172092-13-6Relevant articles and documents
Phosphorus-Carbon Bond Formation in Heterobimetallic Molybdenum-Tungsten Alkyne Complexes
Acum, Gillian A.,Mays, Martin J.,Raithby, Paul R.,Solan, Gregory A.
, p. 3049 - 3056 (1995)
The heterobimetallic complexes (R1 = H, R2 = Ph 1a, Me 1b or H 1c; R1 = R2 = CO2Me 1d or Me 1e) have been isolated from the reaction of a mixture of and with the corresponding alkyne R1CCR2 in diglyme (2,5,8-trioxanonane).Thermolysis of complexes 1a-1d with PPh2Cl proceeded via P-Cl bond cleavage and coupling of the diphenylphosphide unit with the alkyne in one of four different ways, depending on the nature of R1 and R2, to give the products (R1 = H, R2 = Ph 2a; R1 = R2 = H 2c or CO2Me 2d), (R2 = Ph 3a, Me 3b or H 3c), (R2 = Ph 4a or Me 4b) and (CO)2(μ-C5H5)2> 5d.The formation of complexes 2 and 3 can be rationalised as resulting from initial substitution of a molybdenum carbonyl ligand by the halogenophosphine and that of 4 and 5 by initial substitution of a tungsten carbonyl.The significantly higher yield of the former two complexes suggests that initial substitution of a molybdenum carbonyl is the preferred pathway.Attempts at the preparation of an organophosphine-substituted derivative of 1a via its reaction with PPh3 gave 6 as the only product.A single-crystal X-ray structure determination of complex 3a shows a Mo-W distance compatible with a double bond.The phosphorus atom and the α carbon of the four-membered metallacycle are ? bonded to tungsten and the carbon-carbon double bond is ?-coordinated to molybdenum.
