Borate complexes in solution. Part-1. Equilibrium study on the mixed ligand complex formation of copper(II) with boric acid and (N,N) bidentate ligands

Combined pH-metric and spectrophotometric investigations on the mixed ligand complex formation equilibria of Cu^II with boric acid and (N,N) bidentate ligands, viz. bipyridine, 1,10-phenanthroHnc and ethylenediamminc (hereafter, L) in 1:1:1 and 2 : 2 : I Cu^II : L : H3BO3 molar ratios reveal the formation of mixed ligand complexes of the types Cu(L)(H2BO4) and Cu2(L)2(B0)4 • Formation constants of the complexes in aqueous solution at 25° and at a constant ionic strength, I= 0.1 M(NaNO3) are determined and the complex formation equilibria elucidated on the basis of spaciation curves. Composition of the mixed ligand complexes formed in the solution has been confirmed by mole ratio method at I= 0.5 M (NaN03).