The reaction of Os3(CO)12 with triphos {MeC(CH2PPh2)3}: A case of multiple C-P and C-H bond activations

Abstract

The reaction of Os3(CO)12 with the tripodal ligand 1,1,1-tris(diphenylphosphinomethyl)ethane, triphos, results in the formation of the 48e trinuclear cluster complex Os3[μ-Ph2PCH2C(Me)(CH2PPh)CH2PC6H4](CO)7(η1-Ph). This new complex has been characterized by X-ray crystallography as well as by IR and NMR spectroscopy. The activation of the triphos ligand to yield the novel 9e donor ligand Ph2PCH2C(Me)(CH2PPh)CH2PC6H4 is unprecedented. The triphos ligand does not cap the triangular Os3 face; instead, the three phosphorus atoms are coordinated to only two of the metal atoms with the remaining osmium atom coordinated by an ortho-metalated aryl group. The triphos ligand is also transformed in several ways. Two C–P bonds are cleaved during the reaction, yielding an η1 phenyl ligand in the product and free benzene. The bonding in 1 has been examined by electronic structure calculations.