Assessment of the Performance of Four Dispersion-Corrected DFT Methods Using Optoelectronic Properties and Binding Energies of Organic Monomer/Fullerene Pairs
In this study, we employ ω B97x-D, B97-D3, B3LYP-D3, and PBE1PBE-D3 and assess their accuracy by computing binding energies and electronic parameters (such as HOMO and LUMO eigenvalues) of the various (promising) molecular pairings of organic monomers and fullerenes. In addition, we employ time dependent DFT (TD-DFT) to determine optical properties of monomers such as their maximum absorption wavelengths and compare them with the experimental findings. Our results show that B97-D3 and B3LYP-D3 methods give the largest binding energies relative to the other D-DFT methods and they yield (relative to experimental values...
Source: Computational and Theoretical Chemistry - June 19, 2018 Category: Chemistry Source Type: research

Novel method to detect the lung cancer biomarker volatiles using hydrogen vacant silicane nanosheets: A DFT investigation
Publication date: 15 August 2018 Source:Computational and Theoretical Chemistry, Volume 1138 Author(s): V. Nagarajan, R. Chandiramouli Using first-principles calculation, the electronic properties including geometrical stability of bare (BSi) and hydrogenated silicene (HSi) and hydrogen vacant silicane sheets (HvSi) are investigated. The geometrical stability of BSi, HSi and HvSi nanosheets are ensured in accordance with the formation energy and phonon band structure. The prime emphasis of the proposed work is to detect the exhaled human breath biomarkers and to detect the earlier stage of lung cancer disease using HvSi b...
Source: Computational and Theoretical Chemistry - June 19, 2018 Category: Chemistry Source Type: research

The reactivity of coordinatively unsaturated iridium methylene complex IrCH2[N(SiMe2CH2PPh2)2]: A quantum chemistry study
Publication date: 15 August 2018 Source:Computational and Theoretical Chemistry, Volume 1138 Author(s): Zunyi Wu, Chuyue Xiang, Yutong Zhang, Zhijun Song, Qunfang Lei, Wenjun Fang, Hujun Xie The mechanisms for the reactions of the coordinatively unsaturated iridium methylene complex IrCH2[N(SiMe2CH2PPh2)2] with a variety of small molecules including H2, PMe3, CO, Al2Me6, and CH3I have been investigated by the density functional theory (DFT) calculations. The calculation results showed that the reaction of methylene complex with H2 generates the trihydride amine IrH3[HN(SiMe2CH2PPh2)2] via a series of oxidative addition an...
Source: Computational and Theoretical Chemistry - June 19, 2018 Category: Chemistry Source Type: research

Theoretical Study of the Mechanism and Regioselectivity of the Alkylation Reaction of the Phenoxide Ion in Polar Protic and Aprotic Solvents
Publication date: Available online 15 June 2018 Source:Computational and Theoretical Chemistry Author(s): Isac C. Nogueira, Josefredo R. Pliego Alkylation of the phenoxide ion in the solution phase can take place on the oxygen atom (O-alkylation) and the carbon atoms of the aromatic ring in the ortho- and para-positions (C-alkylation). The reaction outcome depends on the alkylating molecule and the solvent. This work presents a density functional theory calculation (X3LYP and M08-SO functionals) of the possible reaction pathways for alkylation of phenoxide ions with ethyl chloride in the following solvents: water, methano...
Source: Computational and Theoretical Chemistry - June 16, 2018 Category: Chemistry Source Type: research

Study of gas-phase reactions within the modified Marcus model. II. CH3OH  + CH3 → CH2OH + CH4
Publication date: 15 August 2018 Source:Computational and Theoretical Chemistry, Volume 1138 Author(s): I.A. Romanskii In the framework of the Marcus theoretical model, using the intramolecular reorganization (IMR) method, the kinetics of the CH3OH + CH3 → CH2OH + CH4 reaction was studied over the temperature range of 10–550 K. The electronic activation energy (Ea ) was calculated at the UCCSD(T)/6-31+G**//B3LYP/6–31+G** level. The calculation of the reaction rate constant, k, defined as the integral over the distance Q(C⋯C), was carried out on the assumption that for a hydrogen atom in th...
Source: Computational and Theoretical Chemistry - June 16, 2018 Category: Chemistry Source Type: research

DFT investigation of methane metathesis with L2AnCH3 actinide complexes catalysts (L = Cl, Cp, Cp ∗; An = Ac, Th, Pa, U, Np, Pu)
Publication date: Available online 14 June 2018 Source:Computational and Theoretical Chemistry Author(s): Fazia Talbi-Ingrachen, Fatiha Talbi, Farida Kias, Aziz Elkechai, Abdou Boucekkine, Claude Daul In order to understand the catalytic activity of the actinide complexes L2AnCH3 (An = Ac, Th, Pa, U, Np and Pu; L = Cl, Cp and Cp∗) towards the activation of the C–H bond of methane, relativistic ZORA/DFT investigations have been carried out. The results obtained from Linear Transit (LT) and Intrinsic Reaction Coordinate (IRC) calculations show that the mechanism involved in these reactions starts with a proton ...
Source: Computational and Theoretical Chemistry - June 15, 2018 Category: Chemistry Source Type: research

Insight into Interaction Properties between Mercury and Lead Cations with Chitosan and Chitin: Density Functional Theory studies
Publication date: Available online 14 June 2018 Source:Computational and Theoretical Chemistry Author(s): S. Jeremić, T.H. Tran, Z. Marković, T.C. Ngo, D.Q. Dao Density functional theory (DFT) studies have contributed to analyze the interaction between chitosan and chitin with Hg(I), Hg(II) and Pb(I), Pb(II) ions in the absence or in the presence of one to three water molecules. All calculations were performed at the M06-2X/LanL2DZ level of theory using Glucosamine and N-acetylglucosamine monomers as models of chitosan and chitin biopolymers, respectively. Geometries of all complexes were optimized, enthalpies and Gibbs...
Source: Computational and Theoretical Chemistry - June 15, 2018 Category: Chemistry Source Type: research

Linear Correlation Between DSSC Efficiency, Intramolecular Charge Transfer Characteristics, and NLO Properties – DFT Approach
Publication date: Available online 15 June 2018 Source:Computational and Theoretical Chemistry Author(s): Dinesh S. Patil, Kiran C. Avhad, Nagaiyan Sekar The trends in the dye-sensitizer solar cells (DSSCs) efficiencies of 4 N, N-dimethylaniline-based polyene sensitizers, NKX-2553, NKX-2554, NKX-2600, and NKX-2569 have been correlated with the trends in intramolecular charge transfer characteristics as revealed by the trends in non-linear optical (NLO) properties. Both an electron-donor and π-linkers play a vital role in the performance of the sensitizer/dye in the DSSCs as well as in NLO properties. Optimized geometri...
Source: Computational and Theoretical Chemistry - June 15, 2018 Category: Chemistry Source Type: research

Theoretical investigation of organotin(IV) complexes of substituted benzohydroxamic acids
Publication date: 15 August 2018 Source:Computational and Theoretical Chemistry, Volume 1138 Author(s): Richa Arora, Upasana Issar, Rita Kakkar The complexing abilities of para-substituted benzohydroxamates to the tin metal center of organotin(IV) ions have been investigated using DFT, since organotin(IV) compounds have been touted as promising anti-cancer agents. We have studied the coordination structures of Sn(IV) complexes (R2SnL2) with organoligands (R = Me, Et, n-Bu) and para-substituted benzohydroxamate ligands (L) so as to study the effect of electron withdrawing (Cl, F, NO2) and electron donating substituents...
Source: Computational and Theoretical Chemistry - June 14, 2018 Category: Chemistry Source Type: research

The Reactivity of Coordinatively Unsaturated Iridium Methylene Complex Ir=CH2[N(SiMe2CH2PPh2)2]: A Quantum Chemistry Study
Publication date: Available online 12 June 2018 Source:Computational and Theoretical Chemistry Author(s): Zunyi Wu, Chuyue Xiang, Yutong Zhang, Zhijun Song, Qunfang Lei, Wenjun Fang, Hujun Xie The mechanisms for the reactions of the coordinatively unsaturated iridium methylene complex Ir=CH2[N(SiMe2CH2PPh2)2] with a variety of small molecules including H2, PMe3, CO, Al2Me6, and CH3I have been investigated by the density functional theory (DFT) calculations. The calculation results showed that the reaction of methylene complex with H2 generates the trihydride amine IrH3[HN(SiMe2CH2PPh2)2] via a series of oxidative addition...
Source: Computational and Theoretical Chemistry - June 12, 2018 Category: Chemistry Source Type: research

Thermodynamic selectivity of multicenter chemical reactions. A statistical quantification of a widespread intuitive approach and its application to reactions of fullerenes
Publication date: Available online 6 June 2018 Source:Computational and Theoretical Chemistry Author(s): Denis Sh. Sabirov, Igor S. Shepelevich, Boris L. Tumanskii Currently, there are many ways to estimate the selectivity of chemical reactions but none of them has the universal character. Therefore, novel approaches are introduced and developed. In the present study, we quantify a comparison of thermodynamic parameters of alternative reaction modes and propose the corresponding equation for thermodynamic selectivity describing the set of the one-type parallel reactions. It is defined as the ratio of the average differenc...
Source: Computational and Theoretical Chemistry - June 7, 2018 Category: Chemistry Source Type: research

Nonlinear optical, IR and orbital properties of Ni doped MgO nanoclusters: A DFT investigation
Publication date: Available online 5 June 2018 Source:Computational and Theoretical Chemistry Author(s): Ali Shokuhi Rad, Khurshid Ayub In the present study, density functional theory calculations have been performed to explore the changes in the electronic properties of Mg12O12 nanocluster through exohedral doping with nickel. The changes in zero-point Energies (ΔZPE), thermal Energies (ΔE), thermal Enthalpies (ΔH), and thermal Free Energies (ΔG) of all positions are also calculated and compared with interaction energies. The HOMO-LUMO gaps of Ni-doped MgO nanocages are reduced significantly mainl...
Source: Computational and Theoretical Chemistry - June 6, 2018 Category: Chemistry Source Type: research

Kinetic effects in 2D and 3D Quantum Dots: Comparison between high and low electron correlation regimes
Publication date: Available online 4 June 2018 Source:Computational and Theoretical Chemistry Author(s): Marlina Slamet, Viraht Sahni Kinetic related ground state properties of a two-electron 2D quantum dot in a magnetic field and a 3D quantum dot (Hooke’s atom) are compared in the Wigner high (HEC) and low (LEC) electron correlation regimes. The HEC regime corresponds to low densities sufficient for the creation of a Wigner molecule. The LEC regime densities are similar to those of natural atoms and molecules. The results are determined employing exact closed-form analytical solutions of the Schrödinger-Pauli ...
Source: Computational and Theoretical Chemistry - June 5, 2018 Category: Chemistry Source Type: research

Mono Substituted Pyrenes as Multifunctional Materials for OLED: Analysis of the Substituent Effects on the Charge Transport Properties Using DFT Methods
Publication date: Available online 1 June 2018 Source:Computational and Theoretical Chemistry Author(s): Niveditha Surukonti, Bhanuprakash Kotamarthi In this work, with a general interest to understand the charge transport properties of mono substituted pyrene molecules which can be used as multifunctional materials in Organic Light Emitting Diodes (OLED), we have analyzed the charge transport properties calculated from DFT methods for a number of the mono substituted pyrene molecules whose crystal structures have been obtained from Cambridge structural data base (CSD). The data for the analysis was obtained by optimizing...
Source: Computational and Theoretical Chemistry - June 2, 2018 Category: Chemistry Source Type: research

Analytic calculation of ground state splitting in symmetric double well potential
Publication date: Available online 1 June 2018 Source:Computational and Theoretical Chemistry Author(s): A.E. Sitnitsky The exact solution of the one-dimensional Schrödinger equation with symmetric trigonometric double-well potential (DWP) is obtained via angular oblate spheroidal function. The results of stringent analytic calculation for the ground state splitting of ring-puckering vibration in the 1,3-dioxole (as an example of the case when the ground state tunneling doublet is well below the potential barrier top) and 2,3-dihydrofuran (as an example of the case when the ground state tunneling doublet is close to ...
Source: Computational and Theoretical Chemistry - June 2, 2018 Category: Chemistry Source Type: research

Diels-Alder Cycloaddition versus Ring-Opening Esterification: A Computational Study of the Mechanism of Formation of Oxa-norbonene Lactones from the Reaction of Furfuryl Alcohol and Itaconic Anhydride
Publication date: Available online 30 May 2018 Source:Computational and Theoretical Chemistry Author(s): Evans Fosu, Cecil Humphrey Botchway, Richard Tia, Evans Adei The reactions of furfuryl alcohol with itaconic anhydride can proceed via four plausible pathways - two pathways involving initial Diels-Alder cycloaddition followed by lactonization and two pathways involving initial esterification followed by intramolecular Diels-Alder cycloaddition - to afford two distinct norbornene products bearing either a five- or six-membered butyrolactone ring respectively. DFT calculations reported herein show that the first-step Di...
Source: Computational and Theoretical Chemistry - May 30, 2018 Category: Chemistry Source Type: research

Comparative study of solvent-CL-20 interactions at different roughness crystal surfaces: Molecular Dynamics Simulation
Publication date: Available online 28 May 2018 Source:Computational and Theoretical Chemistry Author(s): Gang Han, Shu-hai Zhang, Rui-jun Gou, Jing-wen Li The 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20)-solvent (methanol, ethanol, ethyl acetate and acetone) interfacial models were constructed to investigate the intermolecular interaction variances on different roughness surfaces. The constant volume and temperature molecular dynamics (NVT-MD) simulation was performed on the interfacial models. The mass density distributions of four kinds of solvent at interfaces were calculated based on the NVT-MD r...
Source: Computational and Theoretical Chemistry - May 29, 2018 Category: Chemistry Source Type: research

Electronic Stark Effect for a Single Molecule: Theoretical UV Response
Publication date: Available online 29 May 2018 Source:Computational and Theoretical Chemistry Author(s): Nalini D. Gurav, Shridhar P. Gejji, Rajeev K. Pathak Theoretical analysis of optical absorption in the vacuum ultra-violet (VUV) region by single molecules placed in external electrostatic fields reveals characteristic absorption spectra completely at variance with their ‘zero-field’ counterparts consequent to appearance, disappearance, splitting, merging and shifts of absorption bands and extensive intensity redistributions. This ‘molecular electronic Stark effect’ can be tracked through electr...
Source: Computational and Theoretical Chemistry - May 29, 2018 Category: Chemistry Source Type: research

Local density fitting applied to second order propagator equations for core electron binding energies
Publication date: Available online 24 May 2018 Source:Computational and Theoretical Chemistry Author(s): JDJ Villalobos-Castro, José A. Guerrero-Cruz, Bernardo Zuniga-Gutierrez, Roberto Flores-Moreno The second order electron propagator equations were combined with the local density fitting theory. Our equations require only the calculation of analytical three-center electron repulsion integrals. The same set of auxiliary functions employed for the variational fitting of the Coulomb potential are also used for the evaluation of the self–energy in the propagator calculation. Taking advantage of an efficient Ha...
Source: Computational and Theoretical Chemistry - May 25, 2018 Category: Chemistry Source Type: research

Lewis acidity of benzene in half-sandwich ruthenium arene complex. A computational study
Publication date: Available online 24 May 2018 Source:Computational and Theoretical Chemistry Author(s): Shanti G. Patra [Ru(benzene)(en)Cl]+ (en = ethylenediamine) is a very active anticancer drug like cisplatin. It has been shown that upon coordination to metal in half sandwich ruthenium complex the benzene ring becomes electron deficient. A library of Lewis bases: Tetrahydrofuran (THF), Acetonitrile (MeCN), Diethyl ether (Et2O), Water (H2O), Trimethylamine (Me3N), Ammonia (NH3), Pyridine (Py), Benzene (Bz), Furan, Adenine, Carbon monoxide (CO), Thiophene and Phosphine (PH3) are considered to study the Lewis acid charac...
Source: Computational and Theoretical Chemistry - May 25, 2018 Category: Chemistry Source Type: research

Theoretical Study on Abnormal Trans-Effect of Chloride, Bromide and Iodide ligands in Iridium Complexes
Publication date: Available online 24 May 2018 Source:Computational and Theoretical Chemistry Author(s): Chen Wang, Yuan-Ye Jiang Iridium complexes have been widely applied to energy and chemical industry, pharmaceutical industry, and organic synthesis. As a parameter reflecting the interaction between ligands and metal centers, trans-effect plays an important role in the kinetics/thermodynamic stability, the reactivity and the catalytic performance of transition metal complexes. A systematic study was conducted herein to address the abnormal trans-effect of iridium halide complexes reported by Werneke et al. It is found ...
Source: Computational and Theoretical Chemistry - May 25, 2018 Category: Chemistry Source Type: research

Study of gas-phase reactions within the modified Marcus model. II. CH3OH + CH3 → CH2OH + CH4
Publication date: Available online 23 May 2018 Source:Computational and Theoretical Chemistry Author(s): I.A. Romanskii In the framework of the Marcus theoretical model, using the intramolecular reorganization (IMR) method, the kinetics of the CH3OH + CH3 → CH2OH + CH4 reaction was studied over the temperature range of 10-550 K. The electronic activation energy (Ea ) was calculated at the UCCSD(T)/6-31+G**//B3LYP/6-31+G** level. The calculation of the reaction rate constant, k, defined as the integral over the distance Q(C ...C), was carried out on the assumption that for a hydrogen atom in the activated complex (AC)...
Source: Computational and Theoretical Chemistry - May 24, 2018 Category: Chemistry Source Type: research

A Computational Study on Interactions of Ni- and Pt-Doped Boron nitride nano tubes with NH3 in Presence and Absence of Electric Fields
Publication date: Available online 21 May 2018 Source:Computational and Theoretical Chemistry Author(s): Mohsen Mohsennia, Mahdi Rakhshi, Hossein Rasa The density functional theory (DFT) has been used to study the surface interactions of pristine, Ni- and Pt-doped (4,4), (5,5), (7,7) and (8,8) boron nitride nanotubes (BNNTs) with ammonia (NH3) molecules. To verify the impact of external electric field (EF) on the surface interactions between the nanotubes and adsorbed NH3 molecules, in this work, the NH3/(4,4) BNNTs adsorbed complex system under an applied EF with strength of 3×10-2 a.u. and 4×10-2 a.u., along...
Source: Computational and Theoretical Chemistry - May 22, 2018 Category: Chemistry Source Type: research

Effect of side chain edge functionalization in pristine and defected graphene-DFT study
Publication date: 1 July 2018 Source:Computational and Theoretical Chemistry, Volume 1135 Author(s): V.S. Anithaa, S. Vijayakumar The structural and electronic properties of edge-functionalized graphene sheets are systematically investigated utilizing Density Functional Theory (DFT). The functionalization includes alkyl, alkene, and seven different polyacetylene side chains as an alternative for a hydrogen atom in eight different kinds of graphene sheets. CH3 and longer side chains functionalization have high stability and remains unaffected by increasing the size of the graphene sheet. The weak binding energy and large f...
Source: Computational and Theoretical Chemistry - May 22, 2018 Category: Chemistry Source Type: research

Computational design of some TTF-substituted acene-based dyes for solar cell application using hollow ZnO quantum dot as acceptor
Publication date: Available online 19 May 2018 Source:Computational and Theoretical Chemistry Author(s): Md. Habib, Surajit Saha, Ritabrata Sarkar, Anup Pramanik, Pranab Sarkar, Sougata Pal Using first principle methodologies we present here the judicious design of TTF-substituted acene based dyes for solar cell application while hollow ZnO quantum dots could be used as electron sink materials. By calculating the frontier energy level alignment, charge density distribution and optical absorption properties, we way out a route by which the tetrathiafulvalene (TTF) derivatives of different acene molecules could be better ut...
Source: Computational and Theoretical Chemistry - May 20, 2018 Category: Chemistry Source Type: research

Design of the novel neutral organic superacids by comprehensive DFT study on organic fluorosulfuric acids
Publication date: Available online 18 May 2018 Source:Computational and Theoretical Chemistry Author(s): Bahareh Shams, Hamid Saeidian Density functional theory (DFT) calculations at B3LYP/6-311++G(d,p) level have been carried out on organic fluorosulfuric acids, in order to examine their acidities in gas-phase. Strong acidity effect is predicted for a novel series of fluorosulfuric acids in which an oxygen is substituted by an 1,3-cyclohexanedione or 1,3-cyclopentadiene group. The acidity of these acids without any electron withdrawing groups on the ring, was more than fluorosulfuric acid. It is shown that substitution o...
Source: Computational and Theoretical Chemistry - May 19, 2018 Category: Chemistry Source Type: research

All-electron triple zeta basis sets for the actinides
Publication date: Available online 17 May 2018 Source:Computational and Theoretical Chemistry Author(s): A.Z. de Oliveira, C.T. Campos, F.E. Jorge, I.B. Ferreira, P.A. Fantin Non-relativistic and Douglas-Kroll-Hess (DKH) segmented all-electron basis sets of valence triple zeta quality plus polarization functions (TZP) for the actinides are developed. To describe accurately the properties that depend on a good description of the electrons far away from the nuclei, the corresponding augmented sets (ATZP and ATZP-DKH) are reported as well. For the actinide monoxides, bond distances, dissociation energies, natural charges and...
Source: Computational and Theoretical Chemistry - May 18, 2018 Category: Chemistry Source Type: research

Relativistic and nonrelativistic structures, stabilities and electronic properties of small neutral gold clusters
Publication date: Available online 18 May 2018 Source:Computational and Theoretical Chemistry Author(s): Mahnaz Jabbarzadeh Sani, Heidar Ali Pakiari This work uses the nonrelativistic and scalar-relativistic second-order Douglas-Kroll-Hess (DKH2) Hamiltonians together with the all-electron basis sets to determine the structures, stabilities and electronic properties of the small neutral gold clusters, Aun (n≤6). Several levels of theory including the all-electron scalar-relativistic DKH2-M06HF/TZP-DKH, DKH2-B3LYP/TZP-DKH and DKH2-B3LYP/DZP-DKH along with the nonrelativistic B3LYP/DZP are used to calculate the static po...
Source: Computational and Theoretical Chemistry - May 18, 2018 Category: Chemistry Source Type: research

Revisiting electronic nature and geometric parameters of cyclophanes and their relation with stability – DFT, QTAIM and NCI study
Publication date: Available online 12 May 2018 Source:Computational and Theoretical Chemistry Author(s): Caio L. Firme, Diógenes M. Araújo Cyclophanes have several geometric restrictions in their structure due to formation of a closed circuit involving benzenoid rings and aliphatic bridges and they cause instability. We have chosen a wider variety of ciclophanes for the ωB97XD analysis of geometry and thermodynamic data. More detailed geometric parameters have been used in this work such as the deviation from planarity equations and benzenoid CC bond RMSD. Seventy percent of cyclophanes’ stabilit...
Source: Computational and Theoretical Chemistry - May 15, 2018 Category: Chemistry Source Type: research

Theoretical study on reaction mechanism of thermal decomposition of dialkyl peroxides
This study could provide some guidance for understanding the incident-causing process of the thermal decomposition of dialkyl peroxides. Graphical abstract (Source: Computational and Theoretical Chemistry)
Source: Computational and Theoretical Chemistry - May 10, 2018 Category: Chemistry Source Type: research

Oxidation of hydro-silaimine, phosphasilene, and arsasilene structures (CH3)HSiE(CH3) (E: N, P, or As) via concerted 1,3-dipolar cycloaddition of nitrous oxide: A DFT study
Publication date: 15 June 2018 Source:Computational and Theoretical Chemistry, Volume 1134 Author(s): Cem Burak Yildiz Possible concerted 1,3-dipolar cycloaddition reactions of element-hydrogen containing silaimine, phosphasilene, and arsasilene structures (CH3)HSiE(CH3) (denoted as SiE, E = N, P, As) with nitrous oxide (N2O) were investigated at the WB97XD/cc-pVTZ level of theory. In all cases, the nature of E atom determines the kinetic of the reactions. Thereby, the reactivity order of SiE structures toward N2O was observed to be SiAs > SiP>SiN, as it is evident from the calculated energy barriers...
Source: Computational and Theoretical Chemistry - May 9, 2018 Category: Chemistry Source Type: research

Full configuration-interaction calculations of the angular quantities for helium atom
Publication date: Available online 5 May 2018 Source:Computational and Theoretical Chemistry Author(s): Li Guang Jiao, Li Rong Zan, Lin Zhu, Yew Kam Ho The angular quantities 〈 θ 12 〉 and 〈 cos θ 12 〉 for helium atom in both ground and singly-excited states are calculated in the framework of full configuration interaction. The two-electron system wave functions are expanded in terms of the product of Slater-type orbitals. The convergence and accuracy of reported results are examined in detail. From the comparison with previous work, it is shown that the present work establishes the most accurate predic...
Source: Computational and Theoretical Chemistry - May 6, 2018 Category: Chemistry Source Type: research

Rearrangements in Radical Cations of Diazoketones: A DFT Mechanistic Study
Publication date: Available online 5 May 2018 Source:Computational and Theoretical Chemistry Author(s): Ritu Arora, Kriti Kashyap, Rita Kakkar The mechanism of the Wolff rearrangement of some radical cations of diazocarbonyl compounds has been studied using density functional calculations. The C−C bond of diazoketones weakens slightly on cation formation, which lowers the barrier to the syn-anti isomerization of the radical cations, as compared to that of the neutral analogue. The effect of substitution on both carbonyl carbon and diazocarbon of the diazoethanal radical cation has been explored. The planarity of the...
Source: Computational and Theoretical Chemistry - May 6, 2018 Category: Chemistry Source Type: research

Transition metal hydrides MH+/0/ − (M = Sc−Zn): Benchmark study and periodic trends
Publication date: 15 June 2018 Source:Computational and Theoretical Chemistry, Volume 1134 Author(s): Yuyang Cai, Xiaoli Sun, Xuri Huang Transition metal hydride (TMH) plays a critical role in the field of chemical catalysis and catalytic transformations. Knowledge of enthalpies for cleaving metal hydride bonds enables the prediction of chemical reactivity, such as for the bond-forming and bond breaking events that occur in a catalytic reaction especially in the hydrogenation of carbon dioxide. Thermochemistry of the first row TMHs, MH+/0/− (M = Sc−Zn) were calculated at both the Density Functional Theory ...
Source: Computational and Theoretical Chemistry - May 6, 2018 Category: Chemistry Source Type: research

Oxidation of hydro −silaimine, phosphasilene, and arsasilene structures (CH3)HSi=E(CH3) (E: N, P, or As) via concerted 1,3-dipolar cycloaddition of nitrous oxide: A DFT study
Publication date: Available online 3 May 2018 Source:Computational and Theoretical Chemistry Author(s): Cem Burak Yildiz Possible concerted 1,3−dipolar cycloaddition reactions of element−hydrogen containing silaimine, phosphasilene, and arsasilene structures (CH3)HSi=E(CH3) (denoted as SiE, E = N, P, As) with nitrous oxide (N2O) were investigated at the WB97XD/cc−pVTZ level of theory. In all cases, the nature of E atom determines the kinetic of the reactions. Thereby, the reactivity order of SiE structures toward N2O was observed to be SiAs>SiP>SiN, as it is evident from the calculated ener...
Source: Computational and Theoretical Chemistry - May 4, 2018 Category: Chemistry Source Type: research

Ab initio molecular dynamics of electron transfer from gallic acid to small radicals: a comparative study between hydroxyl and nitrogen dioxide radicals.
This study focuses on the radical scavenging activity of gallic acid towards two radicals: hydroxyl and nitrogen dioxide in aqueous cluster. The reactivity was analyzed by ab initio molecular dynamics using CPMD code. For both radicals, the reaction consists in an electron transfer from gallate anion to the radical. The transfer occurs through water molecules chains forming a loop with the reactants. This study shows that the electron transfer occurs before the formation of adduct. It is the main channel excluding other types of reactivity. Graphical abstract (Source: Computational and Theoretical Chemistry)
Source: Computational and Theoretical Chemistry - May 4, 2018 Category: Chemistry Source Type: research

Computational Study of the Chemical Reactivity of the Blue-M1 Intermediate Melanoidin
This study assessed eight density functionals that include CAM-B3LYP, LC- ω PBE, M11, MN12SX, N12SX, ω B97, ω B97X, and ω B97XD related to the Def2TZVP basis sets together with the SMD solvation model. These are assessed in calculating the molecular properties and structure of the Blue-M1 intermediate melanoidin pigment. Notably, the chemical reactivity descriptors for the system are calculated via the Conceptual Density Functional Theory. The choice of active sites applicable to nucleophilic, electrophilic as well as radical attacks is made by linking them with Fukui functions indices, electrophili...
Source: Computational and Theoretical Chemistry - May 4, 2018 Category: Chemistry Source Type: research

Transition Metal Hydrides MH+/0/ – (M = Sc−Zn): Benchmark Study and Periodic Trends
Publication date: Available online 26 April 2018 Source:Computational and Theoretical Chemistry Author(s): Yuyang Cai, Xiaoli Sun, Xuri Huang Transition metal hydride (TMH) plays a critical role in the field of chemical catalysis and catalytic transformations. Knowledge of enthalpies for cleaving metal hydride bonds enables the prediction of chemical reactivity, such as for the bond-forming and bond breaking events that occur in a catalytic reaction especially in the hydrogenation of carbon dioxide. Thermochemistry of the first row TMHs, MH+/0/– (M = Sc−Zn) were calculated at both the density functional theory...
Source: Computational and Theoretical Chemistry - May 3, 2018 Category: Chemistry Source Type: research

Binding of Phenolic Model Compounds with Noble Metal Doped Graphene Sheets
In this study, palladium- and platinum- doped graphene sheets are examined theoretically for all possible interactions of oxygenates such as guaiacol, phenol, anisole, vanillin, and salicylaldehyde on to metal doped graphene catalyst surfaces to understand preliminary adsorption mechanisms. For this purpose, B3PW91 functional of density functional theory (DFT) has been utilized. Adsorption kinetics, for instance, adsorption free energy, adsorption enthalpy, and equilibrium rate constant at a fixed pressure of 1 atm but over a wide range of temperature (400-800 K) are reported. Briefly results indicate that binding of both ...
Source: Computational and Theoretical Chemistry - May 3, 2018 Category: Chemistry Source Type: research

Influence of transition metals Fe, Co, Ni, Cu and Ti on the dehydrogenation characteristics of LiBH4: A first-principles investigation
Publication date: 1 June 2018 Source:Computational and Theoretical Chemistry, Volume 1133 Author(s): Zhuonan Huang, Yuqi Wang, Di Wang, Fusheng Yang, Zhen Wu, Zaoxiao Zhang LiBH4 is among a few chemicals with the highest hydrogen storage capacities. In this paper, the crystal structure, electronic structure and dehydrogenation properties of both pure and transition metal (TM = Fe, Co, Ni, Cu and Ti)-modified LiBH4 were investigated by using first-principles calculations based on density functional theory. According to the computing results, the occupation energies of TM-doped LiBH4 suggest that the metal atoms prefer ...
Source: Computational and Theoretical Chemistry - May 3, 2018 Category: Chemistry Source Type: research

Citric acid: A promising copper scavenger
Publication date: 1 June 2018 Source:Computational and Theoretical Chemistry, Volume 1133 Author(s): Ana Martínez, Rubicelia Vargas, Annia Galano In this investigation, the capacity of citric acid as copper scavenger is analyzed. For the copper scavenger capacity, the formation of the chelate complexes is studied using the Gibbs free energies. The chelates may be formed since the formation reactions are all exergonic. The free radical scavenger ability of chelate complexes is investigated using the single electron transfer mechanism with the Full Electron Donor-Acceptor Map (FEDAM). Different acid-base species of c...
Source: Computational and Theoretical Chemistry - May 3, 2018 Category: Chemistry Source Type: research

Clustering of sulfuric acid, bisulfate ion and organonitrate C10H15O10N: Thermodynamics and atmospheric implications
Publication date: 1 June 2018 Source:Computational and Theoretical Chemistry, Volume 1133 Author(s): Jason Herb, Alexey B. Nadykto, Kirill M. Nazarenko, Nikolai A. Korobov, Fangqun Yu Recently, Highly Oxidized Molecules (HOMs) have been suggested to play an important role in New Particle Formation (NPF) in the atmosphere. Although stable clusters containing organonitrates (ONs), a common form of HOM, have been detected in both laboratory experiments and in-situ measurements, the role of ONs in their stability is still poorly understood. In this paper, we carry out a Density Functional Theory (DFT) study of the bonding of ...
Source: Computational and Theoretical Chemistry - May 3, 2018 Category: Chemistry Source Type: research

Development of firefly oxyluciferin derivatives as pH sensitive fluorescent Probes: A DFT/TDDFT study
Publication date: 1 June 2018 Source:Computational and Theoretical Chemistry, Volume 1133 Author(s): Chun-Gang Min, Qing-Bo Liu, Yan Leng, Shao-Jun Huang, Chun-Xia Liu, Xi-Kun Yang, Ai-Min Ren, Luís Pinto da Silva Because of its high fluorescence quantum yield, high sensitivity and high signal-to-noise ratio, firefly oxyluciferin is widely used in the field of fluorescent probe. However, there are six chemical forms which can possibly co-existence in solution. Reliable relative stability of the different forms in solution made the analysis of their photophysical properties difficult. In order to address this issue ...
Source: Computational and Theoretical Chemistry - May 3, 2018 Category: Chemistry Source Type: research

DFT study of ortho, meta and para –pyridyl cations. Pyridynium found?
Publication date: 1 June 2018 Source:Computational and Theoretical Chemistry, Volume 1133 Author(s): Gary W. Breton The phenyl cation has been the subject of many experimental and theoretical studies because of its importance in synthetic organic chemistry. Based on interesting experimental observations from the literature, we have computationally studied the electronic and structural effects of introducing a nitrogen atom into the aromatic ring (i.e., pyridyl rings) of phenyl cations at the M06–2X/6–311+G(d,p) level of theory. Introduction of the nitrogen at the meta and para positions destabilize the ion rel...
Source: Computational and Theoretical Chemistry - May 3, 2018 Category: Chemistry Source Type: research

Study of the nonlinear optical properties of 4-nitroaniline type compounds by density functional theory calculations: Towards new NLO materials
Publication date: 1 June 2018 Source:Computational and Theoretical Chemistry, Volume 1133 Author(s): Said Figueredo López, Manuel Páez Meza, Francisco Torres Hoyos In the present work, the values of dipolar moment, linear polarizability, first hyperpolarizability, energies of electronic hyperconjugation, and HOMO-LUMO gaps were determined for investigate the nonlinear optical properties of 18 4-nitroaniline type compounds. For this purpose, the finite field approximation and the Natural Bond Orbital method were used, performing the electronic calculations at the DFT level using the chemical model B3LYP/6-311...
Source: Computational and Theoretical Chemistry - May 3, 2018 Category: Chemistry Source Type: research

Stability of endo- and exohedral complexes of all-boron fullerene B40
Publication date: 1 June 2018 Source:Computational and Theoretical Chemistry, Volume 1133 Author(s): Michał Chojecki, Sirous Yourdkhani, Dorota Rutkowska-Zbik, Tatiana Korona In a recent publication [Nature Chemistry, 6, 727 (2014)] the synthesis and properties of a new all-boron fullerene analog, B40, have been reported, and a possibility of utilizing the B40 molecule as a hydrogen storage has been postulated. Therefore, in this contribution we study the stability of endo- and exohedral complexes with the hydrogen molecule and several other small molecules, such as N2, H2O, and CO2. The examination of binding and intera...
Source: Computational and Theoretical Chemistry - May 3, 2018 Category: Chemistry Source Type: research

Graphene induced molecular flattening of meso-5,10,15,20-tetraphenyl porphyrin: DFT calculations and molecular dynamics simulations
Publication date: 1 June 2018 Source:Computational and Theoretical Chemistry, Volume 1133 Author(s): V.A. Karachevtsev, S.G. Stepanian, M.V. Karachevtsev, L. Adamowicz Noncovalent functionalization of graphene with porhyrins that possess a large conjugated π-system of bonds can extend the range of practical applications of this nanomaterial. In this work the structures of hybrids formed by porphin and meso-5,10,15,20-tetraphenyl porphyrin (TPP) with graphene and the corresponding intermolecular interaction energies are studied with the DFT and molecular dynamics (MD) calculations. The influence of the peripheral rings ...
Source: Computational and Theoretical Chemistry - May 3, 2018 Category: Chemistry Source Type: research

Ab inito study on the electronic structure and laser cooling of SiH
Publication date: 15 June 2018 Source:Computational and Theoretical Chemistry, Volume 1134 Author(s): Yun-Guang Zhang, Ge Dou, Jian-Xia Qi, Jie Cui Potential energy curves (PECs) of six electronic states ( X 2 Π , a 4 Σ - , A 2 Δ , B 2 Σ - , C 2 Σ + , and D 2 Σ + ) are calculated based on multi-reference configuration interaction plus Davidson corrections (MRCI + Q), and the spin–orbit coupling (SOC) effects are considered at the MRCI + Q level. By solving the radical Schrödinger equation, the spectroscopic constants of these states are obtained, which agree well wit...
Source: Computational and Theoretical Chemistry - May 3, 2018 Category: Chemistry Source Type: research

Theoretical investigations on copper catalyzed CN cross-coupling reaction between aryl chlorides and amines
Publication date: 15 June 2018 Source:Computational and Theoretical Chemistry, Volume 1134 Author(s): Khalil Ahmad, Bilal Ahmad Khan, Bilal Akram, Jahanzeb Khan, Rashid Mahmood, Soumendra K. Roy The mechanism of CuI/oxalic diamide catalyzed arylation of amines with chlorobenzene was investigated computationally. CuI/N,N′-bis(2,4,6-trimethoxyphenyl)-oxalamide (BTMPO) system was selected as model catalytic system. On the basis of relative Gibbs free energy, five different possible intermediate Cu1 complexes were selected for mechanistic studies. Intermediate complexes Int1–Int3 have a BTMPO ligand deprotonated a...
Source: Computational and Theoretical Chemistry - May 3, 2018 Category: Chemistry Source Type: research

Effect of Ammonia-Water Complex on Decomposition of Carbonic Acid in Troposphere: A Quantum Chemical Investigation
Publication date: Available online 10 April 2018 Source:Computational and Theoretical Chemistry Author(s): Subhasish Mallick, Saptarshi Sarkar, Biman Bandyopadhyay, Pradeep Kumar Quantum chemical calculations at MP2 and CCSD(T) levels of theory have been performed to investigate the effect of ammonia-water complex on the decomposition of carbonic acid. The results indicate that, ammonia-water complex catalyzed channel can compete with other catalysts like formic acid, water, water dimer, ammonia and ammonia dimer, which are known to facilitate this reaction. Potential energy barrier for ammonia-water complex catalyzed cha...
Source: Computational and Theoretical Chemistry - April 11, 2018 Category: Chemistry Source Type: research