Electrocatalytic Properties of Ni(II) Schiff Base Complex Polymer Films

Modification of Glassy Carbon Electrodes with Complexes of Manganese(II) with Some Phenanthroline Derivatives Immobilized in Nafion Layer

Manganese(II) complexes with phenanthroline derivatives modified with different substituents were synthesized and incorporated into Nafion layers covering the surfaces of glassy carbon electrodes and were studied electrochemically. Formal potentials and apparent diffusion coefficients were calculated and discussed. The suitability for electrocatalytic oxidation of ascorbic acid and glycolic acid was examined. The surfaces of modified electrodes were characterized using atomic force microscopy.

Synthesis, Structural Characterization of a New Ni(II) Complex and Its Catalytic Activity for Oxidation of Benzyl Alcohol

In ethanol-water (v:v = 1:1), a new Ni(II) complex, [Ni(L)2(H2O)2] (1) (HL = 6-phenylpyridine-2-carboxylic acid) was synthesized using 6-phenylpyridine-2-carboxylic acid, NaOH and Ni(CH3COO)2.4H2O. The structure of complex 1 has been determined by elemental analysis and single crystal X-ray diffraction. The single crystal analysis shows that complex 1 contains one Ni(II) ion, two L ligands and  two coordinated water molecules. In 1, the Ni(II) ion is six-coordinated to two O atoms and two N atoms from L ligands and two O atoms from coordinated water molecules, respectively, which form a distorted octahedral coordination geometry. The whole unit of complex 1 is interconnected to each other through intermolecular N−H•••O hydrogen bonds involving oxygen atom of coordinated water molecule and the oxygen atoms of  L ligand to form 1D molecular architecture. The catalytic activity of complex 1 for oxidation of benzyl alcohol with O2 was investigated. The complex 1 shows good catalytic performance for the oxidation of benzyl alcohol, the benzyl alcohol conversion, benzaldehyde selectivity, and benzaldehyde yield were 49.1%, 92.0%, and 45.2%, respectively, at 90 °C under 0.7 Mpa O2 for 2 h. Moreover, complex 1 could be recovered easily by centrifugation and used repetitively for at least four times. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

The Influence of Electrolyte Type on Kinetics of Redox Processes in the Polymer Films of Ni(II) Salen-Type Complexes

Electrodes modified with polymers derived from the complexes [Ni(salcn)], [Ni(salcn(Me))] and [Ni(salcn(Bu))] were obtained in order to study the kinetics of electrode processes occurring in polymer films, depending on the thickness of the films, the type of electrolyte and the solvent. FTIR and EQCM methods were used to determine the type of mass transported into polymer films during anode processes and the number of moles of ions and solvent. The rate of charge transport through films was determined by the cyclic voltammetry method, by the quantity cD1/2. It was shown that the charge transport was determined by the transport of anions. The kinetics were most efficient for poly[Ni(salcn(Bu))] modified electrodes, obtained from TBAPF6 and working in TBAClO4 and TBABF4. It was also shown that a solvent with a higher DN value and lower viscosity (MeCN) facilitated the transport of the charge through polymer films.