What is it about?
The solid state spin crossover behavior of neutral Fe(II) complexes through temperature dependent magnetic susceptibility (T1/2 = 260 K and 326 K), variable temperature single crystal X-ray analysis (crystal structures of both compounds were determined at different temperatures, below and above the transition, in order to detect the structural changes associated with the spin transition) and UV-vis analysis. The main structural modifications, when passing from the low-spin to the high-spin form, consist of an important lengthening of the Fe-N(Mebik) and Fe-N (C-S/Se) distances (by ca. 0.20 and 0.18 Å, respectively) and a noticeable variation of the N-Fe-N angles. inally, both complexes exhibit a light-induced excited spin-state trapping under laser light irradiation at low temperature. DFT calculations were also carried out on these complexes in order to rationalize the theoretically predicted magnetic and optical behavior with those of the experimental one.
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Why is it important?
Dramatic alteration of the magneto-structural behavior of the tris-chelate Fe(II) spin-crossover complex upon substituting one chelate ligand with NCS and NCSe ligand. Coexistence of thermally-Induced Spin Crossover and LIESST Effect in Fe(II) COMPLEX.
Perspectives
Finally, it is worth noting that the comparison of these results with previous photomagnetic measurements on related [Fe(Rbik)2(NC-)2] complexes show that the most efficient wavelength can be varied by changing the nature of the –N donor ligands or metallo-ligands. At that stage, advanced physical measurements would be useful, for example, to identify the nature of the excited states involved in the LIESST effect.
Dr. SIDDHARTHA DE
Centre National de la Recherche Scientifique
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This page is a summary of: Thermally-Induced Spin Crossover and LIESST Effect in the Neutral [FeII(Mebik)2(NCX)2] Complexes: Variable-Temperature Structural, Magnetic, and Optical Studies (X = S, Se; Mebik = bis(1-methylimidazol-2-yl)ketone), Frontiers in Chemistry, August 2018, Frontiers,
DOI: 10.3389/fchem.2018.00326.
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