Solubilization of diphenylcarbazide in the micellar system of tetradecyltrimethylammonium bromide: the micellar effect on complex formation of the ligand

ABSTRACT

This work aims to investigate the interaction of diphenylcarbazide (DPC) with tetradecyltrimethyaammonium bromide (TTAB) over concentrations ranging from below and above the critical micelle concentration (CMC) of the surfactant and subsequent complexation of DPC with Zn(II) of the surfactant by visible and NMR spectrophotometry. For this purpose, we determined the CMC of the surfactant in pure water and in the presence of DPC conductometrically. Lower specific conductance values of the surfactant in the presence of DPC indicate the interaction between TTAB and DPC both below and above the CMC. The CMC of the surfactant was found to increase with increasing the concentration of DPC, indicating that hydrophobic interaction between the alkyl chains of the surfactant becomes unfavourable in the presence of DPC. The interaction of Zn(II) with DPC is strongly influenced by the concentration of the surfactant as well as the solubilisation site of DPC in the micelle. The absorbance of the Zn(II)-DPC complex increases initially, attains maximum near the CMC and then decreases with further increase in the concentration of the surfactant. Visible spectra together with NMR data of the Zn(II)-DPC complex in surfactant systems under different conditions provided information about the possible location of the DPC in the micelles.

KEYWORDS:

• Surfactants
• diphenyl carbazide
• CMC
• micellar surface charge
• solubilisation site

Acknowledgements

The authors would like to thank the Committee for Advanced Studies and Research (CASR), BUET for approving the financial assistance (CASR-232/52) to carry out the present work.

Disclosure statement

No potential conflict of interest was reported by the author(s).