Novel Si-Sn ring systems with distanna and tristanna moieties

The synthesis of new cyclic stannaoligosilanes 9, 10 and 11 with a bridging tin-tin unit [((Bu2Sn)-Bu-t)(2)(SiMe2)(n), n = 2, 9; n = 3; 10; n = 4, 11] or an Sn-3 moiety [((Bu2Sn)-Bu-t)(3)(SiMe2)(2)] (12) are reported. All com pounds are fully characterised by NMR, mass spectroscopy and elemental anal ysis. The structure of the five-membered ring 10 is determined by X-ray cry stallography. (C) 1999 Elsevier Science S.A. All rights reserved.