Advances in spin crossover-fluorescence bifunctional complexes

This paper reviews the recent progress in the research of spin crossover-fluorescence bifunctional complexes. The spin crossover property of transition metals provides a core foundation for the design of intelligent functional materials, and their ability to undergo high-spin/low-spin state transitions under external stimuli lays the groundwork for the exploration of their applications in magnetic storage, sensors, and other fields. The bifunctional materials formed by coupling with fluorescence properties can intuitively reflect spin state changes through fluorescent signals, which have become a current research hotspot. At present, the construction of bifunctional materials mainly adopts the single-component strategy, which has both performance tunability and structural resolvability. This paper elaborates on the classification according to structural dimensions: in zero-dimensional complexes, pyridine-azole ligands and amide derivative ligands are the research cores; as for coordination polymers, Hofmann-type, fluorescent ligand-bridged ligand type, and perovskite-type structures show unique structure-property correlations. The field has made remarkable achievements in mechanism exploration, ligand design, and structural optimization, but still faces problems such as the need to deepen the coupling mechanism, practical application bottlenecks, and insufficient multifunctional expansion. These provide a direction for future research.