CHARACTERISTIC OF COMPLEX COMPOUNDS OF CUPRUM (II) NITRATE WITH ALIPHATIC AMINES PYRIDINE AND ITS DERIVATIVES IN CRYSTAL STATE

Abstract

Complex compounds of CuCl 2 і Cu(NO 3 ) 2 with aliphatic amines in a crystalline state from alcohol solutions were obtained. The composition of the obtained compounds was determined by the method of equilibrium shift, molar ratios and intersection of the curves. Their electronic and IR spectra were studied, and a wide asymmetric absorption band was detected in the near region with a maximum of 870 - 900 nm. This band is characteristic of compounds of a tetrigonally curved octahedral configuration. The formation of complex compounds Cuprum (II) with amines of 1:1, 1:2 composition was established. Measured vibrational spectra in the region of 500 to 200 см -1 . IR-spectra of samples of complex compounds Cuprum (II) with the aliphatic amines, pyridine and its derivatives was measured as a suspension in vaseline oil. The measurements were carried out on an IKS-228 spectrophotometer. The frequency of stretching vibrations Me-N characterizes the coordination bond. The stretching vibrations of Me-N should manifest themselves in the low-frequency region as a result of a significant mass of the metal atom and the relatively low strength of the coordination bond. The IR spectra indicate Me-N stretching vibrations, which characterize the coordination bond. For aliphatic amines, absorption bands were identified in the region of 440–420 см -1 , which are assigned to V(Cu–N) vibrations. The bands in this region indicate coordination through the base nitrogen atom. The absorption bands of the ligands in the region of 210-220 см -1 disappear in the complex compounds. Most of the frequencies in complex compounds are explained by the dual nature of the σ- and π- dative interactions. In coordination compounds of Cu(NO 3 ) 2 with pyridine and its derivatives, an increase in vibration frequencies is observed with an increase in the stability of complex compounds, which is explained by the double nature of the bond (σ,-and π-dative interaction). Complex compounds were studied by differential thermal analysis. As a result, it was concluded that the nature of the decay of the complexes is affected by the nature of the ligand, complexing agent, electronegativity and polarizing properties of the ligand, steric effects and the nature of cations. The process of breaking the coordination bond for primary and secondary aliphatic amines occurs stepwise, and for tertiary amines in one step. At the first stage, one ligand molecule is cleaved, and at the second, the second molecule. Secondary amines have small cleavage. With an increase in the spatial factors of amines, the thermal stability of the complexes decreases.