(Phenylthiomethyl)silanes and (butyltelluromethyl)silanes as novel bifunctional ligands for the construction of dithioether-, ditelluroether- and transition metal–silicon complexes

Abstract

The functionalized silanes (PhSCH 2) 2SiPh 2 ( 1a), (PhSCH 2) 2Si(vinyl)Me ( 1b), (PhSCH 2) 2Si(H)Me ( 1c) and (PhSCH 2) 3SiH ( 1d) have been prepared and co-ordinated as chelating dithioether ligands or via a covalent MSi bond to various transition metal centers. Thus, reaction of 1a with [PtCl 2(PhCN) 2] affords the dithioether complex cis-[PtCl 2{(PhSCH 2) 2SiPh 2}] ( 3), which exist in solution as mixtures of dl- and meso-invertomers. Treatment of [Re(μ-Br)(CO) 3THF] 2 with 1a– c yielded the stereochemically rigid chelate complexes fac-[ReBr(CO) 3{(PhSCH 2) 2SiR 1R 2}] (R 1, R 2=Ph ( 4a)), (R 1=vinyl, R 2=Me ( 4b)), (R 1=H, R 2=Me ( 4c)). Due to the presence of two different substituents R 1 and R 2 on Si, 4b and 4c are isolated as 50:50 mixtures of diastereomers. The presence of a SiH function in 1c, d can be exploited for SiH activation reactions. Thus, oxidative addition on [Pt(PPh 3) 2(CH 2CH 2)] yields the fluxional hydrido silyl complex [Pt(H)(PPh 3) 2{Si(CH 2SPh) 2Me}] ( 5a) and the rigid derivative [Pt(H)(PPh 3) 2{Si(CH 2SPh) 3}] ( 5b). The ditelluroether complexes cis-[PtCl 2{(RTeCH 2) 2SiMe 2)] ( 6a, R=Ph), ( 6b, R=n-Bu) are obtained by treatment of [PtCl 2(PhCN) 2] with (PhTeCH 2) 2SiMe 2 ( 2a) and (n-BuTeCH 2) 2SiMe 2 ( 2b), respectively. The complex fac-[ReBr(CO) 3{(n-BuTeCH 2) 2SiMe 2}] ( 7) results from the reaction of [Re(μ-Br)(CO) 3THF] 2 with ( 2b). The new compounds have been studied by multinuclear NMR techniques, the crystal structures of 3, 4a, 5 and 6b have been determined by X-ray diffraction studies.