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NMR Properties of the Formic Acid Dimer

Jaroniec J., Jaszunski M.

Polish Journal of Chemistry

2006

Vol. 80, nr 7

1061-1074

NMR properties - nuclear quadrupole coupling constants, shielding constants and indirect spin-spin coupling constants - in the formic acid dimer are studied using ab initio methods. The accuracy of the calculations is examined for the C2hminimum structure of (HCOOH)2, comparing theMCSCF (multi-configuration SCF) and CCSD (coupled cluster singles and doubles) results. The dependence of the NMR parameters on dimer geometry is analysed for simultaneous double proton transfer, considering the C2h minimum, theD2h transition state and a few intermediate structures, aswell as for two structures representing single proton transfer. For the nuclei involved in the hydrogen bonds not only the effects of the dimerization are very large; the computed NMR parameters also vary significantly with the structure of the cyclic formic acid dimer.

Spectral and thermal studies of yttrium and heavy lanthanide 2,6-dihydroxybenzoates

Brzyska W., Kula A., Rzączyńska Z., Jaroniec J.

Polish Journal of Chemistry

1998

Vol. 72, nr 12

2524-2530

The complexes of Y(III) and heavy lanthanides(III) (Gd-Lu) with 2,6-dihydroxybenzic acid have been prepared and their IR spectra, solubilities in water and thermal decomposition have been investigated. The complexes [Ln(C7H5O4)3(H2O)4]2H2O, when heated, lose their crystalization water in two steps and then decompose to the oxides Ln2O3 and Tb4O7 with intermediate formation of Ln(C7H5O4)(C7H4O4). In the complexes prepared, the carboxylate groups act as monodentate and bidentate chelating ligands. The water molecules are linked in inner and outer spheres. The complexes of Y(III) and heavy lanthanides (Gd-Lu) are isostructural.