DIRECTED SYNTHESIS OF MIXED-LIGAND-HETEROMETALLIC XYLARATOGERMANATES OF Co(II) WITH 1,10-PHENANTHROLINE / 2,2'-BIPYRIDINE

Abstract

Coordination compounds with complex cations of Co2+ with 1,10-phenanthroline, 2,2’-bipyridine and tetrameric xylaratogermanate anion were obtained. Their composition and structure were established by the methods of elemental analysis, IR-spectroscopy and thermogravimetric analysis. In the IR-spectrum of I, II bands of asymmetric υas(COO–) (~1686 cm-1) and symmetric υs(COO–) (~ 1442 cm-1) valence vibrations of carboxylate groups are presented. The presence of υ(C-O) (~ 1069 cm-1) band (alcoholic type) and d(C-OH) (~1144 cm-1) band, which is typical for the xylaric acid, indicates that not all hydroxyl groupsof the H5Xylar ligand are deprotonated. Absorption bands υ(Ge-O) (~737 cm-1), υas(GeOGe) (~851 cm-1) are also detected. They indicate the binding of germanium to xylaric acid and formation of the Ge-O-Ge bridge. The deformation vibration band of the Ge-О-Н (~821 cm-1) indicates the implementation of the hydrolyzed form of germanium. There also appear n(ОН)H2O, ns(C–Harom.), ν(C-Carom.), n(C-Narom.), δ(С-H) bands, that are typical for crystallization water molecules and 1,10-phenanthroline (I), 2,2’-bipyridine (II). The thermal destructions of the both compounds are similar. On the thermograms of both compounds one low-temperature effect is presented at 80-270 °С(for I) and 80-260 °С (for II) respectively. According to the temperature of elimination and the weight loss (8,75% for I and 14,5% for II), crystallization water molecules were calculated (I – 12, II – 20). Due to the mass loss along the thermogravimetric curve at 900 °C, the final products of thermal destruction is a mixture of CoO + GeO2. The molecular formulas of complexes I, II are proposed in the accordance of the results of elemental analysis, IR spectroscopy and thermogravimetric analysis: [Сo(phen)3]2[(OH)2Ge2(m-HXylar)4Ge2(m-OH)2]∙12Н2О (I), [Сo(bipy)3]2[(OH)2Ge2(m-HXylar)4Ge2(m-OH)2]∙20Н2О (II). Their scheme of structure were suggested.

Keywords

• германій
• кобальт
• ксиларова кислота
• 1,10-фенантролін
• 2,2’-біпіридин
• координаційні сполуки