Synthesis and structure elucidation of a novel mixed-ligand Cu(II) Schiff base complex and its catalytic performance for the synthesis of 2-amino-4H-pyrans and tetrahydro-4H-chromenes

Abstract

A novel quinazoline Schiff base ligand, 3-((5-bromo-2-hydroxy-3-methoxybenzylidene)amino)-2-methylquinazolin-4(3H)-one [HL] and its mixed-ligand Cu(II) complex [Cu(L′)(Imi)], [L′] = 2-acetamido-N-(5-bromo-2-oxidobenzylidene) benzohydrazonate, [Imi] = imidazole, were synthesized and characterized by elemental analysis, FT-IR and UV–Vis spectrometry and conductivity measurements. The structure of [HL] and its Cu(II) complex have been accomplished by single crystal X-ray diffraction. The Hirshfeld surface analysis has also been performed to evaluate intermolecular interactions. All experimental results confirmed that in this complex Cu(II) central atom is coordinated by the donor atoms of deprotonated Schiff base ligand and nitrogen of imidazole. Furthermore, the catalytic activities of this complex have been investigated on the electrophilic reaction of malononitrile along with aldehydes, ethyl acetoacetate and dimedone in ethanol solution in order to obtain 2-amino-4H-pyrans and tetrahydro-4H-chromenes, respectively.