SYNTHESIS AND STRUCTURES OF BIS[BIS(TRIMETHYLSILYL)AMIDO]TIN(IV) CYCLIC CHALCOGENIDES [(SN[N(SIME(3))(2)](2)(MU-E))(2)] AND A HETEROBIMETALLIC ANALOG [((ME(3)SI)(2)N)(2)GE(MU-TE)(2)SN(N(SIME(3))(2))(2)] (E=S, SE OR TE)

Each of the four-membered ring compounds [{Sn[N(SiMe(3))(2)](2)(mu-E)}(2)] (E = S 1, Se 2 or Te 3) has been prepared by the oxidative addition of the chalcogen E to Sn[N(SiMe(3))(2)](2) promoted by sonication in a faster reaction and in a higher yield than previously achieved. The first heterobimetallic analogues [{(Me(3)Si)(2)N}Ge-2(mu-E)(2)Sn{N(SiMe(3))(2)}(2)] (E = Te 4 or Se 5) were obtained similarly from a mixture of the two metal(II) amides and the chalcogen. Compounds 1-4 have been characterised by single crystal X-ray diffraction and 1-5 studied by NMR spectroscopy [H-1, C-13, Si-29, Se-77, Sn-177, Sn-179, Te-125 and (by the insensitive nuclei enhanced by polarization transfer technique) N-15].