Synthesis of Tellurasila Cycles Containing an Annelated Dicarba-closo-dodecaborane(12) Unit: Structure of a 1,4-Ditellura-2,3-disilacyclohexane Derivative

Insertion of tellurium into C-Li bonds of dilithiated 1,2-dicarba-closo-dodecaborane(12) gave 1,2-dicarba-closo-dodecaborano(12)-1,2-ditellurolate [(1,2-C2B10H10)Te2Li2](Et2O) which, after reaction with 1,2-dichlorotetramethyldisilane, afforded a six-membered heterocycle containing the Te-Si-Si-Te unit with an annelated carborane moiety, characterized by multinuclear magnetic resonance and X-ray structural analysis. As a byproduct, a five-membered ring containing a Si-Si-Te unit was formed, which was obtained as a major product, using conditions favouring partial insertion of tellurium into C-Li bonds. Treatment of [(1,2-C2B10H10)Te2Li2](Et2O) with dichlorodimethylsilane led to a five-membered heterocycle as a major product containing a Te-Te-Si unit. Various decomposition/hydrolysis/oxidation products could be identified by multinuclear magnetic resonance, among them most notably 1,2-di(hydrotelluro)-1,2-dicarba-closo-dodecaborane(12).