REACTIONS OF 1,2,3,4,5-TETRACHALCOGENASTANNOLANES WITH GROUP-6 AND GROUP-8 TRANSITION-METAL CARBONYLS - FORMATION OF NOVEL TRANSITION-METAL COMPLEXES BRIDGED BY STANNANETHIONES AND STANNANESELONES

The reactions of the 1,2,3,4,5-tetrachalcogenastannolanes Tb(Tip)SnY4 (1: 1a, Y = S; 1b, Y = Se) with W(CO)(5).THF and M(3)(CO)(12) (M = Ru, Os) are reported. Stannolane 1a reacted with W(CO)5.THF to produce Tb(Tip)SnS4.W(CO)(5) (2) in 40% yield, which was analyzed crystallographically. The structure of 2 contains an octahedral tungsten unit, the THF Ligand of W(CO)(5).THF being replaced by a tetrathiastannolane ring at a position beta to tin. While triruthenium complexes (mu(3)-Y)(3)(mu(2)-Y)Ru-3(CO)(7)[Tb(Tip)Sn] (4: 4a, Y = S; 4b, Y = Se) and diruthenium complexes (mu(3)-Y)(2)Ru-2(CO)(6)[Tb(Tip)Sn] (5: 5a, Y = S; 5b, Y = Se) were isolated from the reaction of 1 with Ru-3(CO)(12), the reactions of 1 with Os-3(CO)(12) afforded triosmium complexes (mu(3)-Y)(3)Os-3(CO)(7)[Tb(Tip)Sn] (8: Y = S, Se) together with triosmium complexes (mu(3)-Y)(3)(mu(2)-Y)Os-3(Co)(7)[Tb(Tip)Sn] (9a, Y = S) and diosmium complexes (mu(3)-Y)(2)Os-2(CO)(6)[Tb(Tip)Sn] (10, Y = S, Se), The structures of 4b, 5a, and 8 were characterized crystallographically. The isolation of 5 and 10, which have interesting and strained quadracyclic SnY(2)M(2) (M = Ru, Os) ring systems,was considered to be due to steric protection against polymerization by bulky Tb and Tip ligands. The complexes 4 and 9 contain three triply bridging chalcogen ligands in a cluster of three ruthenium or osmium atoms which have only one Ru-Ru or Os-Os bond. The complexes 8 are regarded as binuclear osmium complexes bridged by a stannanethione and a stannaneselone, though the bond lengths between tin and chalcogen were elongated to those for single bonds and the angles around the tin atom were slightly spread out on account of the complexation of osmium. The possible reaction mechanism is also proposed.