this paper is a density functional theory (dft) calculation of intramolecular proton transfer (ipt) in 6-hydroxypicolinic acid (6hpa, 6-hydroxypyridine-2-carboxylic acid) tautomeric forms. the transition state for the enol-to-keto transition is reported in the gas phase and in four different solvents. the planar and non-planar dimer forms of 6hpa keto and enol, respectively, were also studied i...

Secondary beta-bromo alcohols can be transformed directly to ketones in very good yields by a free radical process. Tertiary beta-bromo alcohols do not react while the primary ones are transformed to aldehydes in lower yields. The reaction involves an abstraction of a hydrogen atom alpha to an OH group, followed by elimination of the bromine atom and subsequent tautomerization of an enol to a k...

This paper is a density functional theory (DFT) calculation of intramolecular proton transfer (IPT) in 6-hydroxypicolinic acid (6HPA, 6-hydroxypyridine-2-carboxylic acid) tautomeric forms. The transition state for the enol-to-keto transition is reported in the gas phase and in four different solvents. The planar and non-planar dimer forms of 6HPA keto and enol, respectively, were also studied i...

Surface-enhanced Raman scattering (SERS) spectra of a metal-complexing ligand, immobilized to a silver electrode surface, exhibits significant structural changes upon application of modest potentials. A detailed spectroscopic investigation shows that the potential applied to the electrode surface governs the tautomerization equilibrium of the immobilized ligand, p-((8-hydroxyquinoline)azo)benze...

using hartree–fock (hf) and ِِdensity functional theory (dft) calculations the thermodynamic properties such as thermal energy , , thermal enthalpy , , thermal entropy , , thermal gibbs free energy , , heat capacity ,cv, and molecular structures of several species involving in keto↔enol tautomerism related to acetaldehyde (a), 5,5-dimethyl-1,3-cyclohexanedione (dimedone) and  acetylacetone (aa) h...

Using Hartree–Fock (HF) and ِِDensity Functional Theory (DFT) calculations the thermodynamic properties such as thermal energy , , thermal enthalpy , , thermal entropy , , thermal Gibbs free energy , , heat capacity ,Cv, and molecular structures of several species involving in keto↔enol tautomerism related to acetaldehyde (A), 5,5-dimethyl-1,3-cyclohexanedione (dimedone) and  acetylacetone (AA) h...

Single walled nanotubes (SWNT) are common interested nanovehicle to make biosensors more sensitive. Carbon nanotubes (CNTs) have many distinct properties make them to be exploited to develop the next generation of such nano sensors .The Keto-Enol tautomerization is one of the most common investigated subjects of isomerism in this regards, sensors are devices that are able to detect and change t...

DFT calculations were conducted to pursue deeper understandings on the mechanism and the explicit role of trace water in the DBU-catalyzed β-amination of NBS to chalcone. Being different from previously proposed by Liang et al., a cooperative participation of both DBU and water is noticed in the preferred mechanism. The preferential mechanistic scenario assisted by water undergoes three major s...

The structure of the genetic code implies strict Watson-Crick base pairing in the first two codon positions, while the third position is known to be degenerate, thus allowing wobble base pairing. Recent crystal structures of near-cognate tRNAs accommodated into the ribosomal A-site, however, show canonical geometry even with first and second position mismatches. This immediately raises the ques...