Hydrostatic pressure investigation of the spin crossover compound [Fe(PM―BiA)₂(NCS)₂] polymorph I using reflectance detection

We investigated by diffuse reflectivity the effect of hydrostatic pressure (1–1800 bar) on the thermal spin transition of Fe(PM−BiA)2(NCS)2 polymorph I, where PM=N-2-pyridylmethylene and BiA=4-aminobiphenyl. We evidenced the onset of a progressive transformation into a phase of higher cooperativity which cannot be assigned to polymorph II. This result is discussed with respect to previous pressure investigations