Authors: T.D. Morozova, O.G. Shakirova

Title of the article: Iron(II) and copper(II) complexes with a new ligand 2,6-bis(1H-imidazole-2-yl)-4-methoxypyridine

Year: 2023, Issue: 3, Pages: 35-43

Branch of knowledge: 2.6.7. Technology of inorganic substances

Index UDK: 541.49

DOI: 10.26730/1999-4125-2023-3-35-43

Abstract: Coordination compounds of iron(II) and copper(II) with 2,6-bis(1H-imidazole-2-yl)-4-methoxypyridine (L) of the compositions [FeL₂]SO₄∙2H₂O (I) и [CuLCl₂] (II) were synthesized and investigated. The compounds were studied using X-ray phase and X-ray diffraction analysis, infrared and electron (diffuse reflection spectra) spectroscopy, static magnetic susceptibility. It was shown that the new ligand is coordinated to metal(II) in a tridentate-cyclic type by an atom of N pyridine and two atoms of N3 imidazole cycles. In complex I, the FeN₆ coordination node is implemented. In complex II, the coordination polyhedron of copper(II) is completed to a tetragonal pyramid due to two chlorine ions, its node is CuN₃Cl₂. In the electronic spectrum of complex I, an absorption band with a maximum at 936 nm (d-d transition ⁵Т₂ → ⁵Е in a weak ligand field) is observed, it is characteristic of the spectra of high-spin octahedral iron(II) complexes with nitrogen-containing ligands. The calculated values of the splitting parameters indicate that in complex I, during cooling, the phenomenon of spin-crossover ⁵Т₂ <-> ¹А₁ (SCO) is very likely to manifest. Experimental study of the dependence of the µ_eff(T) for the iron(II) complex and its dehydrate confirmed the fact of SCO, which is accompanied by thermochromism – the orange color of the sample reversibly changes to dark purple upon cooling.

Key words: synthesis complex iron(II) copper(II) 2,6-bis(1H-imidazole-2-yl)-4-methoxypyridine spectroscopy magnetic properties

Receiving date: 27.12.2022

Approval date: 15.06.2023

Publication date: 30.06.2023

CITE DOWNLOAD