In this talk, I’ll present our recent work on developing switchable molecular chain composites that respond dynamically to external stimuli such as pressure and temperature. These materials are based on coordination compounds that undergo metal-to-metal electron transfer (MMCT) — a process involving a change of oxidation state at metal centres, leading to significant and reversible changes in their electronic and magnetic properties. To make these systems more robust and versatile, we embedded MMCT-active molecular chains, such as the compound {NH₄[Ni(cyclam)][Fe(CN)₆]·5H₂O}ₙ, into organic polymer matrices like poly(ε-caprolactone) (PCL) and poly(2-vinylpyridine-co-styrene) (P2VP-PS). Using electrospinning and drop-casting techniques, we transformed the brittle crystalline materials into flexible, processable composites that retain their switchable behaviour. By probing these composites with X-ray absorption spectroscopy and complementary methods, we were able to track the pressure- and temperature-induced electron transfer between the metal centres. These transitions are fully reversible, demonstrating the potential of these materials for multifunctional sensing applications—for example, as temperature or pressure sensors.
