Synthesis and characterization of 2,5,7-trichalcogena-1,3,4,6-tetrasilanorbornanes (RMeSiSiMe) 2E 3 (R=Me, Ph/E=S, Se, Te)

Abstract

The reactions of the trichlorodisilanes ClRMeSi–SiMeCl 2 (R=Me, Ph) with either H 2S/NEt 3 or Li 2E (E=Se, Te) result in the selective formation of 2,5,7-trichalcogena-1,3,4,6-tetrasilanorbornanes (RMeSiSiMe) 2E 3 (R=Me, Ph/E=S, Se, Te). In the cases of R=Ph, three stereoisomers with different spatial orientations of the phenyl substituents arise. The isomers with both phenyl substituents in equatorial positions are formed preferably. All products have been characterized by multinuclear NMR spectroscopy including 1 J SiSe and 1 J SiTe coupling constants. A crystal structure analysis of the isomer of (PhMeSiSiMe) 2S 3 with both phenyl substituents in equatorial positions reveals a very small bond angle at the bridging sulfur atom of 88.5° which is even 4.6° smaller than in the parent norbornane C 7H 12.