Reactivity of transition metal-phosphorus triple bonds towards triply bonded [{CpMo(CO)2}2]: formation of heteronuclear cluster compounds

Thermolysis of Cp*P{W(CO)5}2] (1) in the presence of {CpMo(CO)2}2] leads to the novel complexes {(CO)2Cp*W}{CpMo(CO)2}(micro,eta2:eta1:eta1-P2{W(CO)5}2)] (6; Cp=eta5-C5H5, Cp*=eta5-C5Me5), {(micro-O)(CpMoWCp*)W(CO)4}{micro3-PW(CO)5}2] (7), {CpMo(CO)2}2{Cp*W(CO)2}{micro3-PW(CO)5}] (8) and {CpMo(CO)2}2{Cp*W(CO)2}(micro3-P)] (9). The structural framework of the main products 8 and 9 can be described as a tetrahedral Mo2WP unit that is formed by a cyclisation reaction of {CpMo(CO)2}2] with an Cp*(CO)2Wtriple chemical bond]P-->W(CO)5] intermediate containing a W--P triple bond and subsequent metal-metal and metal-phosphorus bond formation. Photolysis of 1 in the presence of {CpMo(CO)2}2] gives 8, 9 and phosphinidene complex (micro3-PW(CO)5){CpMo(CO)2W(CO)5}] (10), in which the P atom is in a nearly trigonal-planar coordination environment formed by one {CpMo(CO)2} and two {W(CO)5} units. Comprehensive structural and spectroscopic data are given for the products. The reaction pathways are discussed for both activation procedures, and DFT calculations reveal the structures with minimum energy along the stepwise Cp* migration process under formation of the intermediate Cp*(CO)2Wtriple chemical bond]P-->W(CO)5].