When Stable and Metastable HS States Meet in Spin‐Crossover Compounds

Abstract With the ultimate goal of rationally inducing overlap between the stable high spin state (HSSS) and the metastable high spin state (HSMS) generated by a rapid frozen effect, a series of [FexMn1–x(bpp)2](BF4)2 [bpp = 2,6‐bis(pyrazol‐3‐yl)pyridine] complexes was prepared. For all the materials, the thermal spin crossover (SCO) properties were measured and the stability of the metastable HSMS state was probed through the determination of the T(TIESST) value associated with the Thermally‐Induced Excited Spin‐State Trapping effect. The overlap between the two systems was observed for x ≤ 0.90 and the consequences on the shape and the completeness of the SCO behavior were discussed.