Density-functional calculations of molecular electron affinities

Takahata, Yuji; Chong, Delano P.

doi:10.1590/s0103-50531999000500003

Cited by 18 publications

(10 citation statements)

References 10 publications

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“…EAs obtained with DFT methods are fairly accurate (within 0.2 eV) in most cases . Earlier studies on a variety of molecules (three or fewer heavy atom) concluded that the B3LYP functional could achieve average errors between 0.1 and 0.2 eV as compared to the experiment. − EA values obtained for p -benzoquinone and a number of methyl- and halogen-substituted p -benzoquinones indicated that the B3LYP functional could yield EAs within experimental error for most quinones and within an average absolute magnitude of 0.05 eV of experimental values . A recently published review 30 on EA also indicated that EA values calculated for a set of 91 molecules by using B3LYP functional have an average error of 0.16 eV.…”

Section: Resultsmentioning

confidence: 75%

Density Functional Theory Studies on Radical Ions of Selected Polychlorinated Biphenyls

2002

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Density functional theory studies provided the adiabatic ionization potentials and electron affinities of six polychlorinated biphenyls (PCBs): 3,3‘,4,4‘- and 2,2‘,5,5‘-tetrachlorobiphenyl; 3,3‘,4,4‘,5-, 2,2‘,4,5,5‘-, and 2,3‘,4,4‘,5-pentachlorobiphenyl; and 3,3‘,4,4‘,5,5‘-hexachlorobiphenyl. A popular three-parameter hybrid functional (B3LYP) with the 6-311G(d,p) and 6-311+G(2d,2p) basis sets was used for this study. We present the optimized structures of the cations and anions of the selected PCBs at the B3LYP/6-311+G(2d,2p) level. In almost all of the studied PCBs, the structure of the ions tended to be more nearly planar than the structure of the corresponding neutrals. The radical ions of 2,2‘,5,5‘-tetrachlorobiphenyl and 2,2‘,4,5,5‘-pentachlorobiphenyl have energetically close syn- and antilike structures. The anions of non-ortho-chlorinated PCBs have coplanar structures. Ionization potentials obtained at the B3LYP/6-311+G(2d,2p) level were 8.07, 8.34, 8.16, 8.36, 8.20, and 8.26 eV for 3,3‘,4,4‘- and 2,2‘,5,5‘-tetrachlorobiphenyl, 3,3‘,4,4‘,5-, 2,2‘,4,5,5‘-, and 2,3‘,4,4‘,5-pentachlorobiphenyl, and 3,3‘,4,4‘,5,5‘-hexachlorobiphenyl, respectively. Adiabatic electron affinities obtained for all of the selected PCBs were positive and larger than the electron affinity of biphenyl. Furthermore, the electron affinities of the non-ortho-chlorinated PCBs were higher than those of their ortho-substituted counterparts.

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Section: Resultsmentioning

confidence: 75%

Density Functional Theory Studies on Radical Ions of Selected Polychlorinated Biphenyls

2002

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“…Earlier EA studies on a variety of molecules concluded that the B3LYP functional could achieve average errors between 0.1 and 0.2 eV as compared to the experiment. [58][59][60][61][62][63][64][65][66][67] A recent review on EA also indicated that EA values calculated for a set of 91 molecules by using the same density functional have an average error of 0.16 eV. 68 These conclusions strongly support the use of the B3LYP functional for EA calculations.…”

Section: Resultsmentioning

confidence: 92%

Electron Affinities and Reductive Dechlorination of Toxic Polychlorinated Dibenzofurans: A Density Functional Theory Study

Arulmozhiraja

Morita

2004

J. Phys. Chem. A

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Density functional theory studies were performed to obtain the adiabatic electron affinities of 15 polychlorinated dibenzofurans (PCDFs), including toxic PCDFs. Three-parameter hybrid density functional B3LYP, with different basis sets up to 6-311+G(2d,2p), was utilized. All the studied PCDFs have planar structures, but some of them attain nonplanar structures upon becoming anions. The lowest unoccupied molecular orbitals of all the PCDF neutrals were found to be π* orbitals. The singly occupied molecular orbitals of most of the anions have π character, while the same found for the anions with longer C−Cl bonds have σ character. The present study clearly showed that chlorine atom bends as the carbon−chlorine bond stretches and the dechlorination could take place through the π*−σ* orbital mixing. The electron affinities of all the selected PCDFs, like those of their toxic polychlorinated dibenzo-p-dioxin and biphenyl counterparts, were positive. Interestingly, the calculated electron affinity of the most toxic 2,3,7,8-tetrachlorodibenzofuran (TCDF) is the largest among the electron affinities calculated for the eight selected TCDFs. The adiabatic electron affinities obtained at the B3LYP/6-311+G(2d,2p) level were 1.029, 1.114, 1.161, 1.286, and 1.253 eV for the toxic 2,3,7,8-TCDF, 1,2,3,7,8-PeCDF, 2,3,4,7,8-PeCDF, 1,2,3,4,7,8-HCDF, and 1,2,3,6,7,8-HCDF, respectively.

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“…Similarly, addition of diffuse functions is useful when considering anions, what is important for our systems. This approach was successfully utilized in calculating of EAs of several chemical compounds [25][26][27] .…”

Section: Methodsmentioning

confidence: 99%

Correlation of the first reduction potential of selected radiosensitizers determined by cyclic voltammetry with theoretical calculations

Gál

Kolivoška

Ambrová

et al. 2011

Collect. Czech. Chem. Commun.

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Radiosensitizers are drugs that make cancer cells more sensitive to radiation therapy. The cytotoxic properties of such compounds are due to the fact that in the cell these compounds undergo one-electron reduction to generate radical anions. Therefore, their theoretical and/or experimental study is of high interest. To determine the correlation between reduction potential determined by cyclic voltammetry measurements and some physicochemical properties of selected radiosensitizers theoretical calculations of electron affinities based on the DFT method with B3LYP functional at the level of 6-311++G** basis set in vacuum were utilized. Very good correlation was found between electron affinities of radiosensitizers and their reduction potential and so called E 7 1 potential that account for the energy necessary to transfer the first electron to an electroactive group at pH 7 in aqueous medium to form a radical anion.

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Density-functional calculations of molecular electron affinities

Cited by 18 publications

References 10 publications

Density Functional Theory Studies on Radical Ions of Selected Polychlorinated Biphenyls

Density Functional Theory Studies on Radical Ions of Selected Polychlorinated Biphenyls

Electron Affinities and Reductive Dechlorination of Toxic Polychlorinated Dibenzofurans: A Density Functional Theory Study

Correlation of the first reduction potential of selected radiosensitizers determined by cyclic voltammetry with theoretical calculations

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