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1

Experimental and Density Functional Studies on Two Substituted 1H-Benzimidazoles

Zhao P., Yu H., Jian F., Wang X.

Polish Journal of Chemistry

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2007

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Vol. 81, nr 8

1511-1519

EN

Two substituted 1H-benzimidazoles, 2-(4-chlorophenyl)-1H-benzimidazole and 1-(2- chlorobenzyl)-2-(2-chlorophenyl)-1H-benzimidazole, have been synthesized and characterized by elemental analysis, IR and UV-Vis spectra. An extended MO calculations using density functional theory (DFT) at B3LYP/6-311G** level have been carried out on the two compounds. Comparison of the experiments with the calculated results suggests that the optimized geometries can well reproduce the molecular structures. Atomic charge distributions show that both of the title compounds are potential ligands to coordinate with metallic ions. Natural population analyses indicate that the electronic transitions corresponding to electronic spectra are mainly derived from the contribution of bands pi--pi*. Thermodynamic properties of the two title compounds at different temperatures have also been calculated on the basis of vibration analyses.

2

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.

3

Density Functional Calculations on a Double Hydrogen Bonded Dimer of (p-Methoxyphenyl)thiosemicarbazide

Zhao P., Li R., Zhang L., Jian F.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 12

2031-2039

EN

Density functional theory (DFT) calculations on a double hydrogen-bonded dimer of (p-methoxyphenyl)thiosemicarbazide were carried out at B3LYP/6-31G* level. The optimized geometry of the dimer closely resembles that in the crystal. The calculated results show that the total energy of the dimer is much lower than the sum of energies of the two monomers, and the average strength of the double hydrogen bond is about 21.92 kJ/mol. In order to probe the origin of the interactions in the dimer, natural bond orbital analyses have been performed. The thermodynamic properties of the title compound at different temperatures have also been calculated on the basis of vibrational analyses and the change of Gibbs free energy for dimerization of the twomonomers.GT = –18.40 kJ/mol at 298.15 K and 0.1MPa, which implies the spontaneous process of the dimer formation. The correlation graphs of Sm 0, Hm 0 and temperatures for the dimer are depicted.

4

Experimental Studies on Isonicotinato Zinc(II) Complex [Zn(C6H4NO2)2(H2O)4] and Density Functional Calculations

Zhao P., Jian F., Li C.

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 6

1041-1046

EN

Isonicotinato zinc(II) complex [Zn(C6H4NO2)2(H2O)4] has been synthesized by hydrothermal method and characterized by elemental analysis, electronic-spectra and thermogravimetric analysis. Density functional theory (DFT) method calculations of the structure, atomic charges distribution, electronic spectra, natural population analysis and the thermodynamic properties at different temperatures have been performed. The calculated results show the electronic transitions are mainly derived from the contribution of pi--pi* bands and the decomposition of the title compound should firstly occur at the bond of Zn-O, then at the bond of Zn-N, which agrees very well with the experimental data.

5

Crystal Structure and Ab Initio Studies on (p-Methoxyphenyl)thiosemicarbazide

Zhao P., Jian F., Hou Y.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 10

1945-1951

EN

(p-Methoxyphenyl)thiosemicarbazide [CH3OC6H4NHNHCSNH2] has been prepared and characterized by elemental analysis, IR, electronic absorption spectra and X-ray single crystal diffraction. In the crystal lattice, there exist some intermolecular hydrogen bonds, _-_ stacking interactions and C-Hźźź_ supramolecule interactions, which stabilize the crystal structure. Ab initio calculations at HF/6-31G* level of the structure, charges distribution, electronic spectra, natural population analysis and thermodynamic properties at different temperatures have been performed. The calculated results show that the sulfur atom and nitrogen atoms have bigger negative charges, which result in they are the potential sites to react with the metallic ions. The electronic transitions associated with the electronic absorption spectra are mainly derived from the contribution of bands pi-pi*.

6

Synthesis, Structure and Spectroscopic Properties of Bis(2,4-dichloro-phenol-methylene-1H-benzimidazole-N3)-dichlorocobalt(II)

Jian F., Bei F. I., Wang X., Lu D. L.

Polish Journal of Chemistry

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2003

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Vol. 77 / nr 7

821-828

EN

The title compound, CoL2Cl2 [L = (2,4-dichloro-phenol-methylene-1H- -benzimidazole)], has been synthesized and structurally characterized by elemental analysis, IR and X-ray. The coordination geometry of cobalt(II) may be represented by slightly distorted tetrahedron with the CoN2Cl2 chromophore. In the solid state, the title compound forms infinite one-dimensional chains in the [101] direction through hydrogen bonds and potentially weak intermolecular interactions. The IR data agree with the crystal structure. The thermal gravimetry (TG) data indicate that there are two decomposition steps. The final product of thermal decomposition is Co2O3. The magnetic properties of the title compound are also reported and discussed.