Synthesis, first structures, and catalytic activity of the monomeric rhodium(I)-siloxide phosphine complexes

Abstract

Four new square-plane rhodium siloxide complexes of the general formula [Rh(cod)(PR3′)(OSiR3)] (where R = Me, i-Pr, O-t-Bu, R′ = Cy, Ph) were synthesized and the structures of three of them were resolved by the X-ray method. [Rh(cod)(PCy3)(OSiMe3)] (1) appeared to be a very efficient catalyst for hydrosilylation of allyl glycidyl ether to yield, selectively, 3-glycidoxypropyltriethoxysilane, a commercially important silane coupling agent. Catalytic measurements and stoichiometric experiments of 1 with triethoxysilane suggest a mechanism where an unsaturated Rh-H species is responsible for the catalysis.Key words: rhodium (phosphine) siloxides, hydrosilylation, catalysis.