SYNTHESIS AND REARRANGEMENTS OF TUNGSTEN GERMYL SILYL COMPLEXES

Germyl silyl complexes Cp(2)W(SiMe(3))(GeR(3)) have been synthesized b y the reaction of the tungsten silene complex Cp(2)W(eta(2)-Me(2)Si=CH 2) with germanes HGeR(3) (GeR(3) = GeMe(3) (2), GeMe(2)H (3a), Ge(t)Bu (2)H (3b), GePh(2)H (3c)). Chlorogermyl derivatives are synthesized by the reaction of 3a-c with CCl4 to yield Cp(2)W(SiMe(3))(GeMe(2)Cl) (4 a), Cp(2)W(SiMe(3))(Ge(t)Bu(2)Cl) (4b), and Cp(2)W(SiMe(3))(GePh(2)Cl) (4c). Complex 4a has been structurally characterized by a single-crys tal X-ray diffraction study. The corresponding triflate derivative, Cp (2)W-(SiMe(3))(GeMe(2)OTf) (5a), has been prepared by the reaction of 4a and trimethylsilyl triflate. Substitution of triflate for chloride in Cp(2)W(SiMe(3))(Ge(t)Bu(2)Cl) (4b) requires mild heating (80 degree s C) and is accompanied by concurrent redistribution of groups between silyl and germyl centers to yield the silyl triflate Cp(2)W(SiMe(2)OT f)(Ge(t)Bu(2)Me) (6b). Under thermolytic conditions, germyl silyl comp lexes undergo intra- and intermolecular redistribution of substituents between the germyl and silyl ligands. This process is proposed to occ ur via a cationic germylene complex formed by triflate or chloride dis sociation.