Structural investigation of the photoinduced spin conversion in the dinuclear compound {[Fe(bt)(NCS)2]2(bpym)}: toward controlled multi-stepped molecular switches

• Published in: Journal of applied crystallography Vol. 40; no. 1; pp. 158 - 164
• Main Authors: Trzop, Elzbieta, Buron-Le Cointe, Marylise, Cailleau, Hervé, Toupet, Loïc, Molnar, Gabor, Bousseksou, Azzedine, Gaspar, Ana B., Real, José Antonio, Collet, Eric
• Format: Journal Article
• Language: English
• Published: 5 Abbey Square, Chester, Cheshire CH1 2HU, England International Union of Crystallography 01.02.2007; Blackwell Publishing Ltd
• Subjects: Atomic Physics; Condensed Matter; Crystallography; dinuclear complex; Equilibrium; LIESST effect; Materials Science; photocrystallography; photoinduced phase transition; Physics; Temperature; photoinduced phase transition; dinuclear complex; photocrystallography; LIESST effect
• ISSN: 1600-5767; 0021-8898; 1600-5767
• DOI: 10.1107/S002188980605028X

The photocrystallographic investigation of the light‐induced excited spin‐state trapping effect in the dinuclear spin‐crossover compound {[Fe(bt)(NCS)2]2(bpym)} is reported. In this system, each of the two Fe sites may be either in the high‐spin (HS) or in the low‐spin (LS) state, so that the molecule corresponds to a three‐state system (LS–LS, HS–LS and HS–HS). At low temperature, the laser excitation wavelength controls the photoswitching from the stable LS–LS state to one of the metastable excited states (HS–LS or HS–HS), and also between these two excited states. Significant changes in the crystalline structure associated with the photoinduced change of spin state are detailed here. The low‐temperature photoinduced states look similar to the corresponding states observed at thermal equilibrium within the unit‐cell thermal contraction.