Article ID Journal Published Year Pages File Type
217536 The Journal of Chemical Thermodynamics 2006 5 Pages PDF
Abstract
(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.
Related Topics
Physical Sciences and Engineering Chemical Engineering Chemical Engineering (General)
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