Oxo Ligand Reactivity and Bonding in the Dinuclear W−Re Oxo−Acetylide Complex (η5-C5Me5)W(O)Re(CO)4(μ-H)(CCPh)

Abstract

The trinuclear oxo−acetylide metal cluster (η5-C5Me5)W(O)Re2(CO)8(μ-CCPh) (1) reacts with thiophenol in refluxing toluene to afford the dinuclear metal complex (η5-C5Me5)W(O)Re(CO)4(μ-H)(μ-CCPh) (2) in 90% yield. Upon treatment with Me3NO in acetonitrile, complex 2 loses one CO ligand and is converted initially to an acetonitrile derivative, (η5-C5Me5)W(O)Re(CO)3(NCMe)(μ-H)(μ-CCPh) (4), and then to a head-to-tail dimer, [(η5-C5Me5)WRe(CO)3(μ-O)(μ-H)(μ-CCPh)]2 (5), through the formation of two W⋮O−Re bridges. Extended Huckel MO calculations indicate that the most likely site of electrophilic attack is the oxo oxygen atom, and in agreement with this prediction, protonation of 2 with CF3CO2H is suggested to give the unstable hydroxy complex 6.