Mixed-metal cluster chemistry III . P-C activation at tungsten-triiridium cores; X-ray crystal structures of [CpWIr₃ {μ₃-η²-PPh(C₆H₄)} (μ-CO)₂(CO) ₇]

Abstract

The thermolysis of [CpWIr3(μ-CO)3(CO)7(PPh3)] in refluxing toluene gives [CpWIr3{μ3-η2-PPh(C6H4)}(μ-CO)2(CO)7] (1) in good yield (56%), together with [CpWIr3(CO)11] (2) (32%); an analogous reaction with [CpWIr3(μ-CO)3(CO)6(PPh3)2] gives 1 (23%) and [CpWIr3{μ3-η2-PPh(C6H4)}(μ-CO)2(CO)6(PPh3)] (3) (39%). Products 1 and 3 (in 15 and 44% yield respectively) are also obtained from heating [CpWIr3(μ-CO)3(CO)5(PPh3)3]. Both 1 and 3 have been structurally characterized. The structural studies show that orthometallation has occurred, to afford products with (phenylphosphido)phenyl-P,C ligands capping the triiridium faces. In 3, the intact PPh3 resides at an iridium ligated by the phosphorus of the capping group. Attempts to effect further P-C cleavage of 1 (pyrolysis, photolysis, reaction with trimethylamine-N-oxide) were unsuccessful, as were attempts to effect C-H activation at the analogous [CpWIr3(μ-CO)3(CO)7(PMe3)]. Show more