The [Fe3(µ3-CR)(CO)10]– cluster anions as building blocks for the synthesis of mixed-metal clusters. Part 1. Synthesis of mixed clusters [MFe3(µ3-CMe)-(CO)10(PPh3)](M = Cu or Au) and crystal structure of [CuFe3(µ3-CMe)-(CO)10(PPh3)]
Abstract
The reaction of [Fe3(µ3-CMe)(µ3-CO)(CO)9]– with [MCl(PPh3)](M = Cu or Au) yields the complexes [MFe3(µ3-CMe)(CO)10(PPh3)]. The structure of [CuFe3(µ3-CMe)(CO)10(PPh3)] has been determined by X-ray diffraction. Crystals are monoclinic, space group P2, with Z= 2 in a unit cell with a= 11.828(2), b= 15.605(3), c= 8.939(2)Å, and β= 107.85(2)°. The structure was solved and refined to R and R′ values of 0.036 using 2 821 reflections. It consists of a butterfly metal-atom core (interplanar angle 133.3°) with the copper atom occupying a ‘wing-tip’ site. The CMe ligand triply bridges the triangle of iron atoms. On the opposite site of the triangle a carbonyl ligand bridges one of the basal iron atoms and the iron at the ‘wing-tip’ site. This ligand also interacts with the third iron and the copper atom. Each iron is surrounded by three terminal carbonyl groups and non-bonding contacts are also apparent between the three terminal carbonyl groups bonded to the basal iron atoms and the copper atom. In the case where M = Au, i.r. data in the ν(CO) stretching region suggest a weaker interaction between the carbonyl groups and the gold atom. No catalytic activity of the two mixed clusters toward hydrogenation of 1- heptene was observed.