SYNTHESIS OF THIOAMIDE COMPLEX COMPOUNDS OF COPPER(II) AND STUDY OF THEIR MUTUAL TRANSFORMATIONS

Abstract

The paper presents improved methods of the synthesis of thioamides of various substitution RC(=S)NHR' (R = R' = Alk, Ar, Het), which is the promising chelating ligandsfor complexation reaction with some 3d-metals. Coordination compounds of copper(II) of the composition [Cu(НL)2X2]2, [Cu(НL)X2]2, [CuL2]2, containing neutral or deprotonated molecules of benzimidazole-2-N-(4-methoxyphenyl)carbothioamide (HL) and trichloroacetate anion (Х–) were synthesized. The dimer di(trichloroacetato)-[benzimidazole-2-N-(4-methoxyphenyl)carbothioamide] copper(II) was obtained by the interaction of thioamide (HL) with copper(II) trichloroacetate and trichloroacetic acid in an alcohol medium. The conditions for the transformation (temperature, time, solvent, pH) of one form of the coordination compound into another [Cu(НL)X2]2 ↔ [CuL2]2 ↔ [Cu(НL)2X2]2 have been determined. The study showed that the synthesis of such coordination compounds in methanol or water-methanol solutions depends on the acid-base properties of the reaction medium. The composition and structure of the synthesized compounds during the above transformations were investigated by elemental analysis and IR spectroscopy. Thus, the possibility of targeted synthesis of functionally oriented coordination compounds [Cu(HL)2X2]2, [Cu(HL)X2]2, [CuL2]2 by their mutual transformations has been established.