Theoretical study on the reaction of Cp*(pentamethylcyclopentadienyl)(Cl)Zr(diene) with isonitriles
Publication date: 1 October 2017 Source:Computational and Theoretical Chemistry, Volume 1117 Author(s): Ming-Ran Du, Xiang-Biao Zhang, Feng Yang, Chang-Min Hou The migratory insertion of isonitriles into metalC bonds is a potentially important method for the formation of CC bonds in organic and pharmaceutical syntheses. In this context, the reaction mechanism of Cp*(pentamethylcyclopentadienyl)(Cl)Zr(diene) with isonitriles was studied using density functional theory calculations. Zr imido complexes and α-methylene cyclopentenimines are the confirmed products for N-tBu-, N-2,6-diMePh-, and N-1-adamantyl-substituted ...
Source: Computational and Theoretical Chemistry - August 24, 2017 Category: Chemistry Source Type: research

Theoretical study of intermolecular interactions in FH ⋯C4B2H6⋯X clusters (X=H2O, CH3OH, NH3, O2, N2, HCN, CO, NO and CO2)
Publication date: 1 October 2017 Source:Computational and Theoretical Chemistry, Volume 1117 Author(s): Nahid Zare, Abedien Zabardasti, Ali Kakanejadifard Asa result of HF and X molecules’ (X=H2O, CH3OH, NH3, O2, CO, NO, HCN, CO2 and N2) interactions with nido-C4B2H6, FH⋯C4B2H6⋯X clusters were obtained. Ab initio calculations were applied to analyze the interactions at MP2/6-311++G(2d,2p) computational level. The FH⋯C4B2H6⋯X clusters were obtained from the interactions of HF on the apex and X molecules from the pentagonal base with nido-C4B2H6 pyramid. Energetic, structural and spectral properties of FH⋯C4...
Source: Computational and Theoretical Chemistry - August 24, 2017 Category: Chemistry Source Type: research

Physical adsorption of N-containing heterocycles on graphene-like boron nitride-carbon heterostructures: A DFT study
Publication date: 1 October 2017 Source:Computational and Theoretical Chemistry, Volume 1117 Author(s): Igor K. Petrushenko, Konstantin B. Petrushenko We have studied the physical adsorption of benzene and five different N-containing organic heterocycle molecules on graphene-like boron nitride-carbon heterostructures (GBNCHs) by using dispersion-corrected density functional theory (DFT-D3). Three different initial configurations for each of the studied molecules have been taking into account to find the energetically favorable position of adsorption. It has been shown that the centers of the aromatic rings are preferably ...
Source: Computational and Theoretical Chemistry - August 24, 2017 Category: Chemistry Source Type: research

Best methods for calculating interaction energies in 2-butene and butane systems
Publication date: 1 October 2017 Source:Computational and Theoretical Chemistry, Volume 1117 Author(s): Milana M. Zarić, Branko Bugarski, Mirjana Lj. Kijevčanin Benchmarking study on eighteen methods, including MP2, B2PLYP-D3, B2PLYP-D3BJ, ωB97xD, M05-D3, M06-D3, M052X-D3, M06HF-D3, PBE0-D3, PBE0-D3BJ, B3LYP-D3, B3LYP-D3DJ, TPSS-D3, TPSS-D3BJ, BP86-D3, BP86-D3BJ, BLYP-D3, BLYP-D3BJ and ten basis sets: cc-pVDZ, cc-pVTZ, aug-cc-pVDZ, cc-pVQZ, def2-SVP, def2-TZVP, def2-TZVPP, def2-QZVP, 6-311++G∗∗ and 6-31G∗∗, for each method, have been performed, calculating interaction energies in (1) un...
Source: Computational and Theoretical Chemistry - August 20, 2017 Category: Chemistry Source Type: research

A theoretical study on the mechanism of xylobiose during pyrolysis process
Publication date: 1 October 2017 Source:Computational and Theoretical Chemistry, Volume 1117 Author(s): Zeyu Li, Chao Liu, Xiaoxiao Xu, Qibin Li In order to better understand the pyrolysis behavior of hemicellulose and unveil pyrolytic products distribution at molecular level, xylobiose was selected as a model compound of hemicellulose and relevant degradation processes were theoretically investigated by employing density functional theory (DFT) method. Several important reaction routes including directly bond breaking, Retro-Aldol reaction and Retro-Diels-Alder mechanism were analyzed, and the influence from adjacent xyl...
Source: Computational and Theoretical Chemistry - August 17, 2017 Category: Chemistry Source Type: research

A theoretical investigation on SinMn2+ Clusters (n=1 –10): Geometry, stability, and magnetic properties
Publication date: 1 October 2017 Source:Computational and Theoretical Chemistry, Volume 1117 Author(s): Nguyen Thi Mai, Nguyen Thanh Tung, Phan Thi Thuy, Nguyen Thi Minh Hue, Ngo Tuan Cuong The geometry, stability, and magnetic properties of Si n Mn 2 + clusters (n =1–10) have been systematically investigated using density functional theory. All studied clusters are favorably exohedral. The second Mn atom tends to absorb to singly-doped ones by the fact that losing a Mn atom is the energetically preferred dissociation channel. The derived electron configurations of Mn atoms indicate that high spin states of invest...
Source: Computational and Theoretical Chemistry - August 17, 2017 Category: Chemistry Source Type: research

Formaldehyde adsorption on graphane
Publication date: 1 October 2017 Source:Computational and Theoretical Chemistry, Volume 1117 Author(s): Emiliano Ventura-Macias, J. Guerrero-Sánchez, Noboru Takeuchi Using first principles calculations, we have studied the adsorption of a formaldehyde molecule on a hydrogenated graphene substrate, by a free radical initiated reaction. This kind of reaction begins at a hydrogen vacancy on the graphane layer, in which, the oxygen atom of the formaldehyde molecule attaches. Then, the nearest hydrogen atom is abstracted by the carbon atom of the formaldehyde, forming a stable molecule, and leaving behind a new dangling...
Source: Computational and Theoretical Chemistry - August 17, 2017 Category: Chemistry Source Type: research

Arguing on the roles of various non-covalent interactions in governing the global stabilization/destabilization of 3-hydroxy-2-pyridin-2-yl-propenal: An AIM-based approach
Publication date: 1 October 2017 Source:Computational and Theoretical Chemistry, Volume 1117 Author(s): Aniruddha Ganguly, Bijan K. Paul, Nikhil Guchhait A computational analysis based on the “Atoms in Molecules” i.e. AIM formalism; of the molecular forces present within 3-Hydroxy-2-pyridin-2-yl-propenal (HPYP) has been undertaken in this contribution. The study presents a critical argument on the regulatory role(s) of hydrogen bonds (HBs) and other non-covalent interactions, viz. H···H and N···O/O···O; toward the structural features as well as glo...
Source: Computational and Theoretical Chemistry - August 12, 2017 Category: Chemistry Source Type: research

The interaction of proteins with silica surfaces. Part I: Ab initio modeling
Publication date: 1 October 2017 Source:Computational and Theoretical Chemistry, Volume 1117 Author(s): Michal Trachta, Ota Bludský, Miroslav Rubeš Recently synthesized 2D zeolites with well-defined external surfaces have been used as model systems for the adsorption of proteins on silica materials. In this work the interaction of 19 proteinogenic amino-acid side chains in the Cβ representation and the Ace-NMe backbone model with the 2D-UTL and 2D-MWW zeolites has been investigated. The performance of different DC-DFT methods has been compared against the MP2/CBS and CCSD(T)/CBS levels of theory for clu...
Source: Computational and Theoretical Chemistry - August 12, 2017 Category: Chemistry Source Type: research

Mechanistic and spectral investigation on the deamination of ammeline and ammelide
Publication date: 1 October 2017 Source:Computational and Theoretical Chemistry, Volume 1117 Author(s): Mansour H. Almatarneh, Abd Al-Aziz A. Abu-Saleh, Ismael A. Elayan Melamine and its metabolites: ammeline, ammelide, and cyanuric acid have attracted great attention as food contaminants. They are added illegally to milk to increase the protein content. Melamine combined with cyanuric acid causes kidney stones, renal toxicity, and kidney failure. The deamination reactions of ammeline and ammelide that producing cyanuric acid are studied both in a vacuum and aqueous solution using the (SMD) solvation model. For both deami...
Source: Computational and Theoretical Chemistry - August 12, 2017 Category: Chemistry Source Type: research

Mapping photo-induced current density of Mg-porphyrin under twisted light
We report a characteristic map of the local electron circulation in Mg-porphyrin under twisted light which is a process that is strongly dependent on the frequency of photon. This work is a result of DFT calculation and time-dependent perturbation theory which are used to obtain the electronic structure and the photo-induced current density, respectively. The current density profile has been obtained for different frequency values of light and for single orbital angular momentum value. For comparison, we also obtained the induced current results for the case that orbital angular momentum is zero. Graphical abstract (Source...
Source: Computational and Theoretical Chemistry - August 12, 2017 Category: Chemistry Source Type: research

Assessing the performance of ab initio classical valence bond methods for hydrogen transfer reactions
Publication date: 15 September 2017 Source:Computational and Theoretical Chemistry, Volume 1116 Author(s): Itay Karach, Alina Botvinik, Donald G. Truhlar, Wei Wu, Avital Shurki Ab initio classical valence bond theory in terms of localized orbitals has several advantages over electronic structure methods based on canonical delocalized Hartree-Fock molecular orbitals, with two key distinctions being greater applicability to inherently multiconfigurational systems (also called multireference systems or strongly correlated systems) and great interpretability in terms of covalent and ionic valence bond configurations (also cal...
Source: Computational and Theoretical Chemistry - August 9, 2017 Category: Chemistry Source Type: research

Strategies for extending geminal-based wavefunctions: Open shells and beyond
Publication date: 15 September 2017 Source:Computational and Theoretical Chemistry, Volume 1116 Author(s): Paul A. Johnson, Peter A. Limacher, Taewon D. Kim, Michael Richer, Ramón Alain Miranda-Quintana, Farnaz Heidar-Zadeh, Paul W. Ayers, Patrick Bultinck, Stijn De Baerdemacker, Dimitri Van Neck We discuss some strategies for extending recent geminal-based methods to open-shells by replacing the geminal-creation operators with more general composite boson creation operators, and even creation operators that mix fermionic and bosonic components. We also discuss the utility of symmetry-breaking and restoration, but ...
Source: Computational and Theoretical Chemistry - August 9, 2017 Category: Chemistry Source Type: research

A generalized Brillouin theorem (GBT)-like implementation to optimize Valence Bond wave function for excited states
Publication date: 15 September 2017 Source:Computational and Theoretical Chemistry, Volume 1116 Author(s): Julien Racine, Yannick Carissan, Denis Hagebaum-Reignier, Stéphane Humbel A python code coupled to the ab initio Valence Bond code XMVB, is designed to optimize non-orthogonal orbitals in Valence Bond (VB) wave functions that describe excited states. This code can handle both ground and excited states. Our implementation relies on the general Brillouin theorem (GBT) and super configuration interaction (SCI) processes. We tested our program on the ground and the singlet excited V states of the ethene molecule. ...
Source: Computational and Theoretical Chemistry - August 9, 2017 Category: Chemistry Source Type: research

Applying group functions to description of ionic liquids
Publication date: 15 September 2017 Source:Computational and Theoretical Chemistry, Volume 1116 Author(s): Ilya V. Popov, Andrei L. Tchougréeff Concept of group functions (GF) in quantum chemistry explicates chemical idea of ‘chromophores’ – fragments of molecules responsible for their physical properties and chemical reactivity. This concept permits to construct quantum chemical methods which provide correct qualitative and quantitative results for complex systems being unpretentious in computer resources. This is achieved by basing the form of the trial electronic wave function on adequate &rsqu...
Source: Computational and Theoretical Chemistry - August 9, 2017 Category: Chemistry Source Type: research

High level ab initio calculations on ClFn − (n=1–6): Recoupled pair bonding involving a closed-shell central ion
Publication date: 15 September 2017 Source:Computational and Theoretical Chemistry, Volume 1116 Author(s): Lina Chen, David E. Woon, Thom H. Dunning In this paper we complete our studies of the bonding in the ClF n +,0,− series, characterizing the structures and energetics of the ground and low-lying excited states of ClF n − (n =1–6) via coupled cluster calculations with large correlation consistent basis sets and interpreting the results of the calculations using concepts from generalized valence bond (GVB) theory. The chlorine anion is isoelectronic with the argon atom, possessing three 3p lone pairs....
Source: Computational and Theoretical Chemistry - August 9, 2017 Category: Chemistry Source Type: research

Reassessing spin-coupled (full generalized valence bond) descriptions of ozone using three-center bond indices
Publication date: 15 September 2017 Source:Computational and Theoretical Chemistry, Volume 1116 Author(s): David L. Cooper, Fabio E. Penotti, Robert Ponec Domain-averaged Fermi hole analysis is carried out for the ground state of O3 at its equilibrium geometry using a complete-active-space self-consistent field CASSCF(18,14) wavefunction, based on a slightly expanded full-valence active space. This initial analysis is augmented with an examination of the corresponding localized natural orbitals (LNOs) and of the numerical values obtained with a new improved definition of three-center bond indices for correlated singlet sy...
Source: Computational and Theoretical Chemistry - August 9, 2017 Category: Chemistry Source Type: research

Comparative theoretical study of three C56 fullerenes, their chlorinated derivatives, and chlorofullerene oxides
Publication date: 1 October 2017 Source:Computational and Theoretical Chemistry, Volume 1117 Author(s): Fuwei Zhang The thermal stabilities and electronic properties of the three C56 fullerenes (#916C56, #864C56, and #913C56), their chlorinated derivatives, and the corresponding chlorofullerene oxides are investigated and compared using density functional theory (DFT) at the B3LYP/6-31G(d) level. #916C56 is the most stable isomer, but #916C56 and #864C56 possess almost degenerate energies (relative total energy 0.03kcal/mol). The three experimentally observed C56 chlorides display the rather high chemical stabilities with...
Source: Computational and Theoretical Chemistry - August 8, 2017 Category: Chemistry Source Type: research

Interaction between anti-cancer drug hydroxycarbamide and boron nitride nanotube: A long-range corrected DFT study
Publication date: 1 October 2017 Source:Computational and Theoretical Chemistry, Volume 1117 Author(s): Maryam Hesabi, Reza Behjatmanesh-Ardakani An accurate long-range corrected density functional theory (CAM-B3LYP) is used to optimize hydroxycarbamide (HC) with pristine/Fe-doped boron nitride nanotubes (Fe-BNNTs). In order to investigate the more detailed mechanism of their interactions, Natural Bond Orbital (NBO), Quantum Theory of Atoms in Molecules (QTAIM), and Frontier Molecular Orbital (FMO) calculations are implemented. Weak interactions such as hydrogen bonds and Van der Waals’ dispersion are analyzed via t...
Source: Computational and Theoretical Chemistry - August 5, 2017 Category: Chemistry Source Type: research

Aromaticity of the chelate rings. The case of bis(ethylenediamine)nickel(II)
Publication date: 1 October 2017 Source:Computational and Theoretical Chemistry, Volume 1117 Author(s): Shanti G. Patra, Dipankar Datta The aromaticity of the chelate rings in [Ni(en)2]2+, [Ni(pn)2]2+, [Ni(bn)2]2+, [Zn(en)2]2+ and [Pd(en)2]2+ (en=1,2-diaminoethane, pn=1,3-diaminopropane and bn=1,4-diamino-butane) are studied by means of nucleus independent chemical shift (NICS) calculations. Comparing the data with those of benzene and cyclopropane, it is concluded that the chelate rings in [Ni(en)2]2+, [Ni(pn)2]2+ and [Ni(bn)2]2+ are σ-aromatic while the ones in [Zn(en)2]2+ and [Pd(en)2]2+ are non aromatic. The ord...
Source: Computational and Theoretical Chemistry - July 30, 2017 Category: Chemistry Source Type: research

Computational study on the mechanisms and reaction pathways of the brominated alkyl radical (CHBr2/CBr3) with NO2 reactions
Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): Yunju Zhang, Ruojing Song, Yuxi Sun, Jingyu Sun, Yong-guo Liu, Rongshun Wang Mechanisms and reaction channels of the CHBr2 and CBr3 with NO2 reactions have been studied by quantum chemistry methods. The calculated results indicating that the title reactions can take place on either the singlet or triplet potential energy surfaces (PES) and the pathways on the triplet PES should be much less competitive than that on the singlet PES. On the singlet surface, CHBr2 radical can associate with NO2 to barrierlessly generate ...
Source: Computational and Theoretical Chemistry - July 29, 2017 Category: Chemistry Source Type: research

Exploring cation- π interaction in half sandwiches and sandwiches with XX triple bonds (XC, Si and Ge): A DFT study
Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): Nabajit Sarmah, Bhabesh Chandra Deka, Pradip Kr. Bhattacharyya Density functional theory (DFT) and MP2 calculation have been carried out in order to understand the ability of cation-π interaction to form half sandwiches and sandwiches of CC, SiSi and GeGe triple bond bridged via metal ions (Li+, Na+, K+, Mg2+ and Ca2+). Stability of such complexes is evaluated in terms of interaction energy and thermo-chemical parameters, enthalpy and free energy. Results predict a comprehensive stability of such half sandwiches/sa...
Source: Computational and Theoretical Chemistry - July 29, 2017 Category: Chemistry Source Type: research

A theoretical exploration of new species on the 1[H, Se, I] potential energy surface: Energetics, structures, IR spectra, and heats of formation
Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): Antonio Ricardo Belinassi, Fernando R. Ornellas New molecular species HSeI, HISe, and SeI were investigated theoretically for the first time at a high level of theory, CCSD(T). Computations were carried out with the series of correlation consistent basis sets (aug-cc-pVnZ-PP) and the results extrapolated to the complete basis set limit. Accounting for core-valence correlation into the wavefunction, and of anharmonic effects on the vibrational frequencies were also explored, making the results of structural, energetic,...
Source: Computational and Theoretical Chemistry - July 29, 2017 Category: Chemistry Source Type: research

Computational study of the hydrogen bonding interactions in the [CH2XNO2 ·H2O] clusters (X=H, F, Cl, Br, I)
Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): Zoi Salta, Demetrios K. Papayannis, Agnie M. Kosmas Two kinds of structures are identified for the [CH2XNO2·H2O] (X=H, F, Cl, Br, I) clusters, using ab initio and DFT computational techniques. The configurations of the resulting water complexes arise from the two different ways of possible hydrogen bonding interaction. Both types of complexes present cyclic geometries formed through either the interaction of a methylic H with the O atom of the water molecule, type (a), or via the symmetric coupling of each H at...
Source: Computational and Theoretical Chemistry - July 29, 2017 Category: Chemistry Source Type: research

A theoretical study on platinum-catalyzed cycloisomerization of 2-ethynyl-1-ferrocenylbenzene
Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): XingHui Zhang, LiPing Jiang, ShanShan Li, KeTai Wang Density functional theory calculations are carried out to explore the reaction mechanism for the cycloisomerization of 2-ethynyl-1-ferrocenylbenzene by using PtCl2 as a catalyst at the M06-2X/6-31G (d, p) (LanL2DZ (f) for Pt, Fe) level. The calculation results prove that the platinum-catalyzed cycloisomerization of 2-ethynyl-1-ferrocenylbenzene includes two possible pathways and three steps to afford naphthalene fused ferrocene. One reaction pathway is based on the ...
Source: Computational and Theoretical Chemistry - July 29, 2017 Category: Chemistry Source Type: research

Theoretical studies of unimolecular thermal decomposition reactions of n-hexane and n-hexene isomers
Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): Quan-De Wang Alkenes are not only important components of commercial transportation fuels, but also important intermediates during combustion processes for all hydrocarbon and many alternative fuels. The research of combustion reaction mechanisms and combustion characteristics of alkenes requires accurate rate constants of key reactions during the oxidation processes of alkenes. In the present work, dominant reaction channels of unimolecular thermal decomposition of n-hexane and three isomers of n-hexene: 1-hexene, 2-...
Source: Computational and Theoretical Chemistry - July 29, 2017 Category: Chemistry Source Type: research

First-principles study of CO catalytic oxidation on Pd-doped single wall boron nitride nanotube
In this study, density functional theory (DFT) is employed to explore the catalytic oxidation of CO on Pd-doped boron nitride nanotube (BNNT). The electronic structures and thermodynamic parameters of CO and O2, which are adsorbed on BNNT substrate with Pd embedded at the N- and B- vacancy, are examined in detail. It is revealed that the BNNT substrate with vacancy strongly stabilizes the Pd adatom. Benefit from the B vacancy defect, the Pd atom binds strongly with BNNT. The interaction energy of 3.74eV is strong enough to prevent the aggregation of Pd atom. With B vacancy, Pd atom accepts extra electron from the substrate...
Source: Computational and Theoretical Chemistry - July 29, 2017 Category: Chemistry Source Type: research

A theoretical study on [2+2] cycloaddition reactions under visible light irradiation induced by energy transfer
Publication date: 1 October 2017 Source:Computational and Theoretical Chemistry, Volume 1117 Author(s): Mingyang Jiao, Di Han, Beibei Zhang, Bo-Zhen Chen, Yi-wen Ju In recent years, [2+2] cycloaddition under visible light has been a hot topic because of low energy consumption and high regio- and stereoselectivities when compared with reactions under UV irradiation. However, the mechanism of [2+2] cycloaddition under visible light irradiation is still unclear. In this research, the visible light catalytic intermolecular [2+2] cycloaddition of 3-ylideneoxindoles has been investigated using density functional theory B3LYP an...
Source: Computational and Theoretical Chemistry - July 29, 2017 Category: Chemistry Source Type: research

Theoretical investigation of hydrogen bonding in the H2SO4 ⋯HNO3 system
Publication date: 1 October 2017 Source:Computational and Theoretical Chemistry, Volume 1117 Author(s): F. Mine Balcı Molecular clusters of two acidic species, H2SO4 and HNO3, were investigated using ab initio methods to observe intermolecular interactions. Geometric optimizations were conducted at the MP2 level using aug-cc-pVDZ and aug-cc-pVTZ basis sets. Eleven different stable geometries were detected on the intermolecular potential energy surface. Two main theories, atoms in molecules (AIM) and non-covalent interactions (NCI), were used to analyze the nature of hydrogen bonds in the H2SO4⋯HNO3 system. The results ...
Source: Computational and Theoretical Chemistry - July 29, 2017 Category: Chemistry Source Type: research

Reaction path scans: Aza-Michael reactions of isatin Imines
Publication date: 1 October 2017 Source:Computational and Theoretical Chemistry, Volume 1117 Author(s): Andrus Metsala, Sergei Žari, Tõnis Kanger Several reaction path scans are performed with the help of molecular mechanical and ab initio methods on the example of Aza-Michael isatin imine reactions. A close look is taken at the reaction coordinate development. We use a method such as a conformer scan on the points of the reaction coordinate of approaching reagents. We clarify some computational problems which may arise when pursuing such a treatment. The most probable reaction paths and transition states are foun...
Source: Computational and Theoretical Chemistry - July 29, 2017 Category: Chemistry Source Type: research

New nanostructures of carbon: Quasi-fullerenes Cn-q (n=20, 42, 48, 60)
Publication date: 1 October 2017 Source:Computational and Theoretical Chemistry, Volume 1117 Author(s): Christian A. Celaya, Jesús Muñiz, Luis Enrique Sansores Based on the third allotropic form of carbon (Fullerenes), we have studied novel allotropic carbon structures with a closed cage configuration (quasi-fullerenes) by using DFT at the B3LYP/6-31G(d) theory level. Such carbon Cn-q structures (where, n=20, 42, 48 and 60), combine states of hybridization sp1 and sp2 to form different member rings in their structure. A comparative analysis of quasi-fullerenes with respect to their isomers of greater stabili...
Source: Computational and Theoretical Chemistry - July 29, 2017 Category: Chemistry Source Type: research

Theoretical research on the catalytic reaction mechanism of N2O and CO over Ni5 cluster
Publication date: 1 October 2017 Source:Computational and Theoretical Chemistry, Volume 1117 Author(s): Yan-Xia Han, Chao Kong, Li-Jie Hou, Dong-Ping Chen, Bo-Wan Wu, Zhi-Yuan Geng In this paper, the reaction mechanism for N2O with CO on the surface of Ni5 cluster was investigated by the B3LYP method of density functional theory (DFT). Ni atom of various species was calculated using B3LYP/ LANL2DZ basis set, and C, N, O atoms at B3LYP/6-31G∗ level. In the temperature range of 100–1000K, the statistical thermodynamics and Eyring transition state theory with Winger correction were used to study the kinetic char...
Source: Computational and Theoretical Chemistry - July 28, 2017 Category: Chemistry Source Type: research

The geometric and electronic structures of AlnNam (n=5, 6; n+m ≤10) clusters
Publication date: 1 October 2017 Source:Computational and Theoretical Chemistry, Volume 1117 Author(s): Pengju Jing, Huihui Yang, Ning Du, Yan Zhang, Hongshan Chen The low-energy structures of Al5Nam (m=1–5) and Al6Nam (m=0–4) are searched by using the genetic algorithm combined with MOPAC package. The stabilities and the electronic structures are studied by density functional theory models and by first principle perturbation theory at MP4 level. The results show that the Na atoms are located at the outside of the clusters. Analysis on the density of states and the charge distribution indicate the sodium atoms...
Source: Computational and Theoretical Chemistry - July 28, 2017 Category: Chemistry Source Type: research

Weak bonds between molecular tweezers and their guests
Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): Marlene Bosquez, Alejandra Cambray, Alan Miralrio, Roxana-Mitzayé del Castillo, Roberto Salcedo It is proposed a molecular tweezer, which makes possible to design a scaffold structure, allowing to trap organic molecules, regardless of the size of the guest. Weak carbon-carbon and carbon-hydrogens interactions stabilized the compound. The analysis carried out with the Grimme’s dispersion correction allow to quantify the weak interaction between the molecular tweezer and the guest. These assumptions were co...
Source: Computational and Theoretical Chemistry - July 21, 2017 Category: Chemistry Source Type: research

Fluorination reaction on an inactive sp3 CH bond mediated by manganese porphyrin catalysts: A theoretical study
Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): Xia Du, Hui Zhang, Yang Lu, Ai-Hua Wang, Peng Shi, Ze-Sheng Li Density functional theory (DFT) was used to theoretically explore the catalytic efficiency of four manganese porphyrin catalysts on the substrate of cyclohexyl radical. Mother ring of the manganese porphyrin catalysts is porphine, and the meso-substituted groups are 2,4,6-trimethylphenyl, 1-naphthyl, 2-naphthyl, 4-biphenyl, respectively. Geometry optimizations and frequency calculations of the reactants, transition states, and products were performed at B3...
Source: Computational and Theoretical Chemistry - July 21, 2017 Category: Chemistry Source Type: research

Comparison of PdII vs RhI-catalyzed catalytic cycle for single step styrene production
Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): Yavuz Selim Ceylan, Thomas R. Cundari Styrene production by a (FlDAB)PdII(TFA)(η2-C2H4) complex was modeled using density functional theory (DFT). Benzene CH activation by this complex was studied via five mechanisms, which were oxidative addition/reductive elimination, sigma-bond metathesis, and concerted metalation deprotonation (CMD). The final two mechanisms were calculated without ligated ethylene, CMD activation of ethylene, and benzene substitution of ethylene followed by CMD of the ligated benzene. Calcula...
Source: Computational and Theoretical Chemistry - July 21, 2017 Category: Chemistry Source Type: research

The interaction of propargylamine-based sulfonamide with pristine, Al and Si doped boron nitride nanotubes: A theoretical study
Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): Morteza Abdoli, Hamid Saeidian, Ali Kakanejadifard Interactions of a bioactive propargylamine-based sulfonamide with the pristine, Al, and Si doped boron nitride nanotubes (BNNT) were studied using density functional theory calculations. The relative reactivity of the studied nanotubes toward the sulfonamide-based compound was as: Al-doped≫Si-doped>pristine BNNTs. It was found that there is a weak interaction between the sulfonamide and the pristine BNNT with adsorption energy of about −3.1kcal/mol; the...
Source: Computational and Theoretical Chemistry - July 21, 2017 Category: Chemistry Source Type: research

Donor stabilized borylnitrenes: A theoretical study
Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): Sabnam S. Ullah, Pankaz K. Sharma, Ankur Kanti Guha Quantum chemical calculations have carried out on some donor stabilized (E=NH, PH and O) borylnitrenes (5-7) using density functional theory (DFT) calculations at B3LYP level of theory. Moreover, the effect of non-donor subsituents (E=CH2 and SiH2) are also studied. All these molecules are found to be ground state triplets. Their zero-field splitting (ZFS) parameters D and E are also calculated using complete active space self consistent field (CASSCF) theory. The do...
Source: Computational and Theoretical Chemistry - July 20, 2017 Category: Chemistry Source Type: research

Structural, electronic and catalytic properties of single magnesium atom doped small neutral Rhn (n=2 –8) clusters: Density functional study
In this study magnesium doped rhodium clusters are investigated to evaluate their structure, stability, electronic and magnetic properties using density functional theory (DFT). Stability function, fragmentation energy and LUMO-HOMO gap reveals that Rh5Mg, Rh6Mg and Rh8Mg clusters are more stable than the other magnesium doped rhodium clusters. Chemical reactivity of rhodium cluster increases on doping with magnesium atom. Deformation density, density of electronic state, force vector analysis suggest that electronic redistribution are occurred to attain the higher stability in Rh5Mg as well as in Rh8Mg. Negative electrost...
Source: Computational and Theoretical Chemistry - July 20, 2017 Category: Chemistry Source Type: research

Tanshinone I and isotanshinone I: The effects of media, isomerization and complexation on structural and electronic parameters
Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): Fatemeh Pakzad, Ali Ebrahimi, Abolfazl Azizi In the present study, structural and electronic parameters of two diterpenoid quinones in Salvia miltiorrhiza, tanshinone I (TS1) and isotanshinone I (IS1), and their complexes with Mg2+ cation, TS1-Mg2+ and IS1-Mg2+, have been investigated by the means of quantum mechanical calculations in the gas phase, DMSO and water solvent. Molecular electrostatic potential (MEP) around the O atoms has been used in order to predict the nucleophilic active sites on complexation with Mg2...
Source: Computational and Theoretical Chemistry - July 15, 2017 Category: Chemistry Source Type: research

A first-principles study of the interaction of doxorubicin with graphene
Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): Mariana Zancan Tonel, Mirkos Ortiz Martins, Ivana Zanella, Renato Borges Pontes, Solange Binotto Fagan Graphene is a single layer of graphite whose carbon atoms are arranged in a hexagonal form. On the other side, doxorubicin (DOX) is a drug widely used for the treatment of various cancer diseases. In this work, we performed calculations within the Density Functional Theory (DFT) framework in order to obtain both structural and electronic properties of the graphene interacting with DOX. The results show that, in the m...
Source: Computational and Theoretical Chemistry - July 15, 2017 Category: Chemistry Source Type: research

Theoretical investigation on electronic properties and carrier mobilities of BN-substituted graphyne nanoribbons
Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): Bing Liang, Hongcun Bai, Yuanhe Huang This paper presents the self-consistent field crystal orbital studies of the BN-substituted graphyne nanoribbons (NRs) based on density functional theory. Two kinds of the substitution are considered: one is that the six-membered rings in the graphyne NRs are replaced by the corresponding BN hexagonal rings; another is the substitution of acetylenic linkages by BN units. The calculations show that all the optimized one-dimensional BN-substituted graphyne NRs still keep plane struc...
Source: Computational and Theoretical Chemistry - July 13, 2017 Category: Chemistry Source Type: research

DFT investigations on the conversion of acetylene to undesired vinyl acetylene during vinyl acetate synthesis
Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): Minhua Zhang, Xingyu Wu, Xuewei Huang, Bing Yang, Yingzhe Yu Density functional theory was employed to investigate the alternative mechanisms of vinyl acetylene formation on zinc acetate/activated carbon catalyst, aiming to better understand the deactivation behaviour and illustrate the plausible vinyl acetylene formation routes during vinyl acetate synthesis. The structural and energetic properties of relevant species were calculated and discussed in details. Two possible pathways for vinyl acetylene formation were p...
Source: Computational and Theoretical Chemistry - July 8, 2017 Category: Chemistry Source Type: research

Quantum wave packet dynamics of the H+Li2 reaction at state-to-state level of theory
Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): Ziliang Zhu, Bin Dong, Wang Li The time-dependent wave packet method with a second order split operator is employed to study the state-to-state resolved reaction dynamics of the H+Li2 system. The dynamics properties, such as reaction probability, integral cross-section, differential cross-section and the rovibrational state distribution of the product are fully calculated in the present work. Both forward and backward scattering signals peaked at two extreme angles, indicating that the insert reaction mechanism plays ...
Source: Computational and Theoretical Chemistry - July 7, 2017 Category: Chemistry Source Type: research

The role of intramolecular H-bonds predominant effects in myricetin higher antioxidant activity
Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): Abolfazl Barzegar Flavonoid antioxidants play essential roles in the prevention of damage caused by free radicals, which is concerned in many chemical and biological processes. The structural electronic properties of myricetin (Myc) and six respective radicals such as total electronic energies, bond dissociation enthalpy magnitudes (BDEs), intramolecular H–bonds strength and charges density distributions have been computed using density functional theory approach with B3P86 level. The important Myc molecular cha...
Source: Computational and Theoretical Chemistry - July 5, 2017 Category: Chemistry Source Type: research

Elucidation of the complex deprotonation routes of Changrolin, the antihypertensives LQM-303 and LQM-303b, and their derivatives
Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): Manuel Alejandro Hernández-Olivares, Agustin Ibarra-Escutia, Gabriela Mendoza-Sarmiento, Alberto Rojas-Hernández, Annia Galano Elucidating the most likely deprotonation routes for polyprotic molecules is crucial in order to know the structures of the species prevailing under specific pH conditions. This is particularly important for molecules with potential applications as medical drugs, since different acid-base species, with the same deprotonation degree, may not interact in the same way with biologica...
Source: Computational and Theoretical Chemistry - July 5, 2017 Category: Chemistry Source Type: research

Structure-reactivity relationships of N-hydroxysaccharin analogues as organocatalysts for aerobic oxidation
Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): Hangen Du, Qianqian Shen, Ling Feng, Lin Fei, Xiatao Zhou, Zuguang Li, Kexian Chen, Kezhi Jiang The structure-reactivity relationships of new N-hydroxysaccharin analogous organocatalysts for aerobic oxidation have been theoretically explored based on the replacements of carbonyl groups in the succinimide ring of N-hydroxyphthalimide and N,N-dihydroxypyromellitimide by sulfinyl or sulfonyl groups. Both sulfinyl and sulfonyl groups largely change catalytic reactivity by altering the planar resonance/conjugation structur...
Source: Computational and Theoretical Chemistry - July 5, 2017 Category: Chemistry Source Type: research

The story of the B4H4 molecule told again
Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): Aristotle Papakondylis, Aristides Mavridis Employing ab initio multireference and coupled-cluster methods along with correlation consistent basis sets we have studied three geometrical isomers of the (hydro)borane B4H4 molecule, namely, the highly symmetric geometrical configuration Td (regular tetrahedron) and two isomers of planar Cs geometries tagged Td(II), Cs(I), and Cs(III), respectively. Mostly for reasons of consistency the species BH(X 1 Σ+, a 3Π), BH2( X ̃ 2 A 1 ), and H2BBH2(D2h, D2d) have also...
Source: Computational and Theoretical Chemistry - July 5, 2017 Category: Chemistry Source Type: research

Ab initio investigation of pristine and doped single-walled boron nitride nanotubes as acetone sensor
Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): Guo-hong Fan, Sheng Zhu, Xiao-kun Li, Ke Ni, Hong Xu The sensor properties of single-walled boron nitride nanotubes (BNNTs) towards acetone are studied by investigating the intermolecular interactions of acetone with a serials of pristine and doped BNNTs. Density-functional theory (DFT) with empirical dispersion corrected is adopted to explore the adsorption properties of acetone on the surface of BNNT. Results show that acetone binds strong to the surface of pristine BNNTs with small diameter and the adsorption energ...
Source: Computational and Theoretical Chemistry - July 5, 2017 Category: Chemistry Source Type: research

Time-evolution study of photoinduced charge-transfer in tertiary amine-fluorophore systems
Publication date: 1 September 2017 Source:Computational and Theoretical Chemistry, Volume 1115 Author(s): Demeter Tzeli, Theodoros Mercouris, Giannoula Theodorakopoulos, Ioannis D. Petsalakis Photoinduced charge transfer in a fluorescent sensor of organophosphorus nerve agents is examined by solution of the time dependent Schrödinger equation, under the influence of an external electromagnetic field and employing potential energy curves obtained by density functional theory (DFT) and time dependent DFT (TDDFT) calculations for the ground and the excited states, respectively. The systems of interest here consist of a ...
Source: Computational and Theoretical Chemistry - July 5, 2017 Category: Chemistry Source Type: research