Dirhenium carbonyl compounds bearing cis-1,2-bis(diphenylphosphino)ethylene and cis-1,2-bis(diphenylphosphino)ethylene oxide ligands

Abstract

Reaction of [Re2(CO)9(MeCN)] with cis-1,2-bis(diphenylphosphino)ethylene (cis-Ph2PCH=CHPPh2) in boiling benzene (80 °C) afforded two compounds, ax-[Re2(CO)9(κ1-cis-Ph2PCH=CHPPh2)] (1) and ax-[Re2(CO)9{κ1-cis- Ph2PCH=CHPh2P(O)}] (2) where the ligand is axially coordinated in a κ1 monodentate fashion through phosphorus. The close-bridged compound eq-[Re2(CO)8(μ-κ2-cis-Ph2PCH=CHPPh2)] (3) is obtained from a similar reaction of the same ligand with [Re2(CO)8(NCMe)2] in refluxing benzene. In this case the diphosphine is equatorially coordinated to two Re atoms in a symmetrical bridging fashion. Compounds 1−3 have been characterized by IR, 1H NMR, 31P{1H} NMR spectroscopy and single crystal X-ray diffraction analyses.