Rhodium complexes containing bidentate imidazolyl ligands: synthesis and structure

Abstract

The preparation and characterisation of square planar cationic rhodium(I) dicarbonyl complexes {[Rh((mim) 2CO)(CO) 2] +BPh 4 −] ( 1),{[Rh((mim) 2CH 2)(CO) 2] +BPh 4 −} ( 2) and{[Rh((mBnzim) 2CH 2)(CO) 2] +BPh 4 −} ( 3) [mim= N-methylimidazol-2-yl, mBnzim= N-methylbenzimidazol-2-yl] is reported. The carbonyl ligands in 2 and 3 are readily exchanged for triphenylphosphine to form{[Rh((mim) 2CH 2)(PPh 3) 2] +BPh 4 −} ( 7) and {[Rh((mBnzim) 2CH 2)(PPh 3) 2] +BPh 4 −} ( 8). Complexes 2 and 3 were characterised by multinuclear NMR spectroscopy as well as by X-ray crystallography. Structural characterisation by X-ray analysis confirmed that complexes 2 and 3 are essentially square planar.