C. Knopf, J. Wagler, E. Brendler
Nov 1, 2004
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Journal
Zeitschrift für Naturforschung B
Abstract
Abstract The reactions of N,N’-dimethylethylenediamine 1and N,N’-diphenylethylenediamine 2with equimolar amounts of 1,2-dichlorotetramethyldisilane 3give six-membered heterocycles. Fivemembered rings are formed in the reaction of the diamines 1and 2with 1,1,2,2-tetrachlorodimethyldisilane 4as well as with hexachlorodisilane 5. Whilst the conversions of the disilanes 3and 4with the diamine 2gave no products of a disproportionation reaction, the treatment of the disilane 4with the diamine 1and of the disilane 5with both diamines resulted in cyclic aminosubstituted monosilanes which originate from the disproportionation of 4and 5beside the expected five-membered cyclic disilanes. All compounds have been characterized by multi-nuclear NMR, IR and mass spectroscopy. In case of the N-phenylsubstituted compounds 6, 7and 9the crystal structures have been determined by X-ray diffraction analysis. Bis-[N,N’-diphenyl-2-methyl-1,3-diaza-2-silacyclopentane] 6crystallizes in the chiral orthorhombic space group P212121 (Z = 4). Both silaimidazolidine rings in 6show half chair conformation. All nitrogen atoms of this molecule are almost planarized (sum of angles: 356.3◦ at N1, 359.5◦ at N2, 356.7◦ at N3 and 357.5◦ at N4). Bis-[N,N’-diphenyl-2-chloro-1,3-diaza- 2-silacyclopentane] 7, resulting from the reaction of disilane 5with diamine 2, crystallizes in the orthorhombic space group Pbcn (Z = 4). Its nitrogen atoms are almost planar (sum of angles: 357.9◦ at N1, 356.7◦ at N2). N,N’-diphenyl-2,2,3,3-tetramethyl-1,4-diaza-2,3-disilacyclohexane 9crystallizes in the chiral monoclinic space group P21 (Z = 2) and shows a twisted conformation. One nitrogen atom has a trigonal planar environment (sum of angles: 359.9◦ at N1), while the angle sum of the second one indicates a trigonal pyramidal conformation (sum of angles at N2: 350.6◦).