Reactions of rhodium(V) hydrido–silyl complexes with butyl-lithium and with lithium triethylhydridoborate

Abstract

Reaction of [(η⁵-C₅Me₅)Rh(H)₂(SiR₃)₂](R, = Me₃, Et₃, or Me₂Ph) with LiBuⁿ gave [(η⁵-C₅Me₅)-RhH(SiR₃)₂]^–; these species regenerated [(η⁵-C₅Me₅)Rh(H)₂(SiR₃)₂] on reaction with methanol. By contrast, [(η⁵-C₅Me₅)Rh(H)₂(SiEt₃)₂] reacted with Li[BEt₃H] slowly to give [(η⁵-C₅Me₅)Rh-(H)₂(SiEt₃)]^–, which, with methanol gave the trihydride, [(µ₅-C₅Me₅)Rh(H)₂(SiEt₃)]. The anion, [(η⁵-C₅Me₅)RhH(SiMe₃)₂]^– also reacted with CO₂ to give the labile [(η⁵-Me₅)RhH(SiMe₃)-(CO)], which was also made by reaction of [(µ⁵-C₅Me₅)Rh(CO)₂] with SiMe₃H. Syntheses of [(η⁵-C₅Me₅)Rh(H)₂(SiR₃)₂](R₃= Me₃ Me₂Ph) are described. The secondary isotope shift of ¹H/²H on the ¹⁰³Rh chemical shift on going from [(η⁵-C₅Me₅)Rh(H)₃(SiEt₃)] to [(η⁵-C₅Me₅)Rh(H)₂D(SiEt₃)] has been determined as –9 p.p.m.