The preparation and reactions of trihaolgeno(alkanonitrile)bis(triphenylphosphine)rhenium(III) complexes

The monomeric rhenium(III) complexes, ReX3(RCN)(PPh3)2(R = alkyl; X = Cl or Br), have been prepared in high yield by heating trans-ReOX3(PPh3)2 with triphenylphosphine and an alkanonitrile; other monomeric Re(III) complexes may be obtained from them by ligand substitution, while aerial oxidation gives ReOCl3(PPh3O)PPh3. The nitrile complexes are oxidised rapidly by halogenated compounds of the type R′CY3(R′= any group; Y = Cl or Br) to ReX3Y(PPh3)2 or ReX2Y2(PPh3)2. The properties and structures of the new compounds and the mechanisms of the reactions are discussed.