TY  - JOUR
A1  - Tacke, Reinhold
A1  - Lopez-Mras, A.
A1  - Sperlich, J.
A1  - Strohmann, C.
A1  - Kuhs, W. F.
A1  - Mattern, G.
A1  - Sebald, A.
T1  - Neue zwitterionische \(\lambda_5\)-Spirosilicate: Synthesen, Einkristall-Röntgenstrukturanalysen und Festkörper-NMR-Untersuchungen
T1  - New Zwitterionic \(\lambda_5\)-Spirosilicates: Syntheses, Single-Crystal X-Ray Strudure Analyses, and Solid-State NMR Studies
N2  - 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 düfraction. 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.
KW  - Anorganische Chemie
KW  - Spirosilicates
KW  - zwitterionic
KW  - Silicon
KW  - pentacoordinate
KW  - Bond cleavage
KW  - Si-C I Solid-state NMR
KW  - 29Si and 15N
Y1  - 1993
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64251
ER  - 
TY  - JOUR
A1  - Tacke, Reinhold
A1  - Becht, J.
A1  - Mattern, G.
A1  - Kuhs, W. F.
T1  - Zur Existenz zwitterionischer \(\lambda_5\)-(Ammonioorganyl)tetrafluorosilicate: Synthese sowie Kristall- und Molekülstruktur von Tetrafluoro(pyrrolidiniomethyl)silicat
T1  - On the Existence of Zwitterionic \(\lambda_5\)-(Ammonioorganyl)tetrafluorosillcates: Synthesis and Crystal and Molecular Structure of Tetrafluoro(pyrrolidiniomethyl)silicate
N2  - 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).
KW  - Anorganische Chemie
KW  - Fluorosilicates
KW  - zwitterionic
KW  - Pentacoordinate silicon
Y1  - 1992
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64217
ER  - 
TY  - JOUR
A1  - Strohmann, C.
A1  - Tacke, Reinhold
A1  - Mattern, G.
A1  - Kuhs, W. F.
T1  - Bis(2,3-naphthalindiolato)[2-(pyrrolidinio)ethyl]silicat: Synthese und strukturelle Charakterisierung eines zwitterionischen \(\lambda_5\)-Spirosilicates
N2  - The zwi tterionic spirocyclic bis(2,3-naphthalenediolato )[2-(pyrrolidinio )ethyl]silicate [ ( C\(_{10}\)H\(_6\)O\(_2\)-SiCH\(_2\)CH\(_2\)(H)NC\(_4\)H\(_8\), 3 was synthesized and its structure characterized (single crystal X-ray structural analysis; \(^1\)H, \(^{13}\)C and \(^{29}\)Si NMR studies of solutions in DMSO). 3 was obtained by reaction of cyclohexylmethoxyphenyl(2-pyrrolidinoethyl)silane [C\(_6\)H\(_{11}\)(CH\(_3\)O)Si(C\(_6\)H\(_5\))CH\(_2\)CH\(_2\) NC\(_4\)H\(_8\), 4] with 2,3-dihydroxynaphthalene [C\(_{10}\)H\(_6\)(OH)\(_2\)] in acetonitrile at room temperature (isolated as 3·CH\(_3\)CN, yield 81 %). The formation of 3 involves two unusual Si-C cleavage reactions (cleavage of Si-C\(_6\)H\(_5\) and Si-C\(_6\)H\(_{11}\) under mild reaction conditions). In addition, 3 was prepared by reaction of 2,3-dihydroxynaphthalene with dimethoxyphenyl(2-pyrrolidinoethyl)silane [C\(_6\)H\(_5\) (CH\(_3\)O)\(_2\)SiCH\(_2\)CH\(_2\)NC\(_4\)H\(_8\) , 5] and trimethoxy( 2-pyrrolidinoethyl)silane [(CH\(_3\)O)\(_3\)SiCH\(_2\)CH\(_2\)NC\(_4\)H\(_8\), 6], respectively (isolated as 3·CH\(_3\)CN; yields 83 and 86%, respectively). 3·CH\(_3\)CN crystallizes in the space group Pbca with a = 8.877(2) A. b-= 22.823(4) Ä, c""" 24.597(4) A, and Z = 8 (R- 0.0592, Rw = 0.0529). The pentacoordinated Si atom of 3·CH\(_3\)CN is surrounded by its ligands in a nearly ideal square-pyramidal fashion (four basal 0 atoms and one apical C atom). The CH3CN molecule does not coordinate to the Si atom.
N2  - Das Zwitterionische spirocyclische Bis(2,3-naphthalindiolato )[2-(pyrrolidinio )ethyl)silicat [( C\(_{10}\)H\(_6\)O\(_2\)-SiCH\(_2\)CH\(_2\)(H)NC\(_4\)H\(_8\), 3) wurde synthetisiert und strukturell charakterisiert (Einkristallröntgenstrukturanalyse von 3·CH\(_3\)CN; \(^1\)H-, \(^{13}\)C- und \(^{29}\)Si-NMR-Untersuchungen von Lösungen in DMSO). 3 wurde durch Reaktion von Cyclohexylmethoxyphenyl(2·pyrrolidinoetbyl)silan [C\(_6\)H\(_{11}\)(CH\(_3\)O)Si(C\(_6\)H\(_5\))CH\(_2\)CH\(_2\) NC\(_4\)H\(_8\), 4] mit 2,3-Dihydroxynaphthalin [C\(_{10}\)H\(_6\)(OH)\(_2\)] in Acetonitril bei Raumtemperatur erhalten (isoliert als 3·CH\(_3\)CN, Ausbeute 81%). Der Bildung von 3 liegen zwei ungewöhnliche Si-eSpaltungen zugrunde (Spaltung von Si-C\(_6\)H\(_5\) und Si-C\(_6\)H\(_{11}\) unter milden Reaktionsbedingungen). 3 wurde auch durch Reaktion von 2,3-Dibydroxynaphthalin mit Dimethoxyphenyl(2-pyrrolidinoethyl)silan [C\(_6\)H\(_5\) (CH\(_3\)O)\(_2\)SiCH\(_2\)CH\(_2\)NC\(_4\)H\(_8\), 5) bzw. Trimethoxy(2-pyrrolidinoethyl)silan [(CH\(_3\)O)\(_3\)SiCH\(_2\)CH\(_2\)NC\(_4\)H\(_8\),6] dargestellt (isoliert als 3·CH\(_3\)CN, Ausbeute 83 bzw. 86%). 3·CH\(_3\)CN kristallisiert in der Raumgruppe Pbca mit a- 8.877(2) b = 22.823(4), c- 24.597(4) A und Z-8 (R == 0.0592,
KW  - Anorganische Chemie
Y1  - 1991
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64095
ER  -