Rhodium complexes containing bidentate imidazolyl ligands: synthesis and structure

The preparation and characterisation of square planar cationic rhodium(I) d icarbonyl complexes ([Rh((mim)(2)C=O)(CO)(2)]+BPh4-] (1), {[Rh((mim)(2)CH2) (CO)(2)]+BPh4-} (2) and {[Rh((mBnzim)(2)CH2)(CO)(2)]+BPh4-} (3) [mim = N-me thylimidazol-2-yl, mBnzim = N-methylbenzimidazol-2-yl] is reported. The car bonyl ligands in 2 and 3 are readily exchanged for triphenylphosphine to fo rm{[Rh((mim)(2)CH2)(PPh3)(2)]+BPh4-} (7) and {[Rh((mBnzim)(2)CH2)(PPh3)(2)] +BPh4-} (8). Complexes 2 and 3 were characterised by multinuclear NMR spect roscopy as well as by X-ray crystallography. Structural characterisation by X-ray analysis confirmed that complexes 2 and 3 are essentially square pla nar. (C) 1999 Elsevier Science S.A. All rights reserved.