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Titolo:
Acidity of organic molecules in the gas phase and in aqueous solvent
Autore:
Topol, IA; Tawa, GJ; Caldwell, RA; Eissenstat, MA; Burt, SK;
Indirizzi:
NCI, Frederick Canc Res & Dev Ctr, Adv Biomed Comp Ctr, SAIC Frederick, Frederick, MD 21702 USA NCI Frederick MD USA 21702 p Ctr, SAIC Frederick, Frederick, MD 21702 USA NCI, Frederick Canc Res & Dev Ctr, Struct Biochem Program, SAIC Frederick,Frederick, MD 21702 USA NCI Frederick MD USA 21702 rogram, SAIC Frederick,Frederick, MD 21702 USA Univ Texas, Dept Chem, Richardson, TX 75083 USA Univ Texas Richardson TX USA 75083 s, Dept Chem, Richardson, TX 75083 USA
Titolo Testata:
JOURNAL OF PHYSICAL CHEMISTRY A
fascicolo: 42, volume: 104, anno: 2000,
pagine: 9619 - 9624
SICI:
1089-5639(20001026)104:42<9619:AOOMIT>2.0.ZU;2-P
Fonte:
ISI
Lingua:
ENG
Soggetto:
DENSITY-FUNCTIONAL THEORY; CONTINUUM DIELECTRIC THEORY; SOLVATION FREE-ENERGIES; MOLLER-PLESSET METHODS; AB-INITIO; CONFORMATIONAL ENERGIES; GAUSSIAN-2 THEORY; MODEL; THERMOCHEMISTRY; THERMODYNAMICS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
57
Recensione:
Indirizzi per estratti:
Indirizzo: Topol, IA NCI, Frederick Canc Res & Dev Ctr, Adv Biomed Comp Ctr, SAIC Frederick, POB B, Frederick, MD 21702 USA NCI POB B Frederick MD USA 21702 POB B, Frederick, MD 21702 USA
Citazione:
I.A. Topol et al., "Acidity of organic molecules in the gas phase and in aqueous solvent", J PHYS CH A, 104(42), 2000, pp. 9619-9624

Abstract

Using a combination of ab initio, DFT and continuum solvation methods, thegas phase and aqueous acidities for a set of weak organic acids with high pK(a) values, which cannot be measured experimentally in aqueous solvent, have been calculated. Comparison of the computed and experimental data for different terms used in the thermodynamic cycle for the calculation of pK(a)values allowed us to estimate that the errors in the pK(a) calculations are of order of 2 pK(a) units, i.e., less than 10% of the expected pK(a) values for the studied weak organic acids. It is shown that inclusion of explicit water molecules in the solute cavity of compounds with pK(a) values over40 could lead to dubious results due to the inappropriate description of the corresponding anion solvation. Acidity trends for compounds in the gas phase and in aqueous solvent were found to be different, due to the effects of aqueous solvation.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/11/20 alle ore 06:32:45