Synthesis, spectroscopic, antimicrobial, XRD, fluorescence of new Ni(II), Cd(II), Hg(II) and U(VI) complexes with 1-(2-furylmethylene)-N-(3-phenylallylidene)methanamine Schiff base

The 1:1 condensation of 2-furfurylamine and cinnamaldehyde under template condition gives the Schiff base ligand 1-(2-furylmethylene)-N-(3-phenylallylidene)methanamine (L). The reaction of the ligand with Ni(II), Cd(II), Hg(II) and U(VI) ions gives a series of novel complexes formulated as [NiLCl(H2O)]Cl·1½H2O, [CdL2(H2O)2]·2NO3·½H2O, [HgL2Cl2] and [UO2L3]·2NO3·H2O. The stoichiometry of the complexes was 1:1 for Ni(II), 1:2 for both Cd(II) and Hg(II) and 1:3 (M:L) for U(VI) complexes. The molar conductance of the complexes lies in the range of 135-250 Ω−1mol−1cm2 indicating their electrolytic behavior except Hg(II) complex. Electronic spectra and magnetic moments suggested varieties of geometries around the central metal atoms. The emission spectra of these complexes indicate the luminescence characteristics of the complexes. The X-ray diffraction (XRD) patterns of Schiff base and its complexes were investigated in powder forms. Thermodynamic parameters were computed from the thermal data using Coats and Redfern method. Structural optimization of the ligand and its Ni(II), Cd(II) and Hg(II) complexes was computed using the density functional theory (DFT), where the B3LYP functional was employed. The synthesized complexes exhibited higher antimicrobial activity than its free Schiff base ligand.