Rhodium(III) pentamethyl cyclopentadienyl complexes incorporating 1-(4-cyanophenyl)-imidazole: role of solvent in ligand substitution reactions

Reaction of the dimeric rhodium complex [{(η5-C5Me5)Rh(μ-Cl)Cl}2] with an excess of 1-(4-cyanophenyl)-imidazole in dichloromethane afforded neutral mononuclear complex [(η5-C5Me5)RhCl2(CPI)] (CPI = 1-(4-cyanophenyl)-imidazole) 1. The complex 1 reacted with EPh3 (E = P, As, Sb) and N–N donor bases 2,2′-bipyridine and 1,10-phenanthroline in different solvents to give substitution products wherein, nature of the product was governed by polarity of the solvents employed in the reaction. Resulting complexes have been characterized by elemental analyses, spectral (FAB-MS, IR, 1H,13C, 31P NMR, UV–Vis, Emission) and electrochemical studies. Coordination of CPI through imidazole nitrogen and the presence of pendant nitrile group have been supported by spectral studies.