ON/OFF Photo(switching) along with Reversible Spin-State Change and Single-Crystal-to-Single-Crystal Transformation in a Mixed-Valence Fe(II)Fe(III) Molecular System
journal contribution
posted on 2023-03-03, 15:05 authored by Sujit Kamilya, Sakshi Mehta, Mohini Semwal, Rodrigue Lescouëzec, Yanling Li, Jiri Pechousek, Varimalla R. Reddy, Eric Rivière, Mathieu Rouzières, Abhishake MondalA mixed-valence Fe(II)Fe(III) molecular system, {[Fe(pzTp)(CN)<sub>3</sub>]<sub>2</sub>[Fe(bik)<sub>2</sub>]<sub>2</sub>}·[Fe(pzTp)(CN)<sub>3</sub>]<sub>2</sub>·4MeOH (<b>1</b>·4MeOH) (bik
= bis-(1-methylimidazolyl)-2-methanone, pzTp = tetrakis(pyrazolyl)borate),
exhibits single-crystal-to-single-crystal (SC–SC) transformation
while increasing the temperature and is converted into {[Fe(pzTp)(CN)<sub>3</sub>]<sub>2</sub>[Fe(bik)<sub>2</sub>]<sub>2</sub>}·[Fe(pzTp)(CN)<sub>3</sub>]<sub>2</sub> (<b>1</b>). Both complexes exhibit thermo-induced
spin-state switching behavior along with reversible SC–SC transformation,
where the low-temperature [Fe<sup>III</sup><sub>LS</sub>Fe<sup>II</sup><sub>LS</sub>]<sub>2</sub> phase transforms into a high-temperature
[Fe<sup>III</sup><sub>LS</sub>Fe<sup>II</sup><sub>HS</sub>]<sub>2</sub> phase. <b>1</b>·4MeOH exhibits an abrupt spin-state switching
with <i>T</i><sub>1/2</sub> at 355 K, whereas <b>1</b> undergoes a gradual and reversible spin-state switching with a lower <i>T</i><sub>1/2</sub> at 338 K. Astonishingly, <b>1</b> exhibits
ON/OFF photo-induced spin-state switching with <i>T</i><sub>LIESST</sub> = 67 K, whereas <b>1</b>·4MeOH does not show
such an effect.
