Norbert Auner

Synthesis and structure of 1,6-diaza-2,2-dimethoxy-2-silacyclooctane

Abstract 1,4-Diaza-8,8,8-trimethoxy-8-silaoctane (1) loses methanol upon heating and gives an eight-membered silatrane-like silaheterocyle, 1,6-diaza-2,2-dimethoxy-2-silacyclooctane (2).

29Si chemical shift tensors of silyl silicate cages

Static and 29Si CP MAS spectra (spinning rates of 2000 and 500 Hz) of six silyl silicate cages are analyzed by deconvolution and simulation. The principal values of the various 29Si chemical shift tensors provide information about the point symmetry of the Si sites. The intensities of the signals correspond sufficiently well with the stoichiometries.

Synthesis and structure of 3-(cyclohexylamino) propyldimethylsilanol

Abstract 3-(Cyclohexylamino)propylmethoxydimethylsilane 1 is readily hydrolized to give the silanol 3-(cyclohexyl-amino)propyldimethylsilanol 2, which forms hydrogen bonded chains in the solid state.

Synthesis and structure of silylene complexes of silacyclobutanes

Abstract Reactions of 1.1-dichloro-2-neopentyl-3-vinyl-l-silacyclobutane ( 1a, b ) with carbonyl metallates [{M(CO) n } m ] 2- (M = Fe, m = 1, n = 4; M = Cr, m = 1, n = 5; M = W, m = 2, n = 5) in THF/HMPA lead to novel compounds [(CO) n MSiC 10 H 18 ] · HMPA (M = Fe, n = 4; M = Cr, W, n = 5). 1 H, 13 C and 29 Si NMR spectroscopic studies in solution support the formation of four diastereomeric pairs of enantiomers. The X-ray structure analyses of the crystals show folded 1-metallated 1-silacyclobutane units in which the HMPA ligand increases the coordination number of Si to 3 + 1. Crystals of [(CO) 5 CrSiC 10 H 18 ] · HMPA ( 2 ) and of [(CO) 5 WSiC 10 H 18 ] · HMPA ( 3 ) (corresponding values in brackets) are isotypic: P 2 1 / n (No. 14); a = 1084(1)/[1099(1)], b = 1927(1)/[1937(1)], c = 1342.1(8)/[1342(1)] pm, β = 97.11(7)/[97.18(7)]°, Z = 4. In both crystals enantiomeric [1 S ,2 S ,3 S ]/[1 R ,2 R ,3 R ] pairs are present. In orthorhombic crystals of [(CO) 4 FeSiC 10 H 18 ]. · HMPA ( 4 ) ( P 2 1 2 1 2 1 (No. 19), a = 896.4(5), b = 1693(1), c = 1753(1) pm, Z = 4) only the [1 S ,2 S ,3 S ]-isomer is detected.

New Organosiloxanes Containing Silacycles

Abstract The synthesis of carbon substituted 1, 1-dichloro- and l, l-bis(diethylamino)silacyclobutanes and butenes and their polycondensation reactions with bisphenol A, 1,2-ethanediol and 1,6-hexanediol is described. The monomer silacycles and the organosiloxane polymers are characterized by NMR (1H-, 13C-, 29Si-), GPC, DSC and elemental analysis.