Radical formation in polymeric nickel complexes with N2O2 Schiff base ligands: An in situ ESR and UV–vis–NIR spectroelectrochemical study

Dmitrieva, Evgenia; Rosenkranz, Marco; Danilova, Julia S.; Смирнова, Е. А.; Карушев, М. П.; Chepurnaya, I. A.; Timonov, A. M.

doi:10.1016/j.electacta.2018.07.131

Cited by 38 publications

(58 citation statements)

References 35 publications

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“…UV‐Vis spectra of the film were recorded during stepwise oxidation in the range between −0.20 and 1.00 V. Several potential‐dependent absorption bands (Figure 7B and C) were found, corresponding to different species in the macromolecule. In the reduced state of the polymer (until 0.3 V, Figure 7A), when the doping level is low, the absolute spectra exhibit several absorption bands (Figure 7B) that are typical for polymeric NiSalen complexes [35] . Upon further oxidation, significant spectral changes were noticed, as seen from the different UV‐Vis spectra (Figure 7C) and normalized absorbance curves (Figure 7D).…”

Section: Resultsmentioning

confidence: 98%

The Fast and the Capacious: A [Ni(Salen)]‐TEMPO Redox‐Conducting Polymer for Organic Batteries

Vereshchagin

Lukyanov

Kulikov

et al. 2020

Batteries & Supercaps

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Redox‐active nitroxyl‐containing polymers are promising candidates as possible replacements for inorganic based energy‐storage materials, due to their high energy density and fast redox kinetics. One challenge towards the implementation of such a system is the insufficient electrical conductivity, impeding the charge collection even with highly conductive additives. Herein, the first implementation of a polymeric bis(salicylideniminato) nickel (NiSalen) conductive backbone as an active charge‐collecting wire is reported. NiSalen simultaneously serves as a charge collector for nitroxyl pendants and supports the redox capacity of the material. This novel polymer exhibits a specific capacity of up to 91.5 mAh g−1, retaining 87 % of its theoretical capacity at 800 C and more than 30 % at as high as 3000 C (66 % capacity retention after 2000 cycles). The properties of the new material upon operation was studied by means of operando electrochemical methods, UV‐Vis, and electron paramagnetic resonance spectroscopy.

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Section: Resultsmentioning

confidence: 98%

The Fast and the Capacious: A [Ni(Salen)]‐TEMPO Redox‐Conducting Polymer for Organic Batteries

Vereshchagin

Lukyanov

Kulikov

et al. 2020

Batteries & Supercaps

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“…Poly-[Ni salen ] films present an interesting case of metallopolymers with metal centers directly imbedded into the conjugated organic network, which prompts possible interactions between nickel centers and organic ligand fragments in different effective redox states. In most cases, the electrochemical oxidation of nickel– salen polymers can be described as a primarily ligand-centered process, which involves the consecutive generation of delocalized radical cations and dications in the conjugated polymer backbone and does not involve the change in the redox state of the metal [ 11 , 12 , 13 ]. At the same time, nickel ions constitute an essential part of charge transfer pathways in these conducting systems as they mediate the electronic coupling between the two phenolates of each [Ni salen ] unit.…”

Section: Introductionmentioning

confidence: 99%

Nickel(II) Complex of N4 Schiff Base Ligand as a Building Block for a Conducting Metallopolymer with Multiple Redox States

2021

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Metal–ligand interactions in monomeric and polymeric transition metal complexes of Schiff base ligands largely define their functional properties and perspective applications. In this study, redox behavior of a nickel(II) N4-anilinosalen complex, [NiAmben] (where H2Amben = N,N′-bis(o-aminobenzylidene)ethylenediamine) was studied by cyclic voltammetry in solvents of different Lewis basicity. A poly-[NiAmben] film electrochemically synthesized from a 1,2-dichloroethane-based electrolyte was investigated by a combination of cyclic voltammetry, electrochemical quartz crystal microbalance, in situ UV-Vis spectroelectrochemistry, and in situ conductance measurements between −0.9 and 1.3 V vs. Ag/Ag+. The polymer displayed multistep redox processes involving reversible transfer of the total of ca. 1.6 electrons per repeat unit, electrical conductivity over a wide potential range, and multiple color changes in correlation with electrochemical processes. Performance advantages of poly-[NiAmben] over its nickel(II) N2O2 Schiff base analogue were identified and related to the increased number of accessible redox states in the polymer due to the higher extent of electronic communication between metal ions and ligand segments in the nickel(II) N4-anilinosalen system. The obtained results suggest that electrosynthesized poly-[NiAmben] films may be viable candidates for energy storage and saving applications.

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“…Among various known polymeric Salen-type complexes, Cobalt Salen-type polymers are of special interest because they exhibit both metal-and ligand-based redox activity [8][9][10][11]. This contrasts with more well-studied Ni-and Cu-based Salen-type polymers that are converted from neutral to oxidized state via ligand-based redox reactions involving consecutive formation of cation radicals and di-cations in biphenyl fragments, while metal centers act as structuring and redox-mediating units [12][13][14]. Efficient metal-centered redox reactions in Cobalt Salen-type metallopolymers enhance their capacitive properties [9,15] and make them useful in electrocatalytic [11] and sensing applications [16].…”

Section: Introductionmentioning

confidence: 99%

A Novel Cobalt Metallopolymer with Redox-Matched Conjugated Organic Backbone via Electropolymerization of a Readily Available N4 Cobalt Complex

Карушев

2021

Polymers

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Fast and reversible cobalt-centered redox reactions in metallopolymers are the key to using these materials in energy storage, electrocatalytic, and sensing applications. Metal-centered electrochemical activity can be enhanced via redox matching of the conjugated organic backbone and cobalt centers. In this study, we present a novel approach to redox matching via modification of the cobalt coordination site: a conductive electrochemically active polymer was electro-synthesized from [Co(Amben)] complex (Amben = N,N′-bis(o-aminobenzylidene)ethylenediamine) for the first time. The poly-[Co(Amben)] films were investigated by cyclic voltammetry, electrochemical quartz crystal microbalance (EQCM), in situ UV-vis-NIR spectroelectrochemistry, and in situ conductance measurements between −0.9 and 1.3 V vs. Ag/Ag+. The polymer displayed multistep redox processes involving reversible transfer of the total of 1.25 electrons per repeat unit. The findings indicate consecutive formation of three redox states during reversible electrochemical oxidation of the polymer film, which were identified as benzidine radical cations, Co(III) ions, and benzidine di-cations. The Co(II)/Co(III) redox switching is retained in the thick polymer films because it occurs at potentials of high polymer conductivity due to the optimum redox matching of the Co(II)/Co(III) redox pair with the organic conjugated backbone. It makes poly-[Co(Amben)] suitable for various practical applications based on cobalt-mediated redox reactions.

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Radical formation in polymeric nickel complexes with N2O2 Schiff base ligands: An in situ ESR and UV–vis–NIR spectroelectrochemical study

Cited by 38 publications

References 35 publications

The Fast and the Capacious: A [Ni(Salen)]‐TEMPO Redox‐Conducting Polymer for Organic Batteries

The Fast and the Capacious: A [Ni(Salen)]‐TEMPO Redox‐Conducting Polymer for Organic Batteries

Nickel(II) Complex of N4 Schiff Base Ligand as a Building Block for a Conducting Metallopolymer with Multiple Redox States

A Novel Cobalt Metallopolymer with Redox-Matched Conjugated Organic Backbone via Electropolymerization of a Readily Available N4 Cobalt Complex

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