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Photomagnetism of a sym-cis-dithiocyanato iron(II) complex with a tetradentate N,N'-bis(2-pyridylmethyl)1,2-ethanediamine ligand
J.-F. Létard, , H.J. Shepherd, P. Guionneau, A.E. Goeta, N. Suemura, R. Ishikawa, S. Kaizaki
Published in
2012
Volume: 18
   
Issue: 19
Pages: 5924 - 5934
Abstract
A comprehensive study of the magnetic and photomagnetic behaviors of cis-[Fe(picen)(NCS) 2] (picen=N,N'-bis(2-pyridylmethyl)1,2- ethanediamine) was carried out. The spin-equilibration was extremely slow in the vicinity of the thermal spin-transition. When the cooling speed was slower than 0.1 K min -1, this complex was characterized by an abrupt thermal spin-transition at about 70 K. Measurement of the kinetics in the range 60-70 K was performed to approach the quasi-static hysteresis loop. At low temperatures, the metastable HS state was quenched by a rapid freezing process and the critical T(TIESST) temperature, which was associated with the thermally induced excited spin-state-trapping (TIESST) effect, was measured. At 10 K, this complex also exhibited the well-known light-induced excited spin-state-trapping (LIESST) effect and the T(LIESST) temperature was determined. The kinetics of the metastable HS states, which were generated from the freezing effect and from the light-induced excitation, was studied. Single-crystal X-ray diffraction as a function of speed-cooling and light conditions at 30 K revealed the mechanism of the spin-crossover in this complex as well as some direct relationships between its structural properties and its spin state. This spin-crossover (SCO) material represents a fascinating example in which the metastability of the HS state is in close vicinity to the thermal spin-transition region. Moreover, it is a beautiful example of a complex in which the metastable HS states can be generated, and then compared, either by the freezing effect or by the LIESST effect. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
About the journal
JournalChemistry - A European Journal
ISSN09476539