ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Recent trends in cobalt coordination chemistry: from design to applications

Vivek Sharma, Ramamohana Reddy Maddike, Rajasekhar V. S. R. Pullabhotla, and Vinod

Department of Chemistry, GLA University, Mathura, India

E-mail: vkviitr@gmail.com

Received: 28 December 2025  Accepted: 14 April 2026

Abstract:

Cobalt coordination chemistry continues to attract considerable attention due to the metal’s accessible oxidation states and flexible electronic structure, which enable precise modulation of its redox behaviour. These features underpin its use in catalysis, energy-related processes, sensing, and biologically relevant systems. This review critically examines recent developments with an emphasis on the relationship between ligand architecture and electrochemical response. The discussion is centred on key classes of cobalt complexes, including metal phthalocyanines, porphyrin-derived systems, pyridine-based macrocyclic frameworks, and ferrocenyl chalcone–containing complexes. Particular focus is placed on Co–N₄ coordination environments, the distinction between metal- and ligand-centred redox processes, and the influence of axial ligation on electronic structure and reactivity. Comparisons across these ligand platforms reveal how subtle structural variations govern redox potentials, reversibility, and functional performance. Attention is also given to the experimental and theoretical approaches commonly employed to probe these systems, alongside the limitations that often complicate interpretation of electrochemical data. By consolidating findings from discrete molecular complexes as well as immobilized and hybrid systems, this review identifies inconsistencies in mechanistic understanding and outlines directions for more rational design of cobalt-based redox-active materials.

Keywords: Cobalt complexes; Electrocatalysis; Phthalocyanine; Redox activity; Tetraaza macrocycles

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-04921-3

Chemical Papers 80 (10) 11261–11284 (2026)