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

Elzbieta Trzop (1) , Marylise Buron-Le Cointe (1) , Hervé Cailleau (1) , Loic Toupet (1) , Gábor Molnár (2) , Azzedine Bousseksou (2) , Ana B. Gaspar (3) , José Antonio Real (3) , Eric Collet (1)

1 GMCM - Groupe matière condensée et matériaux
2 LCC - Laboratoire de chimie de coordination
3 ICMol - Instituto de Ciencia Molecular

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.

Mots clés: photocrystallography; photoinduced phase transition; LIESST effect; dinuclear complex

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Physique Atomique [physics.atom-ph]

Elzbieta Trzop, Marylise Buron-Le Cointe, Hervé Cailleau, Loic Toupet, Gábor Molnár, et al.. Structural investigation of the photoinduced spin conversion in the dinuclear compound {[Fe(bt)(NCS)2]2(bpym)}: toward controlled multi-stepped molecular switches. Journal of Applied Crystallography, 2007, 40, pp.158-164. ⟨10.1107/S002188980605028X⟩. ⟨hal-00906044⟩