Structural parameters of 22 halogen phenols were computed at four levels using Hartree-Fock and DFT methods. Based on the experimental data of the acute toxicity to Tetrahymena pyriformis （-lgEC_50）, three-parameter...Structural parameters of 22 halogen phenols were computed at four levels using Hartree-Fock and DFT methods. Based on the experimental data of the acute toxicity to Tetrahymena pyriformis （-lgEC_50）, three-parameter （energy of the lowest unoccupied molecular orbital （E_LUMO）, the molecular volume （V）, and the lowest negative charge （Q_min）） dependent equations were developed using structural parameters as theoretical descriptors. Especially, -lgEC_50dependent equation calculated at the B3LYP/6-31G^＊＊ level is more advantageous than the others in view of their correlation and predictive abilities. This dependent equation was validated by variance inflation factors （VIF） and t-test methods. Upon comparison, the predictive abilities of our work are all more advantageous than those calculated from the semi-empirical PM3 method.展开更多
The ubiquitous distribution of halogenated aromatic compounds（XAr） coupled with their carcinogenicity has raised public concerns on their potential risks to both human health and the ecosystem. Recently, advanced ox...The ubiquitous distribution of halogenated aromatic compounds（XAr） coupled with their carcinogenicity has raised public concerns on their potential risks to both human health and the ecosystem. Recently, advanced oxidation processes（AOPs） have been considered as an＂environmentally-friendly＂ technology for the remediation and destruction of such recalcitrant and highly toxic XAr. During our study on the mechanism of metal-independent production of hydroxyl radicals（UOH） by halogenated quinones and H_2O_2, we found, unexpectedly, that an unprecedented UOH-dependent two-step intrinsic chemiluminescene（CL） can be produced by H_2O_2 and tetrachloro-p-benzoquinone, the major carcinogenic metabolite of the widely used wood preservative pentachlorophenol. Further investigations showed that, in all UOH-generating systems, CL can also be produced not only by pentachlorophenol and all other halogenated phenols, but also by all XAr tested. A systematic structure–activity relationship study for all 19 chlorophenolic congeners showed that the CL increased with an increasing number of Cl-substitution in general. More importantly, a relatively good correlation was observed between the formation of quinoid/semiquinone radical intermediates and CL generation. Based on these results, we propose that UOH-dependent formation of quinoid intermediates and electronically excited carbonyl species is responsible for this unusual CL production; and a rapid, sensitive,simple, and effective CL method was developed not only to detect and quantify trace amount of XAr, but also to provide useful information for predicting the toxicity or monitoring real-time degradation kinetics of XAr. These findings may have broad chemical, environmental and biological implications for future studies on halogenated aromatic persistent organic pollutants.展开更多
基金support by the Natural Science Foundation of University, Anhui Province (No. 2006KJ156B)
文摘Structural parameters of 22 halogen phenols were computed at four levels using Hartree-Fock and DFT methods. Based on the experimental data of the acute toxicity to Tetrahymena pyriformis （-lgEC_50）, three-parameter （energy of the lowest unoccupied molecular orbital （E_LUMO）, the molecular volume （V）, and the lowest negative charge （Q_min）） dependent equations were developed using structural parameters as theoretical descriptors. Especially, -lgEC_50dependent equation calculated at the B3LYP/6-31G^＊＊ level is more advantageous than the others in view of their correlation and predictive abilities. This dependent equation was validated by variance inflation factors （VIF） and t-test methods. Upon comparison, the predictive abilities of our work are all more advantageous than those calculated from the semi-empirical PM3 method.
基金supported by the Strategic Priority Research Program of CAS(No.XDB01020300)NSF China Grants(Nos.21577149,21477139,21237005 and 21321004)NIH Grants(Nos.ES11497,RR01008 and ES00210)
文摘The ubiquitous distribution of halogenated aromatic compounds（XAr） coupled with their carcinogenicity has raised public concerns on their potential risks to both human health and the ecosystem. Recently, advanced oxidation processes（AOPs） have been considered as an＂environmentally-friendly＂ technology for the remediation and destruction of such recalcitrant and highly toxic XAr. During our study on the mechanism of metal-independent production of hydroxyl radicals（UOH） by halogenated quinones and H_2O_2, we found, unexpectedly, that an unprecedented UOH-dependent two-step intrinsic chemiluminescene（CL） can be produced by H_2O_2 and tetrachloro-p-benzoquinone, the major carcinogenic metabolite of the widely used wood preservative pentachlorophenol. Further investigations showed that, in all UOH-generating systems, CL can also be produced not only by pentachlorophenol and all other halogenated phenols, but also by all XAr tested. A systematic structure–activity relationship study for all 19 chlorophenolic congeners showed that the CL increased with an increasing number of Cl-substitution in general. More importantly, a relatively good correlation was observed between the formation of quinoid/semiquinone radical intermediates and CL generation. Based on these results, we propose that UOH-dependent formation of quinoid intermediates and electronically excited carbonyl species is responsible for this unusual CL production; and a rapid, sensitive,simple, and effective CL method was developed not only to detect and quantify trace amount of XAr, but also to provide useful information for predicting the toxicity or monitoring real-time degradation kinetics of XAr. These findings may have broad chemical, environmental and biological implications for future studies on halogenated aromatic persistent organic pollutants.
