Tetrazoles as ligands in Fe(ii) spin crossover compounds: from rational ligand design to multifunctional materials

Abstract

Spin crossover (SCO) compounds are bistable magnetic materials that can be reversibly switched between high-spin and low-spin states by external stimuli, making them promising candidates for applications in sensors, switches, data storage, and display technologies. Iron(ii) tetrazole complexes represent a versatile class of compounds that serve both as model systems for investigating structure–property relationships in SCO materials and as robust platforms for the development of multifunctional materials. This review provides a comprehensive overview of 1-, 2-, and 5-substituted Fe(ii) tetrazole SCO complexes. Design principles governing mononuclear as well as one-, two-, and three-dimensional coordination architectures are discussed, and trends linking structural features to magnetic properties are critically evaluated. In addition, examples of application-oriented research are highlighted.