A novel reaction producing the rhodium(I) complexes with π-coordinated tetraphenylborate anion, (π-PhBPh3)−. X-ray study of [Rh(PPh3)2(π-PhBPh3)]

Treating the complexes [Rh(TFA)(PPh3)2], [Rh(HFA)(PPh3)2], and [Rh(TFA)(Cod)] (TFA – trifluoroacetylacetonate, HFA – hexafluoroacetylacetonate, Cod – 1,5 cyclooctadiene) with an excess of NaBPh4 in acetonitrile yields the rhodium(I) complexes with coordinated [BPh4]− anion, [Rh(PPh3)2(π-PhBPh3)] · 2MeCN (I) and [Rh(Cod)(π-PhBPh3)] (II). The reactions present a new example of β-diketonate ligand replacement. The 1H, 31P, and 11B NMR spectra of I and II are discussed. [Rh(PPh3)2(π-PhBPh3)] has been characterized by single crystal X-ray analysis.