High Spin to Low Spin Relaxation Regime Change in a Multistep 3D Spin‐Crossover Material

The paper reports the study of the photoinduced high spin (HS) state lifetime in a multistep spin crossover compound. Despite the pronounced three‐step transition of the [Fe(dpsme)Pt(CN)4]·2/3dpsme·xEtOH·yH2O {dpsme = 4,4′‐di(pyridylthio)methane; EtOH = ethanol} 3D compound, neither the T(LIESST) nor the relaxation kinetics exhibits stepwise features. From the detailed investigation (experiments and simulations) of these relaxations and the observation of the light‐induced thermal hysteresis, a phase transition around 58 K is suspected. A clear regime change, hiding a probable phase transition, is observed upon detailed analysis of the relaxation kinetics of a multistep spin crossover compound.