Oxygen, sulphur, and selenium abstraction from WCl4Y (Y = O, S, or Se) by triphenylphosphine. Crystal and molecular structure of tetrachlorobis(triphenylphosphine)tungsten(IV)

Excess of triphenylphosphine has been allowed to react with the series of compounds WCl4Y (Y = O, S, or Se). The products from each reaction have been analysed and subjected to spectroscopic studies which have shown that in each reaction abstraction of the chalcogen atom took place thus reducing tungsten(VI) to tungsten(IV) and yielding WCl4·2PPh3 and P(Y)Ph3. With Y = O a second product, WCl4O·P(O)Ph3·PPh3, was also isolated. The complex WCl4·2PPh3 crystallises in the monoclinic space group P21/n, with a= 9.605(8), b= 21.320(13), c= 9.313(8)Å, β= 117.5(1)°, and Z= 2. The WCl4·2PPh3 molecules are centrosymmetric with two equivalent W–Cl distances [2.320(5) and 2.344(6)Å] and a long W–P distance [2.629(6)Å].