New synthesis of seven-coordinate complexes of molybdenum(II) and tungsten(II) containing bidentate phosphorus ligands, [MI 2(CO) 3{Ph 2P(CH 2) nPPh 2}] ( n = 1–6)

Abstract

A new high yielding synthesis of the seven-coordinate complexes [MI 2(CO) 3{Ph 2P(CH 2) n PPh 2}] (M = Mo and W; n = 1–6) is described. The procedure involves reacting the complexes [MI 2(CO) 3(NCMe) 2] in CH 2Cl 2 with an equimolar amount of the bidentate phosphorus ligand. The low temperature (−70 °C) 13C NMR spectra of the complexes [Wl 2(CO) 3{Ph 2P(CH 2) n PPh 2}] ( n = 3 and 5) indicates that the geometry is capped octahedral with a carbonyl ligand in the unique capping position.