Electron affinities from electron transfer equilibria in the gas phase and the electron affinity of SO2

1984 ◽  
Vol 80 (1) ◽  
pp. 577-579 ◽  
Author(s):  
Gary Caldwell ◽  
P. Kebarle
Keyword(s):  
Electron Transfer ◽  
Gas Phase ◽  
Electron Affinity ◽  
Electron Affinities

scholarly journals ANALYSIS OF DIFFERENT DATASETS FOR IONIZATION POTENTIAL AND ELECTRON AFFINITY OF QUINONES ON THE BASIS OF DFT CALCULATIONS

2017 ◽  
Vol 60 (8) ◽  
pp. 4
Author(s):  
Li Sun ◽  
Jianhua Ran ◽  
Cong Zhang ◽  
Felix Yu. Telegin
Keyword(s):  
Electron Transfer ◽  
Dft Calculations ◽  
Ionization Potential ◽  
Electron Affinity ◽  
Density Functional ◽  
Basis Sets ◽  
Electron Affinities ◽  
Linear Quadratic ◽  
Equilibrium Studies ◽  
Chemical Catalysis

The idea of this research deals with theoretical problems of studying quinones as representatives of natural and synthetic compounds with a huge variety of applications in chemical catalysis, biomedical and technical sciences. For this purpose computational chemistry is chosen as an advanced tool for evaluating electronic energies in gase phase for a series of simple quinones, naphthoquinones and anthraquinones as parent compounds for more complicated ones. Ionization potentials and electron affinities (IPs and EAs) of 88 quinones are calculated by the use of B3LYP level of density functional theory (DFT) with different basis sets, and on this base the validation of several databases for electronic energies of quinones is done. The databases for EAs include published results of measurements of absolute electron affinities of pi charge transfer complex acceptors and those determined as relative values from electron transfer equilibrium studies. Non-linear quadratic correlation was found for relationship between calculated and experiment values of electron affinities. Analysis of the relative deviation between obtained calculated results and the three experimental databases indicated the high quality of the database proposed by Hilal et al. based on electron transfer equilibrium studies. The results found in the research are applicable for validation of computational methods and experimental data for electronic energies of quinones.Forcitation:Li Sun, Jianhua Ran, Cong Zhang, Telegin F.Yu. Analysis of different datasets for ionization potential and electron affinity of quinones on the basis of DFT calculations. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 8. P. 4-12.

The acidity of polyhalogenated silanes and silyl radicals

1992 ◽  
Vol 70 (8) ◽  
pp. 2234-2240 ◽  
Author(s):  
C. F. Rodriquez ◽  
A. C. Hopkinson
Keyword(s):  
Gas Phase ◽  
Molecular Orbital ◽  
Electron Affinity ◽  
Substituent Effects ◽  
Linear Interpolation ◽  
Molecular Orbital Calculations ◽  
Electron Affinities ◽  
Silyl Radicals ◽  
Experimental Values ◽  
Cl Atom

The results of abinitio molecular orbital calculations at the MP4SDTQ/6-31++G(d,p)//HF/6-31++G(d,p) level have been used to calculate acidities of fluoro- and chloro-substituted silanes and silyl radicals. The radicals are more acidic than the silanes and substituent effects are also slightly larger in the radicals. For the gas phase deprotonation of fluorosilanes at 298 K, ΔHr (kcal/mol) values are SiH4, 378.5; SiH3F, 374.5; SiH2F, 366.7, and SiHF3, 351.0, i.e., interaction between fluorine atoms leads to increased enhancement of acidity. For chlorosilanes substituent effects are larger but strictly additive (13 kcal/mol for each Cl atom) with ΔHr values SiH3Cl, 365.4; SiH2Cl2 352.5, and SiHCl3 339.4. The electron affinities of silyl radicals calculated using isogyric reactions at the MP4SDTQ/6-31++G(d,p) level are too low by ~0.3 eV, but at the MP4SDTQ/6-311++G(2df,p) level the calculated electron affinity of SiH3 is 1.39 eV, compared with an experimental value of 1.44 ± 0.03 eV. This higher level of theory gives calculated electron affinities of 1.53 eV for SiH2F and 1.92 eV for SiH2Cl. Heats of formation obtained by using isogyric reactions to calculate atomization energies at the MP4SDTQ/6-311++G(2df,p) level are within 3 kcal/mol of experimental values except for SiH2F (where the "experimental" value was obtained from linear interpolation between SiH3 and SiF3). [Formula: see text] (kcal/mol) calculated for the anions are SiH3−, 14.4; SiH2F−, −78.0; and SiH2Cl−, −37.6.

Electron affinities of substituted nitrobenzenes

1989 ◽  
Vol 67 (4) ◽  
pp. 603-610 ◽  
Author(s):  
S. Chowdhury ◽  
H. Kishi ◽  
G. W. Dillow ◽  
P. Kebarle
Keyword(s):  
High Pressure ◽  
Electron Transfer ◽  
Gas Phase ◽  
Substituent Effects ◽  
Negative Ions ◽  
Radical Anions ◽  
Electron Affinities ◽  
Frontier Orbital ◽  
Data Set ◽  
Qualitative Discussion

The electron affinities of 14 substituted nitrobenzenes including nitrobiphenyls were determined by measurement of electron transfer equilibria [1] in the gas phase with a pulsed high pressure mass spectrometer: A− + B = A + B− [1]. These data, when combined with previous determinations from this laboratory, lead to electron affinities for 35 substituted nitrobenzenes and provide a comprehensive data set for the examination of substituent effects. The data are used to derive Taft gas-phase substituent parameters. A qualitative discussion based on frontier orbital molecular theory examines the substituent effect on the benzene and nitrobenzene LUMOs. The lifetimes for electron autodetachment from excited nitrobenzene negative ions, (A−)*, studied earlier by Christophorou, are examined in light of the present electron affinity data. Keywords: electron affinities, substituent effects, frontier orbital treatment, electron autodetachment from nitrobenzene radical anions.

Entropy changes and electron affinities from gas-phase electron-transfer equilibria: A- + B = A + B-

1986 ◽  
Vol 90 (12) ◽  
pp. 2747-2752 ◽  
Author(s):  
Swapan Chowdhury ◽  
Thomas Heinis ◽  
Eric P. Grimsrud ◽  
Paul Kebarle
Keyword(s):  
Electron Transfer ◽  
Gas Phase ◽  
Electron Affinities ◽  
Entropy Changes

Electron Affinities from Thermal Proton-Transfer Reactions: C6H5 and C6H5CH2

1971 ◽  
Vol 49 (17) ◽  
pp. 2918-2920 ◽  
Author(s):  
D. K. Bohme ◽  
L. Brewster Young
Keyword(s):  
Proton Transfer ◽  
Gas Phase ◽  
Electron Affinity ◽  
Transfer Reactions ◽  
Electron Affinities ◽  
Bond Energies ◽  
Preferred Direction ◽  
Proton Transfer Reactions

The observation of the preferred direction of proton transfer reactions in the gas phase at 300 °K has been employed to bracket the electron affinity, e.a., of the radicals C6H5 and C6H5CH2 using well-established values for electron affinities and bond energies. The results indicate that 1.2 eV ≤ e.a.(C6H5) ≤ 1.6 eV and that 0.4 eV ≤ e.a.(C6H5CH2) ≤ 0.9 eV.

Electron affinity states of metal supported phthalocyanines measured by tunneling spectroscopy

2012 ◽  
Vol 16 (03) ◽  
pp. 273-281 ◽  
Author(s):  
K.W. Hipps ◽  
Ursula Mazur
Keyword(s):  
Gas Phase ◽  
Electron Affinity ◽  
Electron Tunneling ◽  
Tunneling Spectroscopy ◽  
Film Deposition ◽  
Solution Phase ◽  
Minor Role ◽  
Electron Affinities ◽  
Langmuir Blodgett ◽  
Metal Insulator Metal

Orbital Mediated Tunneling Spectroscopy OMTS (elastic electron tunneling) was employed in measuring electron affinity levels (EA) of unsubstituted, alkylated, sulfonated, and metalated phthalocyanines (Pc) adsorbed as single molecules or aggregates on metal substrates and imbedded in metal-insulator-metal (M-I-M) devices. MPc complexes were vapor deposited, solution phase doped, or transferred as Langmuir–Blodgett films. It was determined that while the nature of the substituents has a large effect on the gas phase electron affinities, they play a minimal role on the electron affinities of metal supported phthalocyanines. Moreover, the orientation of monolayer films and the method of film deposition (vapor, solution, Langmuir–Blodgett) also appear to play only a minor role in determining the electron affinities. Electrochemical reduction potentials obtained for the solution phase molecular systems are compared to the OMTS data and a strong correlation is observed. In contrast, the predicted EA values for the gas phase molecules show little correspondence with their OMTS equivalents for adsorbed phthalocyanines. Inelastic scattering from phthalocyanine π→π* transitions and metal centered d–d transitions are observed for chromophores imbedded in tunnel diodes. Both the observed lowest spin forbidden transitions and the calculated gas phase HOMO–LUMO gaps are only weakly affected by Pc substitution and surface orientation.

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