Phosphorus donor chemistry of [W(CO)(Ph2PCCPPh2)(S2CNEt2)2]

Abstract

Reactions of [W(CO)(Ph₂PCCPPh₂)(S₂CNEt₂)₂] with [M(CO)₄(pip)₂](M = Cr, Mo or W; pip = piperidine) afford [W(CO){(Ph₂PCCPPh₂)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 Ph₂PCCPPh₂ 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 ¹³C-{¹H} 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 ³¹P-{¹H} NMR spectroscopy. Reactions of [W(CO)(Ph₂PCCPPh₂)(S₂CNEt₂)₂] with [Co₂(CO)₈] and [Fe₂(CO)₉] afford [W(CO){(Ph₂PCCPPh₂)Co₂(µ-CO)₂(CO)₄}(S₂CNEt₂)₂] and [W(CO)(x)₄Fe(Ph₂PCCPPh₂)Fe(CO)₄}(S₂CNEt₂)₂] respectively, which have been characterised by IR, NMR and mass spectroscopy.