scholarly journals Ionisation potential and electron affinity of free 5′,8-cyclopurine-2′-deoxynucleosides. DFT study in gaseous and aqueous phase

2010 ◽  
Vol 8 (1) ◽  
pp. 70-76 ◽  
Author(s):  
Boleslaw Karwowski
Keyword(s):  
Ionization Potential ◽  
Aqueous Phase ◽  
Electron Affinity ◽  
Density Functional ◽  
Zero Point ◽  
Basis Set ◽  
A Cell ◽  
Vertical Detachment Energy ◽  
Vertical Electron Affinity ◽  
The Stability

AbstractOxidatively generated damage to DNA frequently appears in the human genome as an effect of aerobic metabolism or as the result of exposure to exogenous oxidizing agents. Due to these facts it was decided to present, for the first time, the electron affinity, ionization potential of 5′,8-cyclo-2′-deoxyadenosine/guanosine (cdA, cdG) in their 5′R and 5′S diastereomeric forms. For all points of quantum mechanics studies presented, the density functional theory (DFT) with B3LYP parameters on 6-311++G** basis set level was used. The zero-point vibrational corrected adiabatic electron affinity (AEA) and adiabatic ionization potential (AIP) were calculated. Additionally the vertical electron affinity (VEA), vertical detachment energy (VDE) and vertical ionization potential were taken into consideration. AEA in eV (gaseous/aqueous phase) are as follows: 0.3/1.81 (5′R)cdA, 0.13/1.76 (5′S)cdA, 0.17/1.49 (5′R)cdG, 0.14/1.53 (5′S)cdG and AIP followed the order 7.43/5.59(5′S)cdG, 7.49/5.60(5′R)cdG, 7.77/5.97(5′R)cdA, 7.84/5.93(5′S)cdA. The obtained AIPs were found to be lower than that for corresponding natural nucleosides. Therefore, even though the 5′,8-cyclopurine-2′-deoxynucleoside level in a cell was judged as low, they can play an important role in the stability, replication and transcription of genes.

The Electron Affinities of the Alkyldithio Radicals and their Anions

2012 ◽  
Vol 512-515 ◽  
pp. 2059-2063 ◽  
Author(s):  
Hui Yi Pei ◽  
Ai Fang Gao
Keyword(s):  
Electron Affinity ◽  
Density Functional ◽  
Basis Set ◽  
Electron Affinities ◽  
Hartree Fock ◽  
Functional Methods ◽  
Different Types ◽  
Vertical Detachment Energy ◽  
Vertical Electron Affinity ◽  
P Type

The electron affinities of the CnH2n+1SS/CnH2n+1SS- (n=1-5) species have been determined using four different density functional or hybrid Hartree-Fock density functional methods. The basis set used in this work is of double- plus polarization quality with additional diffuse s- and p-type functions, denoted DZP++. Three different types of the neutral-anion energy separations reported in this work are the adiabatic electron affinity (EAad), the vertical electron affinity (EAvert), and the vertical detachment energy (VDE). The most reliable adiabatic electron affinities, obtained at the DZP++ BP86 level of theory, are 1.794 eV (for CH3SS), 1.777 eV (for C2H5SS), 1.778 eV (a) and 1.809 eV (b) for the two isomers of C3H7SS, 1.782 eV (a), 1.825 eV (b) and 1.778 eV (c) for the three isomers of C4H9SS, and 1.784 eV (a), 1.875 eV (b), 1.805 eV (c) and 1.835 eV (d) for the three isomers of C5H11SS, respectively.

The DFT Quantum Chemistry Study of Hexafluorobenzene

2012 ◽  
Vol 610-613 ◽  
pp. 106-110
Author(s):  
Hui Yi Pei ◽  
Ai Fang Gao ◽  
Zhen Ya Zhu
Keyword(s):  
Electron Affinity ◽  
Density Functional ◽  
Molecular Structures ◽  
Basis Set ◽  
Electron Affinities ◽  
Dft Methods ◽  
Dissociation Energies ◽  
Theoretical Predictions ◽  
Vertical Detachment Energy ◽  
Vertical Electron Affinity

The molecular structures, electron affinities, and dissociation energies of the C6F6molecule have been determined using seven hybrid and pure density functional theory (DFT) methods and the DZP++ basis set. Three different types of the neutral-anion energy separations reported in this work are the adiabatic electron affinity (EAad), the vertical electron affinity (EAvert), and the vertical detachment energy (VDE). The most reliable adiabatic electron affinities, obtained at the B3PW91 and B3LYP levels, are 0.59 and 0.69 eV, respectively. The first dissociation energies De(C6F5-F) for the neutral C6F6predicted by the DFT methoSubscript textds except BHLYP are 5.195.44 eV. Compared with the limited experimental dissociation energies, our theoretical predictions of the B3LYP and B3PW91 methods are fairly reasonable.

Theoretical investigation of the stability, reactivity, and the interaction of methyl-substituted peridinium-based ionic liquids

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Emmanuel A. Bisong ◽  
Hitler Louis ◽  
Tomsmith O. Unimuke ◽  
Victoria M. Bassey ◽  
John A. Agwupuye ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Electron Density ◽  
Density Functional ◽  
Natural Bond Orbital ◽  
Stabilization Energy ◽  
Basis Set ◽  
Bond Critical Point ◽  
Electronic Interaction ◽  
Donor And Acceptor ◽  
The Stability

Abstract This research work focuses on the reactivity, stability, and electronic interaction of pyridinium hydrogen nitrate (PHN)-based ionic liquids and the influence of methyl substituent on this class of ionic liquids: Ortho- (O-MPHN), meta- (M-MPHN), and para- (P-MPHN) substitution. Natural bond orbital (NBO) calculations were performed at the density functional theory (DFT) with Becke’s Lee Yang and Parr functional (B3LYP) methods and DFT/B3LYP/6-311++G(d,p) as basis set using GAUSSIAN 09W and GAUSSVIEW 6.0 software and the most important interaction between donor (Filled Lewis-type NBO’s) and the acceptor (vacant non-Lewis NBOs) were observed. From our natural bond orbital (NBO) result, it could be deduced that the higher the stabilization energy value, the greater the interaction between the donor and acceptor NBOs. The stability of the studied compounds is said to follow the order from O-MPHN > PHN > P-MPHN > M-MPHN based on the hyperconjugative interaction (stabilization energy) of the most significant interaction. The result of the highest occupied molecular orbital (HOMO), shows that PHN has the highest HOMO while the substituted derivatives have similar HOMO values between −7.70 and −7.98 eV thus PHN complex is the best electron donor while the substituted derivatives act as electron acceptors due to the presence of methyl group substituent which is observed to be electron deficient as a result of its withdrawal effect from the aromatic ring. Furthermore, the electron density, real space functions such as energy density and Laplacian of electron density at bond critical point (BCP) of the hydrogen bond interaction of the studied compounds were analyzed using Multifunctional Wavefunction analyzer software version 3.7 and it was observed that the hydrogen at position 6 and oxygen at position 11 (H6–O11) of M-methyl pyridinium nitrate with bond distance of 4.59 (Å) gave binding energy with the strongest electrostatic interaction between the cation and anion of the compounds under investigation. We also observed from our results that, substitution at the ortho position enhances the stability and strengthen the extent of charge transfer. This therefore implies that substitution at ortho position is more favorable for inter- and intramolecular interactions resulting to stabilization of the studied molecules.

Reaction kinetics of OH radicals with glutaric acid and adipic acid in the aqueous phase

2021 ◽  
Author(s):  
Liang Wen ◽  
Thomas Schaefer ◽  
Hartmut Herrmann
Keyword(s):  
Aqueous Phase ◽  
Adipic Acid ◽  
Rate Constants ◽  
Density Functional ◽  
Glutaric Acid ◽  
Radical Reaction ◽  
Basis Set ◽  
Oh Radicals ◽  
Oh Radical ◽  
Energy Barriers

<p>Dicarboxylic acids (DCAs) are widely distributed in atmospheric aerosols and cloud droplets and are mainly formed by the oxidation of volatile organic compounds (VOCs). For example, glutaric acid and adipic acid are two kinds of the DCAs that can be oxidized by hydroxyl radical (‧OH) reactions in the aqueous phase of aerosols and droplets. In the present study, the temperature- and pH-dependent rate constants of the aqueous OH radical reactions of the two DCAs were investigated by a laser flash photolysis-long path absorption setup using the competition kinetics method. Based on speciation calculations, the OH radical reaction rate constants of the fully protonated (H<sub>2</sub>A), deprotonated (HA<sup>-</sup>) and fully deprotonated (A<sup>2-</sup>) forms of the two DCAs were determined. The following Arrhenius expressions for the T-dependency of the OH radical reaction of glutaric acid, k(T, H<sub>2</sub>A) = (3.9 ± 0.1) × 10<sup>10</sup> × exp[(-1270 ± 200 K)/T], k(T, HA<sup>-</sup>) = (2.3 ± 0.1) × 10<sup>11</sup> × exp[(-1660 ± 190 K)/T], k(T, A<sup>2-</sup>) = (1.4 ± 0.1) × 10<sup>11</sup> × exp[(-1400 ± 170 K)/T] and adipic acid, k(T, H<sub>2</sub>A) = (7.5 ± 0.2) × 10<sup>10</sup> × exp[(-1210 ± 170 K)/T], k(T, HA<sup>-</sup>) = (9.5 ± 0.3) × 10<sup>10</sup> × exp[(-1200 ± 200 K)/T], k(T, A<sup>2-</sup>) = (8.7 ± 0.2) × 10<sup>10</sup> × exp[(-1100 ± 170 K)/T] (in unit of L mol<sup>-1</sup> s<sup>-1</sup>) were derived.</p><p>The energy barriers of the H-atom abstractions were simulated by the Density Functional Theory calculations run with the GAUSSIAN package using the M06-2X method and the basis set m062x/6-311++g(3df,2p). The results showed that the energy barriers were lower at the C<sub>β</sub>-atoms and are higher at the C<sub>α</sub>-atoms of the two DCAs, clearly suggesting that the H-atom abstractions occurred predominately at the C<sub>β</sub>-atoms. In addition, the ionizations can enhance the electrostatic effects of the carboxyl groups, significantly reducing the energy barriers, leading to the order of OH radical reactivity as  <  < . This study intends to better characterize the losing processes of glutaric acid and adipic acid in atmospheres.</p>

Calculation of Ionization Potential and Electron Affinity of the Optoelectronic Material Iridium (III) Metal Complexes Containing the 2-phenyl Pyridine-Type Ligands

2013 ◽  
Vol 738 ◽  
pp. 52-55
Author(s):  
Hong Ying Xia ◽  
Guo Hua Ge ◽  
Feng Zhao
Keyword(s):  
Density Functional Theory ◽  
Solid State ◽  
Metal Complexes ◽  
Ionization Potential ◽  
Transition Metal Complexes ◽  
Electron Affinity ◽  
Density Functional ◽  
Electron Affinities ◽  
Functional Theory ◽  
Experimental Values

Solid state ionization potential and electron affinity of iridium (III) metal complexes containing the 2-phenyl pyridine-type ligands was calculated using density functional theory (DFT). It is shown that the calculated results are in well agreement with the experimental values. With this approach, it is convince to obtain solid state ionization potentials and electron affinities of a range of neutral transition metal complexes.

Structures and stabilities of (OsnN)0,±(n = 7 − 11) clusters

2015 ◽  
Vol 29 (23) ◽  
pp. 1550163
Author(s):  
W. L. Guo ◽  
L. L. Zhang ◽  
M. Luo ◽  
X. R. Zhang
Keyword(s):  
Density Functional Theory ◽  
Ionization Potential ◽  
Electron Affinity ◽  
Ground State ◽  
Density Functional ◽  
Magic Number ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Generalized Gradient Approximation ◽  
Ground State Structures

Structures and stabilities of [Formula: see text] clusters have been systematically studied via using density functional theory (DFT) with generalized gradient approximation (GGA). The calculations show that the stable configurations of [Formula: see text] are such structures with one N atom bonded to the external of the basic constructions consisting of Os atoms. Meanwhile, [Formula: see text] clusters [Formula: see text] represent “magic number” effect, and 8 is the magic number. Additionally, the ground-state structures of [Formula: see text] clusters have the best stability, while that of [Formula: see text] cluster possesses the worst stability. The result of the study on the ionization potential (IP) and the electron affinity (EA) shows that there are not topological differences among the configurations of [Formula: see text][Formula: see text] clusters.

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