[Zurück]

I. Salitros, O. Fuhr, R. Kruk, J. Pavlik, L. Pogány, B. Schäfer, M. Tatarko, R. Boca, W. Linert, M. Ruben:
"Thermal and Photoinduced Spin Crossover in a Mononuclear Iron(II) Complex with a Bis(pyrazolyl)- pyridine Type of Ligand";
European Journal of Inorganic Chemistry, 2013 (2013), S. 1049 - 1057.

A mononuclear iron(II) compound 1 of the general formula [Fe(L)2](ClO4)2 {L = 4-[2,6-bis(pyrazol-1-yl)pyridin-4-yl]- benzaldehyde} was prepared and structurally characterised.Single-crystal X-ray structure analysis revealed the presence of a complex dication [Fe(L)2]2+ and two ClO4 - counteranions within the unit cell. The bond lengths and angles within the coordination polyhedron FeN6 indicate the low-spin state of the central iron(II) metal ion at T = 180 K. Magnetic investigations elucidate spin crossover with T1/2 = 285 K. The experimental magnetic susceptibility data could be satisfactorily fitted with the Curie law in combination with the Ising-like model. The room-temperature character of the spin crossover was further studied by variable-temperature far-IR, Vis and Mössbauer spectroscopy at 280, 282, 283 and 288 K. Laser irradiation of 1 carried out at 10 K gives rise to a complete low-spin to high-spin photoconversion. A subsequent temperature- dependent investigation revealed the existence of a photoexcited metastable HS state up to TLIESST = 70K (LIESST = light-induced excited-spin-state trapping) as well as the presence of a light-induced thermal hysteresis loop with a width of 10 K.

spin-Crossover, LIESST

http://dx.doi.org/10.1002/ejic.201201123