Syntheses, characterization and redox properties of di- and poly-phosphine linked oligomeric complexes of oxo-centered triruthenium clusters

Abstract

A series of phosphine-linked oligomers of oxo-centered triruthenium-acetate clusters have been prepared by the reaction of [Ru 3O(OAc) 6(py) 2(CH 3OH)](PF 6) ( 1) with di- or poly-phosphine. They have been characterized by elemental analysis, ESI-MS spectrometry, UV–Vis, IR, and 31P NMR spectroscopy, and cyclic and differential pulse voltammetry. The structures of diphosphine-linked dimeric compounds 4 and 7 were determined by X-ray crystallography. As revealed by redox wave splitting, weak to moderate electronic communication is operative between triruthenium clusters across bridging di- or poly-phosphine. With increase of the methylene number in Ph 2P(CH 2) n PPh 2, electronic communication decreases rapidly in diphosphine-linked dimeric complexes [{Ru 3O(OAc) 6(py) 2} 2{μ-Ph 2P(CH 2) n PPh 2}] 2+ ( n = 1–5).