Further studies on formamidinate dirhenium(III) complexes of the type Re2(μ-form)2Cl4 and the isolation and characterization of the ferrocenyl ligand Fe[η5-C5H4C(NHCy)(NCy)]2

The quadruply bonded dirhenium(III) complexes trans-Re2(dpf)2Cl4·H2O·2THF (1) (dpf=N,N′-diphenylformamidinate) and Re2(μ-RNCHO)4Cl2 (R=Ph (2) or Cy (3)) have been prepared in good yield from the reactions of (n-Bu4N)2Re2Cl8 and Re2(μ-O2CCH3)4Cl2, respectively, with the appropriate molten ligands dpfH and RNHCHO. The ferrocenyl ligand Fe[C5H4C(NHCy)(NCy)]2 (4) has been prepared but failed to yield dirhenium complexes that could be characterized. The structures of 1, 2 and 4 have been established by single crystal X-ray crystallography.