Coupling between spin conversion and solvent disorder in spin crossover solids

Coupled Crystallographic Order–Disorder and Spin State in a Bistable Molecule: Multiple Transition Dynamics

“…[13] Recently, this coupling has been modelled for the cases in which the spinactive and inactive components belong to either one or two sublattices (i.e., for one-and two-step SCO, respectively). [8] The issue of bistability in the context of coupled phase transitions involving crystallographic ordering has so far not been treated at this level, perhaps because it has not yet been revealed experimentally.…”

“…The modelling of these systems, however, is usually oversimplified by combining them into one single phenomenological parameter that describes the interaction between the spin-active centres. [8] The structures of SCO solids normally also contain spin-inactive components, such as solvents and counterions. In some cases, temperature-induced (1), with an intricate network of intermolecular interactions.…”

A High Pressure Investigation of the Order-Disorder Phase Transition and Accompanying Spin Crossover in [FeL12](ClO4)2 (L1 = 2,6-bis{3-methylpyrazol-1-yl}-pyrazine)

“…In this latter study [9], the importance of detailed structural studies across a range of temperature (i.e., not simply structures in HS and LS states alone) was specifically highlighted.…”

“…50% of the iron centers have undergone SCO. A subsequent structural study [13] aimed to rationalize the relationship between an observed order/disorder transition in this material and the unusual two-step transition in this complex, and led to the development of an Ising-like Hamiltonian for coupled SCO and order-disorder processes [9]. At no temperature did the structural study identify any indication of symmetry breaking to an intermediate phase with long range order of HS and LS states.…”

“…Order-disorder transitions, in which SCO is accompanied by a significant change in the long-range ordering of counter ions, solvent molecules and/or ligand conformation [5][6][7][8] are a particularly interesting class of systems from the point of view of understanding cooperativity and models have been developed to explore them further [9]. In this latter study [9], the importance of detailed structural studies across a range of temperature (i.e., not simply structures in HS and LS states alone) was specifically highlighted.…”