@article{MuehleisenTacke1994,
  author    = {M{\"u}hleisen, M. and Tacke, Reinhold},
  title     = {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},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-64388},
  year      = {1994},
  abstract  = {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).},
  subject      = {Anorganische Chemie},
  language  = {de}
}
@article{TackeWagnerSperlich1994,
  author    = {Tacke, Reinhold and Wagner, S. A. and Sperlich, J.},
  title     = {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},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-64310},
  year      = {1994},
  abstract  = {No abstract available.},
  subject      = {Anorganische Chemie},
  language  = {de}
}
@article{TackeMuehleisenJones1994,
  author    = {Tacke, Reinhold and M{\"u}hleisen, M. and Jones, P. G.},
  title     = {Das erste zwitterionische, optisch aktive Disilicat mit pentakoordiniertem Silicium},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-64343},
  year      = {1994},
  abstract  = {No abstract available},
  subject      = {Anorganische Chemie},
  language  = {de}
}
@article{TackeMuehleisen1994,
  author    = {Tacke, Reinhold and M{\"u}hleisen, M.},
  title     = {Hexakoordiniertes Silicium in einer molekularen Verbindung mit einer F\(_5\)SiC-Einheit},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-64365},
  year      = {1994},
  abstract  = {No abstract available},
  subject      = {Anorganische Chemie},
  language  = {de}
}
@article{KauppSchnering1993,
  author    = {Kaupp, Martin and Schnering, Hans Georg von},
  title     = {Molekulares Quecksilber(IV)-fluorid, HgF\(_4\): eine ab-initio-Untersuchung},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-60021},
  year      = {1993},
  abstract  = {No abstract available},
  subject      = {Anorganische Chemie},
  language  = {de}
}
@article{TackeLopezMrasSheldricketal.1993,
  author    = {Tacke, Reinhold and Lopez-Mras, A. and Sheldrick, W. S. and Sebald, A.},
  title     = {Synthesen, Einkristall-R{\"o}ntgenstrukturanalysen und \(^{29}\)Si-Festk{\"o}rper-NMR-Untersuchungen eines zwitter- ionischen \(\lambda_5\)-Spirosilicats und eines k{\"a}figartigen Octa(silasesquioxans) : [Professor Hartmut B{\"a}rnighausen zum 60. Geburtstage gewidmet]},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-64243},
  year      = {1993},
  abstract  = {No abstract available},
  subject      = {Anorganische Chemie},
  language  = {de}
}
@article{TackeLopezMrasSperlichetal.1993,
  author    = {Tacke, Reinhold and Lopez-Mras, A. and Sperlich, J. and Strohmann, C. and Kuhs, W. F. and Mattern, G. and Sebald, A.},
  title     = {Neue zwitterionische \(\lambda_5\)-Spirosilicate: Synthesen, Einkristall-R{\"o}ntgenstrukturanalysen und Festk{\"o}rper-NMR-Untersuchungen},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-64251},
  year      = {1993},
  abstract  = {The zwitterionic spirocyclic \(\lambda_5\) -Silicates bis(3,4,5,6-tetrabromo- 1,2-benzenediolato(2- ))[2-(pyrrolidinio)ethyl]silicate (5; and its monohydrate 5 · H\(_2\)O) and bis[1,2-benzenediolato(2- )][( dimethylammonio)methyl]silicate (6) were synthesized by various methods including Si-C bond cleavage reactions. The crystal structures of 5, 5 · H\(_2\)O, and 6 were investigated by Xray d{\"u}fraction. Furthermore, 5, 5 · H\(_2\)O, 6, and the related zwitterionic \(\lambda_5\)-spirosilicates 1 · 1/4 CH\(_3\)CN, 2 · CH\(_3\)CN, 3 · CH\(_3\)CN, and 4 were characterized by solid-state NMR spectroscopy (\(^{29}\)Si and \(^{15}\)N CP/MAS). The pentacoordinate silicon atoms of 5, 5 · H\(_2\)O (two crystallographically independent ZWitterions and two crystallographically independent water molecules), and 6 (two crystallographically independent zwitterions) are surrounded by four oxygen atoms and one carbon atom. The coordination polyhedrons around the silicon atoms of 5 and 6 can be described as distorted (5) or nearly ideal (6) trigonal bipyramids, the carbon atoms being in equatorial positions. 5 forms intramolecular and 6 intermolecular (--+ formation of dimeric units) N- H···O hydrogen bonds. The coordination polyhedrons around the two crystallographically independent silicon atoms of 5 · H\(_2\)O can be described as a nearly ideal and slightly distorted square pyramid, respectively, the carbon atoms being in the apical positions. In the crystal lattice of 5 · H\(_2\)O, intermolecular N-H···O and 0-H···O hydrogen bonds between the zwitterions and water molecules are observed. The results obtained by X-ray diffraction and solid-state NMR spectroscopy are consistent for each compound studied.},
  subject      = {Anorganische Chemie},
  language  = {de}
}
@article{TackeLopezMrasBechtetal.1993,
  author    = {Tacke, Reinhold and Lopez-Mras, A. and Becht, J. and Sheldrick, W. S.},
  title     = {Synthese sowie Kristall- und Molek{\"u}lstruktur von Tetrafluoro[2-(pyrrolidinio)ethyl]silicat},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-64269},
  year      = {1993},
  abstract  = {Das zwitterionische Tctratluoro[2-(pyrrolidinio) ethyl]silicat (4) wurde durch Reaktion von Trimethoxy( 2-pyrrolidinoethyl)silan (5) mit Fluorwasserstoff in einem Ethanol/Flußs{\"a}ure-Gemisch bei 0 °C synthetisiert. Die Kristall- und Molek{\"u}lstruktur von 4 wurde bei - 100 °C mittels einer Einkristall-R{\"o}ntgenstrukturanalyse untersucht. Außerdem wurde 4 durch NMR-Untersuchungen in L{\"o}sung charakterisiert (CD\(_3\)CN: \(^1\)H, \(^{13}\)C).},
  subject      = {Anorganische Chemie},
  language  = {de}
}
@article{TackeBechtMatternetal.1992,
  author    = {Tacke, Reinhold and Becht, J. and Mattern, G. and Kuhs, W. F.},
  title     = {Zur Existenz zwitterionischer \(\lambda_5\)-(Ammonioorganyl)tetrafluorosilicate: Synthese sowie Kristall- und Molek{\"u}lstruktur von Tetrafluoro(pyrrolidiniomethyl)silicat},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-64217},
  year      = {1992},
  abstract  = {The zwitterionic tetrafluoro(pyrrolidiniomethyl)silicate (6) was synthesized by the reaction of trimethoxy(pyrrolidinomethyl) silane (7) with hydrogen fluoride in ethanol/hydrofluoric acid (yield 83\%). 6 crystallizes in the space group P2\(_1\)fc with two crystallographically distinct molecules in the asymmetric unit. In both molecules the pentacoordinate silicon atom is surrounded by four fluorine atoms and one carbon atom, the latter being in an equatorial position. The coordination polyhedron of the silicon atoms can be described as a slightly distorted trigonal bipyramid. The zwitterionic structure was also proved for dissolved 6 (solution in CD\(_3\)CN, NMRspectroscopic studies).},
  subject      = {Anorganische Chemie},
  language  = {de}
}
@article{TackeHengelsbergKlingneretal.1992,
  author    = {Tacke, Reinhold and Hengelsberg, H. and Klingner, E. and Henke, H.},
  title     = {Synthese der Si-funktionellen Acetylsilane tBu(Me\(_3\)SiCH\(_2\))[MeC(O)]SiF und tBu(Me\(_3\)SiCH\(_2\))[MeC(O)]SiH sowie Synthese und Kristallstruktur des Acetylsilanols tBu(Me\(_3\)SiCH\(_2\))[MeC(O)]SiOH: Substrate f{\"u}r mikrobielle Reduktionen},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-64192},
  year      = {1992},
  abstract  = {The racemic Si-functional acetylsilanes tBu(Me\(_3\)SiCH\(_2\))[ MeC(O)]SiF (1) and tBu(Me\(_3\)SiCH\(_2\))[MeC(O)]SiH (2) and the racemic acetylsilanol tBu(Me\(_3\)SiCH\(_2\))[MeC(O)]SiOH (3) were synthesized from Si(OMe)\(_4\) (4) as substrates for microbial reductions [4 -> tBuSi(OMe)\(_3\) (5) -> tBu(Me\(_3\)SiCH\(_2\))Si(OMe)\(_2\) (6) -> tBu(Me\(_3\)SiCH\(_2\))SiF\(_2\) (7)-> tBu(Me\(_3\)SiCH\(_2\))(CH\(_2\) = C(OMe))SiF (8) -> 1; 8 -> tBu(Me\(_3\)SiCH\(_2\))[CH\(_2\) = C(OMe)]SiH (9) -> 2; 6 -> tBu(Me\(_3\)SiCH\(_2\))[CH\(_2\) = C(OMe)]SiOMe (10) -> 3]. Compounds 1-3 were found to be reduced by cells of Trigonapsis variabilis (DSM 70714) ( = SiC(O)Me -> = SiCH(OH)Me}. The crystal and molecular structure of 3 was studied by singlecrystal X-ray diffraction. In the crystal, racemic 3 forms infinite chains built up by intermolecular 0-H .. ·O bonds between the hydroxyl and acetyl groups of molecules of the same absolute configuration.},
  subject      = {Anorganische Chemie},
  language  = {de}
}