Studies on the Protonation Constants and Solvation of α-Amino Acids in Dioxan–Water Mixtures

The Stability Constants of Copper(II) Complexes with Some α-Amino Acids in Dioxan–Water Mixtures

“…The total stoichiometric stability constants (log ␤ 2 ) of ␣-amino acid-copper(II) complexes were determined by the use of formation curves (n -p[L]) plotted by the use of potentiometric titration data (18). The stoichiometric protonation constants of the amino acids were also determined under conditions employed for the determination of the stability constants (19,20).…”

Formation of binary complexes of Pb(II), Cd(II) and Hg(II) with maleic acid in CTAB-water mixtures

“…Some studies were performed in aqua-organic mixtures to mimic these conditions but no attempt was made to account for the compartmentalisation. For example, complexation equilibria of in dioxane (Koseoglu et al, 2000), DMSO-water (Raju et al, 2012), ethylene glycol-water (Vijaya , urea-water and 1,4-dioxane-water (Anand Santhee Devi et al, 2010, 2011Rama Raju et al, 2011, propylene glycolwater (Rama Raju et al, 2011Raju et al, , 2013Santhee Devi et al, 2012) media have been studied in this laboratory. Hence, the speciation of the title systems has been studied in surfactant media, where micellisation leads to compartmentalisation.…”

Protonation equilibria of glycylglycine and histamine in aqueous solution of an anionic surfactant

“…Investigations involving the peptides in acid-base reactions (Sigel, 1975;Lyons et al, 1985;Fonteh et al, 2007) particularly, small peptides have attracted great attention in relation to the chemistry because these compounds are usually considered as good model systems to attain a better insight into the characteristics of naturally occurring metalloproteins (Ivanova et al, 2006;Kozlowski et al, 1999;Mendieta et al, 1996). Much data are available on the protonation and stability constants of the amino acids and simple peptides in water and organic solvents (Kilyen et al, 2003;Diaz-Cruz et al, 2000;Apruzzese et al, 2002;Banipal et al, 2000;Virender et al, 2003;Wada et al, 1982;Carta et al, 1996;Koseoglu et al, 2000;Mekonen Tirfu Zekarias et al, 2011). However, the protonation constants of amino acids and peptides in these organic solvents are often different from those in water, as these media tend to be lipophilic rather than hydrophilic (Carty et al, 1968;Schmidt et al, 1971).…”