Mixed Complexes of Cupric Ion with Bi- and Tridentate Ligands in Aqueous Solution

The formation of complexes of cupric ion with 2,2'-bipyridine and iminodiacetic or dipicolinic acids, or with 2,2',2''-terpyridine and malonic, succinic, phthalic, and cyclopropane-1,1-dicarboxylic acids was studied at 25° in 0.1 M NaClO4 by potentiometric measurements. All the systems, except Cu terpyridine with the cycloalkane deriv, also form protonated species. By comparison with some mixed complexes previously investigated, the no. of coordinated donor atoms are suggested. Some considerations on the stability of these mixed complexes are reported.