GETERONUCLEAR BIS(GALACTARATO)GERMINATES OF COBALT(ІІ), COPPER(ІІ), NICKEL(ІІ): SYNTHESIS, STRUCTURE AND CHEMICOPHYSICAL PROPERTIES

Abstract

Heterometallic bic(galactarato)germanates of cobalt(ІІ), copper(ІІ) and nickel(ІІ) were synthesized for the first time and characterized with the method of elemental analyses, thermogravimetry and IR-spectroscopy.The IR-spectrum of the synthesized compounds showed the presence of nas(COO-) ~ 1600 сm-1, ns(COO-) ~ 1390 сm-1 and valence vibrations of the bond M-O ~ 530 сm-1. All this points on the deprotonation of carboxylic groups. The values of valence vibrations of carboxylate ions, the absence of narrow band ν(ОН) at 3600 сm-1 and presence of ν(Ge-O) at685 сm-1 allows us to conclude, that germanium coordination unit is formed by the bonding with oxygen atoms in hydroxyl groups and without any participation of ones in carboxylic groups. This statement is confirmed by the absence of hydroxyl ν(C-O) vibrations, which are specific for galactaric acid, and presence of alkoxyl n(С-О) vibrations. It was found that inner sphere of the synthesized compounds performs to be different-metal Ge4+–M2+ complex anion, the charge of which is neutralized by the hexa-aqua cation of 3d-meteal [М(Н2О)6][Ge(μ-HGala)2{М(H2O)2}2]·5H2O (HGala5- – galactaric acid anion, М – Сo2+, Ni2+, Cu2+). Their structure and chemical reaction is suggested to be next: GeCl4 + 2H6Gala + 3M(CH3COO)2 + 10NH4OH + 5H2O → [M(H2O)6][Ge(μ3-HGala)2{M(H2O)2}2]·5H2O + 6CH3COONH4 ++4NH4Cl