A critical review of the T(LIESST) temperature in spin crossover materials − What it is and what it is not

Guillaume Chastanet (1) , Cédric Desplanches (1) , Cherif Baldé (2, 1) , Patrick Rosa (1) , Mathieu Marchivie (1) , Philippe Guionneau

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
2 LCPM - Laboratoire de Chimie et Physique des Matériaux

Light-Induced Excited Spin-State Trapping has been studied since 1982 in solution and 1984 in solid state as it offers a reversible way of photoswitching the electronic configuration of spin crossover systems. Since then, the lifetime of the photo-induced state was deeply investigated through kinetics measurements. In 1998, a fast and easy way to record the limit temperature above which the photo-induced state is erased, denoted T(LIESST), was introduced. This procedure has been widely used in the spin crossover community due to its easiness and its efficiency to provide detailed information on the photo-induced state. Correlations between T(LIESST) and structural parameters have been proposed for instance. However, it intrinsically contains drawbacks that can lead to misinterpretation of behaviours and can lead to an over estimation of its scope. This review aims to present and discuss not only the correct way to measure T(LIESST) but also the essential contributions it has brought and the limits not to be exceeded in its interpretation.

Mots clés: Light-Induced Spin Switching; Metastable state lifetime; Structural distortion; Functional materials; Molecular switches; Photophysics

Domaines: Matériaux

Guillaume Chastanet, Cédric Desplanches, Cherif Baldé, Patrick Rosa, Mathieu Marchivie, et al.. A critical review of the T(LIESST) temperature in spin crossover materials − What it is and what it is not. Chemistry Squared, 2018, 2, pp.2. ⟨10.28954/2018.csq.07.001⟩. ⟨hal-01848009⟩