THALLIUM-STABILIZED SILSESQUIOXIDES - VERSATILE REAGENTS FOR THE SYNTHESIS OF METALLASILSESQUIOXANES, INCLUDING HIGH-VALENT MOLYBDENUM-CONTAINING SILSESQUIOXANES

The reactions of the incompletely-condensed silsesquioxanes (c-C6H11)( 7)Si7O9(OH)(3) (1a), (c-C6H11)(7)Si7O9(OTMS)(OH)(2) (2a), (c-C5H9)(7)S i7O9(OTMS)(OH)(2) (2b), and (c-C6H11)(7)Si7O9(OTMS)(2)(OH) (3a) with t hallium(I) ethoxide (1/1 Tl/OH) result in the formation of the corresp onding Tl-substituted silsesquioxanes [(C-C6H11)(7)Si7O9(OTl)(3)](n) ( 7a), [(c-C6H11)(7)Si7O9(OTMS)(OTl)(2)](n), (8a), [(c-C5H9)(7)Si7O9(OTM S)(OTl)(2)](n) (8b), and [(c-C6H11)(7)Si7O9(OTMS)(2)(OTl)](n) (9a). Th ese thallium-stabilized silsesquioxides are not prone to cycloeliminat ion reactions or the formation of ''ate'' complexes. They are versatil e anionic equivalents of incompletely condensed silsesquioxanes which react- with a variety of halide complexes, including POCl3 and MoO2Cl2 , to afford high yields of metallasilsesquioxanes.