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  • 1
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 56 (2000), S. e589-e590 
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: During an investigation of the W/Te/Br2 system, we prepared crystals of the title compound, C20H40N4S8Te, from acetonitrile solution by slow addition of diethyl ether. It appeared to be a new tetragonal modification. The calculated density of the tetragonal modification (1.513 Mg m−3) is slightly greater than found for the known orthorhombic modification (1.46 Mg m−3). The bond distances and angles are practically the same.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The reaction between 2,3-dichloromaleic acid dialkylester (alkyl=CH3 and C2H5) and diphenyl(trimethylsilyl)phosphine, leading to diphenylphosphine substituted esters of maleic and fumaric acid has been studied. With a molar ratio 1:1 of the components 2-chloro-3-diphenylphosphinomaleic acid dimethylester (3) and-diethylester are obtained as colourless crystalline compounds. From a 1:2 reaction however only bis(diphenylphosphino)fumaric acid dimethylester (colourless crystals) and-diethylester (yellow) can be crystallized, the latter in a partially oxydized form. The presence of bis(diphenylphosphino)maleic acid diester in the oily part of the reaction products has been proved by its chelating with Ni2+ and Pd2+ to complexes of the compositionMeCl2·(PP). Pure bis(diphenylphosphino)maleic acid dimethylester (4) could be synthesized by alcoholysis and following methylation of bis (diphenylphosphino)maleic anhydrid. Contrary to this easily chelating and air stable compound the corresponding fumaric acid diesters give no complexes with the metals examined as far and are very sensitive towards oxygen. This sensitivity decreases strongly after oxydation to 2-diphenylphosphino-3-diphenylphosphorylfumaric acid diester, the diethylester of which could be crystallized in pure form. Characteristic vibration bands, uv/vis-absorption and31P-nmr peaks are discussed. The result of X-ray diffraction data of3 and4 are reported and conformation, bond lengthes and bond angles of these molecules are given.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 113 (1982), S. 1225-1238 
    ISSN: 1434-4475
    Keywords: Crystal structure ; α-Halo-nitro-carbonyl-compounds ; Hexachlorobicyclopentenylidentrione ; Octachlorobicyclopentenylidendione ; Tetrachlorobicyclopentenylidentetraone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Treatment of dodecachlorobicyclopentenylidene1 with fuming nitric acid yields mainly octachlorobicyclopentenylidendione5 besides hexachloropentenylidentrione6. Both compounds are obtained as yellow crystalline solids. Octachlorobicyclopentadienylidene2 reacts with fuming nitric acid forming yellow α-halo-nitro-carbonyl-compounds7 and8. Thermical cleavage of NOCl from7 in nitrobenzene leads to the orange tetrachlorobicyclopentenylidentetraone9. The molecular structures of7 and8 are derived from their ir and mass spectra, whilst the molecular structure of5,6 and7 are established by single crystal x-ray diffraction. Bond distances and angles are given and discussed.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1434-4475
    Keywords: Bis(diphenylarsino)maleic acid, derivatives ; Bis(diphenylstibino)maleic anhydride, synthesis, crystal structure ; Bis(phenylthio)maleic acid, derivatives ; Maleic acid derivatives, synthesis, molecular structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The unusual properties of bis(diphenylphosphino)maleic anhydride and similar ditertiary phosphines has prompted the synthesis of analogous arsines and stibines. Bis(diphenylarsino)maleic anhydride,-maleic thioanhydride and-N-methyl maleic imide, bis(diphenylstibino)maleic anhydride (5) and-maleic thioanhydride are obtained as crystalline yellow or red compounds by the reaction of the corresponding 2,3-dichloromaleic acid derivatives with diphenyl(trimethylsilyl)arsine and-stibine resp. The uv/vis spectra and characteristic i.r. bands of selected compounds are given and compared with those of the corresponding phosphines. The strong shift of νC=C to lower wavenumbers observed in all compounds has caused the determination of crystal and molecular structure of5 by x-ray diffraction. Bond distances and angles are given. The complex formation of the new diarsine ligands has been examined by the preparation of Ni-, Cr- and Mo-carbonyl derivatives. As the first organylsulfane substituted maleic acid derivatives bis(phenylthio)maleic thioanhydride,-N-methyl-maleic imide and-maleic acid dimethylester are synthesized and described.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1434-4475
    Keywords: Crystal structure ; Electronic transitions and structure ; Oxalic acid phosphides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The unexpected violet colour of P,P′-tetraphenyl-oxalic acid diphosphide (3) stimulated the synthesis of the following derivatives: P,P′-tetra-t-butyl-oxalic acid diphosphide (2), N,P-tetraphenyl-oxalic acid amide phosphide (4) and P, α-triphenyl-glyoxylic acid phosphide (5). The compounds could be prepared by the reaction of the corresponding acyl chlorides with diorganyl-(trimethylsilyl) phosphine; (organyl=t-butyl and phenyl). The electronic transitions of green-blue2 and red5 in the 450–700 nm region are discussed, also theirv C=O in the ir spectrum. These results are interpreted in connection with the molecule structures of2 and3 which have been determined by X-ray crystal structure analysis. In2 the framework P−C(O)−C(O)−P is only slightly distorted from a coplanartrans-position, in3 somewhat more. The bonds at P have the expected pyramidal arrangement. The direction of the lone pairs at the P-atoms, derived from this bond arrangement, is discussed with respect to the electronic transitions in acyl phosphides.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1572-8862
    Keywords: copper telluride clusters ; copper telluro-tellurolato clusters ; crystal structure ; influence of phosphine ligands ; Frank-Kasper polyhedron
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The reactions of CuCl and tBuTeSiMe3 in the presence of phosphine ligands result in the formation of four new Cu/Te cluster complexes, [Cu18Te6(TetBu)6(PPh2Et)7], [Cu19Te6(TetBu)7(PEt3)8], [Cu27Te15(PiPr2Me)12] and [Cu58Te32(PtBu2 nBu)14], which have been structurally characterized by single crystal structural analysis. The former two clusters show a layer-type tellurium frameworks in which the copper atoms are asymmetrically spread. The latter two clusters possess a tellurium framework in a body-centered Te14-Frank-Kasper polyhedron or a Te28 polyhedron with four interstitial tellurium atoms and belong to mixed-valence Cu/Te compounds.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1572-8862
    Keywords: Copper sulfide clusters ; X-ray determination ; influence of phosphine ligands ; isomers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The synthesis and X-ray determination of two sulfur bridged copper clusters with the known compositions of [Cu12S6(PnPr3)8] and [Cu20S10(PnBu1Bu2)8] but new molecular structures allow a comparison of these isomeric copper sulfide clusters. The Cu-S frameworks of the clusters with twelve copper atoms are highly topologically related and can both be derived flom a hypothetical “naked” [Cu12,S6] cluster that results from theoretical investigations. More dificult is the comparison of the two clusters containing 20 metal atoms. The two cluster types can be called either a “prolate” or an “oblate” isomer of [Cu20S10(pR3)8].
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1421-1428 
    ISSN: 1434-1948
    Keywords: Grid complexes ; Self-assembly ; Co ; Zn ; Coordination chemistry ; Bis(tridentate) ligands ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The tretrametallic [2 × 2] grid-type complexes 1-4 are formed by self-assembly of the bis(tridentate) ligands 5 and 6 with ZnII and CoII cations. They have been characterized by spectroscopic studies in solution as well as by crystal structure determination. The substituents in the central pyrimidine ring play an important role in terms of geometry and physical properties of the complexes. They induce an orthogonal orientation of the ligand in the complexes which is critical for the formation of ordered monolayers and extended self-organized arrays of grids. The physical properties of the complexes such as metal-metal interaction and π-π* stacking between the ligands may be modulated by changing these substituents.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 2 (1996), S. 1292-1302 
    ISSN: 0947-6539
    Keywords: complexes with nitrogen ligands ; ruthenium complexes ; self-assembly ; supramolecular chemistry ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of mono- and dimetallic complexes of rack type containing a dinucleating bis-tridentate ligand and RuII-2,2′:6′,2′-terpyridyl (tpy) sites were synthesised and characterised. The 1H NMR spectra of the dimetallic complexes were correlated to structural features, and the crystal structures of the dimetallic complexes were determined. They provide information about the way in which the central substitutent affects the overall shape of the racks and the relative disposition of the metal centres, measured by the pinching angle of the bis-tridentate ligand and the convergence angle of the ancillary tpy units. The latter demonstrates that a CH3 group yields the least bent complex and indicates how parallel the tpy units are. The dimetallic racks exhibit metal-metal interactions mediated by the bis-tridentate ligands as indicated by electrochemical and spectroscopic methods. The bridging-ligand π* orbital and the dπ metal orbital are stabilised by complexation of a second metal. The results obtained provide guidelines for the design of extended racks bearing several metal centres in a linear arrangement, which also represent potential components of molecular electronic devices.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
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