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A Density Functional Theory Study of Hyperfine Structures of Neutral S,N-Heterocycles

✍ Scribed by J. Gassmann; J. Fabian

Publisher
John Wiley and Sons
Year
1996
Tongue
English
Weight
657 KB
Volume
34
Category
Article
ISSN
0749-1581

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✦ Synopsis

The electronic structures and isotropic hyperfine coupling constants of a series of neutral radicals consisting of ten S,N-heterocyclic compounds were investigated by means of density functional theory (DFT). The molecular geometries were optimized by gradient corrected DFT (UB3LYP) methods and isotropic hyperfine coupling constants (hfccs) were calculated through the Fermi contact analysis. The basis sets were 6-31G(d) and TZVP. The hfcc values were compared with experimental data and with theoretical results obtained by semi-empirical quantum chemical calculations (AMl/UHF and INDO/UHF) and by ab initio quantum chemical calculations (UMP2, UMP3 and UMP4). The results from DFT are highly superior to those of the semi-empirical methods. As shown for 1,3,2-thiadiazolyl, the computationally more demanding ab initio calculations do not provide better results with the same basis sets.

πŸ“œ SIMILAR VOLUMES

Density functional study of neutral allo
Density functional study of neutral allopurinol tautomeric forms
✍ Costas, MarοΏ½a Eugenia; Acevedo-ChοΏ½vez, Rodolfo πŸ“‚ Article πŸ“… 1999 πŸ› John Wiley and Sons 🌐 English βš– 172 KB πŸ‘ 2 views

Optimized structures and total molecular energy density functional theory calculations for the 14 possible neutral allopurinol tautomers Ε½ . Ε½ . Ε½ . Ε½ . give the decreasing stability order N 1 -HrN 5 -H ) N 2 -HrN 5 -H ) Ε½ . cis-enolicrN 1 -H for the three most stable forms. Several molecular and el