Five- and six-membered ring Group 14 chalcogenides of the types (Me2ME)3 (M=Si, Ge, Sn), E(Si2Me4)2E, Me4Si2(E)2MRx (MRx=C(CH2)5, SiMe2, GeMe2, SnMe2, SnPh2, BPh) and [Me4Si2(E)2SiMe]2 (E=S, Se, Te)

The reactions of Me2MCl2 (M=Si, Ge, Sn) with either H2S/NEt3 or Li2E (E=Se, Te) yielded the six-membered-ring compounds (Me2ME)3. Similarly the treatment of ClMe2SiSiMe2Cl (1) with H2S/NEt3 or Li2E resulted in the formation of E(Si2Me4)2E. Mixed species E(Si2Me4)2E′ could be obtained by reaction with mixtures of Li2E and Li2E′ or in the presence of traces of moisture (E′=O). Reactions of 1:1 mixtures of Me2MCl2 and 1 with Li2E resulted in exclusive or at least preferred formation of five-membered rings Me4Si2(E)2MMe2. A carbon analogue, Me4Si2(S)2C(CH2)5, was obtained from 1 and (HS)2C(CH2)5. Boron could also be introduced in these ring systems, starting from PhBCl2 and 1 the compounds PhB(E)2Si2Me4 (E=S, Se) could be synthesized. Mixtures of 1 and Cl2MeSiSiMeCl2 yielded, on treatment either with H2S/NEt3 or Li2E (E=Se, Te), the bis(cyclopentyl) compounds [Me4Si2(E)2SiMe]2. All products have been characterized by multinuclear NMR (1H, 11B, 13C, 29Si, 77Se, 119Sn, 125Te) measurements including coupling constants. Trends of chemical shifts and coupling constants are discussed. The crystal structures of E(Si2Me4)2E (E=S, Se) and [Me4Si2(S)2SiMe]2 are reported.