Theoretical EPR study of Nitroindazoles: 3-alkoxy, 3-hydroxy and 3-oxo derivatives
A DFT study on 5-NI derivatives was carried out at different levels of theory, in order to seek for the best methodology that helps us to calculate hyperfine coupling constants (hfccs), spin density distributions and electronic properties, since it is difficult to obtain a good agreement between calculated and experimental hfccs for nitrogen center radical compounds. Different functional hybrids namely B1LYP, B3LYP and PBE0 were used in conjunction with various medium to large size basis sets. C-PCM model was considered for solute-solvent interactions. Comparisons of our calculations with previous experimental data obtained from EPR and X-ray techniques confirmed that this computational approach represents an important aid. Our results indicated that solvent effects and consideration of diffuse functions are the most important factors on the calculation of hyperfine coupling constants for this nitro-heterocyclic system. Also, we found that some electronic properties calculated (LUMO orbital, condensed Fukui functions for nucleophilic attacks and electron affinity) do not correlate as expected with the biological activity.
| Main Authors: | , , , , , |
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| Format: | Digital revista |
| Language: | English |
| Published: |
Sociedade Brasileira de Química
2010
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| Online Access: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532010001000020 |
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