Synthesis and structure of 3-{[aryl (hetaryl)amino]methylene}chromane-2,4-diones and their metal complexes

3-{[Aryl(hetaryl)amino]methylene}chromane-2,4-diones (HL) were synthesized and used for chemical and electrochemical synthesis of Cu(II), Ni(II), and Co(II) complexes of the general formula ML2, as well as the ZnLOOCCH3 complex. The structure of the complexes was studied by IR, 1Н NMR, and X-ray absorption spectroscopy. Density functional theory (DFT) calculations showed that the energetically most favored form of compounds HL is an aminoketone tautomeric form. The crystal structure of the solvate of bis-{3-[(4-methylanilinato)methylene]chromane-2,4-dionato}copper(II) with two DMF molecules was determined by X-ray diffraction analysis.