Cis-trans isomerism in cobalt(II) complexes with 3-hydroxypicolinic acid. Structural, DFT and thermal studies (CROSBI ID 158745)
Prilog u časopisu | izvorni znanstveni rad | međunarodna recenzija
Podaci o odgovornosti
Kukovec, Boris-Marko ; Kodrin, Ivan ; Mihalić, Zlatko ; Furić, Krešimir ; Popović, Zora
engleski
Cis-trans isomerism in cobalt(II) complexes with 3-hydroxypicolinic acid. Structural, DFT and thermal studies
Pyridine and 4-picoline cobalt(II) complexes with 3-hydroxypicolinic acid, [Co(3-OHpic)2(py)2], (2), and [Co(3-OHpic)2(4-pic)2], (3), were prepared, their molecular and crystal structures were determined by X-ray structure analysis and their thermal stability by TGA/DTA methods. Complex 2 appears only as trans isomer and 3 as cis isomer. Based on DFT calculations, the most significant effect on orientation of (un)substituted ligands around cobalt, i.e. cis-trans isomerism, comes from crystal packing. Theoretical calculations show that exchange of methyl group in pyridine does not affect relative stability of one monomer unit, i.e. cis isomer is for about 1 kcal mol-1 more stable than trans isomer. Hydrogen bonds of the O–H...O type are present only as intramolecular ones in the crystal structures of 2 and 3, while intermolecular C–H...O hydrogen bonds and π–π stacking interactions (π–π interactions present only in 3) assemble molecules in 3D architecture. Interactions between two monomer units in crystal packing could be separated and theoretically investigated to calculate interaction energy. In our case, both non-hypothetical models, i.e. trans isomer of 2 and cis isomer of 3, show more favourable interaction energies than hypothetical ones, i.e. cis isomer of 2 and trans isomer of 3, for the same type of interaction.
cobalt(II) complexes ; 3-hydroxypicolinic acid ; cis-trans isomers ; weak intermolecular interactions ; density functional calculations ; thermal methods (TGA/DTA)
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Podaci o izdanju
363 (8)
2010.
1887-1896
objavljeno
0020-1693
1873-3255
10.1016/j.ica.2010.02.010