THEORETICAL STUDIES ON HEATS OF FORMATION OF PYRIDINE N-OXIDES USING DENSITY FUNCTIONAL THEORY AND COMPLETE BASIS METHOD

The heats of formation (HOFs) for 11 pyridine N-oxide compounds are calculated by employing the hybrid density functional theory (B3LYP, B3PW91, B3P86, PBE1PBE) methods with 6-31G** basis set and ab initio CBS-4M method. It is demonstrated that the B3PW91 method is accurate to compute the reliable HOFs for pyridine N-oxide compounds. It is also noted that the HOF is the smallest for the pyridine N-oxide which has the substituent group on the para-position, such as 4-NC–c- C 5 H 4 NO , 4- H 2 NOC – C 5 H 4 N – O , and 4- HO 2 C –c- C 5 H 4 NO . In addition, we think that the HOF of 2- HO 2 C –c- C 5 H 4 NO is much larger than that of 3- HO 2 C –c- C 5 H 4 NO and 4- HO 2 C –c- C 5 H 4 NO , which may be the result of intramolecular hydrogen bond formation and further measurements are needed to reexamine the HOFs for 2- HO 2 C –c- C 5 H 4 NO , 3- HO 2 C –c- C 5 H 4 NO , and 4- HO 2 C –c- C 5 H 4 NO .

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Accurate quadruple-ζ basis-set approximation for double-hybrid density functional theory with an order of magnitude reduction in computational cost

Theoretical Chemistry Accounts ◽

10.1007/s00214-013-1426-9 ◽

2013 ◽

Vol 133 (2) ◽

Cited By ~ 18

Author(s):

Bun Chan ◽

Leo Radom

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Computational Cost ◽

Basis Set ◽

Hybrid Density Functional Theory ◽

Functional Theory ◽

Order Of Magnitude ◽

Set Approximation ◽

Hybrid Density Functional

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Advanced ab initio and hybrid density functional theory evaluation of the atomization energies, bond dissociation pathways, and heats of formation of the two isomers of HClO4

Journal of Molecular Structure THEOCHEM ◽

10.1016/s0166-1280(01)00431-6 ◽

2001 ◽

Vol 546 (1-3) ◽

pp. 89-97 ◽

Cited By ~ 6

Author(s):

Abraham F. Jalbout ◽

Fouad N. Jalbout ◽

Hadi Y. Alkahby

Keyword(s):

Density Functional Theory ◽

Ab Initio ◽

Density Functional ◽

Heats Of Formation ◽

Hybrid Density Functional Theory ◽

Functional Theory ◽

Bond Dissociation ◽

Theory Evaluation ◽

Hybrid Density Functional

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Infinite basis set extrapolation for double hybrid density functional theory 1: Effect of applying various extrapolation functions

Journal of Computational Chemistry ◽

10.1002/jcc.21745 ◽

2011 ◽

Vol 32 (8) ◽

pp. 1671-1679 ◽

Cited By ~ 7

Author(s):

Yao-Yuan Chuang ◽

Sheng-Min Chen

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Basis Set ◽

Hybrid Density Functional Theory ◽

Functional Theory ◽

Infinite Basis ◽

Hybrid Density Functional ◽

Basis Set Extrapolation

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Hybrid density functional theory and quadratic complete basis set ab initio computational study of structural properties, vibrational spectra, and bond dissociation energy for methyl aluminum and methyl gallium

Journal of Molecular Structure THEOCHEM ◽

10.1016/s0166-1280(97)00262-5 ◽

1998 ◽

Vol 428 (1-3) ◽

pp. 61-66 ◽

Cited By ~ 39

Author(s):

Branko S. Jursic

Keyword(s):

Density Functional Theory ◽

Ab Initio ◽

Vibrational Spectra ◽

Density Functional ◽

Computational Study ◽

Basis Set ◽

Hybrid Density Functional Theory ◽

Functional Theory ◽

Complete Basis Set ◽

Hybrid Density Functional

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Complete basis set, hybrid-density functional theory study, and natural bond orbital interpretations of the conformational behavior of halocarbonyl, thiocarbonyl, and selenocarbonyl isocyanates

Canadian Journal of Chemistry ◽

10.1139/v2012-002 ◽

2012 ◽

Vol 90 (4) ◽

pp. 333-343 ◽

Cited By ~ 1

Author(s):

Seiedeh Negar Mousavi ◽

Davood Nori-Shargh ◽

Hooriye Yahyaei ◽

Kobra Mazrae Frahani

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Energy Difference ◽

Basis Set ◽

Hybrid Density Functional Theory ◽

Total Dipole Moment ◽

Functional Theory ◽

Complete Basis Set ◽

Conformation Stability ◽

Hybrid Density Functional

Complete basis set CBS-QB3, hybrid-density functional theory (B3LYP/Def2-TZVPP) based methods and NBO interpretation were used to investigate the impacts of the stereoelectronic effects and electrostatic and steric interactions on the conformational properties of halocarbonyl isocyanates (halo = F (1), Cl (2), and Br (3)), halothiocarbonyl isocyanates (halo = F (4), Cl (5), and Br (6)), and haloselenocarbonyl isocyanates(halo = F (7), Cl (8), and Br (9)). Both methods showed that the Z-conformations of compounds 1, 4, and 7 are more stable than their corresponding E conformations, but the stability of the E conformations, when compared with the corresponding Z conformations, increases from compound 1 to compound 3, compound 4 to compound 6, and also from compound 7 to compound 9. The NBO analysis showed that the generalized anomeric effect (GAE) is in favor of the Z conformations of compounds 1, 4, and 7. The GAE values calculated (i.e., GAEE–GAEZ) increase from compound 1 to compound 3, compound 4 to compound 6, and also from compound 7 to compound 9. On the other hand, there are none of the same trends between the calculated total dipole moment and the Gibbs free energy difference values between the E and Z conformations (i.e., ΔμE–Z and ΔGE–Z) of compounds 1–3, 4–6, and 7–9. Accordingly, the GAE succeeds in accounting for the increase of the E conformation stability from compound 1 to compound 3, compound 4 to compound 6, and also from compound 7 to compound 9. Therefore, the GAE associated with the electron delocalization, not the total dipole moment changes (i.e., ΔμE–Z), is a reasonable indicator of the total energy difference in compounds 1–3, 4–6, and 7–9. There is a direct correlation between the calculated GAE and Δ[r2–6(E) – r2–6(Z)] parameters. Importantly, there are interesting through-space electron delocalizations (LP2X6→π*C4–O5) that justify the increase of the E conformation stability from compound 1 to compound 3, compound 4 to compound 6, and also from compound 7 to compound 9, when compared with their corresponding Z conformations. The correlations between the GAE, bond orders, total steric exchange energies (TSEE), ΔGZ–E, ΔμE–Z, structural parameters, and conformational behaviors of compounds 1–9 were investigated.

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Complete basis set, the MP2 ab initio, and hybrid density functional theory evaluation of ionization potential and electron affinity for PH, PH2, PHF, PF, and PF2

Journal of Molecular Structure THEOCHEM ◽

10.1016/s0166-1280(99)00327-9 ◽

2000 ◽

Vol 507 (1-3) ◽

pp. 11-16 ◽

Cited By ~ 11

Author(s):

B.S Jursic

Keyword(s):

Density Functional Theory ◽

Ab Initio ◽

Electron Affinity ◽

Density Functional ◽

Basis Set ◽

Hybrid Density Functional Theory ◽

Functional Theory ◽

Theory Evaluation ◽

Complete Basis Set ◽

Hybrid Density Functional

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Study of Magnesium Diboride Clusters Using Hybrid Density Functional Theory

Research Letters in Physics ◽

10.1155/2008/879017 ◽

2008 ◽

Vol 2008 ◽

pp. 1-4 ◽

Cited By ~ 1

Author(s):

D. Rodríguez ◽

D. Soto ◽

E. Ramírez ◽

A. Cruz ◽

A. Santana ◽

...

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Magnesium Diboride ◽

Population Analysis ◽

Equilibrium Structure ◽

Basis Set ◽

Hybrid Density Functional Theory ◽

Functional Theory ◽

Equilibrium Structures ◽

Hybrid Density Functional

Using hybrid density functional theory and a relatively large basis set, the lowest energy equilibrium structure, vibrational spectrum, and natural orbital analysis were obtained for magnesium diboride clusters [(MgB2)x for x=1,2, and 3]. For comparison, boron clusters [Bx for x=2,4, and 6] were also considered. The MgB2 and (MgB2)2 showed equilibrium structures with the boron atoms in arrangements similar to what was obtained for pure boron atoms, whereas, for (MgB2)3 a different arrangement of boron was obtained. From the population analysis, large electron density in the boron atoms forming the clusters was observed.

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