Solvent-Induced Hysteresis Loop in Anionic Spin Crossover (SCO) Isomorph Complexes

Magnetochemistry

Samia Benmansour¹  CarlosJ. Gómez-García¹  Emmelyne Cuza²  Nathalie Cosquer²  Smail Triki²  Françoise Conan² 

[1] Instituto de Ciencia Molecular (ICMol), Departamento de Química Inorgánica, Universidad de Valencia, C/Catedrático José Beltrán 2, 46980 Paterna, Spain;Univ Brest, CNRS, CEMCA, 6 Avenue Le Gorgeu, C.S. 93837, CEDEX 3, 29238 Brest, France;

关键词: tripodal ligands;    pseudohalide coligands;    iron complex;    spin crossover;    magnetic properties;   

DOI  :  10.3390/magnetochemistry7060075

来源: DOAJ

【 摘 要 】

Reaction of Fe(II) with the tris-(pyridin-2-yl)ethoxymethane (py₃C-OEt) tripodal ligand in the presence of the pseudohalide ancillary NCSe⁻ (E = S, Se, BH₃) ligand leads to the mononuclear complex [Fe(py₃C-OEt)₂][Fe(py₃C-OEt)(NCSe)₃]₂·2CH₃CN (3), which has been characterised as an isomorph of the two previously reported complexes, Fe(py₃C-OEt)₂][Fe(py₃C-OEt)(NCE)₃]₂·2CH₃CN, with E = S (1), BH₃ (2). X-ray powder diffraction of the three complexes (1–3), associated with the previously reported single crystal structures of 1–2, revealed a monomeric isomorph structure for 3, formed by the spin crossover (SCO) anionic [Fe(py₃C-OEt)(NCSe)₃]⁻ complex, associated with the low spin (LS) [Fe(py₃C-OEt)₂]²⁺ cationic complex and two solvent acetonitrile molecules. In the [Fe(py₃C-OEt)₂]²⁺ complex, the metal ion environment involves two py₃C-OEt tridentate ligands, while the [Fe(py₃C-OEt)(NCSe)₃]⁻ anion displays a hexacoordinated environment involving three N-donor atoms of one py₃C-OEt ligand and three nitrogen atoms arising from the three (NCSe)⁻ coligands. The magnetic studies for 3 performed in the temperature range 300-5-400 K, indicated the presence of a two-step SCO transition centred around 170 and 298 K, while when the sample was heated at 400 K until its complete desolvation, the magnetic behaviour of the high temperature transition (T_1/2 = 298 K) shifted to a lower temperature until the two-step behaviour merged with a gradual one-step transition at ca. 216 K.

【 授权许可】

Unknown