title: Effect of organized assemblies II. Environmental effect on the pK of (o/p) hydroxybenzylidene-(4/6)-nitro-2-aminobenzothiazoles.
abstract: The dissociation constants (pK's) of aldimines, (o/p) hydroxybenzylidene-(4/6)-nitro-2-aminobenzothiazoles, have been determined spectrophotometrically in the absence and presence of ionic and nonionic surfactant assemblies at 27 degrees C. Substantial shifts in the pK's of the aldimines has been observed in the presence of the organized assemblies compared to water. The results have been attributed to the surface charge of the micelle, the effective hydrophobicity of the surfactants, and field and resonance effects due to NO(2) group substitution. Surfactant assemblies are found to have randomly arranged hydrophobic chains leading to exposure of some of the hydrocarbon chain segments to bulk water. The results also support the presence of intramolecular H-bonding in the o-hydroxybenzylidene-(4/6)-nitro-2-aminobenzothiazoles.
authors.affiliation: Centre of Studies in Surface Science and Technology, Department of Chemistry, Sambalpur University, Jyoti Vihar 768 019, India.
authors.forename: Sagarika
authors.initials: S
authors.lastname: Panigrahi
authors.forename: Moumita
authors.initials: M
authors.lastname: Chakravorty
authors.forename: Pramila K
authors.initials: PK
authors.lastname: Misra
mesh_terms: D052160:Benzothiazoles / Q000737:chemistry*; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D008823:Micelles
chemical_list: D052160:Benzothiazoles; D008823:Micelles