The synthesis and X-ray crystal structure of [(4-ferrocenylphenylimido)]trichlorobis(triphenylphosphine)rhenium(v) and related ferrocenyl–rhenium(v) compounds

Abstract

The reaction of 4-ferrocenylaniline with trans-[ReOCl₃(PPh₃)₂] gave [(4-ferrocenylphenylimido)]trichlorobis(triphenylphosphine)rhenium(V) (1). The molecular structure of 1 has been determined by X-ray diffraction. The X-ray crystal structure of [(4-ferrocenylphenylimido)]tribromobis(triphenylphosphine)rhenium(V) (2) has also been determined and its molecular structure is compared with that of 1. The complexes 1 and 2 have also been investigated by cyclic voltammetry and UV-visible spectroscopy. The results of the cyclic voltammetry suggest that there is insignificant electron delocalization from the ferrocenyl group towards rhenium in 1 and 2. However, both 1 and 2 show a long wavelength absorption in their electronic spectra which is characteristic of conjugated ferrocenyl derivatives. The synthesis and characterization of two further similar imido-complexes but in which the ferrocenyl-phenyl group is part of a more extended unit is described (complexes 5 and 6). The synthesis of a rhenium oxo-complex, fac-oxotrichloro[1,1′-bis(diphenylphosphine)ferrocene]rhenium(V) (3) has also been achieved and 3 has been further derivatized with two different ferrocenylamines to provide rhenium complexes containing two ferrocenyl groups (4 and 7).