Photo-switching spin pairs—synergy between LIESST effect and magnetic interaction in an iron(II) binuclear spin-crossover compound

The decrease of the magnetic response under irradiation at very low temperature was interpreted as a new evidence of synergy between magnetic interaction and spin transition in an iron(II) binuclear SC compound.Real Cabezos, Jose Antonio, [email protected]

Photoinduced HS state in the first spin-crossover chain containing a cyanocarbanion as bridging ligand

A new polymeric approach, based on cyanocarbanion ligands, for the design of spin crossover (SCO) compounds led us to the compound [Fe(abpt)2(tcpd)] (1) (tcpd^2 = (C[C(CN)2|3)^2 , abpt = 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole) which has been characterised as the first SCO molecular chain involving a cyanocarbanion as bridging ligand.Gomez Garcia, Carlos Jose, [email protected]

Photoinduced phenomena and structural analysis associated with the spin-state switching in the [FeII(DPEA)(NCS)2] complex

International audienceOut-of-equilibrium photoinduced switching from the low-spin to the high-spin state has been investigated on the iron(II) complex [Fe(II)(DPEA)(NCS)2] by both optical reflectivity and magnetic measurements under continuous light irradiation at low temperature. The photoinduced HS state can be observed up to 47 K and the relaxation process has been followed. Structural changes of both the temperature- and the photoinduced spin-state switching have been analyzed in detail by x-ray diffraction indicating no change of symmetry. Short intermolecular contacts and intramolecular deformations associated with the change of molecular spin state have been quantified. Actually a crossover behavior is observed at thermal equilibrium with however a quasiabrupt shape indicating significant cooperative effects. These aspects are compared between the temperature- and photoinduced spin crossovers

Photomagnetism of iron(II) spin crossover complexes—the T(LIESST) approach

The Light-Induced Excited Spin State Trapping (LIESST) effect, encountered in some Spin- Crossover (SCO) complexes, is of major interest for the design of optical switches. Nevertheless, until now any applications have been prohibited, because the lifetimes of the photomagnetic states are long enough only at low temperatures. Hereby we review the recent progress made by using the T(LIESST) procedure, which consists of systematically measuring the limit temperature above which a photomagnetic effect in a material is erased by warming the material from 10 K at a rate of 0.3 K min21. This method has been today applied to more than sixty SCO compounds and by comparing the various materials a relation between T(LIESST) and thermal spin transition (T1/2) temperatures has been obtained, i.e. T(LIESST) = T0 2 0.3T1/2. The second section reports part of works done to identify the parameters affecting the T0 factor; that is to find a guideline for the rational design of materials with long-lived photomagnetic lifetimes at working room temperature. Finally, we present the procedure used to simulate a T(LIESST) curve and illustrate it using the examples of a mononuclear SCO complex and of a binuclear SCO system displaying antiferromagnetic interactions

Single laser pulse induces spin state transition within the hysteresis loop of an iron compound

Within the thermal hysteresis loop of the [Fe(PM-BiA)2(NCS)2] compound, a single laser pulse of 14 mJ cm−2 induces a photo-conversion from the low spin (LS, S = 0) to the high spin (HS, S = 2) state of the Fe2+ metallic center..