Perchlorate and difluorophosphate coordination derivatives of rhenium carbonyl

Abstract

The complexes Re(CO)₅ClO₄, Re(CO)₅PO₂F₂, L₂(CO)₃Re(OClO₃) and L₂(CO)₃Re(PO₂F₂), where L₂ = 2,2?-bipyridyl (bpy), have been synthesized by bromide abstraction reactions from the respective rhenium carbonyl bromide precursors. The complexes were characterized by infrared and mass spectroscopy. The crystal structure of (bpy)(CO)₃Re(PO₂F₂) has been determined from X-ray diffraction data by the heavy-atom technique. The crystals are triclinic, space group Pī with a 8.620(3), b 15.912(5), c 6.466(3) Ǻ, α 102.08(8), β 83.29(8), γ 95.08(4) and Z 2. The structure has been refined by full-matrix least-squares from 2829 reflections to R = 0.084, R_w = 0.088. The coordination geometry about rhenium is that of a distorted octahedron. Difluorophosphate coordinates to the metal centre by one of its oxygen atoms. Formation of the difluorophosphate by hydrolysis of hexafluorophosphate was shown by ³¹P n.m.r. spectra.