Матричний синтез комплексних сполук купруму(ІІ) та кадмію(ІІ) з саліциліденсемикарбазоном

Abstract

The template synthesis of complex compounds has several advantages over other methods, because it allows to obtain new macrocyclic coordination compounds with valuable practical properties. At the same time, the composition, structure and properties of the final complex compounds depend both on the nature of the metal cation and the presence of reactive centers of the organic ligand. The purpose of this work was definition the peculiarities of the complex formation of copper(II) and cadmium(II) with salicylidenesemicarbazone and determination of composition and spatial structure of synthesized coordination compounds. The paper presents data of the synthesis of coordination compounds [Cd(Н2L)(H2O)Cl2] І, [Cu(НL)Cl] • 2H2O ІІ, Ba[Cu(Lʹ)]2 ІІІ and salicylaldazine ІV (where Н2L – salicylic aldehyde semicarbozone, Н3L' = N,N'-bis(salicylidene)semicarbazide). Synthesis of the investigated coordination compounds was carried out by the interaction of hot ethanol solutions of salicylic aldehyde semicarbazone, МCl2 • хH2O (M2+ = Cd, Cu; х = 0, 2) and salicylic aldehyde in a molar ratio of 1: 1: 1 at pH = 9-10, which was created by Ba(OH)2 dissolved in a water-ethanol mixture (1:1). The composition and structure of synthesized complex compounds I-III are confirmed by elemental analysis and IR spectroscopy, and in the case of compounds I, II, and IV by X-ray diffraction analysis. Complexation of copper(II) and cadmium(II) salts with salicylidenesemicarbazone under of conditions matrix synthesis was studied. It is shown that in the case of copper(II), as a matrix center, the reaction proceeds rapidly with the formation of chloro(salicylidenesemicarbazone)copper(II) dihydrate, and in the case of cadmium(II) it ends with the formation of cadmium(II) dichloroaquasalicylidenesemicarbazone complex. This is due to the matrix effect of the copper(II) cation, namely, a very significant change in the charge component at potential centers of complexation, which was confirmed by quantum chemical calculations. For salicylaldazine, obtained under conditions of matrix synthesis of cadmium(II) complex, a mechanism of formation which the use of initial salicylidenesemicarbazone and salicylic aldehyde was proposed