The electronic structure of a molecule determines such physical and chemical properties as its charge distribution, geometry (and therefore the dipole moment), ionization potential, electron affinity, and of course, chemical reactivity. If the electronic structure of a molecule were to be changed, one would expect its physical and chemical properties to be altered. Such a rearrangement can occu...

The single-site Solvation, Bond Strength, and Electrostatic (SBE) model accounts for the anomalous position of silica onthe surface acidity versus aqueous acidity correlation developed for metal oxides, by considering the solvation energy change in the protonation reaction implemented through the dielectric constant (1/epsilon(k)) and the electrostatic energy change through the Pauling bond str...

The acidity constants of H(R —M P)~, where R —MP: = 4-nitrophenyl phosphate (NPhP2 ). phenyl phosphate (PhP2 ) and D-ribose 5'-m onophosphate (RibM P2 ). and the stability constants of the binary C u (R -M P ) com plexes w'ere determined by potentiometric pH titrations in aqueous solution and in 20. 30, 40 and 50% (v/v) dioxane-water mixtures. The solvent influence on the corresponding equilibr...

CONSPECTUS: All-atom methods treat solute and solvent at the same level of electronic structure theory and statistical mechanics. All-atom computation of acidity constants (pKa) and redox potentials is still a challenge. In this Account, we review such a method combining density functional theory based molecular dynamics (DFTMD) and free energy perturbation (FEP) methods. The key computational ...

The electronic structure of a molecule determines such physical and chemical properties as its charge distribution, geometry (and therefore the dipole moment), ionization potential, electron affinity, and of course, chemical reactivity. If the electronic structure of a molecule were to be changed, one would expect its physical and chemical properties to be altered. Such a rearrangement can occu...

The dissociation constants for the carboxyl group of a series of glycine (N-acyl)-conjugated and unconjugated bile acids were determined by potentiometric titration using dimethylsulfoxide-water and methanol-water mixtures of varying proportions. The pKa values in water were calculated by extrapolating the experimental values determined in different mole fractions of the organic solvent mixture...

As constantes de acidez do PAR foram determinadas por Análise de Componentes Principais em Rede Neural Artificial, usando-se dados espectrais simulados e experimentais. As equações de balanço de massa do ácido triprótico e os perfis espectrais correspondentes, gerados por um modelo Gaussiano, foram usados para simular todos os dados de absorbância-pH necessários. Um ruído constante, com média z...

Abstract The basis of this research includes the preparation aromatic azoimine complexes resulting from coupling reaction (4) Schiff bases with diazotized dinitroaniline reagent. Ultraviolet spectra, infrared and melting points are among most important physical methods used to identification right compounds prepared in study. After that, stoichiometric ratios components complex were determined ...

Internet Electron. J. Mol. Des. 2004, 1, 000–000 Abstract Motivation. The ionization constants are fundamental to explain the occurrence of numerous and varied processes of great importance in Chemistry and Biology. With the specific aim of contributing to the development of theoretical procedures to study the acidity constants in this work we show the feasibility of a DFT method that makes use...

The effect of SDS (0.03-0.07 M) and Brij-35(0-0.003 M) concentrations and temperature on retention parameters of 30 solutes in micellar reversed- phase liquid chromatography systems were studied using solvation parameter model. The system constants were determined by multiple linear regression analysis from experimental values of the retention factors with known descriptors by computer usin...