Complexation of 2,3-dihydroxyquinaline with some bivalent d metals. Crystal and molecular structures of 2,3-dihydroxyquinoline

The reactions of Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Cd with 2,3-dihydroxyquinoline (H(2)L) were used to synthesize and identify the complexes M(HL)(2) center dot 2H(2)O (M = Mn, Ni, Cu), Fe(HL)OH center dot 2H(2)O, Co(HL)OH center dot H(2)O, Cd(H(2)L)Cl(2), where H(2)L participates in the coordination in the monoanionic or neutral forms with the formation of the chelate cycles. Single crystal was isolated and the crystal structure of H(2)L was determined. The spectral characteristics of a neutral and anionic form of the ligand were measured, and its complexation with MCl(2) was studied in the ethanol solutions. The acidity constant of H(2)L and the formation constants of the complexes in solutions were calculated.