ChemInform Abstract: Symmetry‐Breaking Structural Phase Transitions in Spin Crossover Complexes

Shatruk, Michael; Phan, Hoa; Chrisostomo, Bruno A.; Suleimenova, A.I.

doi:10.1002/chin.201547224

Cited by 3 publications

(3 citation statements)

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“…The dynamics of the phase transition has been interpreted using a structural model built in a wide variety of long-range ordered patterns of HS and LS molecules. [75][76][77][78][79][80]70 Up to now, spin state transitions with up to eight more or less clearly identified steps have been reported. In most of the cases, the crystal structure has been solved for all the steps, allowing a clear description of the HS/LS supramolecular ordering.…”

Section: From Short-range Correlations To Long-range Ordering Of Molecular Spin Statesmentioning

confidence: 99%

“…Ferroelastic crystals may be considered as a type of ferroic crystal which are the mechanical analogues of ferroelectrics and ferromagnetics. Many phase transitions in SCO systems involve symmetry breaking processes, as recently reviewed78 , only a few of these are true ferroelastic transitions, and the resulting ferroelastic domain pattern has rarely been studied in details. One of the most documented ferroelastic SCO compound is [Fe(ptz) 6 ].…”

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Spin-crossover materials: Getting the most from x-ray crystallography

Pillet

2021

Journal of Applied Physics

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The physical phenomenon of spin crossover in molecular crystals is a multiscale process whose properties rely on the supramolecular organization of the spin crossover active elements, their interactions within the crystal packing and their dynamics. The delicate balance between short-range and long-range structural reorganization upon the spin transition is at the origin of remarkable and fascinating physical phenomena such as thermal, light induced and pressure induced hysteresis, multistep transitions and multimetastablility. A complete understanding of the various phenomena associated to spin crossover requires a comprehensive and thorough characterization of the overall structural architecture at all scales which goes beyond the average static crystal structure. This tutorial surveys the practical use of X-ray crystallography notably in non-ambient conditions to provide a direct view of the physical processes operating in spin crossover molecular solids from bulk single crystals to nano-crystalline powder. Advanced X-ray crystallography methods are reviewed and illustrated with a series of model examples.

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Section: From Short-range Correlations To Long-range Ordering Of Molecular Spin Statesmentioning

confidence: 99%

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confidence: 99%

Spin-crossover materials: Getting the most from x-ray crystallography

Pillet

2021

Journal of Applied Physics

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“…In the short range, the molecular packing and the elastic energy costs, related to important structural changes, can also be at the origin of elastic frustration (Watanabe et al, 2016;Paez-Espejo et al, 2016). It can generate stepwise conversions of the fraction of HS molecules HS with temperature, as recently discussed in recent reviews (Shatruk et al, 2015;Ortega-Villar et al, 2016). Structural studies of several Fe II systems have reported periodic and aperiodic long-range order of LS and HS states (Boinnard et al, 1994;Chernyshov et al, 2003;Huby et al, 2004;Reger et al, 2001;Money et al, 2007;Luan et al, 2015;Yamada et al, 2006;Sato et al, 2009;Bré fuel et al, 2009Bré fuel et al, , 2010Collet, Watanabe et al, 2012;Bonnet et al, 2008;Clements et al, 2016;Pillet et al, 2012).…”

Section: Introductionmentioning

confidence: 97%

Formation of local spin-state concentration waves during the relaxation from a photoinduced state in a spin-crossover polymer

Mariette

Trzop

Zerdane

et al. 2017

Acta Crystallogr Sect B

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The complex relaxation from the photoinduced high-spin phase (PIHS) to the low-spin phase of the bimetallic two-dimensional coordination spin-crossover polymer [Fe[(Hg(SCN)3)2](4,4′-bipy)2]nis reported. During the thermal relaxation, commensurate and incommensurate spin-state concentration waves (SSCWs) form. However, contrary to the steps forming at thermal equilibrium, associated with long-range SSCW order, the SSCWs forming during the relaxation from the PIHS phase correspond to short-range order, revealed by diffuse X-ray scattering. This is interpreted as resulting from the competition between the two types of SSCW order and another structural symmetry breaking, due to ligand ordering, occurring at low temperature and precluding long-range SSCW order.

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Multiscale Experimental and Theoretical Investigations of Spin Crossover FeII Complexes: Examples of [Fe(phen)2(NCS)2] and [Fe(PM-BiA)2(NCS)2]

Matar

Guionneau

Chastanet

2015

IJMS

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For spin crossover (SCO) complexes, computation results are reported and confirmed with experiments at multiscale levels of the isolated molecule and extended solid on the one hand and theory on the other hand. The SCO phenomenon which characterizes organometallics based on divalent iron in an octahedral FeN6-like environment with high spin (HS) and low spin (LS) states involves the LS/HS switching at the cost of small energies provided by temperature, pressure or light, the latter connected with Light-Induced Excited Spin-State Trapping (LIESST) process. Characteristic infra red (IR) and Raman vibration frequencies are computed within density functional theory (DFT) framework. In [Fe(phen)2(NCS)2] a connection of selected frequencies is established with an ultra-fast light-induced LS → HS photoswitching mechanism. In the extended solid, density of state DOS and electron localization function (ELF) are established for both LS and HS forms, leading to characterizion of the compound as an insulator in both spin states with larger gaps for LS configuration, while keeping molecular features in the solid. In [Fe(PM-BiA)2(NCS)2], by combining DFT and classical molecular dynamics, the properties and the domains of existence of the different phases are obtained by expressing the potential energy surfaces in a short range potential for Fe–N interactions. Applying such Fe–N potentials inserted in a classical force field and carrying out molecular dynamics (MD) in so-called “semi-classical MD” calculations, lead to the relative energies of HS/LS configurations of the crystal and to the assessment of the experimental (P, T) phase diagram.

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ChemInform Abstract: Symmetry‐Breaking Structural Phase Transitions in Spin Crossover Complexes

Abstract: Symmetry-Breaking Structural Phase Transitions in Spin Crossover Complexes -[49 refs.]. -(SHATRUK, M.; PHAN, H.; CHRISOSTOMO, B. A.; SULEIMENOVA, A.; Coord. Chem. Rev. 289-290 (2015) 62-73, http://dx.

Cited by 3 publications

References 1 publication

Spin-crossover materials: Getting the most from x-ray crystallography

Spin-crossover materials: Getting the most from x-ray crystallography

Formation of local spin-state concentration waves during the relaxation from a photoinduced state in a spin-crossover polymer

Multiscale Experimental and Theoretical Investigations of Spin Crossover FeII Complexes: Examples of [Fe(phen)2(NCS)2] and [Fe(PM-BiA)2(NCS)2]

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