Authors: A.N. Protsenko, D.A. Shulyak, A.E. Protsenko, O.G. Shakirova

Title of the article: Synthesis, structure, and spectral characteristics of copper(II) and cobalt(II) halide complexes with 2-amino-3-bromo-5-methyl pyridine

Year: 2023, Issue: 1, Pages: 71-78

Branch of knowledge: 2.6.7. Technology of inorganic substances

Index UDK: 541.49

DOI: 10.26730/1999-4125-2023-1-71-78

Abstract: Methods of synthesis of new tetrahalide complexes of copper(II) and cobalt(II) with 2-amino-3-bromo-5-methylpyridine (L) of composition (HL)2[CuCl4]∙2H2O (I), (HL)2[CoCl4]∙2H2O (II), (HL)2[CuBr4] (III). Single crystals obtained from a solution of complex III, in contrast to the polycrystalline phase, contain two additional water molecules – (HL)2[CuBr4]∙2H2O (III∙2H2O). The compounds were studied by modern physicochemical methods of analysis (infrared (IR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetry (TG)). The structures of the complexes were determined by X-ray diffraction (XRD). It was shown that in all coordination compounds the protonation process of the organic compound passed through the nitrogen atom of the heterocycle with the formation of the pyridinium cation. It has been shown that the crystal structures of compounds I, II, III∙2H2O are isostructural. The formation of a long polymer chain consisting of alternating anions [МHal4]2- and solvent molecules is observed. The stability of the structure is achieved due to the formation of a dense network of hydrogen bonds between the halogen atoms of the inorganic anion and the hydrogen of the amino group. The data of synchronous thermal analysis showed that two water molecules are removed up to 130 ° C, and anhydrous compounds are thermostable up to 140-180 °C. The compounds have a catalytic effect on the processes of isomerization of hydrocarbons at low temperatures.

Key words: complex copper(II) cobalt(II) 2-amino-3-bromo-5-methylpyridine X-ray diffraction analysis IR spectroscopy thermal properties

Receiving date: 08.12.2022

Approval date: 15.01.2023

Publication date: 30.03.2023

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