Specificity of complex formation of benzoin (phthalazin-1-yl)hydrazone with copper(II) and nickel(II): Physicochemical study and quantum-chemical simulation

Benzoin (phthalazin-1-yl)hydrazone and its complexes with copper(I), copper(II), and nickel(II) were synthesized. Acid-base properties of benzoin (phthalazin-1-yl)hydrazone were studied, and its ionization constants and energies of possible conformers were calculated by quantum-chemical methods. The structure of the isolated complexes was determined on the basis of their elemental compositions, IR spectra, and data of thermogravimetric, conductometric, and magnetochemical measurements. Copper(II) acetate with benzoin (phthalazin-1-yl)hydrazone forms dinuclear complex, nickel(II) acetate and chloride produce mononuclear octahedral complexes, and copper(II) halides give rise to copper(I) complexes with the oxidized hydrazone.