Electrochemical synthesis and crystal structure of iron(II), cobalt(II), nickel(II) and copper(II) complexes of dianionic tetradentate N4 Schiff base ligand

Modulating the DNA cleavage ability of copper(ii) Schiff bases through ternary complex formation

Copper(ii) Schiff-bases were electrochemically synthesized and characterized. The presence of co-ligands such as 2,2′-bpy or phen in the metal coordination environment increases the DNA cleavage efficiency.

Coordination chemistry, thermodynamics and DFT calculations of copper(II) NNOS Schiff base complexes

Synthesis, magnetic and spectroscopy techniques are described for five copper(II) containing tetradentate Schiff bases are synthesized from methyl-2-(N-2'-aminoethane), (1-methyl-2'-aminoethane), (3-aminopropylamino)cyclopentenedithiocarboxylate. Molar conductance and infrared spectral evidences indicate that the complexes are four-coordinate in which the Schiff bases are coordinated as NNOS ligands. Room temperature μeff values for the complexes are 1.71-1.80B.M. corresponding to one unpaired electron respectively. The formation constants and free energies were measured spectrophotometrically, at constant ionic strength 0.1M (NaClO4), at 25˚C in DMF solvent. Also, the DFT calculations were carried out to determine the structural and the geometrical properties of the complexes. The DFT results are further supported by the experimental formation constants of these complexes.

{4-Chloro-2-[(2-hy-droxy-eth-yl)imino-meth-yl]phenolato}{4-chloro-2-[(2-oxido-eth-yl)imino-meth-yl]phenolato}cobalt(III)

In the title mononuclear cobalt(III) compound, [Co(C₉H₈ClNO₂)(C₉H₉ClNO₂)], the Co^II atom is six-coordinated by two imine N atoms, two phenolate O atoms, and one hy­droxy and one oxide O atom from two Schiff base ligands, forming an octa­hedral geometry. In the crystal structure, adjacent mol­ecules are linked through inter­molecular O—H⋯O hydrogen bonds. The 2-oxidoethyl group is disordered over two positions in a 0.638 (3):0.362 (3) ratio.