Synthesis and Spectroscopic Properties of the New bis(Alkyne) Complexes [WI₂(CO)L(η²-RC₂R) ₂] (R = Me or Ph; L = Imidazole or Pyrazole)

Abstract

The reactions of equimolar quantities of the bis(alkyne) complexes [WI₂(CO) (NCMe) (η²-RC₂R)₂] (R = Me or Ph) and L (L = imidazole or pyrazole) in CH₂Cl₂ at room temperature gives the acetonitrile exchanged products [WI₂(CO)L(η²-RC₂R)₂] (1 → 4) in good yield. Complexes 1 → 4 have been characterised by elemental analysis, infrared and ¹H NMR spectroscopy. ¹³C NMR spectroscopy suggests that the two but-2-yne ligands are donating a total of six electrons to the tungsten in two of these complexes.