IDENTIFICATION OF THE STEREOISOMERS OF ,4-TETRAMETHYL-1,2,3,4-TETRAPHENYLCYCLOTETRASILANE

The configurations of three synthetically available stereoisomers (ttt t, ttcc, and tctc) of ,4-tetramethyl-1,2,3,4-tetraphenylcyclotetrasila ne have been unambiguously assigned by using spin labeling techniques and by preparing chemical derivatives. 1J(C-Si), 2J(C-Si), and 3J(C-Si ) values were determined for the three stereoisomers with C-13-labeled methyl groups. The dominating isomer resulting from the synthesis pos sesses an all-trans structure and can be isolated in up to 95% purity.