Substituent Effect on a Family of Quinones in Aprotic Solvents: An Experimental and Theoretical Approach
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- 作者：Carlos Frontana ; Á ; lvaro Vá ; zquez-Mayagoitia ; Jorge Garza ; Rubicelia Vargas ; Ignacio Gonzá ; lez
- 刊名：Journal of Physical Chemistry A
- 出版年：2006
- 出版时间：August 3, 2006
- 年：2006
- 卷：110
- 期：30
- 页码：9411 - 9419
- 全文大小：123K
- 年卷期：v.110,no.30(August 3, 2006)
- ISSN：1520-5215
文摘
In this work a comparison between redox potentials, obtained by constructing current-potential plots fromchronoamperometric measurements, and the parameter 
x, as proposed by Zuman in terms of the Hammettsubstituent parameters, was performed for several quinone compounds. This study shows the limitations ofthis approach and proves that methods based on quantum chemistry can be used to study the substituenteffect in quinone systems. By using the Density Functional Theory, in the Kohn-Sham context with threeexchange-correlation functionals, BLYP, B3LYP, and BHLYP, it was found that the electron affinity is goodenough to give a useful relationship with experimental redox potentials of quinone systems. This conclusionis reached when the basis set functions involve diffuse functions, and also when the Hartree-Fock exchangeenergy is included in the exchange-correlation functional. The Fukui function, to describe preferential sitesinvolved at initial stages of a system that bind an electron, is analyzed when electron donor and electronacceptor groups are present as substituents in quinone systems. The methods applied in this work are validfor any kind of quinone compound and will be used in further analysis of the electron reorganization insemiquinone species.
x, as proposed by Zuman in terms of the Hammettsubstituent parameters, was performed for several quinone compounds. This study shows the limitations ofthis approach and proves that methods based on quantum chemistry can be used to study the substituenteffect in quinone systems. By using the Density Functional Theory, in the Kohn-Sham context with threeexchange-correlation functionals, BLYP, B3LYP, and BHLYP, it was found that the electron affinity is goodenough to give a useful relationship with experimental redox potentials of quinone systems. This conclusionis reached when the basis set functions involve diffuse functions, and also when the Hartree-Fock exchangeenergy is included in the exchange-correlation functional. The Fukui function, to describe preferential sitesinvolved at initial stages of a system that bind an electron, is analyzed when electron donor and electronacceptor groups are present as substituents in quinone systems. The methods applied in this work are validfor any kind of quinone compound and will be used in further analysis of the electron reorganization insemiquinone species.