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Journal articles on the topic 'B3LYP/6-31G*'

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Published: 4 June 2021
Last updated: 8 February 2022

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1

POOLMEE, P., and S. HANNONGBUA. "THEORETICAL INVESTIGATION ON ENERGY GAP OF FLUORENE-THIOPHENE COPOLYMER." Journal of Theoretical and Computational Chemistry 03, no. 04 (2004): 481–89. http://dx.doi.org/10.1142/s0219633604001227.

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In this work, HOMO-LUMO energy gap and the lowest excitation energy of poly [2,7-(9,9-dihexylfluorene)-co-alt-2,5-(decylthiophene) were performed by different methods. The obtained results indicate that TDDFT(B3LYP/6-31G*)//B3LYP/6-31G* calculations can be useful to provide reliable energetic and structural results of this polymer. The HOMO-LUMO predictions were not accurately obtained as compared to the experimental results. The inverse chain length approximation by using TDDFT(B3LYP/6-31G*)//B3LYP/6-31G* calculations provides energy gap of 2.50 eV, which is in an excellent agreement with the
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2

Pantazis, Dimitrios A., Athanassios C. Tsipis, and Constantinos A. Tsipis. "Theoretical Study on the Mechanism of Reaction of Ground-State Fe Atoms with Carbon Dioxide." Collection of Czechoslovak Chemical Communications 69, no. 1 (2004): 13–33. http://dx.doi.org/10.1135/cccc20040013.

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Density functional calculations at the B3LYP level of theory, using the 6-31G(d) and 6-311+G(3df) basis sets, provide a satisfactory description of the geometric and energetic reaction profile of the Fe + CO2 → FeO + CO reaction. The reaction is predicted to be endothermic by 23.24 kcal/mol at the B3LYP/6-311+G(3df)//B3LYP/6-31G(d) level of theory and to proceed by formation of either a Fe(η2-OCO) or a Fe(η3-OCO) intermediate. The Fe(η2-OCO) intermediate in the 5A' ground state is weakly bound with respect to Fe(5D) and CO2 dissociation products by 0.78 (2.88) kcal/mol at the B3LYP/6-31G(d) (B
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3

French, A. D., A. M. Kelterer, G. P. Johnson, and M. K. Dowd. "B3LYP/6-31G ∗ , RHF/6-31G ∗ and MM3 heats of formation of disaccharide analogs." Journal of Molecular Structure 556, no. 1-3 (2000): 303–13. http://dx.doi.org/10.1016/s0022-2860(00)00648-7.

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4

Slanina, Zdenĕk, Olga V. Boltalina, Kaoru Kobayashi, and Shigeru Nagase. "B3LYP/6‐31G* Computations of C60F36(g) Isomers." Fullerenes, Nanotubes and Carbon Nanostructures 12, no. 3 (2004): 691–95. http://dx.doi.org/10.1081/fst-200029529.

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5

Alvarez, Maria, Edgardo Saavedra, Mónica Olivella, Fernando Suvire, Miguel Zamora, and Ricardo Enriz. "Theoretical study of the conformational energy hypersurface of cyclotrisarcosyl." Open Chemistry 10, no. 1 (2012): 248–55. http://dx.doi.org/10.2478/s11532-011-0136-1.

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AbstractThe multidimensional Conformational Potential Energy Hypersurface (PEHS) of cyclotrisarcosyl was comprehensively investigated at the DFT (B3LYP/6-31G(d), B3LYP/6-31G(d,p) and B3LYP/6-311++G(d,p)), levels of theory. The equilibrium structures, their relative stability, and the Transition State (TS) structures involved in the conformational interconversion pathways were analyzed. Aug-cc-pVTZ//B3LYP/6-311++G(d,p) and MP2/6-31G(d)//B3LYP/6-311++G(d,p) single point calculations predict a symmetric cis-cis-cis crown conformation as the energetically preferred form for this compound, which is
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6

Pye, Cory C., Daniel C. M. Whynot, Christopher R. Corbeil, and Darren J. W. Mercer. "Desymmetrization in geometry optimization: application to an ab initio study of copper(I) hydration." Pure and Applied Chemistry 92, no. 10 (2020): 1643–54. http://dx.doi.org/10.1515/pac-2019-1118.

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AbstractGroup theoretical arguments are used to find the subgroup corresponding to symmetry reduction along a particular irreducible representation of a group. The results are used to guide the search for stationary points on the potential energy surface of hydrated copper(I) ion at the HF/6-31G∗, HF/6-31+G∗, HF/6-311+G∗, MP2/6-31G∗, MP2/6-31+G∗, MP2/6-311+G∗, B3LYP/6-31G∗, B3LYP/6-31+G∗, and B3LYP/6-311+G∗ levels. The better levels give the most stable coordination number of two. The effect of desymmetrization on the Cu-O distances and stretching frequencies has been examined.
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7

Hamzehloueian, Mahshid, Yaghoub Sarrafi, and Zahra Aghaei. "An experimental and theoretical study on the regioselective synthesis of a new class of spiropyrrolothiazoles with quinoxaline motifs via a 1,3-dipolar cycloaddition reaction. An evaluation of DFT methods." RSC Advances 5, no. 93 (2015): 76368–76. http://dx.doi.org/10.1039/c5ra14071d.

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8

Toh, Pek Lan, Montha Meepripruk, Lee Sin Ang, Shukri Sulaiman, and Mohamed Ismail Mohamed-Ibrahim. "First Principles Study on the Stability and Electronic Structures of 7,8-Dichloro-4-Oxo-4H-Chromene-3-Carbaldehyde." Applied Mechanics and Materials 855 (October 2016): 31–36. http://dx.doi.org/10.4028/www.scientific.net/amm.855.31.

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The molecular structures and electronic properties of 7,8-Dichloro-4-Oxo-4H-Chromene-3-Carbaldehyde, C10H4Cl2O3 have been studied using Density Functional Theory (DFT) method. The calculation of geometry optimization was conducted to find the local energy minimum of C10H4Cl2O3 molecular system. The equilibrium geometries were used to determine the HOMO-LUMO gaps, Mulliken atomic charges, and other electronic structures of C10H4Cl2O3. The significant findings from DFT/B3LYP functional within the basis sets of 6-31G**, 6-31++G**, 6-311G**, and 6-311++G** show that the optimized geometries of C10
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9

Lewars, E. "Orthogonene: A computational study of a strongly twisted alkene." Canadian Journal of Chemistry 81, no. 10 (2003): 1119–25. http://dx.doi.org/10.1139/v03-150.

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The strongly twisted (calculated dihedral angle 84°) alkene orthogonene (tetracyclo[8,2,2,02,7,03,10]tetradecene-2(3)) was studied at the DFT (B3LYP/6-31G*) and ab initio (HF/6-31G* and MP2(fc)/6-31G*) levels with a view to exploring the question of how realistic a synthetic objective it is, particularly in view of the fact that an attempt was made to synthesize it. Orthogonene is a relative minimum on the potential energy surface at the B3LYP/6-31G* and MP2(fc)/6-31G* levels, but is predicted to have a very low barrier (1.2 kJ mol–1 from the B3LYP calculations) to rearrangement by a 1,2-carbo
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10

Irfan, Ahmad. "First principle investigations to enhance the charge transfer properties by bridge elongation." Journal of Theoretical and Computational Chemistry 13, no. 02 (2014): 1450013. http://dx.doi.org/10.1142/s0219633614500138.

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The ground-state geometries of 2-cyano-5-(4-(phenyl(4-vinylphenyl)amino)phenyl) penta-2,4-dienoic acid (TC4) derivatives have been optimized by using density functional theory (DFT) at B3LYP/6-31G** level of theory. The effect of bridge has been investigated on the electronic and charge transfer properties. The distortion between triphenylamine unit and acceptor moieties revealed there would be recombination barrier. The excitation energies have been computed by time dependent DFT at PCM-CAM-B3LYP/6-31G** and PCM-LC-BLYP/6-31G** level of theories. The absorption spectrum of TC4 computed at PCM
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11

Semire, Banjo, Isaiah Ajibade Adejoro, and Olusegun Ayobami Odunola. "STRUCTURAL AND ELECTRONIC PROPERTIES OF BRIDGED BITHIOPHENE S-OXIDES (BTO) WITH S, S=O, O, SiH2 and BH2 BRIDGE: SEMI-EMPIRICAL AND AB INITIO STUDY." SOUTHERN BRAZILIAN JOURNAL OF CHEMISTRY 18, no. 18 (2010): 1–10. http://dx.doi.org/10.48141/sbjchem.v18.n18.2010.6_2010.pdf.

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In this paper, we theoretically studied the geometries, stabilities, electronic and thermodynamic properties of bridged bithiophene S-oxide (BTO-X) derivates (with X = BH2, SiH2, S, S=O, and O) by using semi-empirical methods, ab-initio, and Density functional theory. The geometries and thermodynamic parameters calculated by PM3 were in good agreement with that of B3LYP/6-31G(d). The bandgap calculated by B3LYP/6-31G(d) ranged from 3.94eV (BTO-O)-3.16eV (BTO-BH2). The absorption λmax calculated suing B3LYP/6-31G(d) shifted to longer wavelength with X=BH2, SiH2, and S=O due to enhancement of π-
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12

CAI, JUN, and ZHIJIAN WU. "SOLVENT AND SUBSTITUENT EFFECTS ON THE INTRAMOLECULAR AMIDE HYDROLYSIS OF N-METHYLMALEAMIC ACID." Journal of Theoretical and Computational Chemistry 08, no. 06 (2009): 1217–26. http://dx.doi.org/10.1142/s0219633609005374.

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Intramolecular amide hydrolysis of N-methylmaleamic acid is revisited at the B3LYP/6-311G(2df, p)//B3LYP/6-31G(d, p) + ZVPE level, including solvent effects at the CPCM-B3LYP/6-311G(2df, p)//Onsager-B3LYP/6-31G(d, p) + ZPVE level. The concerted reaction mechanism is energetically favorable over stepwise reaction mechanisms in both the gas phase and solution. The calculated reaction barriers are significantly lower in solution than in the gas phase. In addition, it is concluded that the substituents of the four N-methylmaleamic acid derivatives considered herein have a significant effect on the
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13

SRIWICHITKAMOL, KRIENGSAK, SONGWUT SURAMITR, POTJAMAN POOLMEE, and SUPA HANNONGBUA. "STRUCTURES, ABSORPTION SPECTRA, AND ELECTRONIC PROPERTIES OF POLYFLUORENE AND ITS DERIVATIVES: A THEORETICAL STUDY." Journal of Theoretical and Computational Chemistry 05, no. 03 (2006): 595–608. http://dx.doi.org/10.1142/s0219633606002520.

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The structural and energetic properties of polyfluorene and its derivatives were investigated, using quantum chemical calculations. Conformational analysis of bifluorene was performed by using ab initio (HF/6-31G* and MP2/6-31G*) and density functional theory (B3LYP/6-31G*) calculations. The results showed that the local energy minimum of bifluorene lies between the coplanar and perpendicular conformation, and the B3LYP/6-31G* calculations led to the overestimation of the stability of the planar pi systems. The HOMO-LUMO energy differences of fluorene oligomers and its derivatives — 9,9-dihexy
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14

Slanina, ZdenĚK, Filip Uhlík, Xiang Zhao, Hiroshi Ueno, and Eiji [Obar]sawa. "B3LYP/6-31G∗//SAM1 Calculations of C36Fullerene andquasi-Fullerene Cages." Fullerene Science and Technology 8, no. 4-5 (2000): 433–47. http://dx.doi.org/10.1080/10641220009351423.

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15

LUO, XIAOMIN, CHENG FENG, XIAO-JIAN TAN, et al. "STRUCTURAL FEATURE OF AChE INHIBITOR HUPERZINE B IN NATURE AND IN THE BINDING SITE OF AChE: DENSITY FUNCTIONAL THEORY STUDY COMBINED WITH IR DETERMINATION." Journal of Theoretical and Computational Chemistry 01, no. 01 (2002): 81–92. http://dx.doi.org/10.1142/s0219633602000063.

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Quantum chemical DFT-B3LYP/6-31G* method and IR spectrometry have been used to investigate the natural and binding structures of Huperzine B (HupB) in order to better understand the interaction nature between acetylcholinesterase (AChE) and its inhibitor, with the view of designing new AChE inhibitors. The predicted and experimental results reveal that both the natural state and binding form of HupB adopt the chair conformation. Furthermore, the B3LYP/6-31G* results suggest that structure S1 should be the dominant form of the two possible chair structures (S1 and S2, Fig. 2). The calculated re
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16

Qi, Zheng-Hang, Ye Zhang, Gui-Yu Ruan, Yi Zhang, Yong Wang, and Xing-Wang Wang. "Theoretical studies on the activation mechanism involving bifunctional tertiary amine–thioureas and isatylidene malononitriles." RSC Advances 5, no. 43 (2015): 34314–18. http://dx.doi.org/10.1039/c5ra01821h.

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DFT studies on the activation mechanism of the Michael addition reactions containing bifunctional tertiary amine–thioureas and isatylidene malononitriles have been performed at the B3LYP/6-311++G(d,p)//B3LYP/6-31G(d) level of theory.
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17

Khalid, Muhammad, Riaz Hussain, Ajaz Hussain, et al. "Electron Donor and Acceptor Influence on the Nonlinear Optical Response of Diacetylene-Functionalized Organic Materials (DFOMs): Density Functional Theory Calculations." Molecules 24, no. 11 (2019): 2096. http://dx.doi.org/10.3390/molecules24112096.

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Herein, we report the quantum chemical results based on density functional theory for the polarizability (α) and first hyperpolarizability (β) values of diacetylene-functionalized organic molecules (DFOM) containing an electron acceptor (A) unit in the form of nitro group and electron donor (D) unit in the form of amino group. Six DFOM 1–6 have been designed by structural tailoring of the synthesized chromophore 4,4′-(buta-1,3-diyne-1,4-diyl) dianiline (R) and the influence of the D and A moieties on α and β was explored. Ground state geometries, HOMO-LUMO energies, and natural bond orbital (N
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18

Simons, J., H. G. Thomas, S. R. Hall, and G. Raabe. "Synthesis and structure of, and bonding in some derivatives of 2,6,9,10-tetraoxatricyclo[3.3.1.13,8]decane." Acta Crystallographica Section B Structural Science 57, no. 1 (2001): 63–71. http://dx.doi.org/10.1107/s0108768100013331.

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Five derivatives of 2,6,9,10-tetraoxatricyclo[3.3.1.13,8]decane were synthesized and their molecular structures in the solid state were determined by means of X-ray diffraction analysis. In addition, the structures of all the molecules were optimized at different levels of computational quantum chemistry (HF/6-31G*, B3LYP/6-31G*). Experimentally determined bond lengths were compared with their calculated counterparts, and striking differences between the Hartree–Fock (HF) results and the experimental data could be traced back to the lack of correlation energy in the geometry optimizations. Two
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19

Schumacher, Maria, and Bernd Goldfuss. "Quantifying N-heterocyclic carbenes as umpolung catalysts in the benzoin reaction: balance between nucleophilicity and electrophilicity." New Journal of Chemistry 39, no. 6 (2015): 4508–18. http://dx.doi.org/10.1039/c5nj00413f.

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Different types of N-heterocyclic carbenes, i.e. normal, reduced heteroatom stabilized, remote and abnormal carbenes, are computationally assessed (THF-CPCM-B3LYP/6-311+G(d,p)//B3LYP/6-31G(d)) in the benzoin reaction to study their characteristics as umpolung catalysts.
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20

Toh, Pek Lan, Montha Meepripruk, and Rosfayanti Rasmidi. "A Computational Study on Structural and Electronic Properties of 1-(4-Chlorophenyl)-2-{[5-(4-Chlorophenyl)-1,2,3-Oxadiazol-2-Yl]Sulfanyl}Ethanone." Applied Mechanics and Materials 892 (June 2019): 1–7. http://dx.doi.org/10.4028/www.scientific.net/amm.892.1.

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In this paper, a first principle Density Functional Theory (DFT) method was conducted to study the geometric and electronic structures of 1-(4-chlorophenyl)-2-{[5-(4-chlorophenyl) -1,3,4-oxadiazol-2-yl] sulfanyl} ethanone, C16H10Cl2N2O2S. Using B3LYP level of theory with four basis sets of 6-31G**, 6-31++G**, 6-311G**, and 6-311++G**, the equilibrium structure of the title molecule was used to determine the total energies, Frontier molecular orbital’s energies, Mulliken atomic charges, and others. The computed findings present that four total energies obtained are close to each other, with the
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21

Bardajee, Ghasem Rezanejade. "SbCl3-catalyzed one-pot synthesis of 4,4′-diaminotriarylmethanes under solvent-free conditions: Synthesis, characterization, and DFT studies." Beilstein Journal of Organic Chemistry 7 (January 31, 2011): 135–44. http://dx.doi.org/10.3762/bjoc.7.19.

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A simple, efficient, and mild procedure for a solvent-free one-step synthesis of various 4,4′-diaminotriarylmethane derivatives in the presence of antimony trichloride as catalyst is described. Triarylmethane derivatives were prepared in good to excellent yields and characterized by elemental analysis, FTIR, 1H and 13C NMR spectroscopic techniques. The structural and vibrational analysis were investigated by performing theoretical calculations at the HF and DFT levels of theory by standard 6-31G*, 6-31G*/B3LYP, and B3LYP/cc-pVDZ methods and good agreement was obtained between experimental and
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22

Arslan, Hakan, Aydin Demircan, Gun Binzet, and Ilhan Ozer Ilhan. "Vibrational Spectroscopy Investigation Using Ab Initio and Density Functional Theory Analysis on the Structure oftert-Butyl 3a-Chloroperhydro-2,6a-epoxyoxireno[e]isoindole-5-carboxylate." Journal of Chemistry 2013 (2013): 1–13. http://dx.doi.org/10.1155/2013/124659.

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The molecular structure, vibrational frequencies, and infrared intensities of thetert-butyl 3a-chloroperhydro-2,6a-epoxyoxireno[e]isoindole-5-carboxylate were calculated by the HF and DFT (BLYP and B3LYP) methods using 6-31G(d) and 6-31G(d,p) basis sets. The FT infrared spectrum of the solid sample was measured under standard condition. We obtained two stable conformers for the title compound; however Conformer 1 is approximately 0.2 kcal/mol more stable than the Conformer 2. The comparison of the theoretical and experimental geometry of the title compound shows that the X-ray parameters fairl
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23

Shlyapnikov, Dmitry B., and Valentin P. Feshin. "Estimation of the 35Cl NQR Frequencies of Some Organic and Organometallic Molecules Using ab initio Calculations at Different Levels and Basis Sets." Zeitschrift für Naturforschung A 57, no. 12 (2002): 974–76. http://dx.doi.org/10.1515/zna-2002-1211.

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Ab initio calculations of organic and organometallic molecules at RHF, B3LYP and MP2 levels and 6-31G(d), 6-31+G(d), 6-311G(d) and 6-311+G(d) basis sets were executed. They were used to estimate the 35Cl NQR frequencies of these molecules. A satisfactory agreement between experimental and estimated NQR frequencies was obtained for the populations of the less diffuse 3p-components of the Cl atom valence p-orbitals obtained from the RHF, B3LYP and MP2 calculations with the split valence basis sets 6-31G(d) and 6-31+G(d). An analogous conformity was not obtained using the 6-311G(d) and 6-311+G(d)
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24

Jin, Jian-Chang, Zhao-Hui Sun, Ming-Yan Yang, Jing Wu, and Xing-Hai Liu. "Synthesis, Crystal Structure, and Theoretical Studies of N-(4-((4-chlorobenzyl)oxy)phenyl)-4- (trifluoromethyl)pyrimidin-2-amine." Journal of Chemistry 2013 (2013): 1–5. http://dx.doi.org/10.1155/2013/521757.

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The title compound (C18H13ClF3N3O) were synthesized and recrystallized from CH3OH. The compound was characterized byH1NMR, MS, HRMS, and X-ray diffraction. The compound crystallized in the monoclinic space groupP2(1)/nwitha=8.2354(14),b=12.686(2),c=16.633(3) Å,α=90,β=97.951(3),γ=90∘,V=1721.0(5) Å3,Z=4,andR=0.0376for 1933 observed reflections withI>2σ(I).X-ray analysis reveals that intermolecular N–H⋯N interactions exist in the adjacent molecules. Theoretical calculation of the title compound was carried out with HF/6-31G(d,p), B3LYP/6-31G(d,p). The full geometry optimization was carried out
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25

Hasanein, Ahmed A., Yasser R. Elmarassi, and Ahmed M. Ramadan. "TD-DFT study on some triphenylamine-based organic dyes as photosensitizers in DSSCs." Journal of Theoretical and Computational Chemistry 13, no. 08 (2014): 1450064. http://dx.doi.org/10.1142/s0219633614500643.

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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 polari
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26

Karaman, Rafik. "Accelerations in the Lactonization of Trimethyl Lock Systems Are due to Proximity Orientation and not to Strain Effects." Research Letters in Organic Chemistry 2009 (March 26, 2009): 1–5. http://dx.doi.org/10.1155/2009/240253.

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DFT at B3LYP/6-31G(d,p) and HF at 6-31G and AM1 semiempirical calculations of thermodynamc and kinetic parameters for the trimethyl lock system (an important enzyme model) indicate that the remarkable enhancement in the lactonizations is largely the result of a proximity orientation as opposed to the currently advanced strain effect.
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27

ZHA, DONG, LAI-CAI LI, YAN ZHENG, XIN WANG, AN-MIN TIAN, and NING-BEW WONG. "THEORETICAL STUDY OF THE HYDROLYSIS MECHANISM OF METABOLIC PRODUCT FROM TIRAPAZAMINE'S UNDERGOING ENZYMATIC CATALYSIS." Journal of Theoretical and Computational Chemistry 05, no. 02 (2006): 235–42. http://dx.doi.org/10.1142/s0219633606002143.

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Two different hydrolysis mechanisms of metabolic product from tirapazamine's enzymatic catalysis have been studied by density functional theory (DFT) at the B3LYP/6-31G(d) and B3LYP/6-311+G(d) levels. The results indicate that the activation barrier of rate-controling step of Brown's model is smaller than that of Denny's model.
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28

Li, Rui, and Xiang Yu Liu. "CH3 and H2 Quantum Chemical Study of Reaction Mechanisms." Applied Mechanics and Materials 142 (November 2011): 225–28. http://dx.doi.org/10.4028/www.scientific.net/amm.142.225.

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Using DFT (B3LYP) method, the 6-31G * ,6-311G ** ,6-311 + + G ** and cc-pvtz basis set level, through the CH3+ H2→ CH4+ H reaction of the reactants, transition state and product geometry optimization show that: the base group selection mode on the stationary geometry has little effect; by B3LYP/6-31G * calculated barrier 39.61kJ/mol only difference with the experimental values ​​39.41kJ/mol 0.20 kJ / mol; analysis along the IRC that the HH bond breaking and CH bond formation is a coordinated manner, and in response there is a guide on ways to respond to the vibration mode, vibration mode, the
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29

LEE, HO-JIN, HYUN-MEE PARK, and KANG-BONG LEE. "CONFORMATIONAL PREFERENCES OF N-ACETYL–GLYCINE–GLYCINE–N′-METHYLAMIDE: A THEORETICAL STUDY." Journal of Theoretical and Computational Chemistry 08, no. 05 (2009): 799–811. http://dx.doi.org/10.1142/s0219633609005118.

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The conformational preferences of peptide models have been investigated to understand the protein folding mechanism and to develop the force field. Here, we report the minimum energy conformations for a model peptide, N-acetyl–glycine–glycine–N′-methylamide ( Ac–1Gly–2Gly–NHMe(I) ) at the HF/3-21G, HF/6-31G*, and the B3LYP/6-31G* level of theory. At the B3LYP/6-31G* level, the 31 minima were identified and the 10 β-turn structures among the minima were observed in gas-phase. The conformational preferences of Gly residue in the model peptide, I depend on its relative position and conformation o
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30

Zhang, Yanli, Jieqiong Li, and Li Wang. "Effect of principal and secondary ligands on the electronic structures and spectra of a series of ruthenium(II) complexes." Journal of the Serbian Chemical Society 81, no. 5 (2016): 521–39. http://dx.doi.org/10.2298/jsc151029031z.

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A DFT(density functional theory)/TDDFT(time-dependent density functional theory) investigation is performed to study the ground-state geometries, electronic structures, and absorption spectra of twelve ruthenium(II) thiosemicarbazone complexes [Ru(CO)(C)(Ln)], where Ln=derivatives of dibasic tetradentate Schiff-base ligand and X=AsPh3/PPh3/Py. The ground-state geometries are optimized at the B3LYP/6-31G(d)-LANL2DZ level, and the spectra are simulated by means of TD-B3LYP/6-31G(d)-LANL2DZ method on the basis of the optimized geometries. The influence of principal and secondary ligands (Ln and X
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31

Babatunde Olasupo, Sabitu. "Density Functional Theory (B3LYP/6-31G*) Study of Toxicity of Polychlorinated Dibenzofurans." International Journal of Computational and Theoretical Chemistry 5, no. 2 (2017): 14. http://dx.doi.org/10.11648/j.ijctc.20170502.11.

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32

Greenberg, Arthur, Alexa R. Green, and Joel F. Liebman. "Computational Study of Selected Amine and Lactam N-Oxides Including Comparisons of N-O Bond Dissociation Enthalpies with Those of Pyridine N-Oxides." Molecules 25, no. 16 (2020): 3703. http://dx.doi.org/10.3390/molecules25163703.

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A computational study of the structures and energetics of amine N-oxides, including pyridine N-oxides, trimethylamine N-oxide, bridgehead bicyclic amine N-oxides, and lactam N-oxides, allowed comparisons with published experimental data. Most of the computations employed the B3LYP/6-31G* and M06/6-311G+(d,p) models and comparisons were also made between the results of the HF 6-31G*, B3LYP/6-31G**, B3PW91/6-31G*, B3PW91/6-31G**, and the B3PW91/6-311G+(d,p) models. The range of calculated N-O bond dissociation energies (BDE) (actually enthalpies) was about 40 kcal/mol. Of particular interest was
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33

Benhalima, N., S. Yahiaoui, N. Boubegra, et al. "Quantum chemical investigation of spectroscopic, electronic and NLO properties of (1E, 4E)-1-(3-nitrophenyl)-5-phenylpenta-1,4-dien-3-one." International Journal of Advanced Chemistry 6, no. 1 (2018): 121. http://dx.doi.org/10.14419/ijac.v6i1.11795.

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In the present work the optimized molecular geometry and harmonic vibrational frequencies of chalcone derivative were calculated by DFT/B3LYP method with 6–31G (d,p) basis set. The vibrational assignments were performed on the basis of the potential energy dis-tribution (PED) of the vibrational modes. Natural bond orbital (NBO) analysis has been performed on title compound using B3LYP/6–31G (d,p) and HSEh1PBE /6–31G (d,p) levels in order to elucidate intermolecular hydrogen bonding, intermolecular charge transfer (ICT) and delocalization of electron density. Mulliken atomic charges, natural po
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34

Muchall, Heidi M., Petrina RN Kamya, and Jean Lessard. "The conformational behaviour of methylenecyclohexanes revisited." Canadian Journal of Chemistry 81, no. 6 (2003): 689–96. http://dx.doi.org/10.1139/v03-083.

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Conformational analyses on 2-substituted (methoxy, vinyloxy, and acetoxy) methylenecyclohexanes have been performed computationally with HF, B3LYP, PBE0, and MP2 and the 6-31G(d) basis set. The global minimum for the methoxy substituent is an axial conformer. For the vinyloxy substituent, except with PBE0, an axial conformer is determined as the global minimum. The acetoxy substituent prefers the equatorial orientation. This sequence is in keeping with the operation of an "unsaturation effect" in addition to an anomeric effect. For a full conformational analysis, torsional potentials for the s
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35

De Souza, Leonardo A., Antônio M. Da Silva, Hélio F. Dos Santos, and Wagner B. De Almeida. "Oxidized single-walled carbon nanotubes and nanocones: a DFT study." RSC Advances 7, no. 22 (2017): 13212–22. http://dx.doi.org/10.1039/c7ra00301c.

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36

Gao, Peng, Yingying Yu, Zhangqin Ni, and Qiwen Teng. "Theoretical studies on the electronic structures and spectra of single silicon-doped SWCNTs." Open Chemistry 8, no. 3 (2010): 587–93. http://dx.doi.org/10.2478/s11532-010-0018-y.

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AbstractThe equilibrium geometries and electronic structures of a series of SWCNTs doped with a silicon atom were studied by using density function theory (DFT). The most stable doping site of silicon predicted at B3LYP/6-31G(d,p) level was located near the boundary of the SWCNTs. The energy gaps of (3,3) C48, (3,3) C60 and (3,3) C72 were respectively decreased by 0.43, 0.25 and 0.14 eV after doping. Based on the B3LYP/6-31G(d) optimized geometries, the electronic spectra of the doped SWCNTs were computed using the INDO/CIS method. The first UV absorption at 973.9 nm of (5,5)-Si(L) (C59Si) com
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37

Ardjani, Ahmed Taki Eddine, and Sidi Mohamed Mekelleche. "Theoretical study of the structure, spectroscopic properties and anti-cancer activity of tetrahydrochromeno[4,3-b]quinolines." Journal of Theoretical and Computational Chemistry 14, no. 07 (2015): 1550052. http://dx.doi.org/10.1142/s0219633615500522.

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In the present work, a theoretical study of the geometrical structures and spectroscopic (IR, 1H and [Formula: see text]C NMR, UV-visible) properties, and anti-cancer activity of cis-fused tetrahydrochromeno[4,3-b]quinolines have been performed. The equilibrium geometries have been optimized at the B3LYP/6-31G(d) computational level and the present study puts in evidence the stability preference of the cis stereoisomers in comparison with the trans ones as expected experimentally. The vibrational frequencies and IR spectra were calculated at the same level of theory and compared to experimenta
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38

Wu, Xiujun, Bernhard Vogler, Betsy R. Jackes, and William N. Setzer. "Terpenoids from Neolitsea Dealbata." Natural Product Communications 3, no. 2 (2008): 1934578X0800300. http://dx.doi.org/10.1177/1934578x0800300204.

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A phytochemical investigation of the crude chloroform bark extract of Neolitsea dealbata from Paluma, north Queensland, Australia, revealed the two common triterpenoids, taraxerone and taraxerol, as well as three furanogermacranolide sesquiterpenoids, linderadine, linderalactone, and pseudoneolinderane. These compounds are reported for the first time from this plant. An ab initio investigation (DFT, B3LYP/6-31G* and post HF, MP2/6-31G**) of the Cope rearrangement of linderalactone has been carried out.
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39

Abraham, Raymond J., and M. Ashley Cooper. "A convenient and accurate method for predicting13C chemical shifts in organic molecules." New Journal of Chemistry 42, no. 7 (2018): 5024–36. http://dx.doi.org/10.1039/c8nj00312b.

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40

Sarojini, K., H. Krishnan, Charles C. Kanagam, and S. Muthu. "Molecular Structure, Vibrational Spectroscopy and Homo, Lumo Studies of 4-methyl-N-(2-methylphenyl) Benzene Sulfonamide Using DFT Method." Advanced Materials Research 665 (February 2013): 101–11. http://dx.doi.org/10.4028/www.scientific.net/amr.665.101.

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The sulfonamide compound, 4-methyl-N-(2-methylphenyl) benzene sulfonamide has been synthesized and characterized by FTIR, NMR, UV-Vis, single crystal X-ray diffraction and thermal analysis. Density functional (DFT) calculations have been carried out for the title compound by performing DFT level of theory using B3LYP/6-31G (d,p) basis set. The calculated results show that the predicted geometry can well reproduce the structural parameters. Predicted vibrational frequencies have been assigned and compared with the experimental IR spectra and they support each other. In addition, atomic charges,
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41

Semire, Banjo, and Olusegun Ayobami Odunola. "Theoretical Study on Structure and Electronic Properties of 4H-Cyclopenta[2,1-b,3;4-b’]dithiopene S-oxide and Its CCl2 and CF2 Bridged Derivatives." Indonesian Journal of Chemistry 15, no. 1 (2015): 93–100. http://dx.doi.org/10.22146/ijc.21229.

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Quantum chemical calculations using semi-empirical, ab initio, density functional theory (DFT) and Møller plesset (MP2) methods were performed on 4H-Cyclopenta[2,1-b,3;4-b’]dithiopene S-oxide derivatives (i.e. bridged dithiophene S-oxides, BTOs). The geometries, stabilities, electronic and thermodynamic properties of the compounds were studied. The thermodynamic parameters calculated at PM3 were in good agreement with those calculated at B3LYP/6-31G(d) level. The band gap energies calculated at B3LYP/6-31G(d) level for the BTOs were lower than the un-substituted trithiophene but higher than 4H
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42

Șen, İbrahim, Cem Burak Yildiz, and Akın Azizoğlu. "Nontemplate synthesis, characterization and theoretical study of tetraazamacrocycles." Analele Universitatii "Ovidius" Constanta - Seria Chimie 23, no. 1 (2012): 121–27. http://dx.doi.org/10.2478/v10310-012-0020-7.

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Abstract The syntheses of new tetraaza macrocyclic compounds of variable ring sizes by non-template methods and their characterization with the help of elemental analysis and spectroscopic techniques (FT-IR, 1H-NMR, and 13C-NMR) have been reported in detail. The vibrational frequencies determined experimentally are compared with those obtained theoretically from density functional theory (DFT) and Hartree-Fock (HF) calculations. The comparisons between the experimental and theoretical results indicate that B3LYP level with both the 3-21G(d) and 6-31G+(d,p) basis sets is able to provide satisfa
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43

Rohit S. Shinde. "Synthesis, Characterization and Theoretical Insights into Molecular Properties of 2-(4-fluorophenyl)-4H-chromen-4-one." Journal of Advanced Chemical Sciences 7, no. 2 (2021): 721–24. http://dx.doi.org/10.30799/jacs.235.21070201.

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Flavone scaffold is one of the most often perceived parts in biologically active organic compounds. In light of this, a flavone; 2-(4-fluorophenyl)-4H-chromen-4-one (FPC) has been synthesized, characterized and studied by using density functional theory (DFT) at B3LYP/6-31G(d,p) basis set. The geometry of the FPC molecules has been optimized by using B3LYP/6-31G(d,p) basis set and in-depth structural analysis on bond lengths and bond angles has been discussed. The HOMO-LUMO analysis and various quantum chemical parameters are computed and discussed for the better understanding of chemical beha
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44

Rauwolf, Cordula, Achim Mehlhorn, and Jürgen Fabian. "Binding Energies of Organic Charge-Transfer Complexes Calculated by First-Principles Methods." Collection of Czechoslovak Chemical Communications 63, no. 8 (1998): 1223–44. http://dx.doi.org/10.1135/cccc19981223.

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Weak interactions between organic donor and acceptor molecules resulting in cofacially-stacked aggregates ("CT complexes") were studied by second-order many-body perturbation theory (MP2) and by gradient-corrected hybrid Hartree-Fock/density functional theory (B3LYP exchange-correlation functional). The complexes consist of tetrathiafulvalene (TTF) and related compounds and tetracyanoethylene (TCNE). Density functional theory (DFT) and MP2 molecular equilibrium geometries of the component structures are calculated by means of 6-31G*, 6-31G*(0.25), 6-31++G**, 6-31++G(3df,2p) and 6-311G** basis
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45

Irfan, Ahmad, Ruihai Cui, Jingping Zhang, and Muhammad Nadeem. "Designing of Disubstituted Derivatives of mer-Alq3: Quantum Theoretical Study." Australian Journal of Chemistry 63, no. 8 (2010): 1283. http://dx.doi.org/10.1071/ch09491.

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Different disubstituted derivatives of tris(8-hydroxyquinolinato)aluminium (mer-Alq3) have been designed. An electron donating group (–CH3) has been substituted at position 4; along with electron withdrawing groups (–Cl, –CN, and –F) at position 5 (i.e. tris(4-X-5-Y-8-hydroxyquinolinato)aluminium), as well as the molecules arising from reversion of these substitutions. The designed systems have been optimized at the B3LYP/6–31G* and TD-B3LYP/6–31G* level of theories, in the ground and excited states, respectively. The absorption and emission spectra have been calculated at the TD-B3LYP/6–31G*
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46

ZHANG, ZHI-HUI, TAO GAO, XIAO-FENG TIAN, and NA HE. "THERMOCHEMICAL PROPERTIES OF THE THIOCARBONYLTHIO COMPOUNDS FROM CONVENTIONAL DENSITY FUNCTIONAL THEORY CALCULATIONS." Journal of Theoretical and Computational Chemistry 09, supp01 (2010): 201–17. http://dx.doi.org/10.1142/s0219633610005542.

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Density functional theory (DFT) calculations employed at two levels, B3LYP/6-31G+(d) and B3P86/6-31G+(d), are reported for the geometry, enthalpy, and free energy of reaction of a number of dithiobenzoate reversible addition fragmentation transfer (RAFT) reagents ( S=C(Ph)S–R , S=C(Z)S–CH2Ph ). Based on these theoretical data, the effectiveness of these RAFT reagents is analyzed. The conclusions, especially obtained at B3LYP/6-31G+(d) level, are in good agreement with the experimental results. Our calculations suggest that the dithiobenzoate ( S=C(Z)S–CH2Ph ), where Z is OC6H5 or N(alkyl)2 , i
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47

Shinde, Rohit S. "Ultrasound Assisted Synthesis, Molecular Structure,UV-Visible Assignments, MEP and Mulliken Charges Study of (E)-3-(4-chlorophenyl)-1-(4-methoxyphenyl) prop-2-en-1-one: Experimental and DFT Correlational." Material Science Research India 18, no. 1 (2021): 86–96. http://dx.doi.org/10.13005/msri/180110.

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Present investigation deals with the synthesis and density functional theory study (DFT) of a chalcone derivative; (E)-3-(4-chlorophenyl)-1-(4-methoxyphenyl)prop-2-en-1-one (CPMPP). The synthesis of a CPMPP has been carried out by the reaction of 4-methoxyacetophenone and 4-chlorobenzalehyde in ethanol at 30 ℃ under ultrasound irradiation. The structure of a synthesized chalcone is affirmed on the basis of FT-IT, 1H NMR and 13C NMR. The geometry of a CPMPP is optimized by using the density functional theory method at the B3LYP/6-31G(d,p) basis set. The optimized geometrical parameters like bon
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48

Luber, Markus, Arafa Musa, Hazem A. Kadry, and Franz Bracher. "Isolation of the Pyrrolizidine Alkaloid Intermedine-N-oxide from Cerinthe glabra and ab initio Calculation of its 13C NMR Shifts." Zeitschrift für Naturforschung B 67, no. 5 (2012): 411–16. http://dx.doi.org/10.5560/znb.2012-0030.

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The pyrrolizidine alkaloid intermedine-N-oxide was isolated from Cerinthe glabra for the first time. Due to the questionable assignments of NMR signals of this compound in previous literature reports ab initio calculations of the 13C NMR values based on the GIAO approach, using HF and B3LYP levels of theory and the four basis sets 6-31G(d), 6-311G(d), 6-31G(d,p), and 6-311G(d,p) were performed. The assignments obtained this way are in very good accordance with the experimental values.
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49

Andrés, J., M. Canle L., M. V. Garcı́a, L. F. Rodrı́guez Vázquez, and J. A. Santaballa. "A B3LYP/6-31G** study on the chlorination of ammonia by hypochlorous acid." Chemical Physics Letters 342, no. 3-4 (2001): 405–10. http://dx.doi.org/10.1016/s0009-2614(01)00579-6.

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50

Slanina, Zdeněk, Filip Uhlı́k, Xiang Zhao, and Eiji Ōsawa. "Enthalpy–entropy interplay for C[sub 36] cages: B3LYP/6-31G[sup ∗] calculations." Journal of Chemical Physics 113, no. 12 (2000): 4933. http://dx.doi.org/10.1063/1.1288368.

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