Novel synthesis of 2-imino-2H-chromene-3-carboximide metal complexes

Abstract

New metal complexes derived from the reaction of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) chlorides with the 2-imino-2H-chromene-3-carboximide organic ligand (HL) have been synthesized. The resulting complexes have been characterized by elemental analysis (CHN), IR, magnetic susceptibility, mass spectra, 1HNMR, UV–Vis, ESR, thermal analysis (TG, DTG and DTA) and molar conductance measurements. All the complexes are 1:2 and 1:3 electrolytes according to their molar conductivities. The microanalyses and spectroscopic data showed that the metal(II)/(III) ions in these complexes achieved coordination number of six and hence have octahedral geometrical structures. This is attained by bonding to the bidentate ligand via its two amino nitrogen atoms and two imine nitrogen atoms, and two monodentate aquo groups via its oxygen atoms. The results showed that the ligand acts as neutral bidentate coordinating via amino and NH nitrogens without displacement of hydrogen. The antimicrobial activities of the chromene ligand and its complexes have been tested against a number of pathogenic bacteria and fungi to assess their inhibiting potential. Antimicrobial studies indicate that these complexes exhibit better activity than the chromene ligand.