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DFT Studies of H3N-X (X = Li, Na, K, Rb, Cs and Fr) Systems

Wieczorek R., Durlak P., Latajka Z.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 5

761-769

EN

Complexes of alkali atoms with ammonium have been studied using the Denity Functional Theory with nonlocal and quasi-relativistic corrections. The stable complexes were found for allalkali atom–ammonia complexes. The calculated interaction energies decrease as one progresses down the periodic table and are in range from –18.9 kcal/mol for lithium system up to –6.5 kcal/mol for the frans complex. Similar tendency is noted for the calculated values of charge transfer. The influence of calculated quasi-relativistic (QR) corrections on values of interaction energies is determined. The QR corrections have no effect on lithium complexes whereas reduce the binding energy from 0.1 kcal/mol for Na system up to 0.9 kcal/mol for Fr complex. The DFT calculated IR harmonic frequencies are compared with experimental values and discussed. The calculated vibrational freuencies of ammonia in complexes exhibit trends that for all systems they are parallel to the strength of the bind ing energies. For the H3N–Li complex the vibrational analysis was supported by an harmonic calculations at the MP2 level. It has been shown that there is a discrepancy between the experimental assignment and MP2 harmonic and an harmonic low frequency intermolecular modes.

2

Crystal Structure and Quantum Chemical Calculations on o-Hydroxyacetophenone Phenylhydrazone

Jian F. F., Li Y. F., Yang X. Y., Zhao P. S., Xiao H. L.

Polish Journal of Chemistry

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2008

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Vol. 82, nr 8

1597-1597

EN

o-Hydroxyacetophenone phenylhydrazone has been synthesized and characterized by elemental analysis, IR and electronic spectroscopy. The X-ray crystal structure study shows that the compound contains two crystallographically independent molecules in the asymmetric unit and crystallizes in the monoclinic system, space group P21/c, with Mr =226.27 (C14H14N2O), a = 13.433(3), b = 10.738(2), c = 18.351(7) Capital A, beta = 114.44(2)°, V = 2409.8(12) Capital A 3, Z = 8, Dc = 1.247 Mg/m3, F (000) = 960, mi (Mo K) = 0.080 mm–1, R = 0.0638, wR = 0.1535. Ab initio calculations of the structure, atomic charge distributions, natural bond orbital analysis and thermodynamic functions of the title compound were performed at HF/6-311G** and B3LYP/6-311G** levels of theory. Electronic absorption spectra were calculated by the time-dependent density functional theory (TD-DFT). Vibrational frequencies were predicted, as signed and compared with the experimental values. The calculation of the second order optical nonlinearity was carried out and the molecular hyperpolarizability of 3.332×10–30 esu was predicted.

3

Experimental and Theoretical Study on 3-Benzyl-4-phenyl-1,2,4-triazole-5-thione

Zhao P., Li R., Xu J., Zhang W.

Polish Journal of Chemistry

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2007

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Vol. 81, nr 8

1495-1503

EN

The 3-benzyl-4-phenyl-1,2,4-triazole-5-thione was synthesized and examined by elementary analysis, IR and electronic spectra. Density functional theory calculations of the structure, natural bond orbitals and thermodynamic functions of the title compound were performed at B3LYP/6-311G** level of theory. Vibrational frequencies were predicted, assigned and compared with the experimental data, and they are supported by the experimental data. Electronic absorption spectrawere calculated by the time-dependent density functional theory (TD-DFT), which indicates that the two absorption bands are mainly derived from the contribution of bands *. The calculation of the second order optical nonlinearity was carried out, giving value of molecular hyperpolarizability equal to 4.025ź10–30 esu. These calculated results were also compared with results obtained for a similar molecule, 4-phenyl-3-[(1,2,4-triazol-1-yl)methyl]-triazole-5-thione, reported earlier by this group.

4

Experimental and Theoretical Study on4-Phenyl-3-[(1,2,4-triazol-1-yl)methyl]-triazole-5-thione

Jian F., Zhao P., Bai Z., Cai Z.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 2

325-333

EN

The title compound, 4-phenyl-3-[(1,2,4-triazol-1-yl)methyl]-triazole-5-thione, was synthesized and characterized by elemental analysis, IR and electronic spectra. Density functional theory calculations of the structure, natural bond orbital and thermodynamic functions of the title compound were performed at B3LYP/6-311G** level of theory. Vibrational frequencies were predicted, assigned, compared with the experimental values, and they are supported each other. Electronic absorption spectra were calculated by the time-dependent density functional theory (TD-DFT), which indicates that the two absorption bands aremainly derived from the contribution of bands pi--pi*. The calculation of the second order optical nonlinearity was carried out with PM3 semi-empirical method that resulted in the molecular hyperpolarizability equal to 4.397x10-30 esu.