Dihydride silyl complexes Cp*(CO)2W(H)2(SiHPhR) (R = Ph, 7; H, 8) were synthesized by treating the donor-stabilized silylene complexes cis-Cp*(CO)2(H)W=SiRPh·Do (R = Ph, H; Do = Py, THF) with LiAlH4, to give Li[Cp*(CO)2W(H)(SiHPhR)] (R = Ph, 5; H, 6) followed by protonation using CF3-COOH. X-ray analyses of the crystals of 7 and 8 revealed that the former adopts a distorted pseudooctahedral structure (7a), while the latter possesses a pseudo-trigonal-prismatic structure (8b). In solution, both complexes exist as equilibrium mixtures of these two structural isomers: the distorted pseudooctahedral isomer (7a/8a) and the pseudo-trigonal-prismatic isomer (7b/8b). In addition to this interconversion process, two dynamic processes involving site exchanges of hydride and silyl ligands in the pseudo-trigonal-prismatic isomer were shown for 8b by detailed NMR studies. The addition of HCl to cis-Cp*(CO)2(H)W=SiHPh·THF afforded Cp*(CO)2W(H)2(SiHPhCl) (9), which also gave an equilibrium mixture of the distorted pseudo-octahedral isomer (9a) and the pseudo-trigonal-prismatic isomer (9b). The presence of an additional dynamic process, hydride site exchange in the distorted pseudooctahedral isomer, was revealed for 9a due to its chiral silicon center.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry