Oxidation of the zwitterionic tungsten amide (OC)5WNPhNPhC(OMe)Ph with Br2 and PCl5. Formation of [(PhN)W(CO)2X2]2 and (PhN)W(CO)2X2L (X = Br or Cl; L = MeCN, Me3C6H2NH2 and i-BuNH2)

Abstract

Oxidation of the zwitterionic tungsten amide (OC)₅WNPhNPhC(OMe)Ph 1 with Br₂ or PCl₅ produced [(PhN)W(CO)₂X₂]₂ (X = Cl or Br). These halide-bridged tungsten(IV) dimers reacted with MeCN to give the mononuclear complexes (PhN)W(CO)₂X₂(MeCN) (X = Cl or Br). The latter complexes can also be obtained directly in high yield by oxidizing 1 in the presence of MeCN. The acetonitrile ligand can be substituted with Me₃C₆H₂NH₂ or i-BuNH₂ to yield (PhN)W(CO)₂X₂L (X = Cl or Br, L = Me₃C₆H₂NH₂ or i-BuNH₂) or with PMe₃ to produce (PhN)W(CO)Br₂(PMe₃)₂. The oxidation of 1 with BrI resulted in the formation of [(PhN)W(CO)₂Br(I)]₂, which reacts with MeCN to produce (PhN)W(CO)₂Br(I)(MeCN). The structures of the dimers [(PhN)W(CO)₂X₂]₂ were determined by X-ray crystallography.