Nucleophilic addition reactions of the osmium-antimony cluster (μ-H)Os3(CO)9(μ3-C6H4 ) (μ-SbPh2): Orthometalation of triphenylphosphine at ambient temperature

Abstract

At ambient temperatures, the reaction of Os3(μ-H)(μ-SbPh2)(μ3,η2 -C6H4)(CO)9, 1, with PPh3 proceeded via a nucleophilic addition product, Os3(μ-H)(μ-SbPh2)(μ2,η2 -C6H4)(CO)9(PPh3), 2a.This can lose CO to give Os3(μ-H)(μ-SbPh2)(μ3,η2 -C6H4)(CO)3(PPh3), 3a, isomerize, deorthometalate to Os3(μ-SbPh2)(C6H5)(CO)9 (PPh3), 5a, or react with excess PPh3 to give an orthometalated product, Os3(μ-SbPh2)(CO)8(PPh2C6 H4)(PPh3)2, 6a. The origin of the orthometalated phenyl ring in 6a has been established via the reaction of a p-tolyl analogue of 2a, viz., Os3(μ-H)(μ-SbPh2)(μ2,η2 -C6H4)(CO)9{(p-tolyl)3P}, 2b, with PPh3.