|Ultima descărcare din IBN:|
| SM ISO690:2012|
RIJA, Andrei; BULHAK, Ion; SHOVA, Sergiu; DANILESCU, Olga. MSP 19 P The synthesis and study of new Co(II) bis-schiff base complex with the HSO4 anion in the external sphere. In: Materials Science and Condensed Matter Physics. Editia a 6-a, 11-14 septembrie 2012, Chișinău. Chișinău, Republica Moldova: Institutul de Fizică Aplicată, 2012, p. 95. ISBN 978-9975-66-290-1.
|Materials Science and Condensed Matter Physics
Editia a 6-a, 2012
Conferința "Materials Science and Condensed Matter Physics" |
Chișinău, Moldova, 11-14 septembrie 2012
The new coordination compound [CoII(L+2H)(H2O)2](HSO4)4 have been obtained, where L is 2,6di-acetylpyridine-bis-(isonicotinic acid hydrazone). Because the direct synthesis was unsuccessful, the compound was synthesized in three steps as it shown in the following scheme:FormulaThe first step includes a template synthesis, the mixture being refluxed under continuous stirring for two hours. The second step consists of treating a methanol suspension of the obtained green crystalline product with NH4OH solution. The precipitate changes its color in orange. The resulting orange precipitate was suspended in methanol, after that was added few drops of H2SO4 the orange prisms suitable for X-ray analysis in less than 24 h are obtained. The structure and composition have been characterized using elemental analysis, IR and X-ray. In the IR spectrum of [CoII(L+2H)(H2O)2](HSO4)4 two band at 2608 and 2467 cm-1 are observed, which confirm the presence of PyH+. The peaks at 1633 cm-1 and 1172-1019 cm-1 were attributed to coordinated ketone group and − 4 HSO anions respectively. The X-ray single crystal study has shown that the seven-coordinated Co(II) ion has a pentagonal-bipyramidal environment formed by the pentadentate bis-Schiff base ligand. The apical coordination positions are occupied by two water molecules. The external sphere anions − HS(2)O4 and − 4 HS(3)O form 1D chains based on O–H···O H-bonds. This chains are connected direct by [CoII(L+2H)(H2O)2]4+ cations through N(1)–H···O and N(8)–H···O Hbonds and indirect by other numerous Hbonds that involve pyridine fragment, coordinated water molecules and the remaining − 4 HS(1)O and − 4 HS(4)O anions. The crystal components are combined into 3D network via hydrogen bonds, and a crucial role is played by the anions which provide majority of the hydrogen-bond acceptors for the coordination cations. In conclusion, it is worth noting that the deprotonation-protonation method is a good way to include in the external sphere different inorganic anions.