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

Abstract

Coordination compounds with complex cations of Co 2+ 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 H 5 Xylar ligand are deprotonated. Absorption bands υ(Ge-O) (~737 cm -1 ), υ as (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)H 2 O, 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 + GeO 2 . 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) 2 Ge 2 (m-HXylar) 4 Ge 2 (m-OH) 2 ]∙12Н 2 О ( I ), [Сo(bipy) 3 ] 2 [(OH) 2 Ge 2 (m-HXylar) 4 Ge 2 (m-OH) 2 ]∙20Н 2 О ( II ). Their scheme of structure were suggested.