Thermal and protonation-induced electron transfer coupled spin transition in a discrete [Fe₂Co₃] Prussian blue analogue

Multi-stimuli responsive switchable molecules have garnered interest for their potential applications in the field of magnetic materials. However, the persistent challenge lies in isolating these properties within the same material. Herein, we report a discrete [Fe₂Co₃] pentanuclear cyanide bridged complex, [Co(L)₂]₃[Fe(CN)₆]₂·20H₂O, (1) (L = (Z)-N′-(4-(trifluoromethyl)phenyl)picolinimidamide) which undergoes electron transfer coupled spin transition (ETCST) from [Fe^II₂Co^II_HSCo^III₂] to [Fe^III₂Co^II₃] configurations through thermal activation and upon protonation.