Tests of second-generation and third-generation density functionals for electron affinities of the alkylthio radicals

The molecular structures and electron affinities of the R – S / R – S -( R = CH 3, C 2 H 5, n- C 3 H 7, n- C 4 H 9, n- C 5 H 11, i- C 3 H 7, i- C 4 H 9, t- C 4 H 9) species have been studied using 17 pure and hybrid density functionals (five generalized gradient approximation (GGA) methods, six hybrid GGAs, one meta GGA method and five hybrid meta GGAs). The basis set used in this work is of double-ζ plus polarization quality with additional diffuse s- and p-type functions, denoted by DZP++. The geometries are fully optimized with each DFT method and discussed. Harmonic vibrational frequencies are found to be within 3.5% of available experimental values for most functionals. Three different types of the neutral-anion energy separations have been presented. The theoretical electron affinities of alkylthio radicals are in good agreement with the experiment data. The M06 method is very good for the adiabatic electron affinity calculations, and the average absolute error is 0.0439 eV. The HCTH method performs better for EA prediction. The M06-HF, mPWPW91, VSXC and B98 are also reasonable. The most reliable adiabatic electron affinities are predicted to be 1.864 eV ( CH 3 S ), 1.946 eV ( C 2 H 5 S ), 1.959 eV (n- C 3 H 7 S ), 1.970 eV (n- C 4 H 9 S ), 1.982 eV (n- C 5 H 11 S ), 2.053 eV (i- C 3 H 7 S ), 1.991 eV (i- C 4 H 9 S ) and 2.100 eV (t- C 4 H 9 S ) at the M06/DZP++ level of theory, respectively.

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The Electron Affinities of the Alkyldithio Radicals and their Anions

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.512-515.2059 ◽

2012 ◽

Vol 512-515 ◽

pp. 2059-2063 ◽

Cited By ~ 1

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.

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GEOMETRICAL AND ELECTRONIC STRUCTURE OF PROPYL-, TETRAMETHYL-, DIMETHYLETHYL- AND BUTYLADAMANTANES AND THEIR THERMODYNAMIC CHARACTERISTIC ACCORDING TO DFT

IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA ◽

10.6060/ivkkt.20186112.5717 ◽

2018 ◽

Vol 61 (12) ◽

pp. 108-114

Author(s):

Amanzhan T. Saginayev ◽

Evgenii I. Bagrii

Keyword(s):

Experimental Data ◽

Qualitative Agreement ◽

Isopropyl Alcohol ◽

Analytical Calculation ◽

Dft Method ◽

Energy Functional ◽

Basis Set ◽

Stationary Points ◽

Important Conclusion ◽

Good Agreement

Propyladamantanes were synthesized by alkylation of adamantane with isopropyl alcohol in the temperature range from 5 to 40 °C in the presence of 96% sulfuric acid. Tetramethyl- and dimethylethyladamantanes were synthesized by isomerization of perhydroanthracene in the presence of aluminium oxide catalyst on the setup of the flow type. Isomers of butyladamantanes were obtained by the reaction of alkylation of the adamantane with isooctane. For each molecule, the optimization of the geometric parameters of atoms was carried out using analytical calculation methods. By calculating the frequencies of normal vibrations using the second derivatives, it was confirmed that the stationary points determined by optimizing the geometry correspond to the minima of the potential energy surface. The structure of 1-n-propyladamantane (I), 1-isopropyl-adamantane (II), 2-n-propyladamantane (III), 1,2-di-n-propyladamantane (IV), 1,3-dimethyl-5-ethyladamantane (V), 1,3,5,6-tetramethyladamantane (VI), 1,3,5,7-tetramethyladamantane (VII), perhydroanthracene (VIII), 1-n-butyladamantane (IX), 1-isobutyladamantane (X), 1-sec-butyladamantane (XI) has been studied using the DFT method with the Becke–Lee–Yang–Parr hybrid energy functional of electron density with the 6-31G* basis set. The geometric and electronic characteristics of the compounds and their total energy, normal vibration frequencies have been calculated. It has been shown that the calculated Gibbs free energies of formation for the perhydroanthracene isomerization products are in qualitative agreement with the experimental product composition of the isomerate and alkylation of adamantane with isopropyl alcohol are in qualitative agreement with the experimental composition of the products. A good agreement of calculated and experimental data on the composition of equilibrium mixtures was obtained. The theoretical geometry of the synthesized alkyladamantanes with Td symmetry very well agrees with the results of electron diffraction. Closest to the results obtained experimentally, the geometry was predicted by B3LYP, in which the lengths of C-C and C-H bonds are close to 1.544 and 1,100Ả, respectively, and the C-Csec-C and C-Cter-C angles are 109°. The results of the calculation using the B3LYP method are in good agreement with the experimental data. There is no definite relationship between the size of the molecules and the convergence of the calculated and experimental data. A practically important conclusion arising from the results of this and previous studies is that the use of the calculation method leads to “chemically accurate” data.

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Theoretical Study of the Substituent and Nitrogen Number Effects on the Uranium Binding Selectivity of Crown Ethers

Acta Chimica Asiana ◽

10.29303/aca.v3i1.30 ◽

2020 ◽

Vol 3 (1) ◽

pp. 147

Author(s):

Saprizal Hadisaputra ◽

Agus Abhi Purwoko ◽

Ria Armunanto ◽

Harno Dwi Pranowo

Keyword(s):

Density Functional ◽

Opposite Effect ◽

Atomic Charge ◽

Basis Set ◽

Structural Parameter ◽

Binding Selectivity ◽

Functional Theory ◽

Experimental Values ◽

Effective Core Potentials ◽

Good Agreement

The compounds, [UO2(dibenzo-18-crown-6)]2+ and [UO2(18-crown-6)]2+, as well as their related complexes: numerous disubstituted dibenzo-18-crown-6 and azacrown complexes are studied using density functional theory (DFT). Quasi-relativistic effective core potentials developed in the Stuttgart and Dresden groups was used together with the accompanying basis set for uranium and DZP basis set was used for crown ether atoms. The effects of substituent and nitrogen number on the binding selectivity were discussed in term of the structural parameter, atomic charge and interaction energy, thermodynamic parameters, and charge transfer. The electron donating substituents increase the capability of dibenzo-18-crown-6 toward UO22+ ion. In contrast, the electron withdrawing substituents have the opposite effect. It clearly shows that UO22+ prefers N donor recognition. For the systems involved, the result shows that the hexaaza-18-crown-6 exhibits the largest metal interaction capability to UO22+ ion. The calculated results are in a good agreement with the experimental values.

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DFT-ONIOM study of the dopamine–β-CD complex: NBO and AIM analysis

Canadian Journal of Chemistry ◽

10.1139/cjc-2014-0481 ◽

2015 ◽

Vol 93 (10) ◽

pp. 1115-1121 ◽

Cited By ~ 8

Author(s):

Rayenne Djemil ◽

Ouassila Attoui-Yahia ◽

Djameleddine Khatmi

Keyword(s):

Intermolecular Hydrogen Bond ◽

Minimum Energy ◽

Reference Method ◽

Dft Method ◽

Relative Performance ◽

Basis Set ◽

Basis Sets ◽

Density Functionals ◽

Cyclodextrin Complex ◽

Aim Analysis

In this work, we conducted a systematic search of the minimum energy of a dopamine–β-cyclodextrin complex via different ONIOM approaches using both mixed (DFT-HF) and nonmixed (DFT-DFT) combinations. Different density functionals were employed: B3LYP, MPW1PW91, M05-2X, M06-2X, and ωB97X-D. Two different basis sets were used on the dopamine–β-cyclodextrin complex; a lower basis set (3-21G*) is used on β-cyclodextrin and a higher basis set (6-31G(d)) is used on dopamine. To fulfill this task, complexation and deformation energies were determined. The relative performance of these functionals was compared with that obtained with the DFT method at the M06-2X/6-31G(d) level that is chosen as a reference method. Although we did not clearly establish an assessment of the relative performance of these density functionals, the efficacy of the ONIOM combination (DFT-HF) is shown compared with a nonmixed ONIOM combination (DFT-DFT). The intermolecular hydrogen bond interactions of the complex obtained with the full M06-2X/6-31G(d) have been analyzed with the atoms-in-molecules and natural bond rrbital methodologies.

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

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc2011067 ◽

2011 ◽

Vol 76 (8) ◽

pp. 937-946 ◽

Cited By ~ 1

Author(s):

Miroslav Gál ◽

Viliam Kolivoška ◽

Marta Ambrová ◽

Ján Híveš ◽

Romana Sokolová

Keyword(s):

Experimental Study ◽

Cyclic Voltammetry ◽

Radical Anion ◽

Reduction Potential ◽

Theoretical Calculations ◽

Dft Method ◽

Basis Set ◽

Radical Anions ◽

Electron Affinities ◽

Electron Reduction

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 E71 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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A Thermochemical Computational Study on Hydroxyquinolines and their Azulene Analogues

10.26434/chemrxiv.7495808 ◽

2018 ◽

Author(s):

Moyassar Meshhal ◽

Safinaz El-Demerdash ◽

Ahmed El-Nahas

Keyword(s):

Gas Phase ◽

Computational Study ◽

Enthalpies Of Formation ◽

Mean Absolute Deviation ◽

Electron Affinities ◽

Absolute Deviation ◽

The Mean ◽

Experimental Values ◽

Theory And Experiment ◽

Good Agreement

Ab initio CBS-QB3 method has been used to determine gas-phase enthalpies of formation for 34 compounds including a number of hydroxyquinoline isomers, the corresponding azulene analogues and their parent systems. The mean absolute deviation of 4.43 kJ/mol reveals good agreement between our results and the available experimental data. Relative thermodynamic stabilities of hydroxyquinoline isomers and related analogues were discussed and several isomerization reactions enthalpies were derived. The same level of theory has also been utilized to calculate adiabatic ionization energies and electron affinities for the molecules with known experimental values and the agreement between theory and experiment was found to be within 8 kJ/mol.

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A Thermochemical Computational Study on Hydroxyquinolines and their Azulene Analogues

10.26434/chemrxiv.7495808.v1 ◽

2018 ◽

Author(s):

Moyassar Meshhal ◽

Safinaz El-Demerdash ◽

Ahmed El-Nahas

Keyword(s):

Gas Phase ◽

Computational Study ◽

Enthalpies Of Formation ◽

Mean Absolute Deviation ◽

Electron Affinities ◽

Absolute Deviation ◽

The Mean ◽

Experimental Values ◽

Theory And Experiment ◽

Good Agreement

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Modeling of Hydrodynamics in a 25 mm ϕ Pulsed Disk and Doughnut Column

ISRN Chemical Engineering ◽

10.1155/2013/547489 ◽

2013 ◽

Vol 2013 ◽

pp. 1-10 ◽

Cited By ~ 9

Author(s):

Rajnish Kumar ◽

D. Sivakumar ◽

Shekhar Kumar ◽

U. Kamachi Mudali

Keyword(s):

Slip Velocity ◽

Drop Size ◽

Absolute Error ◽

Model Parameters ◽

Dispersed Phase ◽

Acid System ◽

Hydrodynamic Parameters ◽

Predicted Values ◽

Experimental Values ◽

Good Agreement

The hydrodynamic parameters, namely, dispersed phase holdup and flooding throughput, have been investigated in 25 mm diameter pulsed disk and doughnut column (PDDC), in no mass transfer conditions. In this work, using existing correlations on plate pulsed columns, the dispersed phase holdup and the flooding throughput are empirically modelled well using the slip velocity concept. A good agreement is observed between experimental values and predicted values obtained from empirical correlation. The experimental data for dispersed phase holdup and flooding throughput has been modelled using the Van Delden model to describe the hydrodynamics characteristics of a PDDC and necessary adjustable parameters for drop size distribution and dispersed phase holdup are updated for 30% TBP-nitric acid system. The model parameters were estimated by minimizing the absolute error between experimental and theoretical values of flooding throughput and holdup data. It was found that the measured values and observed trends could be described accurately using this model after fitting holdup and flooding data. The error between the experimental and theoretical values of flooding throughput and holdup was found to be less than 10%.

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Experimental (FT-IR, Laser-Raman and NMR) and theoretical spectroscopic analysis of 3-[(N-methylanilino)methyl]-5-(thiophen-2-yl)-1,3,4-oxadiazole-2(3H)-thione

Journal of Theoretical and Computational Chemistry ◽

10.1142/s0219633617500249 ◽

2017 ◽

Vol 16 (03) ◽

pp. 1750024 ◽

Cited By ~ 2

Author(s):

Yusuf Sert ◽

Nuri Öztürk ◽

Fatmah A. M. Al-Omary ◽

Can Alaşalvar ◽

Mona M. Al-Shehri ◽

...

Keyword(s):

Molecular Orbital ◽

Chemical Shifts ◽

Molecular Structures ◽

Basis Set ◽

Spectroscopic Techniques ◽

Nmr Chemical Shifts ◽

Laser Raman ◽

Ft Ir ◽

Experimental Values ◽

Vibrational Wavenumbers

The structure of a potential bioactive agent namely, 3-[([Formula: see text]-methylanilino)methyl]-5-(thiophen-2-yl)-1,3,4-oxadiazole-2(3[Formula: see text]-thione was characterized by proton and carbon-13 nuclear magnetic resonance (NMR) chemical shifts, Fourier transform infrared (FT-IR) and Laser-Raman spectroscopic techniques. The quantum chemical computations of molecular structures (disorder I and disorder II forms), vibrational wavenumbers, carbon-13 and proton chemical shifts and UV-Vis spectroscopic parameters have been performed with DFT/B3LYP method at 6-311[Formula: see text]G(d,p) basis set. The highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), nonlinear optical (NLO) properties and natural bond orbital (NBO) analyses have been theoretically examined with the mentioned calculation level. The calculated values have been compared with the recorded experimental data. The computed molecular geometric parameters, vibrational wavenumbers, NMR chemical shifts, and UV-Vis wavelengths have been found to be in a good harmony with the experimental values and spectral results of similar structures in the literature. We believe that the work will be of considerable interest to anyone working in the area of theoretical chemistry, whether in industry or academics.

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Molecular Structures and Spectral Properties of Natural Indigo and Indirubin: Experimental and DFT Studies

Molecules ◽

10.3390/molecules24213831 ◽

2019 ◽

Vol 24 (21) ◽

pp. 3831 ◽

Cited By ~ 4

Author(s):

Zixin Ju ◽

Jie Sun ◽

Yanping Liu

Keyword(s):

Density Functional Theory ◽

Spectral Properties ◽

Density Functional ◽

Dft Method ◽

Molecular Structures ◽

Basis Set ◽

Frontier Molecular Orbital ◽

Visible Absorption ◽

Functional Theory ◽

Uv Visible

This paper presents a comparative study on natural indigo and indirubin in terms of molecular structures and spectral properties by using both computational and experimental methods. The spectral properties were analyzed with Fourier transform infrared (FTIR), Raman, UV-Visible, and fluorescence techniques. The density functional theory (DFT) method with B3LYP using 6-311G(d,p) basis set was utilized to obtain their optimized geometric structures and calculate the molecular electrostatic potential, frontier molecular orbitals, FTIR, and Raman spectra. The single-excitation configuration interaction (CIS), time-dependent density functional theory (TD-DFT), and polarization continuum model (PCM) were used to optimize the excited state structure and calculate the UV-Visible absorption and fluorescence spectra of the two molecules at B3LYP/6-311G(d,p) level. The results showed that all computational spectra agreed well with the experimental results. It was found that the same vibrational mode presents a lower frequency in indigo than that in indirubin. The frontier molecular orbital analysis demonstrated that the UV-Visible absorption and fluorescence bands of indigo and indirubin are mainly derived from π → π* transition. The results also implied that the indigo molecule is more conjugated and planar than indirubin, thereby exhibiting a longer maximum absorption wavelength and stronger fluorescence peak.

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