TY - JOUR

T1 - Metal-centered redox activity in a polymeric Cobalt(II) complex of a sterically hindered salen type ligand

AU - Novozhilova, Maria

AU - Anischenko, Dmitry

AU - Chepurnaya, Irina

AU - Dmitrieva, Evgenia

AU - Malev, Valery

AU - Timonov, Alexander

AU - Karushev, Mikhail

N1 - Funding Information: This work was partially supported by the Russian Foundation for Basic Research [grant number 18-03-00545 ]. Publisher Copyright: © 2020 Elsevier Ltd Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

PY - 2020/9/1

Y1 - 2020/9/1

N2 - This paper reports on the peculiarities of the metal-centered redox activity in a polymeric cobalt(II) complex of a sterically hindered tetradentate N2O2 Schiff base (salen type) ligand. A Co(III)/Co(II) redox process in the polymer film during its formation on the electrode and subsequent electrochemical switching in a monomer-free electrolyte has been characterized by cyclic voltammetry, electrochemical quartz crystal microbalance, and electrochemical impedance spectroscopy. The obtained results indicate that cobalt ions in the polymer can effectively function as independent redox sites. The metal-centered redox activity largely governed by the unique features of a sterically hindered salen type ligand is time-dependent and sensitive to the presence of coordinating species in the electrolyte. In relatively fast potentiodynamic scans, the Co(III)/Co(II) redox switching in an acetonitrile solution exhibits a high degree of chemical and electrochemical reversibility and stability and can be considered as a quasi-equilibrium process. A novel analytical solution for modeling quasi-equilibrium voltammetric curves accounting for the existence of short-range interactions within redox polymer films is proposed and used to estimate the attraction constant in the cobalt-salen type polymer. The study findings contribute to a better understanding of the prospects of using electrodes modified with the investigated polymeric complex in energy storage and catalytic applications.

AB - This paper reports on the peculiarities of the metal-centered redox activity in a polymeric cobalt(II) complex of a sterically hindered tetradentate N2O2 Schiff base (salen type) ligand. A Co(III)/Co(II) redox process in the polymer film during its formation on the electrode and subsequent electrochemical switching in a monomer-free electrolyte has been characterized by cyclic voltammetry, electrochemical quartz crystal microbalance, and electrochemical impedance spectroscopy. The obtained results indicate that cobalt ions in the polymer can effectively function as independent redox sites. The metal-centered redox activity largely governed by the unique features of a sterically hindered salen type ligand is time-dependent and sensitive to the presence of coordinating species in the electrolyte. In relatively fast potentiodynamic scans, the Co(III)/Co(II) redox switching in an acetonitrile solution exhibits a high degree of chemical and electrochemical reversibility and stability and can be considered as a quasi-equilibrium process. A novel analytical solution for modeling quasi-equilibrium voltammetric curves accounting for the existence of short-range interactions within redox polymer films is proposed and used to estimate the attraction constant in the cobalt-salen type polymer. The study findings contribute to a better understanding of the prospects of using electrodes modified with the investigated polymeric complex in energy storage and catalytic applications.

KW - Electrochemical stability

KW - Polymeric cobalt complex

KW - Salen ligand

KW - Schiff base

KW - Short range interactions

KW - NICKEL-COMPLEXES

KW - CHARGE-CARRIERS

KW - PERFORMANCE

KW - ELECTRODES

KW - COMPOSITE

KW - METALLOPOLYMER

KW - REDUCTION

KW - INJECTION

KW - NANOCOMPOSITE

KW - SCHIFF-BASE LIGANDS

UR - http://www.scopus.com/inward/record.url?scp=85085734557&partnerID=8YFLogxK

U2 - 10.1016/j.electacta.2020.136496

DO - 10.1016/j.electacta.2020.136496

M3 - Article

AN - SCOPUS:85085734557

VL - 353

JO - Electrochimica Acta

JF - Electrochimica Acta

SN - 0013-4686

M1 - 136496

ER -