Theoretical Prediction of pKa Values of Seleninic, Selenenic, Sulfinic, and Carboxylic Acids by Quantum-Chemical Methods

被引：27
|
作者：
Ali, S. Tahir [1 ]
Karamat, Sajjad [1 ]
Kona, Juraj [2 ]
Fabian, Walter M. F. [1 ]
机构：
[1] Graz Univ, Inst Chem, A-8010 Graz, Austria
[2] Slovak Acad Sci, Inst Chem, Ctr Glycom, Bratislava 84538, Slovakia
来源：
JOURNAL OF PHYSICAL CHEMISTRY A | 2010年 / 114卷 / 47期
关键词：
DENSITY-FUNCTIONAL THEORY; SELENOPROTEIN GLUTATHIONE-PEROXIDASE; AB-INITIO CALCULATIONS; GAUSSIAN-BASIS SETS; ORGANOSELENIUM COMPOUNDS; AQUEOUS-SOLUTION; ANTIOXIDANT ACTIVITY; HYDROGEN-PEROXIDE; FREE-ENERGY; BENZENESELENINIC ACIDS;
D O I：
10.1021/jp102266v
中图分类号：
O64 [物理化学（理论化学）、化学物理学];
学科分类号：
070304 ; 081704 ;
摘要：
Aqueous acid dissociation constants of substituted areneseleninic, areneselenenic arenesulfinic and benzoic, acids are calculated by ab initio (MP2) and DFT (B3LYP) methods in combination with bulk solvation models (IEFPCM CRSrad) from appropriate thermodynamic cycles Mean absolute deviations (MAD) between experimental and calculated pK(a) values are quite large for basis sets without diffuse functions however trends are reasonably well described Best agreement with experiment as described by MAD as well as correlation coefficient and slope of the correlation equation pK(a) = a*Delta(calc)/RT In(10) + b is obtained with the CPCM solvation model using the defaults optimized within COSMO-RS (CRSrad MAD = 1 54 R-2 = 094, a = 0 83) Sulfenic (sulfenic) acid tautomers are significantly more stable than the corresponding sulfoxide (selenoxide) forms
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页码：12470 / 12478
页数：9
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