The Atypical Hysteresis of [Fe(C<sub>6</sub>F<sub>5</sub>Tp)<sub>2</sub>]: Overlay of Spin‐Crossovers and Symmetry‐Breaking Phase Transition
Amina Benchohra, Yanling Li, Lise‐Marie Chamoreau, Benoı̂t Baptiste, Erik Elkaı̈m, Nathalie Guillou, David Kréher, Rodrigue Lescouëzec
Abstract
] spin-crossover complex is an atypical molecular switch, which can be converted upon annealing between two archetypal spin-crossover behaviours: from an extremely gradual spin-crossover to a broad hysteretic spin-transition (of ca. 65 K). The hysteresis shows an uncommon "rounded shape" that is reproducible upon cycling temperature. In depth structural studies reveal a first crystal phase transition, which occurs upon melting and recrystallizing at high temperature. This first irreversible transition is associated with a radical change in the crystal packing. More importantly, the "rounded and broad" hysteretic transition is shown to occur in a non-cooperative SCO system and is associated with the occurrence of a symmetry-breaking phase transition that appears when roughly ca. 50 % of the SCO complexes are switched.