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  Subjects -> CHEMISTRY (Total: 795 journals)
    - ANALYTICAL CHEMISTRY (47 journals)
    - CHEMISTRY (554 journals)
    - CRYSTALLOGRAPHY (22 journals)
    - ELECTROCHEMISTRY (24 journals)
    - INORGANIC CHEMISTRY (41 journals)
    - ORGANIC CHEMISTRY (43 journals)
    - PHYSICAL CHEMISTRY (64 journals)

CHEMISTRY (554 journals)            First | 1 2 3 4 5 6 | Last

Frontiers of Chemical Science and Engineering     Hybrid Journal   (Followers: 1)
Frontiers of Chemistry in China     Hybrid Journal   (Followers: 2)
Fullerenes, Nanotubes and Carbon Nanostructures     Hybrid Journal   (Followers: 5)
Fundamentals of Interface and Colloid Science     Full-text available via subscription   (Followers: 5)
Future Medicinal Chemistry     Full-text available via subscription   (Followers: 4)
Geochemical Transactions     Open Access   (Followers: 3)
GFF     Hybrid Journal  
Glycobiology Insights     Open Access   (Followers: 1)
Graphene     Open Access   (Followers: 10)
Green and Sustainable Chemistry     Open Access   (Followers: 3)
Green Chemistry Letters and Reviews     Open Access   (Followers: 4)
Green Processing and Synthesis     Full-text available via subscription   (Followers: 1)
Handbook of Exploration and Environmental Geochemistry     Full-text available via subscription   (Followers: 1)
Handbook of Exploration Geochemistry     Full-text available via subscription  
Handbook of Surface Science     Full-text available via subscription   (Followers: 3)
Handbook of Vapor Pressure     Full-text available via subscription  
Helvetica Chimica Acta     Hybrid Journal   (Followers: 9)
Heritage Science     Open Access   (Followers: 1)
Heteroatom Chemistry     Hybrid Journal   (Followers: 2)
High Energy Chemistry     Hybrid Journal  
Indian Chemical Engineer     Hybrid Journal   (Followers: 3)
Indian Journal of Chemical Technology (IJCT)     Open Access   (Followers: 12)
Indian Journal of Chemistry - Section B (IJC-B)     Open Access   (Followers: 5)
Indian Journal of Natural Products and Resources (IJNPR)     Open Access   (Followers: 3)
Industrial & Engineering Chemistry     Full-text available via subscription   (Followers: 9)
Industrial Chemistry Library     Full-text available via subscription   (Followers: 4)
Inorganic Chemistry     Full-text available via subscription   (Followers: 19)
Inorganic Chemistry Communications     Hybrid Journal   (Followers: 7)
Inorganic Materials     Hybrid Journal   (Followers: 2)
Inorganica Chimica Acta     Hybrid Journal   (Followers: 4)
Instrumentation Science & Technology     Hybrid Journal   (Followers: 3)
International Archives of Science and Technology     Open Access  
International Journal for Ion Mobility Spectrometry     Hybrid Journal   (Followers: 1)
International Journal of Adhesion and Adhesives     Hybrid Journal   (Followers: 13)
International Journal of Advanced Chemistry     Open Access  
International Journal of Analytical Mass Spectrometry and Chromatography     Open Access  
International Journal of Bioassays     Open Access   (Followers: 6)
International Journal of Biological and Chemical Sciences     Open Access   (Followers: 2)
International Journal of Biological Chemistry     Open Access   (Followers: 4)
International Journal of Biomedical Nanoscience and Nanotechnology     Hybrid Journal   (Followers: 6)
International Journal of Carbohydrate Chemistry     Open Access   (Followers: 7)
International Journal of Chemical and Analytical Science     Full-text available via subscription   (Followers: 3)
International Journal of Chemical and Life Sciences     Open Access   (Followers: 3)
International Journal of Chemical Kinetics     Hybrid Journal   (Followers: 4)
International Journal of Chemical Technology     Open Access   (Followers: 4)
International Journal of Chemistry     Open Access   (Followers: 7)
International Journal of Chemoinformatics and Chemical Engineering     Full-text available via subscription   (Followers: 2)
International Journal of Corrosion     Open Access   (Followers: 10)
International Journal of High Throughput Screening     Open Access   (Followers: 2)
International Journal of Materials and Chemistry     Open Access   (Followers: 6)
International Journal of Medicinal Chemistry     Open Access   (Followers: 7)
International Journal of Minerals, Metallurgy, and Materials     Hybrid Journal   (Followers: 7)
International Journal of Molecular Imaging     Open Access   (Followers: 1)
International Journal of Molecular Sciences     Open Access   (Followers: 1)
International Journal of Nano Dimension     Open Access   (Followers: 2)
International Journal of Nonferrous Metallurgy     Open Access   (Followers: 1)
International Journal of Photochemistry     Open Access   (Followers: 1)
International Journal of Photoenergy     Open Access   (Followers: 2)
International Journal of Physical Sciences     Open Access  
International Journal of Spray and Combustion Dynamics     Full-text available via subscription   (Followers: 6)
International Journal of Tryptophan Research     Open Access  
Iranian Polymer Journal     Hybrid Journal   (Followers: 4)
Israel Journal of Chemistry     Full-text available via subscription   (Followers: 2)
ISRN Environmental Chemistry     Open Access  
JBIC Journal of Biological Inorganic Chemistry     Hybrid Journal   (Followers: 2)
JCP : BioChemical Physics     Hybrid Journal  
JOT Journal für Oberflächentechnik     Hybrid Journal  
JOT-International Surface Technology     Hybrid Journal   (Followers: 1)
Journal of Chemical Engineering & Process Technology     Open Access   (Followers: 2)
Journal of Chromatography & Separation Techniques     Open Access   (Followers: 7)
Journal of Microbial & Biochemical Technology     Open Access   (Followers: 1)
Journal of Thermodynamics & Catalysis     Open Access   (Followers: 3)
Journal of Adhesion     Hybrid Journal   (Followers: 7)
Journal of Adhesion Science and Technology     Hybrid Journal   (Followers: 6)
Journal of Advanced Oxidation Technologies     Full-text available via subscription   (Followers: 1)
Journal of Advances in Chemistry     Open Access   (Followers: 4)
Journal of Agricultural and Food Chemistry     Full-text available via subscription   (Followers: 17)
Journal of Agricultural Chemistry and Environment     Open Access  
Journal of Amino Acids     Open Access   (Followers: 3)
Journal of Analytical Sciences, Methods and Instrumentation     Open Access   (Followers: 1)
Journal of AOAC International     Full-text available via subscription   (Followers: 8)
Journal of Applied Chemistry     Open Access   (Followers: 2)
Journal of Applied Spectroscopy     Hybrid Journal   (Followers: 7)
Journal of Automated Methods and Management in Chemistry     Open Access  
Journal of Biomaterials and Nanobiotechnology     Open Access   (Followers: 4)
Journal of Carbohydrate Chemistry     Hybrid Journal   (Followers: 5)
Journal of Catalysis     Hybrid Journal   (Followers: 6)
Journal of Catalyst & Catalysis     Full-text available via subscription  
Journal of Catalysts     Open Access  
Journal of Chemical & Engineering Data     Full-text available via subscription   (Followers: 7)
Journal of Chemical Education     Full-text available via subscription   (Followers: 14)
Journal of Chemical Health Risks     Open Access   (Followers: 2)
Journal of Chemical Information and Modeling     Full-text available via subscription   (Followers: 5)
Journal of Chemical Research     Full-text available via subscription   (Followers: 5)
Journal of Chemical Science and Technology     Open Access   (Followers: 2)
Journal of Chemical Sciences     Partially Free   (Followers: 15)
Journal of Chemical Theory and Computation     Full-text available via subscription   (Followers: 9)
Journal of Cheminformatics     Open Access   (Followers: 1)
Journal of Chemistry     Open Access   (Followers: 3)
Journal of Chemometrics     Hybrid Journal   (Followers: 10)

  First | 1 2 3 4 5 6 | Last

Journal Cover Journal of Theoretical and Computational Chemistry
   [9 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 0219-6336 - ISSN (Online) 1793-6888
     Published by World Scientific Homepage  [114 journals]   [SJR: 0.286]   [H-I: 16]
  • Theoretical calculations of π-type pnicogen bonds in the triad
           intermolecular complexes
    • Authors: Hui-Ying Xu, Wei Wang, Jian-Wei Zou, Xiao-Lu Xu
      Abstract: Journal of Theoretical and Computational Chemistry, Ahead of Print. The pnicogen bonding interactions of PCl3 and π-electron systems (acetylene, ethylene, benzene) were calculated by using MP2/aug-cc-pVDZ method and the effect of hydrogen bond on pnicogen bond systems were investigated. It has been indicated that the hydrogen bonding and the pnicogen bonding interactions have influence on each other and the positively cooperative effect has been detected. The interaction energies of pnicogen bonded supramolecular system were also calculated by using DFT method (M06-2X) and some simple comparisons with those by using MP2 method were made. It has been disclosed from natural bond orbitals (NBO) analysis that more the amount of charge transfer of pnicogen bonding interaction, the greater the stability of the corresponding complex. Through AIM topological analysis, it has been revealed that the electron density of pnicogen bond BCP point is positively correlated with the stability of trimeric complex. Electron localization function (ELF) was also adopted to analyze the nature of pnicogen bonding interactions. Furthermore, density difference function (DDF) method was adopted to analyze the variation of electron density of pnicogen bond system because of hydrogen bond.
      Citation: Journal of Theoretical and Computational Chemistry
      PubDate: Tue, 18 Nov 2014 01:46:39 GMT
      DOI: 10.1142/S0219633614500680
       
  • Conformational space analysis of neutral and protonated glycine using a
           genetic algorithm for multi-modal search
    • Authors: B. El Merbouh, M. Bourjila, R. Tijar, R. Drissi El Bouzaidi, A. El Gridani, M. El Mouhtadi
      Abstract: Journal of Theoretical and Computational Chemistry, Ahead of Print. The genetic algorithm based on the Multi-Niche Crowding (MNC) method is used with the semi-empirical methods AM1 and PM3 in order to scan the potential energy surface (PES) of neutral and protonated glycine. The algorithm is implemented as a package of programs interfaced with MOPAC and piloted by scripts. Both methods AM1 and PM3 located six minima on the PES of neutral glycine and seven on the protonated glycine one, of which three are those of the N-protonated form and four of the O-protonated one.
      Citation: Journal of Theoretical and Computational Chemistry
      PubDate: Fri, 14 Nov 2014 01:22:56 GMT
      DOI: 10.1142/S0219633614500679
       
  • Molecular dynamics simulation on the interfacial features of supercritical
           1-butene/subcritical water
    • Authors: Huidong Zheng, Jingjing Chen, Fangdi Wu, Suying Zhao
      Abstract: Journal of Theoretical and Computational Chemistry, Ahead of Print. We studied the interfacial features of 1-butene/water and extraction process of 2-butanol by molecular dynamics (MD) simulations. The infinite dilute diffusion coefficients of 1-butene in water is larger than that of 2-butanol, and one important reason is that 2-butanol molecules can form hydrogen bonds with water molecules. 1-butene is more soluble in water under supercritical condition than that under subcritical condition. 1-butene under supercritical condition can extract more 2-butanol from aqueous solution than that under other conditions. A process of producing 2-butanol by the direct hydration of 1-butene is more competive when it operates under the supercritical conditions of 1-butene which due to a higher solubility of 1-butene in water, a lager diffusion coefficient of 1-butene and a lower 2-butanol concentration in water.
      Citation: Journal of Theoretical and Computational Chemistry
      PubDate: Thu, 13 Nov 2014 02:09:42 GMT
      DOI: 10.1142/S0219633614500667
       
  • First principle calculations of hydrogen sulfide adsorption and
           dissociation on pure Pd (111) and Au (111), and alloy Pd/Au (111) and
           Au/Pd (111) surfaces
    • Authors: Na Liu, Xue-Ye Wang, Ya-Li Wan
      Abstract: Journal of Theoretical and Computational Chemistry, Ahead of Print. The hydrogen sulfide adsorption and dissociation on pure Pd (111) and Au (111), alloy Pd/Au (111) and Au/Pd (111) surfaces have been investigated using the pseudo-potential plane wave method within the generalized-gradient approximation density functional theory (GGA+DFT). The results show that H2S tends to be adsorbed on top site, HS prefers to locate on bridge site, and the S and H locate on fcc site on various surfaces. Compared the adsorption of sulfur-containing species and hydrogen on pure and alloy metal surfaces, a similar trend of adsorption energies on the metal surfaces (Pd/Au (111) > Pd (111) > Au (111) > Au/Pd (111)) is found. In addition, the dissociation process on the Pd (111) and Pd/Au (111) surfaces is predicted to be exothermic. However, on Au (111) and Au/Pd (111), the dissociation process is endothermic. The work reveals that H2S dissociation is more likely to happen on Pd/Au (111) surface. Finally, the adsorption energies of adsorbate on metal surfaces have strong correlation with the d-band center. The d-band center moves away from the Fermi level, and the adsorption energy decreases. According to the LDOS analysis, the inner Au atoms of Pd/Au (111) can enhance the top-layer d-band intensity, whereas the inner Pd atoms of Au/Pd (111) cause the opposite effect. The further electronic state analysis reveals the interaction between H2S and metal surfaces.
      Citation: Journal of Theoretical and Computational Chemistry
      PubDate: Tue, 21 Oct 2014 03:46:16 GMT
      DOI: 10.1142/S0219633614500655
       
  • TD-DFT study on some triphenylamine-based organic dyes as photosensitizers
           in DSSCs
    • Authors: Ahmed A. Hasanein, Yasser R. Elmarassi, Ahmed M. Ramadan
      Abstract: Journal of Theoretical and Computational Chemistry, Ahead of Print. Geometrical and molecular electronic structure calculations on a series of metal free organic dyes based on triphenylamine (TPA) moiety have been performed using the TD-DFT methods. The B3LYP/6-31G, B3LYP/6-31G(d,p), M06-HF/6-31G(d,p) and WB97XD/6-31G(d,p) levels of theory have been utilized to predict the relationships between chemical structure and theoretically calculated molecular electronic properties of the studied dyes which may help in optimizing the properties of TPA-based photosensitizers in DSSCs. The solvation process of these dyes has been taken into account by means of the polarizable continuum model. The light harvesting efficiency, the free energy change for the electron injection process to the surface of TiO2 nanocrystalline semiconductor and the open circuit potential are calculated using all of these methods in different media. Significant charge transfer character of the HOMO → LUMO electronic transition which dominates the So → S1 vertical excitation in these systems facilitates the electron transfer process to the surface of TiO2. The results of the present computations are reported and discussed.
      Citation: Journal of Theoretical and Computational Chemistry
      PubDate: Tue, 14 Oct 2014 02:27:24 GMT
      DOI: 10.1142/S0219633614500643
       
  • Study of dispersion of boron nitride nanotubes by triton X-100 surfactant
           using molecular dynamics simulations
    • Authors: S. Mahmood Fatemi et al
      Abstract: Journal of Theoretical and Computational Chemistry, Ahead of Print. In this study, the dispersion of aggregated boron nitride nanotubes (BNNTs) in aqueous triton X-100 surfactant solution is studied using molecular dynamic simulation. The results indicate that how in the presence of the surfactant, a space between two BNNTs is created, which leads to the dispersion of the BNNTs. The radial distribution functions (RDFs) of the atoms of BNNTs and hydrophilic and hydrophobic segments of the surfactant respect to atoms of water molecules show that in the presence of the surfactant, a layer of water molecules is located in the neighborhood of the BNNTs and then hydrophobic and hydrophilic segments of the surfactant reside at more distances of the BNNTs. In the absence of the surfactant, the hydrogen bond between nitrogen atom of the BNNT and hydrogen atom of water molecules is established and the distance between water molecules and the BNNTs is decreased with increase of the surfactant concentration. The obtained results for the surfactant radius of gyration and the interfacial angle between two BNNTs reveal more information about the arrangement of the surfactants around the BNNTs in the presence and in the absence of water molecules.
      PubDate: Fri, 10 Oct 2014 05:51:45 GMT
       
  • Vibrational population transfer of the HF molecule: One-photon and
           two-photon transitions
    • Authors: Binbin Wang et al
      Abstract: Journal of Theoretical and Computational Chemistry, Ahead of Print. The population transfer process between the vibrational levels of the HF molecule is investigated by solving the time-dependent Schrödinger equation. The two vibrational levels of υ = 0 and 2 are set to be the initial and target states (an overtone transition). The transition processes under the one- and two-photon resonance conditions are considered, respectively. The influences of the laser intensity, frequency and pulse duration on population transfer are explored. It is found that the one-photon transition process is adiabatic, while the two-photon transition process is diabatic. Other vibrational levels, such as υ = 1 and 3, may participate into the two-photon transition process. Compared to the one-photon transition, a much longer pulse duration is required for the two-photon transition to achieve a high population-transfer efficiency, and the two-photon transition is more sensitive to the laser intensity. Almost a complete population transfer can be achieved for the two-photon resonance case, when the intensity is over 0.0091 a.u. with the appropriate duration (1180 fs) and frequency (0.017674 a.u.).
      PubDate: Fri, 10 Oct 2014 05:51:44 GMT
       
  • Acceptors/linkers effects on dye sensitized solar cell: Theoretical
           investigations of structure-property relationship for design of efficient
           dye sensitizers
    • Authors: Ying Guo et al
      Abstract: Journal of Theoretical and Computational Chemistry, Ahead of Print. A series of carbazole-based organic dyes such as CzFCA, CzTCA, CzSeCA, CzFRA, CzTRA and CzSeRA with introduction of various linkers (furan, thiophene and selenophen) and acceptor (cyanoacrylic acid and rhodanine-3-acetic acid) groups, were designed and theoretically investigated by density functional theory (DFT) and time dependent DFT (TD-DFT). The ground state structures and absorption spectra (both in vacuum and solvated form) were optimized by using DFT-B3LYP/6-31G(d,p), TD-B3LYP/6-311G(d,p) and PCM-TD-B3LYP/6-311G(d,p) levels of theory. Substitution of linker groups from furan to selenophen, resulted in red-shift of absorption band. CzTRA and CzSeRA exhibited superior electron injection capabilities. The finding of this study can be helpful to obtain dye-sensitized solar cell (DSSC) with superior conversion efficiency.
      PubDate: Fri, 10 Oct 2014 05:51:44 GMT
       
  • An oniom study of the distribution of skeletal al atoms and brønsted
           acidity in zsm-23 zeolite
    • Authors: Rui Liu et al
      Abstract: Journal of Theoretical and Computational Chemistry, Ahead of Print. This paper, based on the density functional theory (DFT), mainly studies the distribution of Al in seven nonequivalent T sites as well as the acidity of the corresponding Brønsted acids (B-acids). The distribution of the acid sites in the double-Al models is also investigated. Using ONIOM (B3LYP/6-31g(d,p):AM1) method, substitution energies, proton affinities and frequencies are calculated to characterize the Al distribution and Brønsted acidity. The result shows that T6 is the most destabilized site after substitution, while T7 buried in the framework is the most favorable for Al. Besides, Al4–O4–Si5 and Al2–O1–Si1 are the most readily sites to form B-acids, and the acid strength of Al4–O3–Si3 is the strongest. In the case that there are two B-acid sites on the 10-membered ring, one of the B-acid sites will be most likely to form at the Al4–O4–Si5 site, and the other one forms either at the other Al4–O4–Si5 or at Al2–O1–Si1 site on the opposite side.
      PubDate: Fri, 26 Sep 2014 01:35:27 GMT
       
  • The covalence and infrared spectra of cationic hydrogen bonds and
           dihydrogen bonds
    • Authors: Boaz G. Oliveira
      Abstract: Journal of Theoretical and Computational Chemistry, Ahead of Print. A theoretical study of hydrogen bonds and dihydrogen bonds formed by ethyl cation, hydrocarbons and magnesium hydride is presented with calculations performed at the BHandHLYP/6-31G(d,p) level of theory. The structural results and IR analyses demonstrated great insights, mainly the strengthening and weakness of the CC bond of the ethyl cation and π or pseudo-π bonds, respectively. The interaction strength was measured through the supermolecule as well as by means of additional approaches. The QTAIM calculations were applied to characterize not only the intermolecular interactions but specifically the covalent character in the H+⋯π, H+⋯ pseudo-π and H+⋯H contacts. The NBO calculations were useful to interpret the polarization on the CC bond and whether this effect is related with the bond length reduction as well as increase of charge density and frequency shifts.
      PubDate: Fri, 26 Sep 2014 01:35:26 GMT
       
  • Thermodynamic stability and structural parameters of carbon nanoclusters
    • Authors: Mansoor Namazian et al
      Abstract: Journal of Theoretical and Computational Chemistry, Ahead of Print. Thermodynamic stability of neutral carbon nanoclusters of Cm, up to the size of C50 have been investigated using density functional theory. Four different symmetry point groups, C(m/2)h, acetylenic D(m/2)h, cumulenic D(m/2)h and Dmh, have been considered for the clusters and the C(m/2)h has been found to be the most stable isomer for the studied clusters. Peierls transition is also studied for acetylenic D(m/2)h and cumulenic D(m/2)h point groups. It has been revealed that the relative stability of clusters converges to a constant value for clusters larger than C38. The changes of calculated structural parameters for these clusters, such as bond lengths, have been in agreement with their relative stability.
      PubDate: Wed, 24 Sep 2014 02:42:25 GMT
       
  • Intermolecular Π∕Π and H/Π interactions in dimers
           researched by different computational methods
    • Authors: Cuihong Wang et al
      Abstract: Journal of Theoretical and Computational Chemistry, Ahead of Print. The analysis of π/π and H/π interactions in complexes are a challenging aspect of theoretical research. Due to the different approximations of different levels of theory, results tend to be inconsistent. We compared the reliabilities of HF, SVWN, M06L, PW91, BLYP, B3LYP, BHandHLYP, B97D, MP2, and DFTB-D approaches in researching π/π and H/π interactions by calculating the binding energies of five benzene-containing dimers. The effects of 6-31+G**, 6-311++G** and 6-311++G(2df,2p) basis sets on the results were analyzed too. We found that the DFTB-D and B97D methods combined with the 6-311++G** basis set perform well for dimers that contain π/π and H/π interactions. With high efficiency and satisfactory precision, DFTB-D is helpful for the calculation of complexes containing π/π and H/π stacking. We further calculated the structures and properties of phenylalanine-containing dimers using the DFTB-D and B97D methods. The properties of low energy conformers such as rotational constants, dipole moments and molecular orbitals were also analyzed. These data should be helpful for research into systems that contain π/π and H/π stacking.
      PubDate: Thu, 18 Sep 2014 07:12:30 GMT
       
  • DFT study on the interaction between atomic aluminum and graphene
    • Authors: Nicolás F. Domancich et al
      Abstract: Journal of Theoretical and Computational Chemistry, Ahead of Print. In the present work, molecular orbital calculations using cluster models were performed within density functional theory (DFT) in order to study the adsorption of an Al atom on regular and defective graphene. Depending on the theoretical treatment of electronic exchange and correlations effects, different bonding results for the adsorption on the perfect surface are obtained. On the other hand, they are very similar for Al adsorbed on a carbon monovacancy. On regular graphene, the adsorption is exothermic when the Perdew, Burke and Ernzerhof (PBE) functional is used and endothermic with the Becke, 3-parameter, Lee–Yang–Parr (B3LYP) functional. Regarding the defective graphene surface, it was shown that the carbon atoms of concave angles in the vacancy are the most reactive to a radical attack. The adsorption of an Al atom on the vacancy restores the trigonal symmetry lost after the extraction of the C atom from regular graphene. Complementary calculations performed at PBE level on both regular and defective surfaces imposing periodic conditions qualitatively support the results obtained with the cluster model.
      PubDate: Tue, 09 Sep 2014 03:32:05 GMT
       
  • Quantum chemical prediction of structure and stability of the
           benzodihydropyrimidine tautomers
    • Authors: Robert Dobosz et al
      Abstract: Journal of Theoretical and Computational Chemistry, Ahead of Print. B3LYP/maug-cc-pVTZ and MP2/maug-cc-pVTZ calculations show that 3,4-dihydro-quinazoline and its 2- and/or 4-methyl and -phenyl substituted derivatives in solution (chloroform, DMSO, methanol) are only by 0.3 kcal/mol–2.2 kcal/mol more stable than the respective tautomeric 1,4-dihydroquinazolines (the available literature experimental stability data are not coherent). In the gas phase, 2- and/or 4-substituted tautomers of 3,4-dihydroquinazoline are also energetically preferred (B3LYP/maug-cc-pVTZ, MP2/maug-cc-pVTZ and CCSD/cc-pVDZ calculations lead to the same conclusion). In vacuum, 1,4-dihydro tautomer is by 0.1 kcal/mol–0.2 kcal/mol more stable only for unsubstituted dihydro-quinazoline. The observed tautomeric preference was found almost independent on substitution and solvent used. The optimization procedure used shows that the pyrimidine ring in dihydropyrimidines studied is not planar. Noncoplanarity of the 2-phenyl ring and C=N bond in the respective compounds studied is responsible for the weakened conjugation of these two moieties.
      PubDate: Tue, 09 Sep 2014 03:32:05 GMT
       
  • Density functional theoretical study on the reaction mechanism of SiHF
           radical with HNCO
    • Authors: Li-Jie Hou et al
      Abstract: Journal of Theoretical and Computational Chemistry, Ahead of Print. The reaction mechanism of SiHF radical with HNCO has been investigated by the B3LYP method of density functional theory (DFT), while the geometries and harmonic vibration frequencies of reactants, intermediates, transition states and products have been calculated at the B3LYP/6-311++G** level. To obtain more precise energy result, stationary point energies were calculated at the CCSD(T)/6-311++G**//B3LYP/6-311++G** level. In temperature range of 100 K to 1900 K, the statistical thermodynamics and Eyring transition state theory with Winger correction are used to study the thermodynamic and kinetic characters of the channel with low energy barrier at 1.0 Atm. SiHF + HNCO → IM8 → TS8 → SiFNHCHO(P3) was the main channel with low potential energy in the singlet state, SiFNHCHO was the main product. The analyses for the combining interaction between SiHF radical and HNCO with the atom-in-molecules (AIM) theory have been performed. There are three reaction channels in the triplet.
      PubDate: Tue, 09 Sep 2014 03:32:05 GMT
       
 
 
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