Nickel Salicylideniminato 1D MOFs via Electrochemical Polymerization

Abstract

Polymers derived from nickel complexes of salicylaldimines are extensively studied due to their electrochemical, catalytic, and sensing properties. However, almost all studies are devoted to the polymers obtained from tetradentate bis(salicylidenaldiminato) complexes, in which the aromatic rings are bound via an imine bridge. Herein, we report a first systematic study focused on the polymerization of salicylaldimine nickel complexes without a bridge between the imine fragments. As a result, an impact of the ligand structure on the polymerization ability of the complexes and electrochemical behavior of the polymers obtained thereof was discovered and quantified. An observed phenomenon was rationalized both computationally and experimentally, involving the electrochemical and spectroelectrochemical techniques.

Harmonizing Energies: The Interplay Between a Nonplanar SalEn‐Type Molecule and a TEMPO Moiety in a New Hybrid Energy‐Storing Redox‐Conducting Polymer

“…[ 34 ] The analysis of mass variation during deposition indicates the oxidative coupling of the SalEn fragments in the 0.3–0.7 V potential range producing the pNiMeSalP(OH)En polymer. [ 35–39 ] In this case the mass‐potential curve of the first cathodic wave has a two‐step shape with the first mass increase at 0.4–0.7 V, and the second one at 0.2–0.4 V (cathodic direction). Most likely, the high positive charge of the polymer unit in the thin film due to the bipolaron formation at 0.46 V and emergence of a layer of charge compensating ions solvated by electrolyte molecules can inhibit the free growth of the polymer chain.…”

Nickel(II) Cluster-Based Pillar-Layered Metal–Organic Frameworks for High-Performance Supercapacitors

“…The low electrical conductivities and poor electrochemical stabilities of the nonconductive 3D MOFs hindered their applications in supercapacitors. − Energy storage performance can be improved by increasing the specific surface areas of the MOFs, improving the conductivities of the MOFs, and increasing the number of heteroatoms on ligand molecules. Hence, most of the ligands used in conductive MOFs are heterocyclic macroconjugated ligands containing multiple nitrogen atoms. − Nonconductive MOFs can also be assembled with other materials to fabricate MOF composites that can provide higher electrical conductivities and more efficient electrochemical reactivities to mitigate their shortcomings. − Moreover, due to the characteristics of the ligands, conductive 2D MOFs can rarely form single-crystal structures; only a few 3D MOFs with single-crystal structures have been reported as electrode materials. − As a result, their energy storage mechanisms and design of high-performance conductive MOFs have not been extensively studied. − …”