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  • Inorganic Chemistry  (83.665)
  • Engineering General  (9.884)
  • Nuclear reactions  (4.460)
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Erscheinungszeitraum
Schlagwörter
  • 201
    ISSN: 0009-2940
    Schlagwort(e): 2-Li(ZnCl)-substituted oxazoles (thiazoles, imidazoles) ; Acyclic isomers ; NMR spectroscopy ; Lithium ; Zinc ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 2-Metallated oxazoles, thiazoles and imidazoles are of interest for the preparation of derivatives of the respective heterocycles, and - especially in the case of metallated thiazoles - as acyllithium equivalents in organic syntheses. Metallation at C2 of these compounds, however, often leads (more so with Li-oxazoles than with Li-thiazoles and Li-imidazoles) to products derived from the acyclic isomers of the metallated heterocycles. In order to obtain more information on the positions of the relevant equilibria, we have carried out a 13C-NMR study of substituted li- and ZnCl-oxazoles, Li-thiazoles and Li-imidazoles. In the case of Li-oxazoles, the equilibrium is completely on the side of the acyclic isomers. Addition of ZnCl2, however, leads to ring-closure, and, even in the case of 2-ZnCl-substituted benzoxazole, only the ring-closed isomer is observed. This demonstrates a dramatic gegenion effect on the equilibrium between two isomeric anions. In the case of Li-thiazoles, depending on the substitution pattern, either solely the ring-closed or an equilibrium with the ringopened isomer is observed. In the series of Li-imidazoles, only the 2-lithiated benzimidazole is in equilibrium with its ring-opened isomer. The tendency of these compounds to undergo ring-opening parallels the leaving group properties of the various subunits [OLi 〉 SLi 〉 R2NLi, and phenyl-O(S, NR)Li 〉 vinyl-O(S, NR)Li]. The difference between the effects of Li+ vs. ZnCl+ in the (benz)oxazole series is in agreement with results of solid-state structure investigations of 2-lithiated and a 2-zincated thiazole: in the Li compound the C-S bond is 2.9 pm longer than in the ZnCl species, indicating a more facile C-S bond cleavage with Li+ as the gegenion.
    Materialart: Digitale Medien
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  • 202
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1231-1234 
    ISSN: 0009-2940
    Schlagwort(e): Fluorenyl ; Zirconium ; Ether-functionalized fluorenyl ligand ; Chloro-bridged dimer ; Spiro compounds ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The monofluorenyl zirconium complex [(.(5):.1-C13H8CH2CH2OMe)ZrCl2(μ-Cl)]2, (2), has been obtained bby reaction of the respective fluorenyl lithium derivative with ZrCl4 in diethyl ether. A single-crystal X-ray structural analysis shows that 2 is a chloride-bridged dimer, in which the fluorenyl ligand is bonded in a transitional tri- to pentahapto fashion. The relatively weak fluorenyl-zirconium bond is stabilized by intramolecular coordination of the ether sidechain attached to the fluorenyl backbone. Despite this, the bidentate ligand is easily detached upon dissolution of 2 in THF. Simultaneous ether cleavage produces spiro[cyclopropane-1,9′-fluorene].
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 203
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1253-1260 
    ISSN: 0009-2940
    Schlagwort(e): Chiral carbenes ; (Carbene)ruthenium complexes ; (Carbene)rhodium complexes ; Chelate Complexes ; Chirality ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The chloro bridges of the dinuclear complexes [(.65-cymene)-RuCl2]2 and [(.5-C5Me5)RhCl2]2 can be cleaved by reaction wht an N-phenyltriazolium perchlorate (1) and a base, resulting in the formation of (carbene)metal complexes. In this manner, abstraction of one ortho-proton of the phenyl group and elimination of HCl leads to pseudo-tetrahedral ruthenium (2) and rhodium (3) complexes, thereby creating a stereogenic center at the transition metal. By using enantiomerically pure triazolium perchlorates, the diastereoselective synthesis of these complexes with diastereomeric excesses of up to 95% can be achieved, with the possibility of separating the two diastereomers by column chromatography. The relative, and therefore also the absolute configuration of the ruthenium complex (RRu)-2b could be determined by X-ray structure analysis. A stereospecific substitution of chlorine by iodine or acetonitrile to form the diastereomerically pure complexes 4, 5 and 6 (the latter as cationic ruthenium complexes) allows a further variation of the ligands.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
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  • 204
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1295-1298 
    ISSN: 0009-2940
    Schlagwort(e): Boron ; Manganese ; Borylene complexes ; Reactions at metal-coordinated boron ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reaction of the air- and water-stable borylene complex [μ-BNMe2{.5-C5H4Me)Mn(CO)2}2] (1a) with a solution of Hcl in Et2O affords the correspondin chloroborylene complex [μ-Chloroborylenebis{dicarbonyl(.5-methylcyclopentadienyl)manganese}(Mn-Mn)] (2). This compound easily undergoes further substitution reactions with protic reagents such as primary amines, alcohols and water at the metal coordinated borylene moiety with elimination of HCl, giving new products of the type [μ-BX{.4-C5H4ME)Mn(CO)2}2] (3a, ab: X=NHtBu, NHPh; 4a, b: × = OMe, OEt; 5: X= Oh}. All borylene complexes were isolated as crystalline solids in good yield and characterized by multinuclear NMR methods and IR spectroscopy in solution. In addition, the structure of 4b in the crystalline state was determined by a single-crystal X-ray study.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 205
    ISSN: 0009-2940
    Schlagwort(e): Asymmetric induction ; Helical structures ; Coordination polymers ; Copper ; Crystal structures ; Clathrates ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Reaction of a methanolic copper(II) acetate solution of enantiomerically pure (5R)-/(4S)-methyl E-(4-ethyl-2-oxazolidinylidene)cyanoacetate 6 leads to the mononuclear chelate complexes (R, R)-/ (S, S)-7. Recrystallization of (R, R)-/(S, S)-7 from non-coordinating chloroform and asymmetric induction via the stereogenic centers, originating from (R)-/(S)-6, stereospecifically yield the right- and left-handed helical ID-coordination polymers (P)-/(M)-8. The structures of mononuclear complex (R, R)-7 and of helix (P)-8 and its mirror image (M)-8 have been characterised unequivocally by X-ray crystal structure analyses. (P)- and (M)-8 crystallize with chloroform to give the clathrates 1.{[CuLR2]. 2 CHCl3} and 1.{[CuLS2].2CHCl3}, respectively.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 206
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1315-1319 
    ISSN: 0009-2940
    Schlagwort(e): Ruthenium ; Chelating diphosphane ligand ; Phosphane ; Dibenzofuran ; Tridentate ligands ; X-ray scattering ; Crystal engineering ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 4,6-Bis(diphenylphosphanyl)dibenzofuran (1), despite its large P…P distance of 5.74 Å and its bite angle of ca. 131° was found to be Capable of tridentate coordination to ruthenium (II) chloride. Single crystal X-ray structure analyses of the new ruthenium (II) complexes 3,4 and 5 revealed that the ligand 1 coordinates to a single ruthenium atom with both phosphorus centers and the dibenzofuran oxygen atom. The remarkable ligand deformation resulting from the coordination is evident from the decrease of the P…P distance by 1 Å to 4.75 Å and the increase of the bite angle (P-Ru-P) by 25° to 155°-157. The unprecedented in-plane coordination of the dibenzofuran oxygen atom to ruthenium is interesting in view of the hybridisation of the oxygen.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 207
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1339-1341 
    ISSN: 0009-2940
    Schlagwort(e): Pentacarbonyl iron ; Carbonylations ; Insertions ; Bicyclo[4.1.1]octenones ; Bicyclo[3.2.1]octenes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The cyclic vinylcyclopropane 6a reacts at elevated temperatures with iron pentacarbonyl to selectively give the enone 7a in 52% yield. Reducing the reaction time provided the isomeric ketones 7a-b. Partial chromatographic separation of this mixture allowed the complete spectroscopic identification of 7b by 1H NMR. The structure of 7c was determined from selected spectral data of the mixture of 7a and 7c. For comparison, the methyl substituted derivate 6b was subjected to a carbonylation under the above conditions exclusively providing 8 ini 42% yield. A mechanistic rationale for the two different modes of ring opening is presented.
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  • 208
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997) 
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 209
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1375-1378 
    ISSN: 0009-2940
    Schlagwort(e): Phthalocyanines ; Hemiporphyrazines ; Fullerenes ; Diels-Alder reactions ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The synthesis of a new Diels-Alder adduct 7 of [60]fullerene and a phthalocyaninenickel compound containing a longer spacer than the originally reported Diels-Alder adduct 1 is described. The bisenophilic hemiporphyrazinenickel compound 11 reacts with [60]fullerene to form a Diels-Alder adduct 12 containing two fullerene units. Spectroelectrochemical investigations of 7 and 12 reveal multiple reductions, which are attributed to the corresponding subunits of the molecules. In contrast to 1, the election acceptor properties of the [60]fullerene unit in both molecules have no influence on the electronic properties of the phthalocyanine and hemiporphyrazine, respectively.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 210
    ISSN: 0009-2940
    Schlagwort(e): Hydroformylation ; High-pressure NMR ; Homogeneous catalysis ; Rhodium ; Polyphosphane ligands ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The rhodium-catalyzed hydroformylation of 1-hexene in THF with the linear triphosphane PhP(CH2CH2PPh2)2 [PP,] has been studied both in situ and in high-pressure autoclaves. Sapphire NMR tubes with titanium valves have proved useful for studying the in situ reactions under conditions of relatively high syngas pressure (30-90 atm H,/CO) and temperature (60-100 C). Under conditions conducive to effective hydroformylation, the catalyst precursor [ (PP,)Rh(CO)]+ is quantitatively converted to the dicarbonyl [ (PP,)Rh(CO),]+, which is also the termination product of the catalysis. Irrespective of the syngas composition and of the total pressure, the dicarbonyl complex is the only phosphorus-containing species detectable on the NMR time-scale during the course of the isomerization and hydroformylation of the alkene. The PP2-Rh catalytic system exhibits some peculiar features that may be summarized as follows. (i) Very high partial pressures of CO (120 atm) neither inhibit the hydroformylation nor affect the n/i selectivity; (ii) alkene hydrogenation occurs neither at very high partial pressures of H, (120 atm) nor in the absence of added CO; (iii) the isomerization rate is slightly faster than that of hydroformylation; (iv) terminal and internal alkenes (2-, 3-hexenes) are hydroformylated with comparable rates. Various control experiments have been carried out using in-situ NMR, as well as batch experiments under different reaction conditions or with different catalyst precursors. Despite these extensive studies, unambiguous conclusions about the catalysis mechanism have not been reached. In particular, the possibility that different catalysts may be operative depending on the reaction conditions cannot be ruled out. The hydroformylation results rule out the involvement of phosphane-free “Rh-CO” catalysts, even under conditions of very high partial pressure of CO, and point to “(PP,)Rh(CO),” catalysts with small steric hindrance over the whole range of syngas pressures investigated.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 211
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997) 
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 212
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1721-1730 
    ISSN: 0009-2940
    Schlagwort(e): Perhalometallocenes ; Cylopentadienes ; Perhalogenated ; Halogen-metal exchange reactions ; Sandwich complexes ; Ligand effects ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The coordination chemistry of perhalocyclopentadienyl ligands, first developed in the early 1970's as a part of a research program directed towards the synthesis of oxidation-resistant fuel additives, has been revived in the last ten years. This renewed interest stems from the discovery that the coordinated cyclopentadienyl ligand allows multiple functionalizations. Thus, the high versatility of this important class of ligands can be broadened even further, which may be important with regard to industrial applications of metallocenes.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 213
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1745-1749 
    ISSN: 0009-2940
    Schlagwort(e): Density functional calculations ; Tetra(amino)methane ; Tetra(amino)silane ; Transition states ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: In all-electron density functional calculations on mono- and tetraaminosubstituted methane and silane the coordination around the nitrogen center is found, in complete agreement with experiment, to be less pyramidal in the silicon compounds. The calculated barrier to inversion at nitrogen is only 0.6 kcal/mol in silylamine, while in methylamine it is 5.5 kcal/mol. The larger flexibility is attributed to the greater ionic character of the Si-N bond compared to that of the C-N bond. In tetra(amino)methane, inversion of one amino group leads to a local minimum (calculated inversion barrier: 6.4 kcal/mol), while a corresponding structure (or barrier) does not exist for the silicon compound. Due to the steric influence of the amino groups, the barrier to rotation around the C-N bond is larger in the tetrasubstituted compound (6.4 kcal/mol compared to 2.3 kcal/mol in methylamine). While the average binding energy of the amino groups is similar in both tetra(amino)compounds, the binding energy of the fourth ligand is about 25% larger in the silicon compound for both homolytic and heterolytic bond cleavage. This difference arises from the relative stabilization of the tri(amino)-methyl species, due to some n contribution to the C-N bond.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 214
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1771-1776 
    ISSN: 0009-2940
    Schlagwort(e): Chelates ; P ligands ; Phosphaferrocene ; Carbonyl complexes ; Heterocycles ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Dicyclohexyl-acid diphenylphosphanyl-substituted phosphaferrocenes 2 and 3 were synthesized by substitution of the amino group in 2-dimethylaminomethyl-3,4,-dimethylphosphaferrocene 1 · Homologization of 2-formyl-3,4-dimethylphosphaferrocene 4 by one CH2 unit via Wittig olefination provided access to the phosphanylethyl derivative 9. Ligands 2, 3 and 9 formed P, P-chelate complexes with tetracarbonyl metal fragments in good yield. X-ray crystal structure determinations were carried out for the five-ring chelate complex 2. Mo(CO)4 (≡ l0), and the six-ring chelate complex 9 . Mo(CO)4, (≡ 13).
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 215
    ISSN: 0009-2940
    Schlagwort(e): Bisphosphane, bisdichloromethylene-bridged ; Oxidation with tetrachloro-o-benzoquinone(TOB) ; σ 6 λ5-phosphorate ; Phosphorus Heterocycles ; Structure elucidation ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The title compound 3 was formed in the reaction of Cl2PCCl2PCl2 (2) with catechol in the presence of triethylamine. The reaction of 3 with tetrachloro-o-benzoquinone (TOB), 4, led to the σ3P/σ5P-species 5, and the σ5P/σ5P-species 6a/6b. 5 was stable only in solution, and its existence and identity are postulated on the basis of its 31P-NMR spectrum. The structure of 6a/6b could not be assigned unambiguously to one isomer. The reaction of 6a/6b with water yielded the phosphorate 10. The structures of 3 and 10 were determined by single crystal X-ray methods. A wide P—C—P angle (123.2°) was observed in 3. The cation of 10 is a centrosymmetric, protonated DMF dimer with O—O 241.3 pm.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 216
    ISSN: 0009-2940
    Schlagwort(e): [2 + 1] Cycloadditions ; Hydrogen cyanide ; Phosphorus dipolarophiles ; Three-membered rings ; Calculations, ab initio ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: We performed a systematic investigation of [2 + 1] cycloadditions of HN≡C to dipolarophiles of the type CH2=X and PH=X with X=CH2, NH, O, SiH2, PH, and S, as well as HN=NH and H2Si=SiH2. Ab initio MO calculations at the QCISD(T)/6-311G(d,p)/MP2/6-31G(d,p)+ZPE level were applied to construct the minimum-energy reaction pathways. Calculated results concerning the regiochemistry of the approaches and the stereochemistry of the product formation were analyzed in relation with established concepts such as frontier orbital, net charge distribution and stereoelectronic effect. For some systems, up to four distinct transition structures for cycloaddition were found. In general, there is a certain similarity between the behavior of both C and P series of dipolarophiles. The characteristics of the transition structures can be, in most cases, recovered by using qualitative concepts. The [2 + 1] cycloadditions are highly regioselective and stereospecific. Silicon-containing dipolarophiles are particularly attractive as they exhibit very small energy barriers to addition to isocyanides.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 217
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 89-94 
    ISSN: 0009-2940
    Schlagwort(e): (Triphenylphosphonio)phosphaethyne ; Azides ; [3 + 2] Cycloadditions ; Phosphonio-1,2,3,4-triazaphospholes ; Diphosphonio-1,2,4-diazahospholes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Several products resulting from the condensation of the bis-(trimethylsilyl)ylide 1 with PCl3 serve as synthetic equivalents of a phosphoniophosphaethyne. Cycloaddition reactions with azides lead to phosphonio-1,2,3,4-triazaphosphole cations 5, 7 and to the zwitterionic phosphonio-1,2,3,4-triazaphospholide 6. The latter readily undergoes a cycloreversion yielding a phosphoranediyl diazomethane 12 as intermediate. Its cycloaddition affords the diphosphonio-1,2,4-diazaphosholide chloride 9a as the final product. 9a is a remarkably stable and unreactive derivative of the two-coordinate phosphorus. By HCL it is protonated at a nitrogen atom to give dication without any tendency to associate with the chloride counterions.
    Zusätzliches Material: 1 Tab.
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  • 218
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 105-110 
    ISSN: 0009-2940
    Schlagwort(e): Sulfides ; Selenides ; Copper complexes ; Ambidentate ligands ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Triphenylphosphite has been converted into tris(phenylthiomethyl)phosphane (1) by reaction with LiCH2SPh/DABCO, and subsequently into the corresponding sulfide (2) and selenide (3) by treatment with elemental sulfur or selenium, respectively. Ligands 2 and 3 react with copper(I) halides CuX (X = Cl, Br, I) in polar organic solvents to give either 1:1 (X = Cl: 4, 7, X = Br: 5, 8 ) or 1:2 complexes (X = Br: 9, X = I: 6, 10). The crystal structures of five of these complexes have been determined by single crystal X-ray diffraction studies. All compounds of the type [(PhSCH2)3P=S/Se]CuX (X = Cl, Br) form centrosymmetrical dinuclear complexes featuring a four-membered ring core Cu2[S/Se], fused to two five-membered rings Cu[S/Se]PCS through common trans edges. Only one of the three phenyl-thiomethyl functions is involved in coordination to a metal center. The compound [(PhSCH2)3P=S](CuI)2 (6) is associated into a centrosymmetrical tetranuclear complex containing two four-membered rings (ICu2S) bridged via iodine atoms in 1,3-cis positions. The ligand is found to employ two of its PhSCH2 functions for metal coordination, giving rise to two five-membered rings fused to the four-membered rings via neighbouring edges. In all cases, therefore, the P=S/Se functions of the ligands are the preferred donor sites, which are used for the building of bridgehead structural units of polynuclear complexes.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 219
    ISSN: 0009-2940
    Schlagwort(e): Iridium ; Hydrido complexes ; Olefin complexes ; C-H activation ; P ligands ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Etheneiridium(I) complexes of the general composition trans-[IrCl(C2H4)L2] [L = iPr2PCH2CO2Me (2a), iPr2PCH2CO2Et (2b), iPr2P(CH2)3NMe2 (2c)] have been prepared either from [IrClL2] (3) or [IrCl(C2H4)2]2 (7) as starting materials. The corresponding carbonyl derivatives trans-[IrCl(CO)L2] (6, 10, 11) are obtained along similar routes. Photolysis of trans-[IrCl(C2H4)L2] (L = 2a, 2b) leads, by intramolecular C-H activation, to the formation of the octahedral hydrido(vinyl)iridium(III) compounds [IrHCl(CH=CH2)(k-L)(k2-L)] (16, 17), which are highly fluctional in solution. Carbonyl(hydrido)(vinyl) complexes are accessible either from 16 or 17 and CO, or from trans-[IrCl(C2H4)L2] (L = 2a) and the propargylic alcohol HC≡CCH(Ph)OH, respectively. Treatment of 3 or the corresponding dihydrido compound [IrH2ClL2] (4) with methyl vinyl ketone or methyl acrylate also yields hydrido(vinyl)iridium(III) complexes [IrHCl(CH=CHX)L2] [X = C(=O)Me (18), C(=O)OMe (19)], in which instead of the C=O function of the phosphanyl ester the carbonyl group of the vinylic moiety is coordinated to the metal. The reaction of 16 (L = 2a) with terminal alkynes HC≡CR (R = Ph, CO2Me) affords the structurally related alkynyl(hydrido)iridium(III) compounds [IrHCl(C≡CR)(k-L)(k2-L)] (28, 29), while from 16 and internal alkynes RC≡CR) the iridium(I) complexes trans-[IrCl1(RC≡CR)L2] (30, 31) are obtained, Stepwise treatment of trans-[IrCl(RC≡CR)L2] (6: L = 2a) with NaN(SiMe3)2, (ii) H2O, and (iii) HCl leads, in the coordination sphere of the metal center, to a conversion of iPr2PCH2CO2Me to iPr2PCH2CO2H via the isolated phosphanylenolate and phosphanylacetate complexes 32 and 33 as intermediates.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 220
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1643-1646 
    ISSN: 0009-2940
    Schlagwort(e): Nickel Schiff base complexes ; Base adducts ; Chirality ; Steric hindrance ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Reaction of the ligand meso-H2L, derived from cis-diaminocyclohexane and ethyl cyano(ethoxymethylene)acetate, with nickel(II) acetate gives meso-NiL. Spectrophotometric titration of RR-NiL and meso-NiL with various nitrogen bases reveals a strong influence of the steric hindrance of the diaminocyclohexanediyl bridge in meso-NiL on the base adduct stability. The structures of RR-NiL and meso-NIL have been established by X-ray diffraction.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 221
    ISSN: 0009-2940
    Schlagwort(e): Hexadeamino-hexaisocyano-neomycin B ; Organometallic complexes ; Gold ; Chromium ; Rhodium ; Iridium ; Ruthenium ; Palladium ; Platinum ; Hexanuclear carbene gold(I) complexes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: From the amino glycoside neomycin B, the acetate-protected hexaisocyanide 4 has been prepared. 4 forms the hexanuclear complexes [(4)(AuCl)6] (5), {(4)[Cr(CO)5]6}, {(4)[MCl2(η5-C5Me5)]6} (M = Rh, Ir), {(4)[RuCl2(p-cymene)]6}, {(4)-[MCl2(PR3)]6} (M=Pd, Pt), and 4{(4)[PdCl(C6H4CH2NMe2)]6). The hexaisocyanohexagold(I) complex 5 reacts with H2NtBu and PhNH2 to give the corresponding carbene complexes. The compounds have been characterized by IR, 13C- and 31P-NMR spectroscopy, and (partially) by FAB-MS data.
    Zusätzliches Material: 4 Tab.
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  • 222
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1693-1698 
    ISSN: 0009-2940
    Schlagwort(e): P,N ligands ; Rhodium complexes ; Iridium complexes ; Hydrogen bonding ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Treatment of trans-[MCl(CO)(PPH3)2] (M = Rh, Ir) with the lithium salts fof the bidentate hybride ligands 2-Ph2PC6H4N(R)H [‘PN(R)H’ R = H, Me] produced the chelate complexes [M(CO)(PPH3)(‘PNR’)] [M/NR = Rh/NH (1a), Ir/ NH (2a), Rh/NMe (1b), Ir/NMe (2b)] containing the CO ligand and the NR substituent in mutual trans-arrangement. 2b was shown by single-crystal X-ray diffraction to possess an amido-nitrogen atom in a trigonal-planar environment. Oxidative addition of H2 to 2b reversibly formed cis-[IrH2(CO)(PPh3)(‘PNMe’)] (3), in which H2 has added perpendicular to the N-Ir-CO axis. While both 1a,b and 2a, b proved to the completely unreactive toward CO2 at ambient temperature and pressure, reactions of 1a and 2a/b with sulfur dioxide reversibly formed pentacoordinate SO2 adducts, [M(SO2)(CO(PPh3)(‘PNR’)][M/NR = Rh/Nh (4a), Ir/NH (5a), Ir/NMe (5b) with M-S-bonded pyramidal MSO2 units as established by an X-ray structure analysis of 5a. Complex 5b reacted with dioxygen to form the sulfato compound [Ir(O2SO2)(CO)(‘PNMe’)] (6). Combination of 2a with HCl in CHCl3 at -60°C resulted in protonation of both the iridium and the nitrogen atom to give an ionic chelate complex, [IrHCl(CO)(PPh3)(‘PNH2’)]Cl (7), containing one of its NH groups hydrogen-bonded to Ir-Cl. Ring opening of the chelate structure with formation of [IrHCl2(CO)(PPh3)(PPh2C6H4N(Me)H-o)] (8) was observed in the analogous reaction of 2b with hydrogen chloride. NMR spectroscopy showed 8 to exist in CDCl3 solution as a mixture of three Ir-PPh2C6H4N(Me)H-o rotamers, stabilized by intramolecular -N(Me)H  - ClIr hydrogen bonding.
    Zusätzliches Material: 2 Ill.
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  • 223
    ISSN: 0009-2940
    Schlagwort(e): 6,7,8,9-Tetrafluoro-1,3,5,2,4-benzotrithiadiazepine ; 1,2,3,4-Tetrafluoro-5,6-bis(1-trimethylsilyl-2,4-dithia-1,3-diaza-1,2-butadien-4-yl)benzene ; Photoelectron spectroscopy ; Semiempirical calculations ; Nitrogen heterocycles ; Sulfur heterocycles ; Fluorine compounds ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The 14π-electron title compound 7 has been synthesized by two different ring-closure approaches. Its structure has been determined by X-ray diffraction to be planar within ±0.018 Å. The He(I) photoelectron spectrum of the title compound is assigned by Koopmans' correlation with PM3 eigenvalues based on the structural data, and by the π-perfluoro effect observed. The π-system can be rationalized y heteroatom first-order perturbation, which reduces the cycli π-delocalization. Replacement of the four fluorine substituents by hydrogen affects neither the long-wavelength absorption band in the UV/Vis spectrum nor the δ15N shift in the 15N-NMR spectrum. The synthesis of 20π-electron heterocycles related to the title compound has been attempted.
    Zusätzliches Material: 3 Ill.
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  • 224
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 299-305 
    ISSN: 0009-2940
    Schlagwort(e): Iodine ; Phosphorus ; Charge transfer ; NMR spectroscopy ; Raman spectroscopy ; Structure elucidation ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The solid-state and solution structures of Ph3P · I2 have been studied in detail by electronic, 31P{1H}-NMR and Raman spectroscopy as well as conductometric measurements. When 1 : 1 ratios of triphenylphosphane and diiodine are mixed in dichloroethane, the molecular adduct is shown to exist also in solution. On the basis of the overall results, this molecular adduct is best described as a charge-transfer complex of the donor I- with the acceptor Ph3PI+, rather than the charge-transfer complex of the donor Ph3P with the acceptor I2 or the ionic species [Ph3PI]I as previously proposed. When higher diiodine to triphenylphosphane ratios are used, the Ph3P · I2 adduct dissociates to give Ph3PI+ and I3- or I5- depending on the diiodine excess. Previously reported solution data, which were ascribed to the ionic form of the adduct, are instead in agreement with hydrolysis products (Ph3PO, PH3POH+) of the very reactive adduct, formed in the presence of traces of water.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 225
    ISSN: 0009-2940
    Schlagwort(e): Gold ; Phosphanes ; Phosphaneimines ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: [Tris(dimethylamino)phosphane]gold(I) chloride, μ-tris-{[tris(dimethylamino)phosphane]gold(I)}oxonium tetrafluoroborate, {μ3-tris(dimethylamino)phosphaneimidotris[tris(dimethylamino)phosphane]gold(I)}(2+) bis(tetrafluoroborate) and N-trimethylsilyltris(dimethylamino)phosphaneimine were prepared using modifications of established procedures. Their structures were determined in single-crystal X-ray diffraction studies. The ligand (Me2N)3P, here introduced into gold(I) chemistry for the first time, lends high stability to these compounds through efficient steric shielding of the reaction sites and through a balanced electronic substituent effect. The structural details of the (Mr2N)3P groups are of current interest because of the unusual nonequivalent configuration of the nitrogen atoms in the dimethylamino groups. This behaviour has been observed for most of the (Me2N)3P units in the compounds studied in this work.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 226
    ISSN: 0009-2940
    Schlagwort(e): Rhenium complexes ; Technetium complexes ; Radiopharmaceuticals ; Dithioether ligands ; Dithiaalcohols ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Neutral oxorhenium(V) complexes of the general formula ReO(L)Cl2 are obtained by reaction of [ReO4]- or [ReOCl4]- with functionalized dithiaalcohols (L) containing the donor atom sequences S, S, O- and S, O-, S. Ligand exchange reaction of [ReOCl4]- with HO(CH2)2S(CH2)2S(CH2)2O (R = H, Et ) leads to the formation of ReOCl2[O(CH2)2S(CH2)2-S(CH2)2OEt] (1b). Reduction of [ReO4]- with a 1:1 mixture of concentrated HCl and glacial acetic acid in the presence of nBuSCH2- CH(OH)CH2S-nBu yield ReOCl2[OCH(CH2S-nBu)2) (4). X-ray structure analysis of 1a, 1b and 4 shows distorted octahedral coordination with the chlorine and sulfur atoms in the equatorial plane. The oxygen of the hydroxyl group coordinates in a trans position with respect to the Re=O core. 1a reacts with an excess of acetyl chloride in an unexpected way, resulting in cleavage of the trans Re-O bond and acylation of both of the hydroxyl groups to form the μ-oxo bridged complex [ReOCl2{CH3COO{CH2)2S(CH2)2PPC-CH3}}2O (3).
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 227
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1833-1836 
    ISSN: 0009-2940
    Schlagwort(e): Phthalocyanines ; Phthalonitrile derivatives ; Pentanuclear complexes ; Nickel ; Zinc ; Cobalt ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Novel phthalocyanines (M = Ni, Zn, Co) bearing eight 2′-aminophenoxy and 2′-amino phenylsulfanyl substitutents on peripheral positions have been prepared starting from 4,5-bis(2′-aminophnoxy)-1,2-dicyanobenzene and the corresponding anhydrous metal salts [NiCl2, Zn(O2CMe)2, CoCl2]- Complexation of octakis(2′-amino phenylsulfanyl)-substituted metallo phthalocyanines (2b, 3b and 4b) with Pd11 to form the pentanuclear product was accomplished from their mixtures.
    Zusätzliches Material: 1 Ill.
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  • 228
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1-8 
    ISSN: 0009-2940
    Schlagwort(e): Chalcogenides ; Reactive flux ; Layered compounds ; Structures ; Physical properties ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The syntheses, crystal structures, and physical properties of some recently discovered layered ternary and quaternary chalcogenides are reviewed. One component of these systems is an alkali metal or thallium; another is a d-, f-, or p- block metal.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
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  • 229
    ISSN: 0009-2940
    Schlagwort(e): Alkoxopalladium(II) ; Conformational analysis ; Hydrogen bonding ; Two-dimensional and cage structures ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reaction of palladium acetate with two equivalents of di- and triethanolamines RN(CH2CH2OH)2 in the presence of a base affords the new chelate-stabilized alkoxo Pd(II) complexes [Pd(OCH2CH2N(R)CH2CH2OH)2] [R = Me (1), Et (2), n-Bu (3), benzyl (4) or CH2CH2OH (5)]. These N,O-ligated complexes are isolated in high yield as yellow, crystalline solids and are thermally stable despite the presence of several β-hydrogen atoms in the ligand system. Both complexes possess a square-planar palladium coordination geometry with the two oxygen atoms positioned mutually trans. The most notable difference in the molecular structures is that 1 forms a two dimensional network of intermolecular O-H≡O hydrogen bonds, whereas 5 forms intramolecular O-H⃛O hydrogen bonds, which cage the palladium center. In solution 1-4 exist as a diastereoisomeric mixture (a racemic enantiomeric pair SNSN, RNRN and a mesomeric form RNSN) in a 1:1 molar ratio, and this ratio is independent of temperature in nonalcoholic solvents, When complexes 1-4 are dissolved in protic solvents (e.g. MeOH) the diastereomeric excess is temperature-dependent due to an exchange process between the meso diastereoisomer and the (racemic) enantiomeric pair. Thermodynamic parameters for this process in a mixture of MeOH-toluene have been determined with NMR and show this process to be influenced by the steric nature of the alkyl substituent (R) on nitrogen. A conformational analysis based on 1H-NMR coupling constants within the N,O-chelate ring of complexes 1-4 provides details on the solution structure of the ring in both diastereoisomers.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 230
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 307-316 
    ISSN: 0009-2940
    Schlagwort(e): Halogen oxides ; Solid-state structures ; Intermolecular interactions ; Halogens ; Oxygen ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The development of new preparative and analytical techniques that allow appropriate handling and characterizations of the capricious halogen oxides have initiated a revival of their chemistry. Due to these recent activities, the amount of well-confirmed knowledge about such oxides has considerably increased. This is especially valid for the structural chemistry in the solid state, which (among other topics) has greatly benefitted from developments in the techniques of in situ crystal growth of low melting substances on a diffractometer. As a consequence, some general crystal chemical features have become apparent: The coordination polyhedra of the halogen oxides can be readily understood in terms of the qualitative VSEPR concept, and there is a pronounced tendency to form mixed valence compounds where the respective valence states can be easily deduced from the coordination polyhedra. Furthermore, intermolecular or interionic bonds are significant, with increasing importance when moving from chlorine to iodine. Finally, ClO2 appears to be the only representative with the halogen in an even oxidation state.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
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  • 231
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 341-346 
    ISSN: 0009-2940
    Schlagwort(e): Carbenoids ; Carbolithiation ; Cyclization ; Cyclopropanation ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The dichotomy between concerted cyclopropanation and carbolithiation pathways on intramolecular carbenoid cyclopropanation reactions has been studied. These studies have been extended to the intramolecular carbenoid/aldehyde addition reaction.
    Materialart: Digitale Medien
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  • 232
    ISSN: 0009-2940
    Schlagwort(e): Bis(triphenylmethoxy)hydroborane ; Naphtho[2,3-d], -1,3,2-dioxaborolane ; Naphtho[1,8-de]-1,3,2-dioxaborinane ; Phenanthro[9,10-d]-1,3,2-dioxaborolane ; Dibenzol[d,g]-1,3,2-dioxaborocine ; Bis(diphenylmethoxy)borane ; Tetrachlorobenzo-1,3,2-dioxaboraolen ; Hydroborations ; Boron ; Catalysis ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: New and stable bis(organyloxy)boranes, 1,3,2-dioxaborolanes and 1,3,2-dixoaborinanes have been prepared (i) from the corresponding diol and BH3·THF and (ii) from 1,2-diketones and BH3·THF. They were characterized by spectroscopic techniques. The BH stretching frequency seems to be a measure of ring strain and Lewis acidity. The compounds have been qualitatively tested in the transition-metal-catalysed hydroboration of cyclopentene, and the dioxaborinane 11 proved to be superior to the 1,3,2-dioxaborolanes 9 and 18.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 233
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 473-478 
    ISSN: 0009-2940
    Schlagwort(e): Clusters ; Zirconium ; Metal alkoxides ; Sol-gel processes ; Carboxylato complexes ; Oxo complexes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The crystalline oxozirconium methacrylate clusters Zr6(O-H)4O4(OMc)12 and Zr4O2(OMc)12 were obtained by reaction of Zr(OnPr)4 with an excess of methacrylic acid and analysed by X-ray diffraction. The oxide and hydroxide groups are in a μ3- bridging mode in both structures, and the methacrylate ligands are chelating or bridging. The zirconium atoms in Zr6(OH)4O4(OMc)12 form an octahedron the cluster having crystalographic C3v symmetry. Each metal atom is square-antiprismatically coordinated by eight oxygen atoms. In Zr4O2(OMc)12, the zirconium atoms have a distorted butterfly arrangement; their coordination geometry is square-antiprismatically coordinated by eight oxygen atomes. In Zr4O2)OMc)12, the zirconium atoms have a distorted butterfly arrangement; their coordination geometry is square-antiprismatic or capped octahedral.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 234
    ISSN: 0009-2940
    Schlagwort(e): Osmium(0) complexes ; Nitrosyl complexes ; Oxidative addition reactions ; Alkynyl(hydrido)osmium complexes ; Diynyl(hydrido)osmium complexes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The coordinatively unsaturated starting materials trans-[OsCl(NO)PiPr3)2] (2) and trans- [(sCl(NO)(PiPr2Ph)2] (3), for which a new one-pot synthesis is reported, react with isocyanides, SO2 and O2 to give the corresponding 1:1 adducts [OsCl(NO)(L)(P)(PiPr2R)2) (4-7). The corresponding methyleneosmium complex [OsCl(NO)(=CH2)(PiPr3)2] (9), on treatment with SO2 and HCl, affords the six-coordinate osmium(II) compounds [OsCl(NO)(K2(C,O)-CH2S(O)O)()iPr3)2] (10) and [OsCl2(NO)(CH3(PiPr3)2]2] (11), respectively. The reactions of 2 and 3 with HCl, I2, CH3I, CH2=CHBr, R'CO2H, PhSH, CH3OH, PhCOSH, and R'CHO lead by oxidative addition to the corresponding octahedral osmium(II) complexes [OsCl-(NO)(X)(Y)(PiPr2R)2] (12-24). The initially formed compound [OsHCl(NO){SC(=O)Ph}(PiPr3)2] (20a) rearranges smoothly to the more stable S-bonded isomer [OsHCl(NO){OC(=S)Ph}(PiPr3)2] (20b). Alkynyl(hydrid)- and diynyl(hydrido)-osmium(II) complexes 20-31 and 34, 35 are obtained from 2 or 3 and HC≡CCO2/sb〉Me, propargylic alcohols HC≡CCPh-(R')OH or the diyne HC≡CC≡CCPh2OH. The compounds [OsHCl(NO)[C≡CCPh(R')OH)(PiPr3)2] (30, 31) react with aqueous HCl in benzene to give the η1-allenylosmium(II) derivatives [OsCl2(NO)(η1-CH=C=C(Ph)R'](PiPr3)2] (32, 33). [OsHCl(NO)(C≡CC≡CCPh2OH)(PiPR3)2] (34) has been characterized by X-ray structural analysis.
    Zusätzliches Material: 3 Ill.
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  • 235
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 521-528 
    ISSN: 0009-2940
    Schlagwort(e): Macrocycles ; Hydrogenation ; Cyclam, binding constant ; N ligands ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: We report here a new synthetic route to highly-substituted tetraazamacrocycles. Raney nickel hydrogenation of macrocyclic phenylenediamine-acetylacetone condensation products gives cyclams in high yield with complexes all-cis stereoselectivity. The extensive C-substitution of the cyclam 2a changes its ligand properties markedly. The X-ray structure analyses of NiII, CuII, and ZnII complexes of 2a reveals a deviation of the metal ion coordination geometry from the usual square-planar arrangement. This may account for the differences in the redox properties of the NiII and CuII complexes of 2a leads to more positive oxidation and reduction potentials compared to the analogous unsubstituted cyclam complexes. While the binding constant between Zn(ClO4)2 and 2a is lower by a factor of 105 compared to cyclam, the subsequent binding of uridine to the zinc-cyclam complexes in methanol/water is slightly stronger in the case of 2a · Zn(ClO4)2].
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 236
    ISSN: 0009-2940
    Schlagwort(e): Alkali metal organophosphanylamide ; Carbon-potassium bonding ; Phosphazane ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The metalation of bis(diphenylphosphanyl)amine [HN-(PPh2)2,1 with KOtBu at 95°C in toluene affords a pale yellow precipitate of potassium bis(diphenylphosphanyl)amide (3a). On addition of liquid N,N,N′,N“,N“-pentamethyldiethylenetriamine (PMDTA, 4) the precipitate dissolves in toluene at 115°C to give a yellow solution, from which yellow-green blocks of [(Ph2P)2NK·PMDTA] (3b) are obtained. X-ray analysis reveals that the coordination sphere of potassium consists of the chelating triamine ligand and [N(PPh2)2]- as N-donor as well as η1 and η2 C-donor with two phenyl fragments. No phosphorus coordination of [N(PPh2)2]- is observed.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 237
    ISSN: 0009-2940
    Schlagwort(e): α-Bromoglycine derivatives ; Amino acids ; Iron ; Chromium ; Tungsten ; Transition-metal-labeled α-amino acids ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reactions of protected α-bromoglycine esters R1(O)CNHCH(Br)CO2R2 (R1=Ph, OCMe3; R2 =Me, tBu) with organometallic anions of acetylferrocene, CpFe(CO)(PPh3)-C(O)CH3, (OC)5M=C(OMe)CH3 (M=Cr, W), (OC)3Cr(η6-diphenylmethane), (OC)3Cr[η6-fluorene), (OC)3Cr(η6-dihydroanthracene) and of (OC)3Cr(-η6aniline) and (OC)3Cr(η6-o-toluidine) provide a method for the introduction of organometallic fragments into the side chains of α-amino acids.The complexes may be useful as markers for α-amino acids in peptides.The compound (OC))3Cr(η-o-C6H4(CH3)NHC-(H)(CO2Me)NHC(O)Ph was characterized by X-ray diffraction.
    Zusätzliches Material: 1 Ill.
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  • 238
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 183-194 
    ISSN: 0009-2940
    Schlagwort(e): Iron ; Alkyne complexes ; Vinylidene complexes ; C-H oxidative addition ; Rearrangements ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reaction of a mixture of Fe(CO)2(PEt3)2N2 (1a) and [Fe-(CO)2(PEt3)2]2N2 (1b) with acetylene leads to three complexes: Fe(CO)2(PEt3)2(π-HC≡CH) (2a), Fe(CO)2(PEt3)2(H)(C≡CH) (2b), and Fe(CO)2(PEt3)2=C=CH2 (2c). Upon chromatography on silylated silica gel the mixture of 2a-c is completely transformed into 2c. The analogous reaction of 1a, b or of Fe(CO)2[P(OiPr)3]2N2 (1d) with HC≡CSiMe3 affords the primary oxidative addition products Fe(CO)2L2(H)(C≡CSiMe3) [L = PEt3, 3a; L = P(OiPr)3, 3c]. The presence of a small amount of Al2O3 in hexane irreversibly converts 3a and 3c into the vinylidene compounds Fe(CO)2L2=C=C(H)SiMe3[L = PEt3, 4a; L = P(OiPr)3, 4c]. The chromatographic work-up of 4c additionally leads to the hydrolysis product Fe(CO)2[P(OiPr3)2]2=C=CH2 (2d). The reaction of the phosphite-substituted derivative Fe(CO)2[P(OMe)3]2I- (1c) with silylacetylene allows detection of the acetylene species Fe(CO)2 [ P(OMe)3]2 (HC ≡CSiMe3) (3b), as well as the acetylido hydrido derivative Fe(CO)2[P(OMe)3]2(H)(C=CSiMe3) (4b). In a slow subsequent process, or with promotion by Al2O3 in hexane, the vinylidene compound Fe(CO)2[P(OMe)3]2=C=C(H)SiMe3 is formed. 3b or 4b are hydrolyzed to Fe(CO)2[P(OMe)3]2=C=CH2 (5c) in the presence of SiO2. The reaction of disilylacetylene with 1a-d results in the formation of disilylvinylidene complexes Fe(CO)2L2=C=C(SiMe3)2 (L = PMe3, 7a; L=PEt3, 7b; L = PiPr3, 7c). An intermediate acetylene derivative could be isolated for L = PEt3 (6a) and spectroscopically detected for L = P(OMe)3 (6b), but could not be traced for L = P(OiPr)3. Further studies were devoted to the reactions of silyl diynes (Me3SiC≡CR, R = C≡CSiMe3, p-C6H4-C-CSiMe3) with 1a-c. In all cases the acetylene compounds Fe(CO)2L2(Me3-SiC≡CR) [L = PEt3, R = C≡CSiMe3, 8a; R = p-C6H4-C≡CSiMe3, 9a; L = P(OMe)3 R = CSiMe3, 8b; R = p-C6H4-C≡CSiMe3, 9b] were isolated, but only for 8b was an equilibrium process observed to form the corresponding vinylidene derivative Fe(CO)2[P(OMe)3]2=C=C(SiMe3)C-C-SiMe3 (10b). 10b hydrolyzes upon chromatography on silica gel to give Fe(CO)2[P(OMe)3]2=C=CH-C≡CSiMe3 (11b): Finally, the reaction of p-diethynylbenzene with 1a-c was explored. The acetylido hydrido species Fe(CO)2L2(H)C≡C-p-C6H4-C≡CH was isolated in the case of L = PEt3 (12a) and spectroscopically detected for L = P(OMe)3 (12b). 12b and 12a transform spontaneously and in the presence of Al2O3 in hexane, respectively, to the vinylidene complexes Fe(CO)2L2=C=C(H)R [R = C6H4-C≡CH, L = PEt3, 13a; L = P(OMe)3, 13b]. 6a, 7a, and 8a have been characterized by single-crystal X-ray diffraction studies.
    Zusätzliches Material: 2 Ill.
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  • 239
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 225-230 
    ISSN: 0009-2940
    Schlagwort(e): Sesquifulvalene ; Heterobimetallic complexes ; Manganese ; Chromium ; Stille coupling ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The synthesis of the heterobimetallic sesquifulvalene complex [(OC)3Mn(μ-η5:η7-C5H4-C7H6)Cr(CO)3]BF4 (2) is reported. [(2,4,6-Cycloheptatrien-1-yl)-η5-cyclopentadienyl]tricarbonylmanganese (3) reacts with (CH3CN)3Cr(CO)3 to give a mixture of endo- and exo-[(OC)3Mn(μ-η5:η6-C5H4C7H7)Cr(CO)3] (4a, b). Hydride abstraction from this mixture resulted in the formation of 2 in low yield. Alternatively, Stille coupling of 2-trimethylstannyl-1,3,5-cycloheptatriene (5) with (iodocyclopentadienyl)tricarbonylmanganese (6) gave [(1,3,5-cycloheptatrien-2-yl)-η5-cyclopentadienyl]tricarbonylmanganese (7). After treatment of 7 with (CH3CN)3Cr(CO)3, a mixture of two heterobimetallic complexes [(OC)3Mn(μ-η5:η6-C5H4-C7H7)Cr(CO)3] (8a, b) was isolated. In 8a, a bridging (1,3,5-cycloheptatrien-2-yl)cyclopentadienyl ligand was found, while 8b contains a (1,3,5-cycloheptatrien-1-yl)cyclopentadienyl ligand. The mixture 8a, b was converted quantitatively into 2 by reaction with triphenylcarbenium tetrafluoroborate. The X-ray crystal structures of 2, 4a, 4b and 8a are reported.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 240
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 335-340 
    ISSN: 0009-2940
    Schlagwort(e): Allylsilanes ; Superbases ; Metalations ; Stereoselectivity ; Cyclizations ; Silicon ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: When treated with two equivalents of a butyllithium/potassium tert-butoxide mixture, terminal olefins carrying unprotected hydroxy or carboxy groups generate allylmetal intermediates which can be trapped with chlorotrimethylsilane to afford functionalized (Z)-2-alkenyltrimethylsilanes. One equivalent of the superbasic reagent suffices if the unsaturated alcohols are first protected as acetals before being subjected to the metalation/silylation/hydrolysis sequence.
    Materialart: Digitale Medien
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  • 241
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 77-82 
    ISSN: 0009-2940
    Schlagwort(e): Monoterpenes ; Sesquiterpenes ; Stereoselectivity ; Alk-l-enyllithium(sodium) Metal exchange, halogen vs. hydrogen ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: (Z)-(3,3-Dimethylbicyclo[2.2.1]hept-2-ylidene)methyllithium can be readily generated by treatment of (Z)-3-bromomethylene-2,2-dimethylbicyclo[2.2.1]heptane with tert-butyl-lithium. At -75°C, the organometallic intermediate is configurationally stable and reacts with a variety of electrophiles under stereochemical retention.
    Materialart: Digitale Medien
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  • 242
    ISSN: 0009-2940
    Schlagwort(e): Zinc complexes ; Alkyl carbonate complexes ; CO2 fixation, reversible ; Catalysis ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The zinc hydroxide complexes Tp*Zn-OH with TpCum,Me = tris(3-cumenyl-5-methylpyrazolyl)borate and TptBu,Me = tris(3-tert-butyl-5-methylpyrazolyl)borate can be converted to the alkyl carbonate complexes Tp*Zn-OCOOR by reaction with dialkyl dicarbonates or with alcohol and CO2. An alternative formation reaction is the treatment of the pyrazolyl borate with zinc perchlorate and potassium carbonate in alcohol. The interconversion between TpCum,MeZn-OH and TpCum,MeZn-OCOOMe in methanol-containing solution can be repeatedly performed in both directions by bubbling either CO2 or N2 through the solution. The alkyl carbonate complexes show a variable sensitivity towards hydrolytic destruction with reformation of the hydroxide complexes. The complexes TptBu,MeZn-OCOOR (R = Me, Et) release CO2 under high vacuum to form the alkoxide complexes TptBu,Me-Zn-OR, which could not be obtained pure due to their extreme water sensitivity. Indirect evidence for their existence is also obtained by the reaction between TpCum,MeZn-OCOOMe and methyl iodide, forming TpCum,MeZn-I and dimethyl ether. The Zinc hydroxide complexes catalyse the formation of diethyl carbonate from ethanol and CO2.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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  • 243
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 771-777 
    ISSN: 0009-2940
    Schlagwort(e): Titanium enolate ; Cyclic voltammetry ; EPR spectroscopy ; Radical ion ; Mesolytic bond cleavage ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: For the first time titanium enolate radical cations were characterized in cyclic voltammetry experiments. Preparative one-electron oxidation of titanium enolates 1-3 led to the formation of benzofurans B1-B3 through mesolytic Ti-O bond fragmentation to α-carbonyl radical and a cationic titanocene(IV) species. With 1+·, the kinetics of the Ti-=O bond cleavage was investigated by fast scan cyclic voltammetry providing a first-order rate constant k1=850 ± 50 s-1 in acetonitrile at room temperature. The titanium enolate radical cations 1+·, 3+·, 4+· and 5%% were characterized by EPR spectroscopy, qualifying these species as electrophilic radicals. This feature can be exploited in C—C bond formation reactions such as the formal dimerization of 6 to 2,3-dimethyl-1,4-diphenylbuta-1,4-dione D6, which takes place on stage of the radical cation 6+·.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 244
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997) 
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 245
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 179-181 
    ISSN: 0009-2940
    Schlagwort(e): Matrix isolation ; Pyrolysis ; Photochemistry ; Iodine compounds ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Flash pyrolysis of a gas mixture containing iodine, oxygen and argon yields the hitherto unknown iodine superoxide, which can be identified by its UV absorption (λ max= 254 nm) after trapping the pyrolysate at 12 K. Irradiation converts iodine superoxide into iodine dioxide, identified by its IR and UV spectra.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 246
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 201-207 
    ISSN: 0009-2940
    Schlagwort(e): Group-4 metallocenes ; Ziegler catalysts ; Cyclizations ; Sandwich complexes ; C-C coupling ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A variety of bent metallocene dichloride/methylalumoxane catalysts, derived from the zirconocene complexes 10, 12-18, have been employed in intramolecular olefin-coupling reactions yielding monomeric or dimeric products. This was achieved by using optimized reaction conditions employing low substrate concentrations (1.0-1.8 M) and rather long reaction times. Under these particular conditions, 1,5-hexadiene was cyclodimerized to give 1-methylene-3-(cyclopentylmethyl)cyclopentane (11). 1,6-Heptadiene was cleanly converted to methylenecyclohexane, and cis-1,2-divinylcyclopentane (19) and cis-1,2-divinylcylohenxane (22) were cyclized to yield 2-methylenebicyclo[3.3.0]octane (20) and 7-methylenebicyclo[4.3.0]nonane (23), respectively. In many cases, the cyclization products were accompanied by isomers originating from double-bond shift reactions that often occur rapidly at these catalyst systems under the specific reaction conditions chosen to keep the products in the monomeric regime.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
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  • 247
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 221-223 
    ISSN: 0009-2940
    Schlagwort(e): Gold ; Polygoldammonium salts ; (1-Adamantyl)ammonium salts ; Trinuclear complex, X-ray structure of ; Tetranuclear complex ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reaction of 1-adamantylamine with tris(triphenylphosphaneaurio)oxonium tetrafluoroborate results in the formation of the trinuclear adamantyltris(triphenylphosphaneaurio)ammonium tetrafluoroborate {C10H15[Au(PPh3)]3}+BF4-. The product can be further aurated by addition of equimolar amounts of triphenylphosphanegold(I) tetrafluoroborate to give the tetranuclear complex {C10H15N[Au(PPh3)]4}2+(BF4minus;)2. Both compounds have been fully characterized by analytical and spectroscopic data, and in the case of the trinuclear complex by a single crystal X-ray structure determination.
    Materialart: Digitale Medien
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  • 248
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 241-246 
    ISSN: 0009-2940
    Schlagwort(e): (2-Pyrrolidinylmethoxo)borane, anomalous dimer ; 5-Phenyl-3,4-dimethyl-1,3,2-oxazaborolidine, anomalous dimer ; Reaction intermediates ; Boron compounds ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reaction of (S)-prolinol (LH) with H3B · THF proceeds via [L2BH2〈]BH4, which decomposes with elimination of hydrogen at ca. -40°C to give the BH3 adduct of spirocyclic 7. On heating, 7 loses more H2 to give the “anomalous” dimerization product 11, which features a tetracoordinated B atom in a “tetrahedral” BN2O2 unit and another B atom in an N2BH2 environment. It is also shown that the product resulting from the reaction of pseudoephedrin with H3B·THF undergoes an analogous anomalous dimerization, affording product 8.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 249
    ISSN: 0009-2940
    Schlagwort(e): Macrocyclic ligands ; Lanthanides ; Copper ; Polyamines ; Polycarboxylic acids ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The optimized synthesis of two new macrocyclic polyamine polycarboxylic ligands, 1,4,7,10,14,17,20,23-octaazacyclohexacosane-1,4,7,10,14,17,20,23-octaacetic acid (H8OHEC) (10) and 1,4,7, 10,13,16,19,22-octaazacyclotetracosane-1,4,7,10, 13,16,19,22-octaacetic acid (H8OTEC) (12), is presented. The key step in the synthesis of both is the high yield carboxymethylation of the corresponding macrocyclic amines using tert-butyl bromoacetate followed by acidic hydrolysis of the acetate protecting groups. The molecular structures of the intermediates 1,4,7,10,14,17,20,23-octaazacyclohexacosane (OHEC-amine) (8), and octa-tert-butyl 1,4,7,10,13,16,19,22- octaazacyclotetracosane-1,4,7,10,13,16,19,22-octaacetate (OTEC-ester) (11) are determined by X-ray crystal structure analysis. OHEC-amine 8 reacts with 2 equiv. of CuSO4 yielding the dinuclear complex [Cu2(OHEC-amine)](SO4)2 (13). Complex 13 crystallizes with 16 molecules of water. 13 · 16 H2O contains two copper atoms, which are coordinated in a strongly distorted octahedral fashion by four nitrogen atoms, one oxygen atom from the sulfate dianion and one oxygen atom from a water molecule. The new ligands 10 and 12 are fully characterized by 1D- and 2D-NMR spectroscopy. Both ligands form dinuclear lanthanide(III) chelates (Ln=Y, Sm, Eu, Gd, Yb, Lu), which are stable and highly water soluble. With lanthanum(III) only mononuclear complexes are formed.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 250
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997) 
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 251
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 317-322 
    ISSN: 0009-2940
    Schlagwort(e): Ribonucleotide reductase ; Tyrosyl radical ; Adenosyl radical ; Glycyl radical ; Iron-sulfur cluster ; Cobalamin ; (S)-Adenosyl methionine ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The activation of the three classes of ribonucleotide reductases as free radical enzymes is reviewed. Class I uses O2 and a diferric μ-oxo center to generate a stable tyrosyl protein radical. Class II operates with adensoyl cobalamin as the precursor of a putative transient thiyl protein glycyl radical by the concerted forms an O2-sensitive protein glycyl radical by the concerted action of an iron-sulfur cluster and (S)-adensoyl methionine.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 252
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 581-584 
    ISSN: 0009-2940
    Schlagwort(e): Vinylferrocene ; Pd-catalyzed twofold and fourfold couplings ; Electron-donor-acceptor[2.2]paracyclophanes ; Charge transfer ; Cyclic voltammetry ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: As potential nonlinear optical material. 12-nitro-4,7-bis(2-ferrocenylvinyl)[2.2]paracyclophane (1) and 12-nitro-4,5,7,8-tetrakis(2-ferrocenylvinyl)[2.2]paracyclophane(2) have been synthesized by pd-catalyzed coupling reactions of vinylferrocene with the precursor cyclophanes 9 and 13, respectively. The absorption and electrochemical properties of 1 and 2 are also described.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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  • 253
    ISSN: 0009-2940
    Schlagwort(e): C-H activation ; Alkyne complexes ; Cyclopentadienyl cobalt ; Fluxionality ; Hydrido complexes ; Clusters ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Vicinal C-H bonds of the cycloalkenes CnH2n (n = 5-8) were activated upon treatment under mild conditions with reactive sources of the (C5H5)CO fragment. With [C5H5)CO(C2H4)2] (2a), the trinuclear cluster complexes [H2((C5H5)CO)3(μ3-C2(CH2)n-2)] (5a: n = 5; 5c: n = 5d: n = 8) were formed. Using the more reactive [(C5H5)2Co]/K, 5a-5dwere obtained, along with small amounts of the tetranuclear [{(C5H5)CO}4r{μ4-C2(CH2)n-2}] (8a-c: n = 5-7). X-ray structure analyses of 5c, d and 8b, c were performed. A μ-‖ (orμ3-η1:η2:η1) coordination of the cycloalkyne ligands was found in the trinuclear cluster complexes. The tetranuclear 8b, c had the cycloalkynes quadruply bridging (μ4-η1:η2:η2:η1_ a butterfly arrangement of the metal atoms. The acetylenic carbon-carbon bonds are considerably lengthened upon coordination [1.392(4), 1.398(3) å in 5c d; 1.464(8), 1.499(5) Å in 8b, c]. Three dynamic processes - alkyne “walk” on top of the CO3 triangle, μ2-hydride migration, and μ2/μ3-hydride exchange - are operational in the trinuclear 5a-d. Dynamic NMR data for 5a are consistent with a “windshield-wiper” mechanism for the alkyne migration. Hydride exchange is associated with a higher energy barrier, and is probably and independent dynamic process.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 254
    ISSN: 0009-2940
    Schlagwort(e): Alkali metals ; ate compounds ; Dihydrotriazine ; Potassium ; N ligands ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A series of dihydro-s-triazinidopotassium complexes have been synthesised and structurally characterised by X-ray diffraction. Two of them, the sesqui-pyridine solvate 2 and the mono-THF solvate 3, can be classified in formal terms as “potassium potassates” in conforming to the structural pattern established previously for the sesqui-THF solvate 1, the first reported ate of this type. Formally complex [(R2K)-] anions are linked to K+ cations in polymeric, zig-zag chain arrangements. Solvate 3 also possesses a unique RK coordination as a direct result of having fewer solvent ligands. DMSO analogue 4 deviates from this uniformity in adopting a centrosymmetric, dimeric (OK)2 ring structure featuring both terminal and bridging DMSO ligands. The dihydro-s-triazinidosodium tris(THF) solvate 5 is found to be a monomer. For comparative purposes, the metal-free, parent triazine molecule 6 has also been subjected to an X-ray crystallographic study: it displays a 1,2-dihydro ring setup as opposed to the 1,4-dihydro alternative existing in the metallo examples. Triazine 6 is also found to form a N-H…Br bridge in the dimeric structure of the lithium bromide bis (THF) solvate 7, a suspected hydrolysis product from the reaction of dihydro-s-triazinidolithium 8 and magnesium bromide bis(ether) adduct.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 255
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 651-657 
    ISSN: 0009-2940
    Schlagwort(e): Vanadium ; Haloperoxidase ; Schiff bases ; Diethanolamine ; Water ligation ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Reaction of vanadyl sulfate with the Schiff base H2L1 derived from o-vanillin and glycine leads to [VIVO(H2O)L1 (1), treatment of which with acetyl chloride affords cis-[VIVCl2L1] (2). Reaction of [VO(acac)2] with the Schiff base H2L2 derived from o-hydroxynaphthaldehyde and o-hydroxyaniline under aerobic conditions yields [{VVO(L2)}2μ-O] (3), which undergoes methanolysis in excess methanol to form [VVO(MeOH)(OMe)L2] (5a). Complex 5a is also obtained via [VVOCl(L2)] (4) and MeOH. On treatment of 3 with an equimolar amount of ethanol, [VVOCl(L2)] (4) and MeOH. On treatment of 3 with an equimolar amount of ethanol. [VVO(OEt)L2] (5b) is obtained. With the chiral tertiary bis(ethanol)amine (S)- or (R)-(HOCH2CH2)2NCH(Ph)Me, H2L3, [VO(acac)2] loses only one acetylacetonate (1-) ligand, and the complexes (S)- and (R)-[VVO(acac)L3] (6a) are formed. As is evident for the corresponding reaction with (HOCH2CH2)2NPh, H2L4, which affords [VVO(acac)L4 (6b), the substitution is a second-order process (rate constant 0.013 M-1 h-1). 5a…MeOH, 5b, (R)-6a, and (S)-6a have been structurally characterized by single crystal X-ray diffraction analysis. The molecular connectivities have also been established for 1-H2O. All of the structurally characterized complexes contain an O*O3N donor set (O* denotes a doubly-bonded oxo group) and thus model the coordination environment of the active site in vanadate-dependent haloperoxidases. This model character is particularly pronounced in 5b, the coordination geometry of which is half-way to trigonal-bipyramidal. 5a and 6a contain, in addition to the O*O3N set, a labile V-O or V-N bond, respectively, which may mimic substrate binding to the active centre. 6a is also of relevance to the enantioselective peroxide oxidation of sulfides to sulfoxides by catalyst systems containing vanadium and H2L3.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 256
    ISSN: 0009-2940
    Schlagwort(e): Acyllithium equivalents ; Lithium ; Carbenes ; Structure elucidation ; Ab initio calculations ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 3-Lithiated 4-tert-butyl-imidazol-2-ylidene, 3-lithiated 4-tert-butyl-thiazol-2-ylidene, and the ZnBr species of the latter, are shown to be stable carbenes by X-ray crystal structure determination. The crystal data are confirmed by 13C-NMR investigations in solution and quantum-chemical calculations. The exceptional stability of the acyl anion equivalents is due to the p(.) stabilization of the carbene carbon atoms by the adjacent amino (thio) substituents, as is also the case in the structurally related stable carbenes, which have recently been isolated for the first time by A. J.Arduengo III et al., and in stable nitrenium ions, as found by our group.
    Zusätzliches Material: 5 Ill.
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  • 257
    ISSN: 0009-2940
    Schlagwort(e): Carbene complexes ; Iron ; Alkene complexes ; Carbamates ; Trimethylenemethane complexes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The title complexes 8 and 9 are easily prepared in two or three steps from iron carbonyls and isobutene diol 5 by Meerwein alkylation of the intermediate acyl complexes 6 and 7. With carbon and heteroatom nucleophiles like enolates and triphenylphosphane they form either stable 4-substituted alkene-carbene complexes 10 and 11, or substituted trimethylenemethane tricarbonyliron complexes like 12. Oxidation with H2O2/NaOH both of the alkene-carbene complexes 11 and of the less stable β-oxo-substituted trimethylene-methane complexes 13, as obtained from reaction of 8 with lithium enolates, yields the corresponding substituted allyl carbamates 15 or the allyl alcohols 14, which are formally bis- and monosubstituted derivatives, respectively, of the starting isobutene diol.
    Zusätzliches Material: 2 Ill.
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  • 258
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1269-1272 
    ISSN: 0009-2940
    Schlagwort(e): Indium ; Clusters ; Low-valent compounds ; Trapping reactions ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The tetrahedral cluster compound tetrakis[[Tris(trimethylsilyl)methyl]indium(I)] 91) reacts in boiling n-hexane with benzil derivatives (p-X-C6H4)C(O)(p-X-C6H4) (X = H, OMe, Br), to yield the 1,4-cycloadditon products of the monomeric alkylindium(I), In-C(SiMe3)3, in which the In atoms are coordinated by a chelating enediolato ligand, to form a five-membered InO2C2 heterocycle. As shown by two crystal structure determinations (X = H, OMe), the products are dimeric in the solid state, with a four-membered In2O2 heterocycle in the molecular center and both C(SiMe3)3 groups, as well as both enediolato substitutents in a cis arrangement.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 259
    ISSN: 0009-2940
    Schlagwort(e): Germanium ; Digermenes ; Tin ; Germylenes ; Stannylenes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Treatment of GeCl2 · dioxane with the Grignard reagent RMgBr (R=2-tBu-4,5,6-Me3C6H) furnishes the tetraaryldigermene R2Ge=GeR2 (8). X-ray structure-analysis of 8 reveals a short Ge=Ge double bond, a nearly planar environment of both germanium atoms and extremely widened C—Ge—C angles of 128°. In solution, 8 dissociates into two germylene molecules R2Ge, which can be trapped with oxygen or by [4+1] cycloaddition reactions with 1,4-dihetero-1,3-dienes. A similar cycloadduct of a stannylene wa obtained by thermolysis of (R′2Sn)3 (R′=2,4,6-iPr3C6H2), in the presence of a 1,4-diazabutadiene and characterized by an X-ray structure-analysis.
    Zusätzliches Material: 2 Ill.
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  • 260
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1321-1325 
    ISSN: 0009-2940
    Schlagwort(e): Arene Complexes ; Ruthenium ; Diastereoselective ; Reduction ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Two preparative routes are reported that give access to the racemic series of planar chiral [(arene)(COD)Ru] derivatives containing η6-bonded o-tolyl ketone or aldehyde arene units. The ketone and aldehyde functions of these have subsequently been reduced by nBuLi and PhLi, respectively. Hydrolysis converts the initially formed lithium salts into diastereomeric benzyl alcohol complexes lithium salts into diastereomeric benzyl alcohol complexes in high yields. The formation of the new stereogenic centre is diastereoselective (88% de) for the aldehyde and diastereospecific for the ketone (de 〉 99%). Due to a sterically overcrowded situation, the rotation of the chiral side chain of [(COD) (η6-o-tolyl-tert-butylphenylmethanol) Ru] (7) is hindered, as is the rotation of the phenyl and tert-butyl substituents. As a consequence, the hydroxyl group is fixed at a position close to the metal both in solution and in the solid state.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 261
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1349-1352 
    ISSN: 0009-2940
    Schlagwort(e): Heterocycles ; 1,1-Organoboration ; Disilanes ; 1- Alkynylsilanes ; NMR spectroscopy ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 1,2-Di-1-propynyl-tetramethyldisilan (1) reacts with triorganoboranes R3B [R = Et (2a), CH2Ph (2c), 2-thienyl (2d)], 9-ethyl-9-borabicyclo[3.3.1]nonane (3), and diethyl(N-pyrrolyl)borane (4) by twofold 1,1-organoboration to give selectively the respective organo-substituted 1,2-dihydro-1,2,5-disilaborepines 5a-d,6, and 7 in high yields. The compounds 5-7 were characterized by 1H-, 11B-, 13C-, and 29Si-NMR spectroscopy in solution. The molecular structures of the distance 1 and of the heterocycle 5c were determined by X-ray structure analysis.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 262
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1361-1363 
    ISSN: 0009-2940
    Schlagwort(e): Titanium ; Lead ; Alkoxides ; Amides ; Mixed-Metal species ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reaction between Ti(OiPr)4 and [Pb(NtBu)2] (1) in refluxing THF afforded the complex Ti(OiPr)4OPb4(NtBu)3] (2) which has been characterized by X-ray diffraction studies and by 1H- and 13C-NMR spectroscopy. Titanium is five coordinate and it displays a trigonal bipyramidal stereochemistry with the pb4(tBuN)3O cage ligand bonded to titanium through the oxygen atom and occupying an apical position. The origin of the cubane lead ligand is discussed.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 263
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1393-1403 
    ISSN: 0009-2940
    Schlagwort(e): Tripod ligands ; Phosphane oxides ; Cobalt ; Oxidation ; Catalysis ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reactivity of complexes of triphos [CH3C(CH2PPh2)3] and CoCl2 towards dioxygen has been investigated. Reaction of the pseudo-tetrahedral complex (η2-triphos)CoCl2 (1) with dioxygen yields after work-up the mixed phosphane/phosphane oxide ligands triphosO and triphosO2. The novel ligand triphosO2 can be obtained in quantitative yield using catalytic amounts of 1. In order to gain some insight into the catalytic dioxygen activation reaction, experiments with various triphos/Co/Cl species, in different solvents and at several concentrations have been carried out. A mechanism involving two separate reaction pathways is proposed. Complexes of triphosO and triphosO2 with CoCl2, [η2-(P, P)-triphosO]CoCl2 (4), and [η2-(P, O)-triphosO2]CoCl2 (5), which are present as intermediates in the oxygenation reaction, have been isolated and fully characterized including X-ray structural analyses.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 264
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1417-1422 
    ISSN: 0009-2940
    Schlagwort(e): Gold ; N ligands ; Gold(I) complexes ; (Imine)gold(I) complexes ; Guanidines ; Ketimines ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: (Tetramethylguanidine)gold(I) chloride (1) and bromide (2) are readily prepared in high yield from (Me2N)2C=NH and [AuCl(Me2S)] or [AuBr(tht) (tht = tetrahydrothiophene), repectively. NMR spectra of chloroform solutions of the two products indicate equilibria of the type 2 LAuX = L2Au+AuX2-. The cationic complex [Au(NH=C(NMe2)2)(PPh3)]+ is obtained as the triflate salt 3 from tetramethylguanidine and [Au(PPh3)]+O3SCF3-. In solution at low temperature (-60°C), this compound adopts a rigid structure whereby the NMe2 groups are rendered non-equivalent, but at ambient temperature there is coalescence of the NMe2 signals in the 1H- and 13C-NMR spectra. The related benzophenoneimine complex [Au{NH=CPh2}(PPh3)]+BF4- (4), which was synthesized as a reference3 compound, exhibits similar behaviour. In solution at low temperature (-60°C) the two phenyl rings of the ligand are diastereotopic. In contrast, the triisopropylphosphane derivative [Au[NH=CPh2](PiPr3)]+BF4- (5) is rigid on the NMR time scale, even at 25°C. Thbe solid-state structures of 2, 3, 4, and 5 have been determined by single-crystal X-ray diffraction. Compound 2 crystallizes in the ionic form with discrete Au … Au bonded ion pairs [Au[NH=C(NMe2)2]2]+ [AuBr2]- [Au … Au 3.1413(8) Å]. The cations of 3, 4, and 5 show the [Au(PPh3)]+ units N-coordinated to the imino groups, with the nitrogen atoms in a trigonal-planar configuration.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 265
    ISSN: 0009-2940
    Schlagwort(e): Alkynes ; Allenes ; Furans ; Palladium ; Catalysis ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: By making the choice of either PDCl2(MeCN)2 or PTH rac-4 as catalyst, the allenyl ketones 1 could be preferentially cycloisomerized/dimerized to either 2,4-disubstituted furans 3 or preferentially cycloisomerized to the monosubstituted furans 2. Since the PTH catalyst tolerates functional groups like terminal alkynes, α-halogen ketones, and alkyl halides that inhibit the silver catalysis, the latter method is an important extension of Marshall's Ag1-catalyzed isomerization of 1 to 2. Some of these latter reactions also showed exciting chemoselectivities, e.g. with allenyl ketones, such as 1c and 1d, which also also possess a 1,6-enyne substructure, no enynecyclization was observed. This is also the first reported example of catalysis by a PTH.
    Zusätzliches Material: 1 Tab.
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  • 266
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1069-1077 
    ISSN: 0009-2940
    Schlagwort(e): Planar-tetracoordinate carbon ; Dynamic organometallic systems, μ-alkyne complexes ; π-Agostic systems ; Zirconium ; Metallocenes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The benzonitrile hydrozirconation product Cp2ZrCl(N—CHPh) 8 was treated with propynyl lithium to yield the (propynyl)(benzaldimido)ZrCp; complex 9. Subsequent treatment with trityl tetraphenylborate generated [Cp2Zr(C—C—CH3)-BPh-4] that instantaneously added to 9 to eventually form the (μ-aldimido)(μ-η1:η2-hexadiyne)ZrCp2 cation 11. The X-ray crystal structure analysis showed that 11 contains a planar-tetracoordinate carbon atom that is stabilized by forming a three-center-two-electron bond with the two adjacent metal atoms. Similarly, complex 9 reacted with [Cp2Zr(CH3)+CH3B(C6F5)3 1 to yield the planar-tetracoordinate carbon containing (μ-aldimido)(μ-η1:η2-2-butyne) Cp; cation 12. Both complexes 11 and 12 exhibit dynamic NMR spectra due to their rapid reorganization of the dimetallabicyclic frameworks (ΔG* = 10 kcal mol-1) in addition to an anchimerically assisted C—N bond rotation (ΔG* =15 kcal mol-1).
    Materialart: Digitale Medien
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  • 267
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1099-1103 
    ISSN: 0009-2940
    Schlagwort(e): Porphyrinatomanganese(IV) ; Monooxygenase model ; Dichloro monoxide ; Catalytic alkene epoxidation ; Catalytic alkane oxygenation ; Catalytic alkane chlorination ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The isolation at -78°C and characterization of the novel crystalline reactive porphinatomanganese(IV) complex Mn-(TDCPP)(OCl)2 (5) is described. 5 is compared with the porphinatomanganese(IV) complexes Mn(TDCPP)(C6H5IOCl)2 (2), Mn(TDCPP)(C6F510C1)CI (3) and Mn(TDCPP)(OCH3)2, (4). The stoichiometric reaction of 5 with triphenylphosphane yields 2.5 equivalents of triphenylphosphane oxide and 1.0 equivalent of Mn(TDCPP)Cl (1). Complex 5 epoxidizes stilbene, and oxygenates and chlorinates cyclohexane.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
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  • 268
    ISSN: 0009-2940
    Schlagwort(e): Selenium ; Fluorine ; Amides ; Cleavage reactions ; Cycloadditions ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Bis(trifluoromethylketiminoalkyl)diselanes [SeC(=NR)CF3]2 (6) [R = Me (a), iPr (b), tBu (c)] have been prepared in high yields (55-70%) by reaction of the diselane (SeC2F5)2 (2) with RNH2. However, the analogous reaction of 2 with secondary amines, R2NH, results in the cleavage of the Se-Se bond and leads to the N,N-dialkyl-2,2,2-trifluoroselenoacetamides Se=C(NR2)CF3 (7) [R = Me (a), iPr (b)]. Cleavage of 6a-6c with Me3SnH affords the selenoamides Se=C(NHR)CF3 (9) and the corresponding stannylselanes Me3SnSeC(=NR)CF3 (10) [R = Me(a), iPr (b), tBu (c)]. Selenoamides 7 and 9 can also be prepared from pentafluoroethylselenol HSeC2F5 (3), Se=C(F)CF3, (1) or its polymer [SeC(F)CF3]n (4) and primary or secondary amines. N,N-dialkyl-2-methyl-3-fluoro-4,4,4-trifluoroselenoacrylamides Se=C(NR2)C(Me)=C(F)CF3[R = Et (13a), iPr (13b)] are prepared in moderate yields under mild conditions by treating either trifluoromethylselenocarbonyl fluoride (1) or its polymer [SeC(F)CF3]n with 1-dialkylamino-1-propynes. The reaction proceeds by [2 + 2] cycloaddition and stereospecific electrocyclic ring-opening, yielding, with respect to the resulting C=C double bond, the E isomer as the only product. The molecular structures of 7b, 9a and 13b show the typical features of selenoamides with C(Se)-N bond shortening and C-Se bond elongation due to π interaction of the N lone pair with the C=Se double bond. The observed perpendicular orientation of the selenoamide and the alkene units of 13b prevents π delocalization.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 269
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 933-937 
    ISSN: 0009-2940
    Schlagwort(e): Boron ; Phosphorus ; Spiro compounds ; Cage compounds ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Reactions of 1-lithio · DME-2,4-bis(dialkylamino)-l,3,2,4-diphosphadiboretanes (1a, 1b) with SiCl4 followed by dehydrohalogenation with tBuLi produce spirocyclic compounds [(R2NB)2P2]2Si (2a, 2b). The compounds have been characterized by spectroscopic methods and X-ray crystallography. The assembly process has also been followed and one intermediate species [(iPr2NB)2P2][(iPr2NB)P(H)(iPr2NB)P]SiCl (3) has been isolated and fully characterized.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 270
    ISSN: 0009-2940
    Schlagwort(e): Rhodium ; Cations ; Tridentate ligand ; Alkene complexes ; P Ligands ; N ligands ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The cationic rhodium(1) complexes [Rh(PNP)(C2H4)]X; X = BF4 (1a), PF6 (1b), CF3SO3 (1c ) were prepared by addition of the tridentate ligand 2,6-bis(diphenylphosphanylmethyl)pyridine (PNP) to a solution of [Rh(C2H4)2(solv)2]X (solv = acetone or THF) under ethylene. The complexes were characterized by IR and 1H-, 13C-, and 31P-NMR spectroscopy. The coordination of two ethylene molecules at the [Rh(PNP)]+ fragment could be detected by dynamic proton resonance of a solution of 1a under free ethylene. The styrene complex [Rh(PNP)(styrene)]BF4 (4) was obtained by substitution of the ethylene from 1a with an excess of styrene. The π coordination of C2H4 and styrene in 1a and 4 respectively was confirmed by X-ray crystal structure analysis. The olefin complexes react with an excess of the secondary amine to give the corresponding amine complexes [Rh(PNP)(HNR2)]X; HNR2 = piperidine (5), HNMe2 (6 ), HNEt2 (7). Conversly, the amine could be released from the amine complexes with an excess of ethylene at low temperature by the formation of the ethylene complex 1.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 271
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1197-1200 
    ISSN: 0009-2940
    Schlagwort(e): Binuclear complexes ; Manganese ; Napthalene complexes ; Dienyl complexes ; Alkynes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Pentacarbonyl(μ-.4:6-1,4-dimethylnapthalene)dimanganese-(Mn-Mn) (1), upon UV irradiation at 193 K in the presence of 2-butyne (2), yields tetracarbonyl(μ-.2:2-2-butyne)(μ-1,2,3,4-.:1,4,4a,8a-.-1,4-dimethylnaphthalene)dimanganese (3) and tricarbonyl(4a,6,7,8,8a-.-5-hydro-1,4-dimethylnapthalene)-manganese (4). The tetracarbonyl complex 3 rearranges in solution at room temperature to give tetracarbonyl(μ-.2:2-2-butyne)(μ-4a,5,8,8a-.:5,6,7,8-.-1,4-dimethylnaphthalene)-dimanganese (5). The complexes 3 and 5 were characterised by IR and NMR spectroscopy, and by mass spectrometry, and complex 4 by IR and NMR spectroscopy. The molecular structures of 3 and 4 were determined by single-crystal X-ray diffraction analyses.
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  • 272
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1671-1676 
    ISSN: 0009-2940
    Schlagwort(e): Silicon ; Disilanes ; Diaryldisilanes ; Disilanyl-arenes ; 1,2-Disila-acenaphthene ; Fluorescence spectroscopy ; UV/Vis spectroscopy ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: For the synthesis of the diaryldisilanes Ar-SiH2SiH2-Ar (1a, Ar = phenyl; 1b, Ar = p-tolyl 1c, Ar = mesityl; 1d, Ar = p-anisyl) two convenient preparative routes are reported. The crystal structures of 1c and 1d have been determined in X-ray diffraction studies; the disilanes have a staggered transconformation with a crystallographically imposed center of inversion. For 1a-d no photoluminescence phenomena can be observed. 1,2-Disila-acenaphthene (2) is synthesized in acceptable yield by treatment of 1,8-dilithionaphthalene with 1 equivalent of 1,2-bis[((trifluoromethyl)sulfonyl)oxy]disilane Tf-SiH2SiH2-Tf. The crystal structure of 2 has been determined by X-ray diffraction. The molecule has no crystallographically imposed symmetry but closely follows the symmetry elements of points group C2v. Solutions of 2 exhibit intense fluorescence in the near UV region at room temperature. The fluorescence spectra are discussed in comparison with data on acenaphthene and naphthalene.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 273
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1699-1707 
    ISSN: 0009-2940
    Schlagwort(e): Trivalent phosphorus ; Ruthenium ; Photolysis ; Electron transfer ; Ligand exchange ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Solutions of tris(2,2′-bipyridyl)ruthenium(II) dichloride (Ru2+) and various types of trivalent phosphorus compounds Z3P (Z = Ph, n-Bu, OR; 1) in methanol have been photolyzed with visible light at 20 °C under an argon atmosphere, resulting in the oxidation of 1 to the corresponding pentavalent oxo compounds Z3P=O and ligand exchange of Ru2+ with 1. The former process takes place via single-electron transfer (SET) from 1 to Ru2+ in the photoexcited state, Ru2+*, which generates the radical cation intermediate Z3P.+ from 1. The latter results from nucleophilic attack of 1 upon Ru2+*. The results show that 1 can act either as an electron donor or as a nucleophile toward Ru2+*. The rate constants for both processes are estimated. An excellent linear correlation is found between the logarithm of the SET rate and the oxidation potential for both the aromatic and aliphatic trivalent phosphorus comparison with SET quenching by amines. On the other hand, a dualparameter correlation analysis shows that the ligand exchange is regulated by both steric and electronic factor in 1.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 274
    ISSN: 0009-2940
    Schlagwort(e): Lead ; Tetrachloroaluminate ; Arenes ; o-Xylene ; Bis(arene) Complexes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Bis(o-xylene)lead(II) bis(tetrachloroaluminate), obtained from lead(II) chloride and aluminium trichloride in o-xylene, has been shown by X-ray crystallography to be a mononuclear lead complex with point group symmetry C2 The two aromatic ligands are arranged similarly to those in monomeric plumbocene. The coordination sphere is completed by two bidentate AlCl4-ions. The lead center uses about a quarter of its bonding capability for each of the four ligands
    Zusätzliches Material: 1 Ill.
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  • 275
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1751-1759 
    ISSN: 0009-2940
    Schlagwort(e): Amido complexes ; Titanium ; Zirconium ; Alkylmetal compounds ; Amido complexes ; Titanium ; Zirconium ; Alkylmetal compounds ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The novel tridentate diamidoamine ligands [RC(2C5H4N)(CH2NSiMe3)2)2- (R = H, CH3) have been synthesized and coordinated to TiIV giving the pentacoordinate complexes [MX2(RC(2-C5H4N)(CH2NSiMe3)2}] (M = Ti, Zr; X = Cl, Br). The crystal structure analysis of [TiBr2{HC(2-C5H4N)(CH2)2}] (M = Ti, Zr; X = Cl, Br). The crystal structure analysis of [TiBr2{HC(2-C5H4N)(CH2NSiMe3))] (10b) confirmed the involvement of the pyridyl function in the coordination to the meta centre occupying an apical position in the trigonal bipyramidal ligand polyhedron. alkylation of [TiCl2{H3CC(2-C5H4N)(CH2NSiMe3)2)] (12a) with one or two molar equivalents of [RMgCl](R = PhCH2, Me3SiC2) yielded the mono- and dialkyl complexes [TiClR{H3CC(2-C5H4N)(CH2NSiMe3)2)] and [TiR2(H3CC(2-C5H4N)(CH2NSiMe3)2)] and [TiR2(H3CC(2-C5H4N)(CH2NSiMe3)2}] in good yields. Depending on the steric demand of the alkyl group coordination or decoordination of the pyridyl group leads to four- or five-coordinate species. A crystal structure analysis of the pentacoordinate complex [TiCl(CH2SiMe3){H3CC(2-C5H4N)(CH2NSiMe3)2}] (16) was carried out.
    Zusätzliches Material: 3 Ill.
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  • 276
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1787-1790 
    ISSN: 0009-2940
    Schlagwort(e): Silicon ; Titanium ; Diazadisilatitanacyclopentane ; Aminodisilanes ; Tetrachlorodisilanes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Reaction of two equivalents of N-trimethylsilylaniline (1) with two equivalents of n-butyllithium, followed by subsequent treatment with Si2Cl6 (2) leads to the formation of the tetrachlorodisilane RSiCl2SiCl2R (3) (R = PhNSiMe3). 3 is converted to RSi(NH2)2Si(NH2)2R (4) by reaction with liquid ammonia. 4 reacts with cp*TiMe3 (5) (cp* = η5-CsMe5) to yield the diazadisilatitanacyclopentane RSi(NH2)NHTiMe(cp*)NHSi(NH2)R (6). The crystal structure of 6 is reported.
    Zusätzliches Material: 1 Ill.
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  • 277
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1777-1785 
    ISSN: 0009-2940
    Schlagwort(e): Lithiation ; Aminomethylation ; Nitrogen heterocycles ; Diazasilaheterocycles ; Diazaphosphaheterocycles ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The aminals tetramethylmethylenediamine (TMMDA) la, dicyclohexyldimethylmethylenediamine (CMMDA) lb, and di-isopropyldimethylmethylenediamine (IMMDA) lc are doubly metalated by LitBu to give LiCH2N(R)CH2N(R)CH2Li [2a: R = Me, 2b: R = Cy (Cy = cyclohexyl), 2c: R = iPr], which precipitate out of pentane as highly pyrophoric substances. Deuteration confirms N-methyl metalation exclusively. A series of aminomethylation reactions were performed by means of the doubly lithiated aminals 2a-c. The reactions of 2a-c with monochlorosilanes yield the silylated species R′3SiCH2MN(R)CH2N(R)CH2SiR′3 (3a: R′= Me, R == Me; 3b: R′ == Me, R == Cy; 3c: R′= Me, R = iPr 4: R′= Ph, R = Me, see Scheme 2). The use of dichlorosilanes lead to six-membered heterocycles 6a-6d. 6a is transferred into a mono quarternary ammonium salt 7 by methylation with MeI. The spirocycle 8 is obtained from SiCl4 and two equivalents of 2a. Similarly, several substituted 1,3-diaza-5-phosphacyclohexanes 9a-e (R1 = Me, Ph, NPh2, NCy2, see Scheme 3) are synthesized by the reaction of dichlorophosphanes R1PC2, with 2a and 2b, respectively. Oxidation of 9d with sulfur yields 12a, which is characterized by X-ray structure determination.
    Zusätzliches Material: 1 Ill.
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  • 278
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1807-1811 
    ISSN: 0009-2940
    Schlagwort(e): Alkynes ; Photoelectronspectroscopy ; Electronic structure ; X-ray investigation ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The structures of 6-isopropylidene-1,1-dimethyl-1-silacyclodeca-3,8-diyne (2), 1,6-dimethyl-1,6-disilabicyclo[4.4.4]tetradeca-3,8,12-tryine (4), and 1,1,2,2,3,3-hexamethyl-1,2,3-trisilacyclodeca-4,9-diyne (6) have been investigated by means of X-ray crystallography. In 2 and 6 a chair conformation is adopted in the solid solid state. In 4 the three butyne groups are twisted around the Si—Si axis against one another. The torsion along the triple bond axis (Si-CH2-CH2,/Si) amounts to 29.0(1). The He(I) photoelectron (PE) spectra of 2 and 6 together with those of 1,1-dimethyl-1-silacyclodeca-3,8-diyne (1), 1,1,6,6-tetramethyl-1,6-disilacyclodeca-3,8-diyne (3),1,12,2,3,3-hexamethyl-1,2,3-trisilacycloundeca-4,10-diyne (7) have also been recorded. The PE spectra were interpreted on the basis of results from SCF MO calculations (3-21G*). They reveal a smaller splitting of the π-bands in 1-3 as compared to cyclodeca-1,6-diyne. In the PE spectra of 5-7 we encountered a strong interaction between the silicon chain and the in-plane π-orbitals.
    Zusätzliches Material: 3 Ill.
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  • 279
    ISSN: 0044-2313
    Schlagwort(e): Trihalogenogermane ; Germatrane ; Transmetalation ; Crystal structure ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Darstellung, Charakterisierung und Strukturen von 1-(9-Fluorenyl)germatran and 1-(Phenylacetylenyl)germatranÜber die Synthesen der Titelverbindungen, nämlich N(CH2CH2O)3GeY (2 Y=Fluorenyl; 4 Y=PhC≡C) durch Reaktion von X3GeY (1 Y=Fluorenyl, X=Br; 5 Y=PhC≡C, X=Cl) mit N(CH2CH2OSnR3)3 (3 R=Et; 6 R=Bu) wird berichtet und die Darstellung der neuen Verbindung 1 wird beschrieben. Die Strukturen der Verbindungen wurden durch Elementaranalysen sowie mittels 1H and 13C NMR-Spektroskopie bestimmt, 2 und 4 massenspektrometrisch charakterisiert. 1, 2 und 4 wurden mit Röntgenbeugungsmethoden analysiert.
    Notizen: Syntheses of the title compounds, viz. N(CH2CH2O)3GeY (2 Y=Fluorenyl; 4 Y=PhC≡C) by the reaction of X3GeY (1 Y=Fluorenyl, X=Br; 5 Y=PhC≡C, X=Cl) with N(CH2CH2OSnR3)3 (3 R=Et; 6 R=Bu) are reported including the preparation of the new compound 1. Identity and structures were established by elemental analyses, 1H and 13C NMR spectroscopy. 2 and 4 were characterized by mass spectrometry. Single crystal structures of 1, 2 and 4 were determined by X-ray diffraction methods.
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  • 280
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1151-1156 
    ISSN: 0044-2313
    Schlagwort(e): Tetraalkyl phosphonium triiodide ; tetraalkyl arsonium triiodide ; tetraalkyl stibonium triiodide ; crystal structures ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Syntheses and Crystal Structure Analyses of Tetraalkyl Phosphonium, Arsonium, and Stibonium TriiodidesThe reaction of Me4EI (E=P, As), Me3EtSbI, Me2Et2SbI, MeEt3SbI, or Et4SbI with I2 in absence of solvent gives Me4PI3 (E=P, As), Me3EtSbI3, Me2Et2SbI3, MeEt3SbI3, or Et4SbI3. Me4SbI3 is formed in a reversible reaction by addition of I2 to (Me4Sb)3I8 or by reaction of a solution of Me4SbI in ethanol with I2 in benzene. The crystal structures of Me4EI3 (E=P, Sb), and Me3EtSbI3 and the syntheses of the novel compounds are reported.
    Notizen: Die Reaktion von Me4EI (E=P, As), Me3EtSbI, Me2Et2SbI, MeEt3SbI oder Et4SbI mit I2 im Substanzgemisch ohne Lösungsmittel führt zu den entsprechenden Triiodiden Me4EI3 (E=P, As), Me3EtSbI3, Me2Et2SbI3, MeEt3SbI3 oder Et4SbI3. Me4SbI3 entsteht in reversibler Reaktion durch Zugabe von I2 zu (Me4Sb)3I8 oder durch Umsetzung einer ethanolischen Lösung von Me4SbI mit einer Lösung von Iod in Benzol. Über die Kristallstrukturen von Me4EI3 (E=P, Sb) und Me3EtSbI3 und die Synthese der neuen Verbindungen wird berichtet.
    Zusätzliches Material: 4 Ill.
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  • 281
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1135-1143 
    ISSN: 0044-2313
    Schlagwort(e): Copper(I) ; 1-azadienes ; oxidation ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Copper(I) Complexes with 1-Azadiene Chelate Ligands and Their Reaction with OxygenThe reaction of the bidendate 1-azadiene ligands Me2N—(CH2)n—N=CH—CH=CH—Ph with CuX results in the formation of the dimeric compounds [ACuX]2 and [BCuX]2 (A: n = 2, B: n = 3, X: I, Cl). The structure of complex 1 [ACuI]2 was determined by X-ray crystal structure analysis. 1 consists of two tetrahedrally coordinated Cu atoms connected by two iodo bridges. (Cu—Cu bond length: 261 pm).The ligand Me—N(CH2CH2N=CH—CH=CH—Ph)2 (C) reacts with CuX to form the monomeric complexes [CCuX] (5: X=I, 6: X=Cl). The crystal structure of 5 shows that the ligand acts as a tridendate ligand. The bond lengths of the CuN(sp2) bonds are significantly shorter than the Cu—N(sp3) distance.Reacting the podand-type ligands N(CH2CH2—N=CH—R)3 (D: R=Ph, E: R=-CH=CH—Ph) with CuX yields the ionic complexes 7 [DCu][CuCl2] and 8 [ECu][CuCl2]. 7 was characterized by X-ray analysis which confirmed that D acts as a four-dendate podand ligand.The compounds 1-8 are unreactive towards CO2 but take up O2 even at deep temperatures. At -78°C the orange-red complex 4 [BCuCl]2 reacts with O2 in CH2Cl2 to form a deep violet solution, but the primary product of the oxidation could not be isolated. It reacts at room temperature to form the green complex 9 [μ-Cl, μ-OH][BCuCl]2. The X-ray structure analysis of 9 confirms that a dimeric CuII complex is formed in which both a chloro- and a hydroxo group are bridging the monomeric units. The CuII centers exhibit a distorted tetragonal-pyramidal coordination.The pathway of the reaction with O2 will be discussed.
    Notizen: Die Reaktion der zweizähligen 1-Azadienliganden Me2N—(CH2)n—N=CH—CH=CH—Ph mit CuX führt zu den dimeren Komplexen [ACuX]2 and [BCuX]2 (A: n = 2, B: n = 3, X: I, Cl). Die Struktur des Komplexes 1 [ACuI]2 wurde durch Kristallstrukturanalyse bestimmt. 1 enthält zwei tetraedrisch koordinierte Cu-Atome, die über zwei Iodobrücken miteinander verknüpft sind Cu—Cu-Bindungslänge: (261 pm).Der Ligand Me—N(CH2CH2N=CH—CH=CH—Ph)2 (C) reagiert mit CuX unter Bildung der monomeren Komplexe [CCuX] (5: X = I, 6: X=Cl). Die Kristallstruktur von 5 zeigt, daß der Ligand dreizählig koordiniert. Die Bindungslängen der Cu—N(sp2)-Bindungen sind signifikant kleiner als der Cu—N-(sp3)-Abstand.Die Reaktion der Podand-Liganden N(CH2CH2—N=CH—R)3 (D: R=Ph, E: R=-CH=CH—Ph) mit CuX führt zu den ionischen Komplexen 7 [DCu][CuCl2] bzw. 8 [ECu][CuCl2]. 7 wurde durch Röntgenstrukturanalyse charakterisiert, die ausweist, daß D als vierzähliger Ligand fungiert.Die Komplexe 1-8 sind gegenüber CO2 nicht reaktiv, nehmen aber O2 schon bei tiefen Temperaturen auf. Bei -78°C reagiert der orangerote Komplex 4 [BCuCl]2 mit O2 in CH2Cl2 zu einer tiefvioletten Lösung, das Primärprodukt der Oxidation konnte jedoch nicht isoliert werden. Es reagiert bei Raumtemperatur zu dem grünen Komplex 9 [μ-Cl, μ-OH][BCuCl]2. Die Kristallstrukturanalyse belegt, daß ein dimerer CuII-Komplex gebildet wird, in dem eine Chloro- und eine Hydroxobrücke die Monomereinheiten verbrücken. Die CuII-Zentren weisen eine verzerrt tetragonal-pyramidale Koordination auf.Der Reaktionsweg der Umsetzung mit O2 wird diskutiert.
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  • 282
    ISSN: 0044-2313
    Schlagwort(e): Thia- and selena-arachno-undecaborane ; preparation ; spectroscopy ; ab initio/IGLO ; GIAO/NMR method ; crystal structure ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Thia- and Selena-arachno-undecaborane 6,7-μ-(CH3E)B10H13. Crystal Structure of arachno-6,7-μ-(CH3Se)B10H13. Theoretical Investigations of the Molecular Structures and 11B NMR Shifts of arachno-6,7-μ-(CH3E)B10H13The reaction of B10H14 with (CH3)2S yields with loss of H2 the base adduct 6,9-[(CH3)2S]2B10H12. Although an analogous reaction between B10H14 with disulfanes or diselenanes was expected to produce 6,9 bridged dichalcogen derivatives, (CH3)2S2 failed to react even under reflux conditions. Trisulfane (CH3)2S3 does react, but the pathway is different and leads to (CH3S)B10H13 2 without loss of H2. Unlike of (CH3)2S2, (CH3)2Se2 yields (CH3Se)B10H13, 3. Both 2 and 3 are formed by substitution of a bridging hydrogen and could be obtained in pure form and characterized 11B NMR spectroscopically. A single crystal X-ray structure analysis also was performed on 3 (space group P21/c). The molecular structures of 2 and 3 were optimized at the MP2 level and 11B NMR shifts were computed at the IGLO-SCF, GIAO-SCF and GIAO-B3LYP levels of theory.
    Notizen: Bei der Reaktion zwischen B10H14 und (CH3)2S erfolgt unter H2-Abspaltung eine zweifache Adduktbildung, die zu 6,9-[(CH3)2S]2B10H12 führt. Die analoge Umsetzung zwischen B10H14 mit Disulfanen bzw. Diselenanen führte jedoch nicht zu den 6,9-Dichalkogen-verbrückten Derivaten. Bei der Umsetzung mit (CH3)2S2 findet selbst unter Refluxbedingungen keine Reaktion statt, wohl aber mit dem Trisulfan (CH3)2S3. Die Reaktion verläuft aber nicht unter H2-Abspaltung. Vielmehr wird dabei ein Brücken-H-Atom durch eine CH3S-Gruppe substituiert unter Bildung von (CH3S)B10H13 2. Im Gegensatz zu (CH3)2S2 findet aber mit (CH3)2Se2 ebenfalls eine Brücken-H-Substitution statt, wobei (CH3Se)B10H13 3 gebildet wird. 2 und 3 konnten in reiner Form isoliert und 11B-NMR-spektroskopisch charakterisiert werden. Von 3 wurde eine Röntgenstrukturanalyse durchgeführt (Raumgruppe P21/c) und von 2 und 3 die Molekülstrukturen auf MP2-Niveau optimiert sowie 11B-NMR- Verschiebungen mit IGLO-SCF, GIAO-SCF und GIAO-B3LYP berechnet.
    Zusätzliches Material: 3 Ill.
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  • 283
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1163-1167 
    ISSN: 0044-2313
    Schlagwort(e): Titanium-Aluminium Alkoxide ; Aluminium Titanate (Tialite) ; Ceramics Precursor ; X-Ray Structure Determination ; 1H/13C-NMR (2 D) ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Synthesis and Structural Characterization of a Novel Titanium-Aluminium AlkoxideThe novel Ti-Al-Alkoxide TiAl2(OiPr)10, was synthesized from aluminium turnings and titanium tetraisopropoxide in 2-propanol and isolated by subsequent fractionating distillation. Colourless prismatic crystals precipitated after 24 h at 20°C from the main fraction. They proved very moisture sensitive. The compound crystallizes in the monoclinc space group C2/c (no. 15) with a = 2303.1(4), b = 1097.2(3), c = 1685.0(3) pm, β = 104.32(1)° and Z = 4. The molecular structure exhibits a bent Al-Ti-Al′ unit, in which Al shows tetrahedral, but Ti octahedral1 coordination. The polyhedra are connected via cis-edges of the octahedron. The structure of the compound in solution was determined by NMR spectroscopy (1H, 13C, COSY) and proved to be identical to the structure in the solid state.
    Notizen: Das neue Ti-Al-Alkoxid TiAl2(OiPr)10 wurde durch Umsetzung von Al-Spänen mit Titantetraisopropoxid in Isopropanol und anschließender fraktionierender Destillation dargestellt. Die nach 24 h bei 20°C aus der Hauptfraktion gebildeten farblosen, prismatischen Kristalle sind sehr hydrolyseempfindlich. Die Kristallstruktur konnte bei -83°C bestimmt werden: monokline Raumgruppe C2/c (Nr. 15) mit a = 2303,1(4), b = 1097,2(3), c = 1685,0(3) pm, β = 104,32(1)° und Z = 4. Die Molekülstruktur besteht aus einer gewinkelten Al-Ti-Al′-Einheit, in der Al tetraedrisch und Ti oktaedrisch koordiniert sind. Die verknüpfenden Kanten am Ti-Oktaeder sind cis angeordnet. Die Struktur der Verbindung in Lösung wurde NMR-spektroskopisch (1H, 13C, COSY) ermittelt und stimmt mit der Struktur im Einkristall überein.
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  • 284
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1168-1174 
    ISSN: 0044-2313
    Schlagwort(e): Sulfoximide ; Sulfoximidium Salts ; Structure ; Hydrogenbonding ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Sulfoximide and Sulfoximidium Salts - Structures and Hydrogen BondingIn the solid state dimethylsulfoximide (1) (orthorhombic; space group Pbca; a = 577.8, b = 931.2 and c = 1645.6 pm) makes intermolecular N—H ≡ N hydrogen bonds. The hydrogen halide salts (CH3)2S(O)NH2+Hal- ((2), Hal-=Cl-; (4), Hal-=Br-) reacts with metal halides to yield (CH3)2S(O)NH2+MHalyn- with the complex anions ((5), MHalyn-=SbCl4-; (6), MHalyn-=SbCl52-; (7), MHalyn-=SbCl6-; (8), MHalyn-=SbBr52-; (9), MHalyn-=AlCl4-). 2 crystallizes from ethanol (96%) as [(CH3)2S(O)NH2+Cl-]2 · H2O (3). The structures of 3 (monoclinic; space group P21/c; a = 917.0, b = 1344.7, c = 1080.8 pm and β = 103.8°; Z = 10), 4 (orthorhombic; space group Pbcn; a = 1028.9, b = 1132.6, c = 1074.1 pm; Z = 8) and 6 (monoclinic; space group C2/c; a = 2041.1, b = 1101.4, c = 3365.6 pm and β = 153.8°; Z = 8) are determined by X-ray analysis. In 6 Sb is coordinated in a distorted octahedra by 6 Cl in three short (mean 245,5 pm; SbCl3) and three long distances (291 to 299 pm; Cl-). Two of the chloride ions connect the Sb atoms to infinite Sb … Cl … Sb chains. Except for 7 and 9 there are bridges between the NH2 groups and the halide ions. The NH valence vibrations are discussed in view of hydrogen bonding.
    Notizen: Im festen Dimethylsulfoximid (1) (orthorhombisch; Raumgruppe Pbca; a = 577,8, b = 931,2 und c = 1645,6 pm) sind zwischen den Imidgruppen N—H … N-Brückenbindungen ausgebildet. Die mit HHal darstellbaren Salze (CH3)2S(O)NH2+Hal- ((2), Hal-=Cl-; (4), Hal-=Br-) reagieren mit MHalx zu (CH3)2S(O)NH2+MHalyn- ((5), MHalyn-=SbCl4-; (6), MHalyn-=SbCl52-; (7), MHalyn-=SbCl6-; (8), MHalyn-=SbBr52-; (9), MHalyn-=AlCl4-). 2 kristallisiert aus 96% Ethanol als [(CH3)2S(O)NH2+Cl-]2 · H2O (3). Die Strukturen von 3 (monoklin; Raumgruppe P21/c; a = 917,0, b = 1344,7, c = 1080,8 pm und β = 103,8°; Z = 10), 4 (orthorhombisch; Raumgruppe Pbcn; a = 1028,9, b = 1132,6, c = 1074,1 pm; Z = 8) und 6 (monoklin; Raumgruppe C2/c; a = 2041,1, b = 1101,4, c = 3365.6 pm und β = 153,8°; Z = 8) wurden bestimmt. In 6 ist Sb verzerrt oktaedrisch von 6 Cl in drei kurzen (im Mittel 245,5 pm; SbCl3) und drei langen Abständen (291 bis 299 pm; Cl-) umgeben. Zwei der lang gebundenen Cl-Ionen verknüpfen die Sb-Atome zu unendlichen Sb … Cl … Sb-Ketten. Die NH2-Gruppen der Kationen bilden außer in 7 und in 9 H—Brückenbindungen zu den Halogenidionen. Die NH-Valenzschwingungen werden im Hinblick auf die Wasserstoffbrückenbindungen diskutiert.
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  • 285
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1183-1189 
    ISSN: 0044-2313
    Schlagwort(e): Tris(perfluoroalkyl) arsenic and antimony ; tris(pentafluoroethyl) arsenic and antimony(V) halides ; synthesis ; NMR ; mass spectra ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Preparations and Properties of Tris(perfluoroalkyl) Arsenic and Antimony(III, V) CompoundsAs(Rf)3 and Sb(Rf)3 (Rf=C2F5, C4F9, C6F13) are prepared in good yields by the polar reactions of AsCl3 and SbCl3 with bis(perfluoroalkyl) cadmium compounds as colourless liquids or solids. The oxidation of As(C2F5)3 and Sb(C2F5)3 with XeF2 gives the difluorides M(C2F5)3F2 (M=As, Sb). As(C2F5)3Cl2 is prepared by chlorination of As(C2F5)3 in the presence of AlCl3, while Sb(C2F5)3Cl2 is formed in the reaction of Sb(C2F5)3F2 with (CH3)3SiCl. During the reaction of M(C2F5)3F2 with (CH3)3SiBr 19F-NMR spectroscopic evidence is found for M(C2F5)3 Br2. The thermal decompositions of M(C2F5)3F2 mainly yield C4F10 and M(C2F5)F2, while the thermal decompositions of M(C2F5)3Cl2 yield M(C2F5)2Cl and C2F5Cl. The properties and spectroscopic data of the new compounds are described.
    Notizen: As(Rf)3 und Sb(Rf)3 (Rf=C2F5, C4F9, C6F13) werden durch Umsetzungen von AsCl3 und SbCl3 mit Bis(perfluoralkyl)cadmium-Verbindungen unter polaren Bedingungen in guten Ausbeuten als farblose Flüssigkeiten bzw. Festkörper dargestellt. Durch Oxidation von As(C2F5)3 und Sb(C2F5)3 mit XeF2 entstehen die Difluoride M(C2F5)3F2 (M=As, Sb). Die Darstellung von As(C2F5)3Cl2 gelingt durch Chlorierung von As(C2F5)3 in Gegenwart von AlCl3; die Darstellung von Sb(C2F5)3Cl2 durch Reaktion von Sb(C2F5)3F2 mit (CH3)3SiCl. Die Dibromide M(C2F5)3Br2 sind nur 19F-NMR-spektroskopisch bei der Reaktion von M(C2F5)3F2 mit (CH3)3SiBr nachweisbar. Bei der thermischen Zersetzung von M(C2F5)3F2 entstehen hauptsächlich C4F10 und M(C2F5)F2, während die thermische Zersetzung von M(C2F5)3Cl2 unter Bildung von M(C2F5)2Cl und C2F5Cl verläuft. Eigenschaften und spektroskopische Daten der neuen Verbindungen werden beschrieben.
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  • 286
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997) 
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 287
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1190-1200 
    ISSN: 0044-2313
    Schlagwort(e): Phase investigation ; chemical transport reactions ; zinc molybdate ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: On the System Zn/Mo/O. II. Chemical Transport of Ternary Zinc MolybdatesThe Chemical Transport is a method for preparation of phasepure multinary compounds with defined composition. We report about the possibilities to transport ternary compounds of the Zn/Mo/O system using Cl2, HCl, Br2, HBr, and I2 as an agent. The influence of the solid-gas equilibria on the compositions of solids, the transport direction, and the rate is showed.
    Notizen: Der Chemische Transport ermöglicht eine gezielte phasenreine Darstellung von mehrkomponentigen Verbindungen mit definierter Zusammensetzung. Für das System Zn/Mo/O wird über die Möglichkeiten des Chemischen Transports der ternären Phasen mit den Transportmitteln Cl2, HCl, Br2, HBr und I2 berichtet. Dabei wird der Einfluß der Bodenkörper-Gasphase-Gleichgewichte auf die Bodenkörperzusammensetzungen, die Transportrichtung und Transportraten gezeigt.
    Zusätzliches Material: 5 Ill.
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  • 288
    ISSN: 0044-2313
    Schlagwort(e): Bis(dimesy1amido-O)tetraaquametal(II) complexes ; bis(dimesy1amido-O)tetrapyridinemetal(II) complexes ; synthesis ; X-ray structure; isotypic series ; Jahn-Teller distortion ; O—H…O, O—H…N and C—H…O hydrogen bonds ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Polysulfonylamines. LXXXIV. Isotypic Structures in the Dimesylamide Complex Series [M(H2O)4{(CH3SO2)2N}2] (M=Mg, Ca, Ni, Cu, Zn, Cd) and [M(py)4{(CH3SO2)2N}2] (M=Ni, Cu, Zn, Cd)The crystal structures of the trans-octahedral complexes [M(H2O)4{(CH3SO2)2N}2] (M=Ca, Cd), in which the dimesylamide anion acts as a monodentate O-ligand and a tetrafunctional hydrogen bond acceptor, were determined by low-temperature X-ray diffraction. Both belong to an isotypic series (triclinic, space group P1, Z = 1) that had previously been characterized for M=Mg, Ni, Cu and Zn (Z. Anorg. Allg. Chem. 1996, 622, 1065). In this structure there exists an extended network of strong hydrogen bonds which is probably the underlying reason why the structure type surprisingly persists across the whole series. To support this explanation by indirect evidence from comparison with suitable structures devoid of strong hydrogen bonding, the analogous trans-octahedral complexes [M(py)4{(CH3SO2)2N}2] (M=Mn, Co, Ni, Cu, Zn, Cd) were prepared by treating M[(CH3SO2)2N]2 with pyridine, and the crystal structures of the Ni, Cu, Zn and Cd compounds were studied by low-temperature X-ray crystallography. As anticipated, the four pyridine complexes do not form an isotypic series but instead two isotypic pairs consisting of the Ni and Zn compounds (monoclinic, space group P21/n, Z =2) and of the Cu and Cd complexes (triclinic, space group P1, Z = 1). All molecules of the aqua and the pyridine complexes display crystallographic centrosymmetry. In the hydrates, the mean M—OH2 and the M—O(anion) distances are 232.6 and 232.7 pm for M = Ca, 225.5 and 230.3 pm für M = Cd. The mean M—N and the M—O(anion) bond lengths of the pyridine species amount to 211.8 and 213.1 pm for M = Ni, 217.0 and 218.5 pm for M = Zn, 232.8 and 234.4 pm for M = Cd; the corresponding values for the severely Jahn-Teller distorted Cu complex are 203.6 and 254.5 pm. In the crystals of the pyridine complexes, each methyl group is connected through a weak C—H…O bond to a sulfonyl oxygen atom of an adjacent molecule.
    Notizen: Die Kristallstrukturen der trans-oktaedrischen Komplexe [M(H2O)4{(CH3SO2)2N}2] (M=Ca, Cd), in denen das Dimesylamid-Anion als einzähniger O-Ligand und tetrafunktioneller Wasserstoffbrücken-Akzeptor wirkt, wurden durch Tieftemperatur-Röntgenbeugung ermittelt. Beide gehören zu einer isotypen Reihe (triklin, Raumgruppe P1, Z = 1), die zuvor für M=Mg, Ni, Cu und Zn charakterisiert worden war (Z. Anorg. Allg. Chem. 1996, 622, 1065). Hauptursache für die überraschende Persistenz der Isotypie in der gesamten Reihe ist vermutlich das in der Struktur auftretende hochorganisierte Netzwerk aus starken intermolekularen Wasserstoffbrücken. Um diese Annahme durch indirekte Evidenz an vergleichbaren Strukturen ohne starke H-Brücken zu überprüfen, wurden die analogen trans-oktaedrischen Komplexe [M(py)4{(CH3SO2)2N}2] (M=Mn, Co, Ni, Cu, Zn, Cd) aus M[(CH3SO2)2N]2 und Pyridin dargestellt und die Vertreter mit M=Ni, Cu, Zn und Cd durch Tieftemperatur-Röntgenbeugung untersucht. Der Erwartung entsprechend bilden die vier Pyridin-Komplexe keine isotype Reihe, aber zwei isotype Paare, die aus der Ni- und der Zn- Verbindung (monoklin, Raumgruppe P21/n, Z = 2) bzw, dem Cu- und dem Cd-Komplex (triklin, Raumgruppe P1, Z = 1) bestehen. Sämtliche Moleküle besitzen kristallographische Inversionssymmetrie. Die Mittelwerte der M—OH2- und die M—O(Anion)-Abstände in den Wasser-Komplexen betragen 232,6 und 232,7 pm für M=Ca, 225,5 und 230,3 pm für M=Cd. In den Pyridin-Komplexen sind die mittleren M—N- und die M—O(Anion)-Bindungslängen 211,8 und 213,1 pm für M=Ni, 217,0 und 218,5 pm für M=Zn, 232,8 und 234,4 pm für M=Cd sowie 203,6 und 254,5 pm für den eine erhebliche Jahn-Teller-Verzerrung aufweisenden Cu-Komplex. In den Kristallen der Pyridin-Komplexe ist jede Methylgruppe über eine schwache C—H … O-Wechselwirkung mit einem Sulfonyl-Sauerstoffatom eines Nachbarmoleküls verknüpft.
    Zusätzliches Material: 3 Ill.
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  • 289
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1475-1482 
    ISSN: 0044-2313
    Schlagwort(e): Lithiumhydridosiloxysilylamides ; reaction behaviour ; N-silylation ; Si—O bond splitting ; cyclodisilazanes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Lithium Hydridosiloxysilylamides - Reactions in n-Octane and Tetrahydrofuran in Presence of ChlorotrimethylsilaneThe hydrido-siloxy-silylamino-silanes (Me3SiO)HSiMe(NHSiMe3) 1, (Me3SiO)HSi(NHSiMe3)2 2 and (Me3SiO)2HSi(NHSiMe3) 3 were prepared by coammonolysis of the chlorosiloxysilanes (Me3SiO)HSiMeCl and (Me3SiO)3-nHSiCln (n = 1, 2) with chlorotrimethylsilane. The reaction behaviour of lithiated compounds 1, 2 and 3 has been investigated in n-octane and tetrahydrofuran (THF) in presence of chlorotrimethylsilane.
    Notizen: Durch Koammonolyse der Chlorsiloxysilane (Me3SiO)HSiMeCl und (Me3SiO)3-nHSiCln (n = 1, 2) mit Chlortrimethylsilan wurden die Hydrido-siloxy-silylamino-silane (Me3SiO)HSiMe(NHSiMe3) 1, (Me3SiO)HSi(NHSiMe3)2 2 und (Me3SiO)2HSi(NHSiMe3) 3 dargestellt und das Reaktionsverhalten der lithiierten Verbindungen 1, 2 und 3 in n-Octan und Tetrahydrofuran (THF) in Gegenwart von Chlortrimethylsilan untersucht.Sowohl das Monoamid (Me3SiO)HSiMe(NLiSiMe3) als auch das Diamid (Me3SiO)HSi(NLiSiMe3)2 reagieren unter N-Silylierung zu N-Substitutionsprodukten und unter Si—O-Bindungsspaltung und LiOSiMe3-Eliminierung zu Cyclodisilazanen, wobei THF die N-Silylierung, n-Octan die Bildung von Cyclodisilazanen begünstigt. Das Monoamid ergibt in n-Octan (Me3SiO)HSiMe[N(SiMe3)2] 4, [Me(H)Si-NSiMe3]2 5 (Hauptprodukt) und 6, in THF 4 als Hauptprodukt und 5. Aus dem Diamid werden in THF (Me3SiO)HSi[N(SiMe3)2](NHSiMe3) 7, bevorzugt (Me3SiO)HSi[N(SiMe3)2]2 8, [(Me3SiNH)HSi—NSiMe3]2 9 und 10 gebildet, in n-Octan 7, bevorzugt 9 und 10.Hauptprodukt der Reaktion des Amids (Me3SiO)2HSi(NLiSiMe3) in THF und n-Octan ist das N-Silylierungsprodukt (Me3SiO)2HSiN(SiMe3)2 11.Eine Reaktion unter Beteiligung der Si—H-Gruppe wird nur im Falle von (Me3SiO)HSiMe(NLiSiMe3) beobachtet, Produkt dieser Reaktion ist 6.The monoamide (Me3SiO)HSiMe(NLiSiMe3) and the diamide (Me3SiO)HSi(NLiSiMe3)2 react under N-silylation to N-substitution products and under Si—O-bond splitting and LiOSiMe3-elimination to cyclodisilazanes in n-octane as well as in THF. The favour reaction is in THF the N-silylation, in n-octane the formation of cyclodisilazanes. The monoamide gives in n-octane (Me3SiO)HSiMe[N(SiMe3)2] 4, [Me(H)Si-NSiMe3]2 5 (main product) and 6, in THF as main product 4 and 5. The diamide reacts in THF to give (Me3SiO)HSi[N(SiMe3)2](NHSiMe3) 7, mainly (Me3SiO)HSi[N(SiMe3)2]2 8, [(Me3SiNH)HSi—NSiMe3]2 9 and 10, in n-octane 7, mainly 9 and 10.The N-silylation product (Me3SiO)2HSiN(SiMe3)2 11 is the main product of the reaction of (Me3SiO)2HSi(NLiSiMe3) in THF and in n-octane.A reaction with participation of the Si-H group is only observed in the case of (Me3SiO)HSiMe(NLiSiMe3). 6 is the product of this reaction.
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  • 290
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1489-1491 
    ISSN: 0044-2313
    Schlagwort(e): 2,9-{N,N′-(2-aminopyridine)}octahydro-closo-decaborate(2-) ; Crystal Structure ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Synthesis and Crystal Structure of [P(C6H5)4][2,9-{N,N′-(2-NH—(C5H4N))}B10H8][N(C4H9)4]2[B10H10] reacts with 2-aminopyridine forming a product mixture from which [2,9-{N,N′-(2-NH—(C5H4N))}B10H8]- can be isolated by ion exchange chromatography on diethylaminoethyl(DEAE) cellulose. The crystal structure of [P(C6H5)4][2,9-{N,N′-(2-NH—(C5H4N))}B10H8] (triclinic, space group P1, a = 10.1103(9), b = 11.5665(9), c = 14.877(2) Å, α = 102.600(8), β = 107.567(8) und γ = 96.487(7)°, Z = 2) reveals the bonding of 2-NH2-(C5H4N) via both N atoms to vicinal B atoms of the two square planes of the B10 cluster (B2—N1 = 1,541(7) und B9—N2 = 1.505(7) Å) forming a five-membered ring.
    Notizen: [N(C4H9)4]2[B10H10] reagiert mit 2-Aminopyridin unter Bildung eines Produktgemisches, aus dem durch Ionenaustauschchromatographie an Diethylaminoethyl(DEAE)-Cellulose [2,9-{N,N′-(2-NH—(C5H4N))}B10H8]- isoliert werden kann. Die Röntgenstrukturanalyse an [P(C6H5)4][2,9-{N,N′-(2-NH—(C5H4N))}B10H8] (triklin, Raumgruppe P1, a = 10,1103(9), b = 11,5665(9), c = 14,877(2) Å, α = 102,600(8), β = 107,567(8) und γ = 96,487(7)°, Z = 2) beweist, daß 2-NH2-(C5H4N) über beide N-Atome an benachbarte B-Atome der beiden quadratischen Ebenen des B10-Clusters (B2—N1 = 1,541(7) und B9—N2 = 1,505(7) Å) unter Ausbildung eines Fünfringes gebunden ist.
    Zusätzliches Material: 2 Ill.
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  • 291
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1493-1495 
    ISSN: 0044-2313
    Schlagwort(e): Synthesis ; Crystal structure ; Crown ether ; Lanthanides ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: [La2I2(OH)2(dibenzo-18-crown-6)2]I(I3), a Cationic Dimeric in-cavity Complex with Iodide and Triiodide as AnionsSingle crystals of [La2I2(OH)2(dibenzo-18-crown-6)2]I(I3) are obtained from the reaction of LaI3 and dibenzo-18-crown-6 in acetonitrile. The crystal structure monoclinic, C2/m, Z = 4, T = 293 [100] K, a = 2179(3) [2162.3(3)], b = 1070.3(3) [1069.6(1)], c = 1118.2(3) [1110.6(1)] pm, β = 93.1(1) [92.83(1)]°, R1 = 0.0601 [0.0411], wR2 = 0.1449 [0.1014] contains hydroxide-bridged cationic dimers and iodide as well as triiodide as anions.
    Zusätzliches Material: 2 Ill.
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  • 292
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1499-1500 
    ISSN: 0044-2313
    Schlagwort(e): Methylindium Compound ; Heterocubane ; Synthesis ; X-ray Structure ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The X-Ray Structure Determination of tert-Butylimido Methylindane, [CH3In—NC(CH3)3]4The reaction of MeInCl2 with LiN(H)tBu in a 1 : 2 molar ratio forms [MeIn—NtBu]4 in high yield, lithium chloride, and the free amine H2NtBu. The crystal structure of the imidomethylindane with a cubic In4N4 skeleton has been determined.
    Zusätzliches Material: 1 Ill.
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  • 293
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1287-1289 
    ISSN: 0044-2313
    Schlagwort(e): Calcium hexahydroxodizincate dihydrate ; synthesis ; crystal structure ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Crystal Structure of CaZn2(OH)6 · 2 H2OThe electrochemical oxidation of zinc in a zinc/iron-pair leads in an aqueous NH3 solution of calciumhydroxide at room temperature to colourless crystals of CaZn2(OH)6 · 2 H2O. The X-ray structure determination was now successful including all hydrogen positions.P21/c, Z = 2, a = 6.372(1) Å, b = 10.940(2) Å, c = 5.749(2) Å, β = 101.94(2)° N(F2o ≥ 3σF2o) = 809, N(Var.) = 69, R/RW = 0.011/0.012The compound CaZn2(OH)6 · 2H2O contains Zn2+ in tetrahedral coordination by OH- and Ca2+ in octahedral coordination by four OH- and two H2O. The tetrahedra around Zn2+ form corner sharing chains, three-dimensionally linked by isolated polyhedra around Ca2+. Weak hydrogen bridge bonds result between H2O as donor and OH-.
    Notizen: Die elektrochemische Oxidation von Zink in einem Zink/Eisen-Paar führt in einer wäßrigen NH3-Lösung von Calciumhydroxid bei Raumtemperatur zu farblosen Kristallen von CaZn2(OH)6 · 2 H2O. An ihnen wurde röntgenographisch die Struktur jetzt einschließlich aller H-Lagen bestimmt.P21/c, Z = 2, a = 6,372(1) Å, b = 10,940(2) Å, c = 5,749(2) Å, β = 101,94(2)° Z(F2o ≥ 3σF2o) = 809, Z(Var.) = 69, R/RW = 0,011/0,012In CaZn2(OH)6 · 2 H2O ist Zn2+ tetraedrisch von OH- und Ca2+ oktaedrisch von vier OH- und zwei H2O umgeben. Die Tetraeder um Zn2+ bilden Ketten über gemeinsame Ecken, die durch voneinander isolierten Oktaedern um Ca2+ dreidimensional verknüpft werden. Es liegen schwache H-Brückenbindungen von H2O als Donator zu OH- vor.
    Zusätzliches Material: 2 Ill.
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  • 294
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1299-1305 
    ISSN: 0044-2313
    Schlagwort(e): Pseudoelement compounds ; cyanamidonitrate ; copper(I) ; silver(I) ; platinum(II) ; crystal structure ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Pseudoelement Compounds. XI. [1] Investigations on the Coordination Behaviour of Cyanamidonitrate [NO2NCN]-With the ionic, potentially ambidentate ligand cyanamidonitrate complexes of the types [MX(PPh3)3], [MX(PPh3)2]2 (M=CuI, AgI) and trans-[Pt(H)X(PPh3)2] (X-=[NO2NCN]-) are introduced. The new compounds are characterized by 1H NMR, 31P NMR, and IR spectroscopy. The crystal structures of [Cu(NO2NCN)(PPh3)2]2 and [Ag(NO2NCN)(PPh3)2]2 are reported. In the complexes [MX(PPh3)3] and trans-[Pt(H)X(PPh3)2] cyanamidonitrate is unidentately coordinated through the nitrile group end-on. In the dimeric complexes [MX(PPh3)2]2 the anion acts bidentately as a bridging ligand. Surprisingly, both coordinative bonds are formed through nitrogen atoms of the NCN group.
    Notizen: Es werden mit dem ionischen, potentiell ambidenten Liganden Cyanamidonitrat Komplexe der Typen [MX(PPh3)3], [MX(PPh3)2]2 (M=CuI, AgI) sowie trans-[Pt(H)X(PPh3)2] (X-=[NO2NCN]-) vorgestellt. Die Verbindungen wurden 1H-NMR-, 31P-NMR- und IR-spektroskopisch charakterisiert. Für [Cu(NO2NCN)(PPh3)2]2 und [Ag(NO2NCN)(PPh3)2]2 liegen Kristallstrukturanalysen vor.Cyanamidonitrat wird in den Komplexen [MX(PPh3)3] und trans-[Pt(H)X(PPh3)2] einzähnig über das endständige N-Atom der Nitrilgruppe koordiniert. In den dimeren Komplexen [MX(PPh3)2]2 liegt das Anion als zweizähniger Brükkenligand vor. Überraschend werden beide koordinativen Bindungen über die Stickstoffatome der NCN-Gruppe ausgebildet.
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  • 295
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1290-1298 
    ISSN: 0044-2313
    Schlagwort(e): Amine Alcohol Ligands ; Density Functional Calculations ; Magnetic Properties ; Magneto-Structural Correlations ; Vanadium Complexes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Oxovanadium(IV) Complexes with Multidentate Amine Alcohol Ligands: Magneto-Structural Correlations for the {VO(μ-OR)2VO} CoreThe trivalent, pentadentate amine alcohol ligand 1,1-bis(2-hydroxyethyl)-4-(2-hydroxybenzyl)-1,4-diazabutane (H3hebab) reacts with [VO(acac)2] in methanol solution to yield the binuclear oxovanadium(IV) complex [{VO(Hhebab)}2] with a {VO(μ-OR)2VO}2+ core. The compound has been characterized by vibrational (IR, Raman), UV/Vis/NIR, and ESR spectroscopy and the measurement of the magnetic susceptibility in the temperature range of 2 to 280 K. A classification is given for the correlation of the configuration of the {VO(μ-OR)2VO} core and the magnetic properties of the related oxovanadium(IV) complexes. Antiferromagnetic interactions are operative in the case of anti-and syn-orthogonal as well as syn-coplanar configurations. whereas in the case of anti-coplanar and twist configurations ferromagnetic interactions are observed. Based on the antiferromagnetic behavior of [{VO(Hhebab)}2] with J = -170 cm-1 this classification allows together with the spectroscopic data and density functional calculations the unequivocal assignment of an anti-orthogonal configuration for its {VO(μ-OR)2VO}2+ core. The structural and magnetic data of a series of oxovanadium(IV) complexes with anti- and syn-orthogonal {VO(μ-OR)2VO} core are used to investigate the quantitative correlation between the V(IV) … V(IV) distance and the corresponding isotropic interaction constant J.
    Notizen: Der dreibasige, fünfzähnige Aminoalkohol 1,1-Bis(2-hydroxyethyl)-4-(2-hydroxybenzyl)-1,4-diazabutan (H3hebab) reagiert mit [VO(acac)2] in Methanol als Lösungsmittel zum zweikernigen Oxovanadium(IV)-Komplex [{VO(Hhebab)}2] mit einer zentralen {VO(μ-OR)2VO}2+-Einheit. Zur Charakterisierung wurden Schwingungs- (IR, Raman), UV/Vis/NIR- und ESR-Spektren aufgenommen und die magnetische Suszeptibilität im Temperaturbereich von 2 bis 280 K gemessen. Für zweikernige Oxovanadium(IV)-Verbindungen mit {VO(μ-OR)2VO}-Einheit besteht ein Zusammenhang zwischen der Konfiguration dieser Einheit und den magnetischen Eigenschaften der zugrundeliegenden Oxovanadium(IV)-Verbindungen. Die magnetischen Eigenschaften der zweikernigen Einheit lassen sich qualitativ entsprechend ihrer Konfiguration klassifizieren. Danach führen anti- und syn-orthogonale sowie syn-komplanare Konfigurationen zu antiferromagnetischen Wechselwirkungen, wogegen im Falle anti-komplanarer und twist Konfigurationen ferromagnetische Wechselwirkungen beobachtet werden. Aufgrund der für [{VO(Hhebab)}2] ermittelten antiferromagnetischen Kopplungskonstanten J=-170 cm-1 erlaubt diese Klassifizierung zusammen mit den spektroskopischen Daten und Dichtefunktionalrechnungen die eindeutige Zuordnung einer anti-orthogonalen Konfiguration für die zentrale {VO(μ-OR)2VO}2+-Einheit dieses Komplexes. Anhand bekannter struktureller und magnetischer Daten von Oxovanadium(IV)-Verbindungen mit kantenverknüpften {VO(μ-OR)2VO}-Einheiten in anti- und syn-orthogonaler Konfiguration wird die quantitative Beziehung zwischen dem Abstand der Vanadium(IV)-Zentren und der zugehörigen isotropen Wechselwirkungskonstante J untersucht.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 296
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1306-1310 
    ISSN: 0044-2313
    Schlagwort(e): Lithium Cluster ; Carbdianion ; NMR spectra ; Crystal Structure ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: [Li7(CHPMe2NSiMe3)3(OSiMe2nBu)]2, a Mixed-Ligand-Li14 Cluster with the Carbdianion (CHPMe2NSiMe3)2-The title compound is formed as colourless moisture and oxygen sensitive crystals by the reaction of [LiCH2PMe2NSiMe3]4 with zinc or cobalt chloride in a toluene suspension in the presence of silicongrease (-OSiMe2-)n and n-butyllithium. It is characterized by multinucleus NMR spectroscopy and by crystal structure determinations of two different crystal individuals.1. Space group P1, Z = 1, lattice dimensions at -70 °C: a = 1272.0, b = 1392.6, c = 1417.6 pm, α = 115.33°, β = 96.75°, σ = 106.81°; R = 0.042.2. Space group P21/n, Z = 2, lattice dimensions at -50 °C: a = 1424.8, b = 1457.1, c = 1997.0 pm, β = 90.32, R = 0.069.
    Notizen: Die Titelverbindung (farblose, feuchtigkeits- und sauerstoffempfindliche Kristalle) entsteht bei der Reaktion von [LiCH2PMe2NSiMe3]4 mit wasserfreiem Zink- oder Cobaltchlorid in einer Toluolsuspension in Gegenwart von Siliconfett (-OSiMe2-)n und n-Butyllithium. Sie wird durch Multikern-NMR-Spektroskopie und durch Kristallstrukturanalysen zweier kristallchemisch verschiedener Individuen charakterisiert.1. Raumgruppe P1, Z = 1, Gitterkonstanten bei -70 °C: a = 1272,0; b = 1392,6; c = 1417,6 pm; α = 115,33°; β = 96,75°; σ = 106,81°; R = 0,042.2. Raumgruppe P21/n, Z = 2, Gitterkonstanten bei -50 °C: a = 1424,8; b = 1457,1; c = 1997,0 pm; β = 90,32°; R = 0,069.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 297
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1311-1316 
    ISSN: 0044-2313
    Schlagwort(e): Polyoxohexatantalate(V) ; synthesis ; crystal structures ; polyoxoanion packing ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The Crystal Structures of K8Ta6O19 · 16H2O and K7NaTa6O19 · 14H2OBy alkaline digestion of Ta2O5 with p.a. KOH transparent single crystals of the composition K8Ta6O19 · 16H2O are formed. When technical grade KOH is used, the same kind of synthesis yields crystals of the composition K7NaTa6O19 · 14H2O. The latter compound has been given the formula K8Ta6O19 · 14H2O until now. In both cases the isopolyoxoanion [Ta6O19]8 consists of six TaO6-octahedra connected by edge sharing. This means that the heavy atom partial structure found by Lindquist et al. is confirmed. Additionally the complete structures including the atomic positions of the oxygen atoms of the polyanions as well as those of the cations and crystal water molecules (without hydrogen positions) are determined.
    Notizen: Durch basischen Aufschluß von Ta2O5 mit p. a. KOH erhält man durchsichtige Einkristalle der Zusammensetzung K8Ta6O19 · 16H2O. Der Einsatz von technischer KOH dagegen führt beim gleichem Synthese-Verfahren zu Einkristallen der Zusammensetzung K7NaTa6O19 · 14H2O, einer Verbindung, die in der Literatur als K8Ta6O19 · 14H2O beschrieben ist. Das Isopolyanion [Ta6O19]8- besteht in beiden Fällen aus sechs kantenverknüpften (TaO6)-Oktaedern in der Anordnung eines großen Oktaeders. Es konnte somit die von Lindqvist et al. angegebene Schweratom-Teilstruktur bestätigt werden. Zusätzlich wurden die kompletten Kristallstrukturen einschließlich der Positionen der Sauerstoffatome des Isopolyanions sowie der Kationen und Kristallwasser Moleküle (ohne Wasserstoffatome) ermittelt.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 298
    ISSN: 0044-2313
    Schlagwort(e): Allyldichloro- and allyldifluorophosphite-carbonyl-metal(0) complexes (metal = Cr, Mo, W, Fe) ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Reactions of Allyldichlorophosphite and Allyldifluorophosphite with some Transition Metal Compounds; Synthesis and Spectroscopic Identification of Allyldichloro- and Allyldifluorophosphite-Carbonyl-Metal(0) Coordination Compounds (Metal=Cr, Mo, W, Fe)In the reactions of allyldifluorophosphite (1) and allyldichlorophosphite (2) with the carbonyl compounds (C7H8)M(CO)3 (M=Cr, Mo; C7H8 = cycloheptatriene), W(CO)5THF (THF = tetrahydrofuran), Fe(CO)5 or Fe2(CO)9 the allyldichloro- and allyldifluorophosphite-carbonyl-metal compounds fac-(AllOPF2)3Cr(CO)3 3 a, mer-(AllOPF2)3Cr(CO)3 3 b, fac-(AllOPF2)3Mo(CO)3 4, fac-(AllOPCl2)3Mo(CO)3 5, (AllOPF2)W(CO)5 6, (AllOPCl2)W(CO)5 7, (AllOPF2)Fe(CO)4 8 and (AllOPCl2)Fe(CO)4 9 were formed (All = CH2=CHCH2). In 8 and 9 the ligands 1 or 2 are axially orientated. The validity of the concept of hard and soft acids and bases (HSAB-concept) and of the 18-valency electron rule (18-VE-rule) was confirmed. The allyl dihalophosphites 1 and 2 coordinate via phosphorus. The allylic π-system was not involved in the coordinative bond. The characterization of the coordination compounds 3, 4, 5 a, 5 b und 6-9 was based on their IR and NMR spectra, and on the mass spectra.
    Notizen: Bei den Umsetzungen von Allyldifluorphosphit (1) bzw. Allyldichlorphosphit (2) mit den Carbonylverbindungen (C7H8)M(CO)3 (M=Cr, Mo; C7H8=Cycloheptatrien), W(CO)5THF (THF=Tetrahydrofuran) sowie Fe(CO)5 bzw. Fe2(CO)9 wurden die Allyldichlor- bzw. Allyldifluorphosphit-Carbonyl-Metallverbindungen, fac- (AllOPF2)3Cr(CO)3 3 a, mer-(AllOPF2)3Cr(CO)3 3 b, fac- (AllOPF2)3Mo(CO)3 4, fac-(AllOPCl2)3Mo(CO)3 5, (AllOPF2)W(CO)5 6, (AllOPCl2)W(CO)5 7, (AllOPF2)Fe(CO)4 8 und (AllOPCl2)Fe(CO)4 9 erhalten (All=CH2=CHCH2). In 8 und 9 sind die Liganden 1 bzw. 2 axial orientiert. Die Gültigkeit des Konzeptes der harten und weichen Säuren und Basen (HSAB-Konzept) und der 18-Valenzelektronenregel (18 VE-Regel) wurde bestätigt. Die Allyldihalogenphosphite 1 und 2 koordinieren über das Phosphoratom; eine Beteiligung des π-Systems der Allylgruppe an einer koordinativen Bindung wurde nicht beobachtet. Die Charakterisierung der Komplexverbindungen 3, 4, 5 a, 5 b und 6-9 beruht auf den IR- und NMR-Spektren sowie den Massenspektren.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
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  • 299
    ISSN: 0044-2313
    Schlagwort(e): Hexafluoroacetone ; Oxidative addition ; Spirophosphoranes ; Phosphorus ; NMR spectroscopy ; X-ray structure analysis ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Ungewöhnliche Bildung von Spirophosphoranen während der oxidativen Addition von Hexafluoraceton an σ5P-σ3P-Diphosphorverbindungen und in der Reaktion von 2-Chlor-l,2-dimethyl-3-phenyl-2-phenylseleno-1,3,5σ5-diazaphosphetidin-4-on mit Bis(2-chlorethyl)aminhydrochlorid/TriethylaminDie Umsetzung von (Chlormethyl)dichlorphosphin 1 mit N,N′-Dimethyl-N,N′-bis(trimethylsilyl)harnstoff 2 lieferte die σ5P-σ3P-Diphosphorverbindung 3. Die Reaktion von 3 mit Hexafluoraceton nahm einen ungewöhnlichen Verlauf: unter Spaltung der P—P-Bindung resultierten dabei 4,4-Bis(trifluormethyl)-3-chlor-2-hexafluorisopropoxy-2-oxo-l,2-oxaphosphetan 7 und das Spirophosphoran 4-Chlormethyl-1,3,5,7-tetramethyl-1,3,5,7-tetraaza-4σ5-phosphaspiro[3.3]heptan-2.6-dion 8. Auch die Reaktion von 2-Chlor- l,2-dimethyl-3-phenyl-2-phenylseleno-1,3,2σ5-diazaphosphetidin-4-on 9 und Bis(2-chlorethyl)aminhydrochlorid/Triethyl-amin 10 verlief nicht erwartungsgemäß: dabei wurde das Spirophosphoran 11 als einziges identifiziertes Produkt erhalten. Einkristallstrukturanalysen der Verbindungen 8 und 11 wurden durchgeführt. In beiden Fällen zeigte die Koordinationsgeometrie am Phosphor starke Abweichungen von der Idealstruktur. Die Verzerrungen sind hauptsächlich auf die Gegenwart der viergliedrigen Ringe zurückzuführen.
    Notizen: The reaction of (chloromethyl)dichlorophosphine 1 with N,N′-dimethyl-N,N′-bis(trimethylsilyl)urea 2 furnished the σ5P-σ3P-diphosphorus compound 3. The reaction of 3 with hexafluoroacetone proceeded in an unusual fashion, with the rupture of the P—P bond, resulting in 4,4-bis(trifluoromethyl)-3-chloro-2-hexfluoroisopropoxy-2-oxo-1,2-oxaphosphetane 7 and the spirophosphorane 4-chloromethyl-1,3,5,7-tetramethyl-1,3,5,7-tetraaza-4σ5-phosphaspiro-[3,3]heptan-2,6-dione 8. The reaction of 2-chloro-1,2-dimethyl-3-phenyl-2-phenylseleno-1,3,2σ5-diazaphosphetidin-4-one 9 with bis(2-chloroethyl)amine hydrochloride/triethylamine 10 also proceeded in an unexpected fashion, leading to the spirophosphorane 11 as the only identified product. Single-crystal X-ray structure analyses of compounds 8 and 11 were conducted. The coordination geometry at phosphorus in both compounds shows a large deviation from idealized forms. This distortion arises mainly from the presence of the four-membered rings.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 300
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1657-1660 
    ISSN: 0044-2313
    Schlagwort(e): Ruthenium ; chalcogenide ; chemical transport ; crystal structure ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Crystal Structure of the Low Temperature Modification of RuTe2Black shining, platelet like single crystals of α-RuTe2 were obtained by chemical transport reaction with Cl2/AlCl3 (crystal dimensions up to 1 mm). The crystal structure of this low temperature modification of α-RuTe2 hitherto only known from powder measurements, was redetermined at room temperature by single crystal X-ray diffraction on a four-circle diffractometer. α-RuTe2 crystallizes in the marcasit structure typ in the orthorhombic spacegroup Pnnm (No. 58) with the lattice constants a = 528.12(13), b = 639.43(19), c = 400.85(13) pm.
    Notizen: Durch chemischen Transport mit dem Transportmittel Cl2/AlCl3 konnten schwarzglänzende, plattenartige Einkristalle von α-RuTe2 erhalten werden (Kantenlänge bis zu 1 mm). Die Kristallstruktur dieser bisher nur aus Pulverdaten bekannten Tieftemperaturmodifikation von RuTe2 wurde röntgenographisch an einem Einkristall auf einem Vierkreisdiffraktometer bei Raumtemperatur neu bestimmt. α-RuTe2 kristallisiert im Markasit-Strukturtyp in der orthorhombischen Raumgruppe Pnnm (Nr. 58) mit den Gitterkonstanten a = 528,12(13), b = 639,43(19), c = 400,85(13) pm.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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