Preparations and reactions of tris(pentafluorophenyl)phosphine, phenylbis(pentafluorophenyl)phosphine, and diphenylpentafluorophenylphosphine complexes of rhodium

Abstract

The reaction of (C₆F₅)₃P with RhCl₃,xH₂O gives the dark green complex [(C₆F₅)₃P]₄Rh₂Cl₂; similar chloro- and bromo-compounds are obtained with (C₆F₅)₂PhP and (C₆F₅)Ph₂P. Carbon monoxide readily cleaves the halogen bridge present in these complexes to give trans-[C₆F₅)_x(Ph)_3–xP]₂RhCOCl (x= 1, 2, or 3). The reactions of the tris(pentafluorophenyl)phosphinerhodium complexes with cyclo-octa-1,5-diene, triphenylphosphine, and triphenylphosphite show that these ligands readily displace (C₆F₅)₃P. Treatment of the rhodium(I) complexes of (C₆F₅)₃P with chlorine gives ill-defined rhodium(III) materials.

[(C₆F₅)₃P]₄Rh₂Cl₂ abstracts carbon monoxide from aldehydes and from ethanol–chloroform mixtures yielding trans-[(C₆F₅)₃P]₂RhCOCl.

The ¹⁹F n.m.r. data are consistent with the presence of d_π→d_π bonds between the rhodium and phosphorus.