S. Han

Progressive study and robustness test of QSAR model based on quantum chemical parameters for predicting BCF of selected polychlorinated organic compounds (PCOCs).

Systematic analyses on the effects of chemical structures of 31 polychlorinated organic compounds (PCOCs) on their bioconcentration behavior in rainbow trout (Oncorhynchus mykiss) were conducted using quantitative structure-activity relationship (QSAR) techniques. The cluster analyses of individual variables as well as the quality control chart of QSAR model implies the existence of outliers, while the simulation model excluding such samples showed an extreme robustness even if it was tested with different methods. Furthermore, the quantum chemical parameters entering into QSAR model were used to describe the bioconcentration pathways, and the results indicated that bioconcentration behaviors of selected compounds were complicated processes involving permeation stages as well as bio-chemical reaction stages.

The genotoxicity of substituted nitrobenzenes and the quantitative structure-activity relationship studies

The genotoxicity of 22 substituted nitrobenzenes was evaluated by the chromosome aberrations test in cultured human peripheral lymphocytes. 18 of 22 compounds exhibit genotoxic activities. A quantitative structure-activity relationship model was established to correlate the genotoxicity of substituted nitrobenzenes and the characteristics of the substituents on the benzene ring.

Experimental and theoretical study on molecular structure and FT-IR, Raman, NMR spectra of 4,4′-dibromodiphenyl ether

In this work, both experimental and theoretical study on the FT-IR and Raman spectra as well as (1)H NMR and (13)C NMR chemical shifts of 4,4-dibromodiphenyl ether have been carried out. The optimized geometry was obtained by using both HF and density functional B3LYP method with the 6-31G(d) and 6-311+G(d, p) basis sets. The calculated bond lengths and dihedral angles for both methods on 6-31G(d) level show the best agreement with the experimental data, while the dihedral angles of C(1)-O-C(1)-C(6) and C(1)-O-C(1)-C(2), critical geometry parameters for conformers in the ground state, indicates significant deviation of HF results from the experimental information. The harmonic vibration frequencies and intensities in IR and Raman spectra and chemical shifts of the molecule were calculated on the B3LYP/6-31G(d) and B3LYP/6-311+G(d, p) levels. The scaled theoretical vibration frequencies present good agreement with the experimental values. The larger basis set makes no significant improvement in the accuracy of the vibration frequencies. Besides, chemical shifts of hydrogen and carbon computed on B3LYP/6-31G(d) level agree well with the observations.

Joint QSAR Analysis Using the Free-Wilson Approach and Quantum Chemical Parameters

Abstract A new quantitative structure-activity relationship (QSAR) technique combining the Free-Wilson method and constructed quantum chemical parameters was used to simulate the aqueous solubility (S w), 1-octanol/water partition coefficient (K ow) of 14 new synthesized benzanilide derivatives and their 96 h acute toxicity (EC50) to Daphnia magna. The mode of action of the 14 selected compounds to Daphnia magna was shown to be a complex process involving a physical partition stage and a biochemical reaction stage. The results also indicated that the joint (QSAR) analysis was much effective than the original Free-Wilson method and Hansch method not only in predicting properties/toxicity, but also in investigating the mode of action of chemicals.