The addition of small molecules to (η-C 5H 5) 2Rh 2(CO)(CF 3C 2CF 3) : I. The coordinative-addition of CO, CNR, and some group V donor ligands

Abstract

Treatment of the μ(η 1)-alkyne complex (η-C 5H 5) 2Rh 2(CO) 2(CF 3C 2CF 3) with trimethylamine- N-oxide results in mono-decarbonylation to give the μ(η 2)- alkyne complex (η-C 5H 5) 2Rh 2(μ-CO)(CF 3C 2CF 3). Coordinative addition of a variety of ligands L to the monocarbonyl complex has been achieved at room temperature, and stable adducts (η-C 5H 5) 2Rh 2(CO)L(CF 3C 2CF 3) (L  CO, CNBu t, PPh 3, PMePh 2, P(OMe) 3, AsPh 3, PF 3 and PF 2(NEt 2)) have been fully characterized by infrared and NMR spectroscopy. In each complex, there is a μ(η 1)-attachment of the hexafluorobut-2-yne and a trans-arrangement of CO and L. The spectroscopic data establish that there is rapid scrambling of CO and L when L  CNBu t. An unstable adduct is formed when (η-C 5H 5) 2Rh 2(μ-CO)(CF 3C 2CF 3) is dissolved in pyridine.