Photochemically generated reactive sites at ruthenium/gallium complexes: catalysis vs. cluster growth

Abstract

Irradiation of [Ru(GaCp*)₃(SiEt₃)H₃] (1) at 350 nm induces reductive elimination of dihydrogen and triethylsilane and generates unsaturated Ru/Ga species. This photochemically induced cascading reductive elimination processes generate the reactive intermediate [Ru(GaCp*)₃], which can be trapped by diphosphine coordination to yield the stable complex [(dppe)Ru(GaCp*)₃] (4). The photochemically generated RuGa₃ species is catalytically active in the hydrogenation of alkynes, which is further investigated by ¹H NMR and mass spectrometry. Formation of intermetallic Ru/Ga clusters is observed as a competing and for the catalytic activity of the species limiting side reaction.