Alkanediyl-α,ω–type gemini micelles–catalyzed study between ninhydrin and [Ni(II)-Trp]+ complex

Abstract

In this work, a series of alkanediyl-α,ω–type gemini micelles symbolized as 16-s-16 (s = spacer) was synthesized. Synthesized products were characterized by 1H NMR technique. By conductivity method, cmc of these surfactants was determined by measuring specific electrical conductivity at different concentrations. Alkanediyl-α,ω–type gemini micelles–catalyzed interaction between [Ni(II)-Trp]+ complex and ninhydrin has been studied with the help of spectrophotometric studies. The catalytic implication of gemini micelles on rate constant (kψ) in ninhydrin and [Ni(II)-Trp]+ has been explored and discussed at 343 K and pH 5.0. Catalyzing behavior obtained by geminis confirmed that they influenced the study remarkably over their monomeric conventional counterpart. Results were also suggested that small amount of geminis at concentration below cmc was sufficient to induce the reaction more than aqueous. Though, 16-4-16 is detected to catalyze the work more among geminis and follows the order at each concentration as: 16-4-16 > 16-5-16 > 16-6-16. This catalytic implication produced by gemini micelles can efficiently be deduced using pseudophase model for micellar activity. In addition, by varying temperatures, several thermodynamic quantities were evaluated. A lower enthalpy value, ΔH#, with significant negative entropy value, ΔS#, is acquired in geminis than aqueous system.