Theoretical investigation of substituent effects on the silicon–metal bond for a series of transition metal-substituted base-stabilized silylene complexes

Abstract

Hartree–Fock ab initio calculations were used to investigate the effects of various silicon substituents on the silicon–ruthenium bond for four transition metal-substituted base-stabilized silylene complexes. To provide comparison information, one silyl complex, Cp*(PMe 3) 2Ru–Si[S(Tol- p)] 3, and four base-free silylene complexes ([Cp*(PMe 3) 2RuSiMe 2]BPh 4, Cp*(PMe 3) 2RuSi[S(Tol- p)][Os(CO) 4], a bis(silylene)nickel compound and [ trans-(P(Cy 3) 2(H)PtSi(SEt) 2]BPh 4) were also studied. Results of the calculations indicate that the order of promotion of silylene character for base groups is NCMe>OTf≫S(Tol- p). Of those considered, the best substituent group in terms of transition metal–silicon double bond promotion is methyl followed by triflate. The worst group with respect to this property is S(Tol- p).