Guido Drsam  Volker Kahlenberg  Reinhard X. Fischer 《无机化学与普通化学杂志》2003,629(6):981-984

Hydrothermally synthesized CsHSi₂O₅ was studied by single‐crystal X‐ray diffraction. The compound is orthorhombic (space group Pnma). Unit cell parameters are a = 4.9758(3), b = 8.8089(6), c = 12.9295(9) Å with four formula units per cell. The structure was solved by direct methods and refined to a residual R₁ = 0.025 for 621 independent observed reflections with I > 2σ(I) and 41 parameters. Residual electron densities were used to locate positions of the H atoms. They are part of silanol groups and show a disorder involving two positions related by a center of symmetry. The resulting O—H···O distance of 2.44 Å is one of the shortest hydrogen bonded O···O distances in inorganic compounds containing silanol groups. The structure belongs to the class of unbranched zweier double chain silicates. The [Si₂O₄(OH)^—] chains run parallel [100]. Cesium cations providing additional linkage between the anionic ribbons reside in voids between the chains and coordinate to nine oxygen ligands.  相似文献   

    

Klaus Jacob  Piero Zanello  Marco Fontani  Claus Pietzsch  Klaus Bohmhammel  Volker Lorenz 《无机化学与普通化学杂志》2003,629(11):2004-2012

The thermic decomposition of the cyclotetrametaloxanetetrols [(FcN)₄M₄O₄(OH)₄] (M= Si( 1 ), Ge( 2 )) as well as the cyclohexagermoxanediol [(FcN)₆Ge₆O₈(OH)₂] ( 3 ) takes place in three defined steps. At the monomer silandiol [(FcN)₂Si(OH)₂] ( 4 ) only two such steps are observed. The cyclovoltammetric oxidation of the metaloxanes 1 ‐ 2 occurs in two two‐electron steps and following two one‐electron transitions. The oxidation of 3 occurs in a four‐electron process and a following two‐electron transition. Silandiol 4 is oxidized via two one‐electron transitions. The oxidation of the educt [FcNGeCl₃] ( 5 ) occurs in a one‐electron step. Temperature depending ⁵⁷Fe‐Mössbauer‐measurements confirm as well intervalent electron transitions in 1 ‐ 5 as the chelate stucture in 5 .  相似文献   

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Krivovichev SV  Kahlenberg V  Kaindl R  Mersdorf E  Tananaev IG  Myasoedov BF 《Angewandte Chemie (International ed. in English)》2005,44(7):1134-1136

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Danila C  Böhmer V  Bolte M 《Organic & biomolecular chemistry》2005,3(19):3508-3513

O-Alkylation of the dinitro calix[4]arene 2, easily available by selective ipso-nitration of the di-cyanomethyl ether 1, with allylbromide (DMF/Cs2CO3) gave tetraethers 3 and 4 with anti- and syn-orientations of the two allyl ether residues. The two possible stereoisomers of in the partial cone and 1,2-alternate conformation exist as an equilibrium mixture which could be quantitatively analysed by 1H NMR spectroscopy. The temperature dependence of this equilibrium leads to deltaH0 = -7.6 to -9.7 kJ mol(-1) in different solvents (tetrachloroethane, benzene, dimethylsulfoxide). Since 3(1,2-alt) could be obtained in pure form, its isomerisation to the equilibrium mixture with 3(paco) could be followed also kinetically. An activation energy of E(a) = 110.5 kJ mol(-1) was found for this reaction in DMSO-d6. The results were confirmed by similar studies with tetraethers 5 and 6 obtained by O-allylation of 1, although exact thermodynamic and kinetic studies were not possible in this case, since the NMR signals of the respective isomers were strongly overlapping. Single crystal X-ray structures were obtained for 2, 3(1,2-alt), 4(paco) and 5(1,2-alt).  相似文献   

    

Michael Veith  Michael Opsölder  Michael Zimmer  Volker Huch 《欧洲无机化学杂志》2000,2000(6):1143-1146

The synthesis of new silyl-substituted tin-nitrogen heterocubanes and the structural analysis of [Me₃SiNSn]₄ is described. A sharp signal in the ¹⁴N NMR spectrum and a septet in the ¹¹⁹Sn NMR spectrum are among the interesting properties of this new type of compound with nitrogen surrounded by four (hemi)metals.  相似文献   

    

Michael Veith  Oliver Schütt  Volker Huch 《无机化学与普通化学杂志》1999,625(7):1155-1164

Synthesis and Metalation of Tripodal Siloxazane Ligands ^tBuSi(OSiMe₂NHR)₃ [R = H, Me, ^tBu, Ph, SiMe₃] ^tBuSi(OSiMe₂Cl)₃ ( 1 ) was generated by the condensation of tert-butylsilanetriol with dichlorodimethylsilane under elimination of HCl. A series of tripodal amines ^tBuSi(OSiMe₂NHR)₃ [R = H ( 2 ), R = Me ( 3 ), R = ^tBu ( 4 ), R = Ph ( 5 )] was synthesized by ammonolysis, aminolysis or salt elimination of 1 with primary lithium amides. 5  has been subjected to single crystal X-ray diffraction, which confirmed the triarmed amine. The siloxamine ^tBuSi(OSiMe₂NHSiMe₃)₃ ( 6 ) was generated by the reaction of 2 with three moles of chlorotrimethylsilane. The lithium amides ^tBuSi(OSiMe₂N[Li]^tBu)₃ ( 7 ), ^tBuSi(OSiMe₂N[Li]Ph)₃ ( 8 ) and ^tBuSi(OSiMe₂N[Li]SiMe₃)₃ ( 11 ) and the sodium amide ^tBuSi(OSiMe₂N[Na]^tBu)₃ ( 9 ) were obtained by the complete hydrogen–metal exchange of the amines 4 – 6 with n-butyl lithium and n-butyl sodium in hexane, respectively. The transmetalation of 7 with copper(I) chloride gave the copper amide ^tBuSi(OSiMe₂N[Cu]^tBu)₃ ( 10 ). The single crystal X-ray diffraction of the metal amides 7 , 9 and 11 shows a trifold coordination by additional interactions between each of the two metal atoms with oxygens in the siloxane groups in contrast to the copper amide 10 , which lacks such contacts. The almost isostructural metal amides 7 , 9 – 11 are monomeric and possess, similary to 5 , a pseudo three fold symmetry in the solid state. 5 and 7 crystallize in the monoclinic space group P2₁/c whereas the compounds 9 – 11 crystallize in the centrosymmetric triclinic space group P 1.  相似文献   

    

Volker Lorenz  Klaus Jacob  Christoph Wagner  Helmar Grls 《无机化学与普通化学杂志》2002,628(13):2855-2861

Metalloxanes of Silicon and Germanium with the 2‐(Dimethylaminomethyl)‐ferrocenyl Ligand (FcN): Synthesis and Molecular Structures of (FcN)₄M₄O₄(OH)₄(M = Si, Ge), (FcN)₆Ge₆O₈(OH)₂ and of (FcN)₂Si(OH)₂ (FcN)₄M₄O₄(OH)₄ · H₂O [FcN = 2‐(dimethylaminomethyl)ferrocenyl, M = Si ( 2 ) und Ge ( 3 )] are prepared by hydrolysis of FcNSiCl₃ or FcNGeCl₃ ( 1 ) in Et₂O in the presence of (NH₄)₂CO₃. The tricyclic compound (FcN)₆Ge₆O₈(OH)₂ ( 4 ) is formed after treatment of the hydrolysis solution of FcNGeCl₃ with CaH₂. (FcN)₂Si(OH)₂ ( 5 ) was sythesized by hydrolysis of (FcN)₂SiCl₂ under similar conditions. Compounds 1 — 5 are obtained as yellow orange crystals, the molecular structures of 1 — 5 were determinated by X‐ray diffraction. 2 and 3 are 8‐membered Si‐O/Ge‐O cycles with one OH and one FcN‐ligand on each Si or Ge atom, respectively. Compound 4 represents a stair‐like tricyclic Ge‐O structure whereas 5 is a discrete Silanediol. 2 — 5 show O‐H···N hydrogene bridges of the OH groups to the nitrogen atoms of the FcN substituents.  相似文献   

    

Christian W. K. Gstttmayr  Volker P. W. Bhm  Eberhardt Herdtweck  Manja Grosche  Wolfgang A. Herrmann 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2002,114(8):1421-1423

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Martin Reischl  Karin Stana-Kleinschek  Volker Ribitsch 《Macromolecular Symposia》2006,244(1):31-47

Summary: Electrokinetic investigations of different cellulosic fibres were reviewed with special emphasis on polymer composite materials and textile applications of cellulose fibres. The possibilities in the interpretation of zeta-potential data regarding chemical and physical modification, specific adsorption, swelling and changes in hydrophobicity/hydrophilicity of cellulose polymers are discussed. Using recent data from literature, advantages and limitations of electrokinetic measurements of oriented polymers are described, finding that the zeta-potential is a valuable parameter in polymer surface characterisation.  相似文献   

    

Meshcheryakov D  Böhmer V  Bolte M  Hubscher-Bruder V  Arnaud-Neu F  Herschbach H  Van Dorsselaer A  Thondorf I  Mögelin W 《Angewandte Chemie (International ed. in English)》2006,45(10):1648-1652

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