Syntheses, characterizations and structures of NO donor Schiff base ligands and nickel(II) and copper(II) complexes (original) (raw)
Related papers
SYNTHESIS AND CHARACTERIZATION OF SOME NICKEL (II) COMPLEXES VIA BIOACTIVE SCHIFF BASES
A large number of Schiff bases and their complexes have been studied for their interesting and important properties. E.g. their ability to reversibly bind oxygen, catalytic activity in hydrogenation of olefins and transfer of amino groups, photocromic properties and complexing ability towards some toxic metals. The high affinity for the chelation of the Schiff bases towards the transition metal ions is utilized in preparing their solid complexes. Here we have synthesized some Complexes of Schiff base with First series transition Metal Ni (II) and characterized by elemental analysis, molar conductance, 1H NMR, and IR studies.
This article reports the synthesis and characterization of four Ni(II) Schiff base complexes, [Ni(L) (H2O)], where H2L = N-(dehydroacetic acid)-thiosemicarbazide (H2dha-tsc), N-(dehydroacetic acid)- 4-methyl-3-thiosemicarbazide (H2dha-mtsc), N-(dehydroacetic acid)-4-phenyl-3-thiosemicarbazide (H2dha-ptsc), or N-(dehydroacetic acid)-4-phenylsemicarbazide (H2dha-psc). The nature of bonding and stereochemistry of these complexes have been deduced from elemental analysis, infrared and electronic spectral studies, molar conductance, magnetic measurements, mass spectrometry, thermogravimetric analysis, 1H NMR and 13C NMR studies, and cyclic voltammetry. The stabilities of the complexes were determined in both solid state and solution. Molecular geometry optimizations and vibrational frequency calculations were performed with Gaussian 09 software package using density functional theory (DFT) with B3LYP/6-311G for a ligand (dha-ptscH2) and B3LYP/LANL2DZ combination for [Ni(dha-mtsc)(H2O)]. Based on the combined experimental and theoretical studies, square planar geometry has been proposed for the Ni(II) complexes. The Schiff base ligands and their metal complexes were screened for antibacterial activities against gram-negative bacteria (Escherichia coli ) at different concentrations to get their minimum inhibition concentration values. The bactericidal activity was enhanced in metal complexes as compared to free ligands.