TY - JOUR A1 - Tacke, Reinhold A1 - Mühleisen, M. T1 - Bis[benzilato(2-)-O\(^1\),O\(^2\)][2-(dimethylammonio)ethoxy]silicate: synthesis and structural characterization of a zwitterionic \(\lambda^5\)Si-silicate with a SiO\(_5\) framework N2 - No abstract available KW - Anorganische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64400 ER - TY - JOUR A1 - Mühleisen, M. A1 - Tacke, Reinhold T1 - meso-[1,4-Piperaziniumdiylbis(methylene)]bis{bis[2-methyllactato(2-)-O1,O2]silicate} octahydrate: synthesis and crystal structure analysis of a zwitterionic dispirocyclic \(\lambda^5\)Si,\(\lambda^5\)Si'-disilicate N2 - The zwitterionic dispirocyclic \(\lambda^5\)Si,\(\lambda^5\)Si'-disilicate meso-[1 ,4-piperaziniumdiylbis( methylene)]bis{ bis[ 2-methyllactato(2-)-O\(^1\),O\(^2\)]silicate} octahydrate (6-8H\(_2\)O) was synthesized by reaction of 1,4-bis[(trimethoxysilyl}methyl] piperazine (8) with 2-methyllactic acid (molar ratio 1:4) in water/acetone (yield 82%). The molecular dinuclear silicon(IV) complex 6 contains two pentacoordinate (formally negatively charged) silicon atoms and two tetracoordinate (formally positively charged) nitrogen atoms. The crystal structure of 6•8H20 was studied by X-ray diffraction. KW - Anorganische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64396 ER - TY - JOUR A1 - Mühleisen, M. A1 - Tacke, Reinhold T1 - Twofold deprotonated citric acid as a bidentate ligand of pentacoordinate silicon: synthesis and structural characterization of the zwitterionic \(\lambda_5\)Si-spirosilicate bis[citrato(2-)-O\(^3\),O\(^4\)][(dimethylammonio)methyl]silicate hydrate N2 - The zwitterionic \(\lambda_5\) Si-spirosilicate bis[ citrato(2-)-0\(^3\) ,0\(^4\) )[ ( dimethylammonio) methyl]silicate (4) was synthesized by reaction of (MeO)\(_3\)SiCH\(_2\)NMe\(_2\) (3) with citric acid (molar ratio 1 :2) in acetonitrile at room temperature and isolated, after crystallization from water, as the hydrate 4 · H\(_2\)O (yield 81 %). The crystal structure of 4 · H\(_2\)O was studied by single-crystal X-ray diffraction. The alcoxide oxygen atoms and central carboxylate oxygen atoms of two citrato(2-) ligands and one carbon atom coordinate to the silicon atom of 4 · H\(_2\)O. The coordination polyhedron around the pentacoordinate silicon atom (SiO\(_4\)C framework) can be described as a distorted trigonal bipyramid, the two carboxylate oxygen atoms occupying the axial sites. The \(\lambda_5\) Si~silicon(IV) complex 4 also exists in solution (DMSO, H\(_2\)O). KW - Anorganische Chemie KW - Silicon KW - pentacoordinate KW - Lambda5Si-Spirosilicate KW - zwitterionic KW - Citrato(2-)-03 KW - 04ligand Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64388 ER - TY - JOUR A1 - Tacke, Reinhold A1 - Mühleisen, M. T1 - Hexacoordinate silicon in a compound with an F\(_5\)SiC unit N2 - No abstract available KW - Anorganische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64378 ER - TY - JOUR A1 - Tacke, Reinhold A1 - Mühleisen, M. T1 - Hexakoordiniertes Silicium in einer molekularen Verbindung mit einer F\(_5\)SiC-Einheit N2 - No abstract available KW - Anorganische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64365 ER - TY - JOUR A1 - Tacke, Reinhold A1 - Mühleisen, M. A1 - Jones, P. G. T1 - The first zwitterionic, optically active disilicate with pentacoordinate silicon N2 - No abstract available KW - Anorganische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64358 ER - TY - JOUR A1 - Tacke, Reinhold A1 - Mühleisen, M. A1 - Jones, P. G. T1 - Das erste zwitterionische, optisch aktive Disilicat mit pentakoordiniertem Silicium N2 - No abstract available KW - Anorganische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64343 ER - TY - JOUR A1 - Tacke, Reinhold A1 - Lopez-Mras, A. A1 - Jones, P. G. T1 - Syntheses, crystal structure analyses, and NMR studies of [2-(dimethylammonio)phenyl]bis[glycolato(2-)-O1,O2]silicate and related zwitterionic spirocyclic \(\lambda_5\)Si-silicates N2 - No abstract available KW - Anorganische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64339 ER - TY - JOUR A1 - Tacke, Reinhold A1 - Sperlich, J. A1 - Becker, B. T1 - Bis[2,3-naphthalenediolato(2-)](pyrrolidinio-methyl)germanate-tetartoacetonitrile, the first zwitterionic \(\lambda_5\)-germanate: synthesis and crystal structure analysis N2 - The zwitterionic spirocyclic \(\lambda_5\)-germanate bis(2,3-naphthalenediolato( 2-)](pyrrolidiniomethyl)germanate (8) was synthesized and the crystal structure of its tetartoacetonitrile solvate 8 · 1/4 CH\(_3\)CN studied by single-crystal X-ray diffraction. Compound 8 was prepared by reaction of (MeO)\(_3\)GeCH\(_2\)NC\(_4\)H\(_8\) (11; NC\(_4\)H\(_8\) = pyrrolidino) with two equivalents of 2,3-naphthalenediol (isolated as 8 · 1/4 CH\(_3\)CN; yield 92%). The coordination polyhedron around the pentacoordi- naphthalenediolatonate germanium atom of 8 · 1/4 CH\(_3\)CN can be described as a strongly distorted trigonal bipyramid (the structure is displaced by 38.9% from the ideal trigonal bipyrarnid towards the ideal square pyramid), the carbon atom occupying an equatorial position. In the crystal lattice of 8 · 1/4 CH\(_3\)CN, the zwitterions form intermolecular N-H ... o hydrogen bonds leading to the formation of dimers. 1H- and \(^{13}\C-NMR studies revealed that 8 also exists in solution ([D\(_6\)]DMSO). KW - Anorganische Chemie KW - Lambda5-Germanate KW - zwitterionic KW - Germanium KW - pentacoordinate Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64329 ER - TY - JOUR A1 - Tacke, Reinhold A1 - Wagner, S. A. A1 - Sperlich, J. T1 - Synthese von (-)-(Acetoxymethyl)(hydroxy-methyl)methyl(phenyl)german [(-)-MePhGe(CH\(_2\)OAc)(CH\(_2\)OH)] durch eine Esterase-katalysierte Umesterung: Die erste enzymatische Synthese eines optisch aktiven Germans N2 - No abstract available. KW - Anorganische Chemie KW - Germane KW - optically active KW - Biotransformation KW - stereoselective Transesterification KW - enzymatic KW - Porcine liver esterase Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64310 ER -