Synthesis, crystal structure, and spectroscopic studies of 10-(1-phthalazinylazo)-9-phenanthrol (HL). Complexation of cadmium and zinc chlorides with HL

10-(1-Phthalazinylazo)-9-phenanthrol (HL, I) was synthesized by the reaction between 1-hydrazinophthalazine and 9,10-phenanthrenequinone. The crystal and molecular structures of compound I were determined by X-ray diffraction (XRD). According to XRD, EAS, and 1H and 13C NMR data, a HL molecule in solutions and in crystals exists in the form of quinohydrazone tautomer (b) (s-trans, cis) stabilized by intramolecular N(3)H.O(1) hydrogen bond. The "mobile" H atom is localized at the N(3) atom of the azo group. The phthalazine (A) and phenanthrenequinone (B) moieties of the HL molecule are nearly coplanar. The HL basicity and acidity constants (pKa = 1.90 and pKa = 11.65, respectively) and the formation constants of HL complexes with Zn2+ and Cd2+ and their compositions in solutions were determined. ML2 · DMFA complexes, where M = Zn2+, Cd2+, were synthesized. The coordination mode of the L- ligand with metal atoms was suggested. © 2013 Pleiades Publishing, Ltd.