Light-induced excited spin state trapping in iron(iii) complexes

This review discusses the correlation of the local and whole molecular structure of iron(iii) complexes with the magnetic properties including the light-induced excited spin-state trapping (LIESST) effect.

Homochiral versus racemic polymorphs of spin-crossover iron(ii) complexes with reversible LIESST effect

Homochiral and racemic polymorphs show different spin-crossover behaviours due to different intermolecular interactions, and reversible LIESST effects can be realized on homochiral complexes.

Spin-crossover iron(ii) complex showing thermal hysteresis around room temperature with symmetry breaking and an unusually high T(LIESST) of 120 K

The Fe(ii) complex of 4′,4′′ carboxylic acid disubstituted dipyrazolylpyridine shows spin-crossover around room temperature and the LIESST effect with T(LIESST) of 120 K.

The excited electron: photophysical properties

After a review of fundamental notions such as absorption, emission and the properties of excited states, the chapter introduces excited-state electron transfer. Several examples are given, using molecules to realize photodiodes, light emitting diodes, photovoltaic cells, and even harnessing photochemical energy for water photolysis. The specificities of ultrafast electron transfer are outlined. Energy transfer is then defined, starting from its theoretical description, and showing its involvement in photonic wires or molecular assemblies realizing an antenna effect for light harvesting. Photomagnetic effects; that is, the modification of magnetic properties after a photonic excitation, are then studied. The examples are taken from systems presenting a spin cross-over, with the LIESST effect, and from systems presenting metal–metal charge transfer, in particular in Prussian Blue analogues and their molecular version.

Evidencing size-dependent cooperative effects on spin crossover nanoparticles following their HS→LS relaxation

The size dependence of the relaxation mechanism after photo-excitation through the Light-Induced Excited Spin-State Trapping (LIESST) effect of [Fe(pz)Pt(CN)4] micro- and nanoparticles is evidenced experimentally and simulated in the framework of the mechanoelastic model.

Photomagnetic properties of an Fe(ii) spin-crossover complex of 6-(3,5-diamino-2,4,6-triazinyl)-2,2′-bipyridine and its insertion into 2D and 3D bimetallic oxalate-based networks

The Fe(ii) complex of 6-diaminotriazyl-2,2′-bipyridine shows the LIESST effect and has been used as a countercation of two oxalate-based ferromagnets.