Isolation and crystal structure of [Rh(PPh3)3(MeCN)][BF4], acetonitriletris(triphenylphosphine)rhodium(I) tetrafluoroborate

Abstract

The salt [Rh(PPh₃)₃(MeCN)][BF₄] has been isolated as one product of the reaction between [Rh₂(O₂CMe)₂(MeCN)₆][BF₄]₂ and PPh₃(1 : 4), and its structure determined by single-crystal X-ray diffraction. The cation possesses an essentially square-planar co-ordination geometry, with the length of the Rh–P bond trans to the acetonitrile ligand [2.261(3)Å] significantly shorter than those of the mutually trans PPh₃ groups [2.311(3) and 2.367(3)Å]. Proton, ¹³C, ¹⁹F, and ³¹P n.m.r. spectra have been recorded for this compound and, with reference to these properties and the crystallographic data, the relationship of [Rh(PPh₃)₃(MeCN)][BF₄] to the hydrogenation catalyst precursor [Rh(PPh₃)₃Cl] and to a material previously reported as Rh(PPh₃)₃BF₄ is discussed.