-d5 counterparts reveal that the thienyl ring is markedly more reactive than the phenyl ring under electron impact. In one process, that leading to loss of C2H2S, the atoms lost are apparently derived solely from the thienyl ring, quite probably from the original molecular configuration.
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  • 86
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The triphenylmethyl (trityl) moiety is frequently used for the protection of alcohols but the mass spectra of such trityl ethers have hitherto escaped scrutiny. It has now been found that triphenylmethyl derivatives of primary alcohols yield abundant molecular ions which permit the determination of the isotopic purity of the parent alcohol. Upon electron impact the triphenyl-methyl entity directs the fragmentation of trityl ethers as demonstrated by a detailed study of n-pentyl trityl ether and its deuterated analogs. Ions formed by migration of phenyl groups were observed in the mass spectra of the trityl ethers investigated as well as in the spectrum of triphenyl-methane itself.
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  • 87
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    Biological Mass Spectrometry 1 (1968), S. 231-250 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The different influence of functional groups on fragmentation reactions is demonstrated by the example of 17β-hydroxy-5α-androstanes.In 17β-hydroxy-5α-androstane the tendency of steroids to be cleaved by rupture of the C-13/C-17 bond under production of a charged centre at C-13 is only enhanced by the hydroxyl group. This influence of the hydroxyl group only predominates as long as substituents are absent which need less energy for ionization than is necessary to ionize the C-13/C-17 bond. Even the presence of a double bond may change the fragmentation pattern completely.If, however, an additional alkyl group is located at C-17, ionization occurs with high probability by elimination of an electron from the OH group connected to C-17. Therefore, other main degradation reactions occur than in molecular ions, having the charge located at C-13. In such compounds even the dominant influence of a conjugated system on the fragmentation reactions is considerably reduced. By etherfication of the hydroxyl group this effect is still very much increased.In the course of this investigation some not yet known degradation reactions, rather typical for the presence of certain groups in the steroid skeleton, were found. These are discussed briefly.
    Notes: AM Beispiel des 17β-Hydroxy-5α-androstans wird der unterschiedliche Einfluß funktioneller Gruppen auf die Bruchstückbildung von Steroiden studiert.Im 17β-Hydroxy-5α-androstan wird durch die Hydroxylgruppe lediglich die in Steroiden vorhandene eigung zur Spaltung der C-13/C-17 Bindung unter Ausbildung eines positiven Ladungszentrums an C-13 vertärkt. Dieser Einfluß der Hydroxylgruppe überwiegt aber nur, solange Substituenten fehlen, die zur Ionisation einen geringeren Energieaufwand benötigen, als zur Ionisation der C-13/C-17 Bindung erforderlich ist. Bereits bei Vorhandensein einer Doppelbindung kann sich das Spaltbild stark wandeln.Wenn sich aber in Stellung 17 noch eine zusätzliche Alkygruppe befindet, so erfolgt die Ionisation mit hoher Wahrscheinlichkeit durch Abspaltung eines Elektrons vom Hydroxylsauerstoff in Stellung 17. Es treten daher andere Hauptabbaureaktionen ein als in Molekülionen, die das Ladungszentrum am C-13 haben. In solchen Verbindungen ist selbst der dominierende Einfluß eines konjugierten Systems auf die Bruchstückbildung weitgehend eingeschränkt. Bei Verätherung der Hydroxylgruppe wird dieser Effekt potenziert.Im Zuge dieser UNtersuchungen wurden einige bisher noch nicht bekannte, für die Anwesenheit bestimmter Strukturelemente im Steroidskelett typische Abbaureaktionen aufgefunden, die ebenfalls kurz diskutiert werden.
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  • 88
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    Biological Mass Spectrometry 1 (1968), S. 279-284 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of some δ-lactones substituted in various positions by methyl groups have been studied both by accurate mass measurements at high resulution and by deuterium labelling. The loss of carbon dioxide has been shown to be important only for a mono-substituted lactone. A fragmentation mode common to all the lactones studied is the elimination of the ring oxygen atom, plus the adjacent carbon atom with its substituents, as a neutral carbonyl molecule such as formaldehyde, acetaldehyde or acetone. Deuterium labelling has uncovered the existence of a rearrangement involving hydrogen transfer in an even-electron ion, and a mechanism involving a six-membered transition state is proposed for this. The bond fissions, common to all the lactones, by which the principal ions in the mass spectra arise, are summarised.
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  • 89
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    Biological Mass Spectrometry 1 (1968), S. 285-294 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of nineteen substituted benzothiazoles have been recorded and the identity of the various ions in the mass spectra has been established by high resulution (accurate) mass measurement. Deuterium labelling has been used to elucidate the fragmentation processes of these compounds. The parent compound of the series, benzothiazole, exhibits the loss of hydrogen cyanide and carbon monosulphide from the parent ion as the most important decomposition pathways. The hydrogen atom concerned in the loss of hydrogen cyanide is shown to originate from the 2-position of benzothiazole, while in 2-substituted benzothiazoles, different mechanisms are apparent for the loss of hydrogen cyanide, and these are clarified by deuterium labelling. Some substituted benzothiazoles can lose sulphur from their molecular ions, a process which does not occur in benzothiazole itself. The substituted benzothiazoles undergo many other types of fragmentations, in some cases retaining the substituent, and in other cases losing it prior to collapse of the thiazole ring.
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  • 90
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    Biological Mass Spectrometry 1 (1968), S. 315-322 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The mass spectra of 19 aromatic isocyanides are reported and discussed. The main feature of the fragmentation of these compounds is loss of HCN usually indicated by a metastable peak. Although this process is characteristic of the behaviour of aromatic isocyanides the extent to which it dominates the mass spectrum of any aromatic isocyanide is determined by the relative ease of cleavage of other bonds within the molecule. 2,4,6-d3-phenylisocyanide (Ib) loses predominantly DCN from the molecular ion while 2,4-d2-1-naphthylisocyanide (lIIb) eliminates HCN. It is therefore concluded that the loss of HCN from aromatic isocyanides is mainly a non-random process (no randomization prior to fragmentation).
    Notes: Die Massenspekren von 19 aromatischen Isocyaniden werden angegeben. Hauptmerkmal des Elektronenstoß-induzierten Zerfalls dieser Verbindungen ist der Verlust von HCN, der gewöhnlich von einem metastabilen Peak begleitet wird. Obsleich dieser Prozeß charakteristisch ist für das Verhalten von aromatischen Isocyaniden, tritt er mehr und mehr in den Hintergrrund, wenn andere leicht spaltbare Bindungen im Molekül vorhanden sind. 2,4,6-d3-Phenylisocyanid (Ib) spaltet aus dem Molekülion vorwiegend DCN ab, während 2,4,d2-1-Naphthyl-isocyanid (IIb) hingegen HCN eliminiert. Es wird deshalb angenommen, daß bei der Abspaltung von HCN aus aromatischen Isocyaniden der dazu benötigte Wasserstoff aus einer spezifischen Stellung des Benzolkerns kommt und keine statistische Verteilung der Wassertoff-Atome vor der Fragmentierung eintritt.
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    Biological Mass Spectrometry 1 (1968), S. 910-912 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The loss of HCN and DCN from 2,4,6-d3-phenyl isocyanide is preceded by H/D randomization in the large majority of k-states which could be sampled in this study.
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    Biological Mass Spectrometry 1 (1968), S. 918-918 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 1 (1968), S. 323-329 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: It is shown that in porphin derivatives the McLafferty rearrangement occurs preferentially in even electron systems, in fact with high relative abundance starting from M2+, but less favorably in ions formed by elimination of a radical. Starting from this observation the formulation of a general scheme for the McLafferty rearrangement is attempted.
    Notes: Es wird gezeigt, daß in Porphin-Derivaten die McLafferty-Umlagerung bevorzugt in geradelektronischen Systemen abläuft. und zwar mit großer relative Häufigkeit ausgehend von M2+, jedoch weniger begünstigt in Ionen, die durch Radikalabspaltung entstanden sind. Von dieser Beobachtung ausgehend wird ein allgemeines Schema für die McLafferty-Umlagerung vorgeschlagen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 1 (1968) 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 95
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 1 (1968), S. 343-343 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 96
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 1 (1968), S. 531-536 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The p-fluoro labeling technique is used to demonstrate that the ions formed by the loss of CO from tetracyclones pass through a tetrahedral transition state or intermediate before they fragment.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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  • 97
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 1 (1968), S. 537-542 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Contrary to previous suppositions, it appears that the produced by the loss of 2 CO from para-benzoquinones passes through the symmetry of not a substituted cyclobutadiene, but rather a substituted tetrahedrane, at least for inert R. The p-fluoro labeling technique is used to obtain this result.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 98
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 1 (1968), S. 81-86 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cracking patterns of thirty-three fluorinated methanes, ethanes and propanes have been tabulated. For many of the compounds molecular ions were not observed. A comparison has been made of some of the halomethyl ion abundances with stabilization energies that have recently been derived from appearance potential measurements. Rearranged halomethyl ions occur frequently in the fluoroethane spectra. Their intensities often exceed those resulting from simple carbon bond rupture.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
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  • 99
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 1 (1968), S. 71-80 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The spectra of certain deuteriated binuclear chromium complexes have been obtained which help to elucidate some of the fragmentation processes of the molecular ion.The effect of the relative strengths of the metal-ligand and metal nitrosyl bonds is also discussed.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 100
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    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 1 (1968) 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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