Spin crossover in iron(II) complexes with new ligand 2,6-bis(4,5-dimethyl-1H-imidazole-2-yl)pyridine

• Published in: Inorganica Chimica Acta Vol. 532; p. 120746
• Main Authors: Ivanova, Alina D., Korotaev, Evgeniy V., Komarov, Vladislav Yu, Sukhikh, Taisiya S., Trubina, Svetlana V., Sheludyakova, Liliya A., Petrov, Sergey A., Tikhonov, Alexsei Ya, Lavrenova, Lyudmila G.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2022; Elsevier Science Ltd
• Subjects: 2,6-bis(4,5-dimethyl-1H-imidazol-2-yl)pyridine; Composition; Coordination compounds; Crossovers; Crystal structure; Dehydration; EXAFS spectroscopy; Fine structure; High temperature; Imidazole; Iron; Iron(II) complexes; Ligands; Magnetic permeability; Mössbauer spectroscopy; Pyridines; Spin crossover; Temperature dependence; X ray absorption; EXAFS spectroscopy; Iron(II) complexes; 2,6-bis(4,5-dimethyl-1H-imidazol-2-yl)pyridine; Mössbauer spectroscopy; Spin crossover; Crystal structure
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2021.120746

Iron(II) complexes with new ligand 2,6-bis(4,5-dimethyl-1H-imidazole-2-yl)pyridine possessing a high-temperature 1A1 ↔ 5T2 spin crossover were obtained. [Display omitted] •Fe(II) complexes with 2,6-bis(4,5-dimethyl-1H-imidazole-2-yl)pyridine are studied.•Fe(II) complexes exhibit high-temperature 1A1 ↔ 5T2 spin crossover.•Coordination core structure of the [FeL2]2+ was determined from the EXAFS spectra. Iron(II) coordination compounds containing a new ligand, 2,6-bis(4,5-dimethyl-1H-imidazol-2-yl)pyridine (L), of composition [FeL2](NO3)2·H2O (1·H2O), [FeL2](ClO4)2·0.5H2O (2·0.5H2O), [FeL2]SO4·0.5H2O (3·0.5H2O), or [FeL2](ReO4)2·2H2O (4·2H2O) have been synthesized and studied by UV–vis (diffuse reflectance), infrared, extended X-ray absorption fine structure (EXAFS), and Mössbauer spectroscopies, as well as X-ray diffraction and static magnetic susceptibility methods. The structure of a copper(II) complex with L of composition [CuL2]SO4·3H2O has been successfully determined. The analysis of the μeff(T) dependence in the temperature range of 80–520 K showed that complexes [FeL2](NO3)2·H2O, [FeL2](ClO4)2·0.5H2O, and [FeL2](ReO4)2·2H2O and their dehydrated counterparts are subject to high-temperature spin crossover 1A1 ↔ 5T2.