PHOSPHORUS DONOR CHEMISTRY OF [W(CO)(PH2PCCPPH2)-(S2CNET2)2]

Reactions of [W(CO)(Ph2PC = CPPh2)(S2CNEt2)2] with [M(CO)4(pip)2] (M = Cr, Mo or W; pip = piperidine) afford [W(CO){(Ph2PC = CPPh2)M(CO)4}(S2CNEt2)2]. The molecular structures of all three compounds have been determined by X-ray diffraction studies and found to be isostructural. In all three cases the acetylenic bond of Ph2PC = CPPh2 is co-ordinated to the tungsten(II) centre, which is also ligated by carbonyl and dithiocarbamate ligands, while both phosphorus atoms are co-ordinated to the metal tetracarbonyl fragment to form a five-membered chelate ring. The C-13-{H-1} NMR data are discussed in relation to the molecular structures, and the barriers to alkyne rotation in these complexes have been established by variable-temperature P-31-{H-1} NMR spectroscopy. Reactions of [W(CO)(Ph2PC = CPPh2)(S2CNEt2)2] with [Co2(CO)8] and [Fe2(CO)9] afford [W(CO){(Ph2PC = CPPh2)Co2(mu-CO)2(CO)4}(S2CNEt2)2] and [W(CO)(x)4Fe(Ph2PC = CPPh2)Fe(CO)4}(S2CNEt2)2] respectively, which have been characterised by IR, NMR and mass spectroscopy.