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

Out-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.