Reaction of halogenophosphinecarbonylrhenium(I) complexes with anhydrous hydrazine: preparation of isocyanato derivatives of rhenium(I)

Abstract

cis-[Re(CO)₄LBr](L = AsMe₂Ph, PMe₂Ph, and PPh₃) and trans-[Re(CO)₄(PPh₃)Br] react with anhydrous hydrazine to yield air-sensitive isocyanato(tricarbonyl)hydrazine(phosphine or arsine)rhenium(I) complexes. Similarly, trans-[Re(CO)₃L₂X](L = PPh₃, (10), PMe₂Ph, (11), or PMePh₂, (12); X = Cl or Br) react with anhydrous hydrazine yielding isocyanato(dicarbonyl)hydrazinebis(phosphine)rhenium(I) complexes, (13), (14), and (15). These new complexes are characterized by a study of some of their reactions and their i.r. and ¹H n.m.r. spectra. A possible mechanism for the formation of the isocyanato-ligand is discussed. The complexes [ReCl(CO)₃L₂](L = PMe₂Ph or PMePh₂) react with sodium azide or benzoyl azide yielding the azido complexes [Re(N₃)(CO)₃L₂]. [ReCl₃(CO)(PMe₂Ph)₃] is reduced by anhydrous hydrazine to [ReCl(CO)(PMe₂Ph)₄]. mer-[ReCl₃L₃](L = PMe₂Ph or PMePh₂) reacts with anhydrous hydrazine yielding the known nitrido-complexes [ReNCl₂L₃] in good yield.