Experimental evidence of the acidic character of lanthanide ions in protic solvents

Addition of Gd(NO3)3·6H2O to a methanol suspension of a self-assembled (CuL·H2O)n imidazole complex yielded a protonated imidazole complex [Cu(HL)H2O]+ which has been characterized by a structural determination. Such a behavior evidences the acidic character of lanthanides ions in protic solvents.