Heating-rate dependence of spin-crossover hysteresis observed in an iron(ii) complex having tris(2-pyridyl)methanol

Abstract

Me₄N[Fe(py₃COH)(NCS)₃](H₂O) showed an abrupt spin-crossover with thermal hysteresis, and temperature-scan rate dependence was recorded upon heating at 10–0.02 K min⁻¹. At the slowest scan the product of magnetic susceptibility and temperature initially increased at 246 K, then decreased at around 250 K and finally increased again to reach the high-spin state at around 280 K. A polymorphic spin-crossover model is plausible.