scholarly journals Performance of density functional theory methods to describe intramolecular hydrogen shifts

2005 ◽  
Vol 117 (5) ◽  
pp. 555-560 ◽  
Author(s):  
Nelly González-Rivas ◽  
Andrés Cedillo
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Functional Theory ◽  
Hydrogen Shifts ◽  
Intramolecular Hydrogen ◽  
Intramolecular Hydrogen Shifts

scholarly journals Role of intramolecular hydrogen bonds and electron withdrawing groups in the acidity of aldimines and ketimines: a density functional theory study

2019 ◽  
Vol 138 (4) ◽  
Author(s):  
Fernando Aguilar-Galindo ◽  
Ana María Tuñón ◽  
Alberto Fraile ◽  
José Alemán ◽  
Sergio Díaz-Tendero
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bonds ◽  
Density Functional ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Intramolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen

scholarly journals Mechanism of Reactions of 1-Substituted Silatranes and Germatranes, 2,2-Disubstituted Silocanes and Germocanes, 1,1,1-Trisubstituted Hyposilatranes and Hypogermatranes with Alcohols (Methanol, Ethanol): DFT Study

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2803 ◽  
Author(s):  
Denis Chachkov ◽  
Rezeda Ismagilova ◽  
Yana Vereshchagina
Keyword(s):  
Density Functional Theory ◽  
Quantum Chemical ◽  
Density Functional ◽  
Activation Energies ◽  
Functional Theory ◽  
Gibbs Energies ◽  
The Density Functional Theory ◽  
Lower Activation ◽  
One Step ◽  
Intramolecular Hydrogen

The mechanism of reactions of silatranes and germatranes, and their bicyclic and monocyclic analogues with one molecule of methanol or ethanol, was studied at the Density Functional Theory (DFT) B3PW91/6-311++G(df,p) level of theory. Reactions of 1-substituted sil(germ)atranes, 2,2-disubstituted sil(germ)ocanes, and 1,1,1-trisubstituted hyposil(germ)atranes with alcohol (methanol, ethanol) proceed in one step through four-center transition states followed by the opening of a silicon or germanium skeleton and the formation of products. According to quantum chemical calculations, the activation energies and Gibbs energies of activation of reactions with methanol and ethanol are close, their values decrease in the series of atranes–ocanes–hypoatranes for interactions with both methanol and ethanol. The reactions of germanium-containing derivatives are characterized by lower activation energies in comparison with the reactions of corresponding silicon-containing compounds. The annular configurations of the product molecules with electronegative substituents are stabilized by the transannular N→X (X = Si, Ge) bond and different intramolecular hydrogen contacts with the participation of heteroatoms of substituents at the silicon or germanium.

Intramolecular addition of oxyradicals to benzene rings: A DFT study

2011 ◽  
Vol 76 (8) ◽  
pp. 947-956
Author(s):  
Götz Bucher
Keyword(s):  
Density Functional Theory ◽  
Phenyl Ring ◽  
Density Functional ◽  
Hydrogen Abstraction ◽  
Radical Addition ◽  
Addition Reactions ◽  
Theory Analysis ◽  
Functional Theory ◽  
Benzene Rings ◽  
Intramolecular Hydrogen

The reactivity of a series of oxyradicals related to the triplet state of β-phenylpropiophenone was investigated by density functional theory. Analysis of the potential energy hypersurfaces indicates that radical addition to the β-phenyl ring should occur with a smaller barrier than intramolecular hydrogen abstraction from the benzylic position, although the latter reaction is far more exothermic. Addition can occur in ipso- and ortho-position of the β-phenyl ring, with ortho addition being slightly more favourable. As both addition reactions are predicted to be mildly exothermic and exergonic, intermolecular trapping of the resulting cyclohexadienyl- type radicals should be feasible.

scholarly journals A Density Functional Theory Investigation on Intramolecular Hydrogen Transfer of the [Os3(CO)11P(OMe)3(Ru(η5-C5H5))2] Cluster

2010 ◽  
Vol 31 (4) ◽  
pp. 934-940
Author(s):  
Radchada Buntem ◽  
Kraiwan Punyain ◽  
Yuthana Tantirungrotechai ◽  
Paul R. Raithby ◽  
Jack Lewis
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Hydrogen Transfer ◽  
Functional Theory ◽  
Intramolecular Hydrogen

scholarly journals Crystal structure and DFT study of 8-hydroxy-1,2,3,5,6,7-hexahydropyrido[3,2,1-ij]quinoline-9-carbaldehyde

2017 ◽  
Vol 73 (5) ◽  
pp. 791-794
Author(s):  
Md. Serajul Haque Faizi ◽  
Necmi Dege ◽  
Maria L. Malysheva
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Density Functional Theory ◽  
Density Functional ◽  
Aromatic Rings ◽  
Functional Theory ◽  
Compound C ◽  
Structure Density ◽  
Intramolecular Hydrogen ◽  
Ring Motif

In the title compound, C13H15NO2, the fused non-aromatic rings of the julolidine moiety adopt envelope conformations. The hydroxy group forms an intramolecular hydrogen bond to the aldehyde O atom, generating anS(6) ring motif. Weak intermolecular C—H...O hydrogen bonds help to stabilize the crystal structure. Density functional theory (DFT) optimized structures at the B3LYP/6–311 G(d,p) level are compared with the experimentally determined molecular structure in the solid state.

scholarly journals A DFT Investigation of the Molecular Structure and UV Absorption Spectra of 2-Ethylhexyl 2-Hydroxybenzoate (Octisalate) and Meta-Substituted 2-Ethylhexyl 2-Hydroxybenzoate: Sunscreen Applications

2016 ◽  
Vol 855 ◽  
pp. 15-21 ◽  
Author(s):  
Wikorn Punyain
Keyword(s):  
Molecular Structure ◽  
Density Functional Theory ◽  
Absorption Spectrum ◽  
Density Functional ◽  
Polarizable Continuum Model ◽  
Uv Absorption ◽  
Functional Theory ◽  
Vertical Excitation ◽  
Intramolecular Hydrogen ◽  
Uv Absorption Spectrum

2-ethylhexyl 2-hydroxybenzoate (octisalate) is one of organic compounds containing in sunscreen products to absorb ultraviolet radiation. Density Functional Theory (DFT) was used to investigate the molecular structure and the ultraviolet (UV) absorption spectrum of 2-ethylhexyl 2-hydroxybenzoate and meta-substituted 2-ethylhexyl 2-hydroxybenzoate to model the novel sunscreen compounds. The geometry optimizations and frequency calculations were done at B3LYP/6-311++G(d,p) level of theory. The 10 vertical excitation calculations were performed by Time-Dependent Density Functional Theory (TD-DFT) at B3LYP/6-311++G(d,p) level. The solvent effects were taken into account by using the Polarizable Continuum Model (CPCM). It was found that the intramolecular hydrogen bond occurred in the 2-ethylhexyl 2-hydroxybenzoate structure. The UV absorption spectrum in the UVA and UVB regions are π→π* transitions (HOMO→LUMO transitions). The calculated UV absorption spectrum of the 2-ethylhexyl 2-hydroxybenzoate and its derivatives are significantly affected by the substitution groups.

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