کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
217536 1426337 2006 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Potentiometric studies of acid-base interactions in substituted 4-nitropyridine N-oxide systems
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
Potentiometric studies of acid-base interactions in substituted 4-nitropyridine N-oxide systems
چکیده انگلیسی
(Acid + base) equilibrium constants, involving the acidity (pKaAC) and cationic homoconjugation constants (in the form of lgKBHB+AC), have been determined by the potentiometric method in 13 systems formed by substituted 4-nitropyridine N-oxides in the polar aprotic solvent, acetone (AC). The derivatives covered a wide range of proton-acceptor properties and inherent diversified tendencies towards formation of hydrogen-bonded homocomplexed cations. In addition, the constant values (expressed as pKaANandlgKBHB+AN) for two of the systems studied, N-oxides of 2-methylamino- and 2-ethylamino-4-nitropyridine, were determined in acetonitrile (AN). The acidity constants in the non-aqueous media studied have been found to change in line with their substituent effects and the sequence of acidity changes in water. The values of the cationic homoconjugation constants increased with increasing basicity of the N-oxides and decreased with increasing solvent basicity.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: The Journal of Chemical Thermodynamics - Volume 38, Issue 5, May 2006, Pages 554-558
نویسندگان
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