A Novel Design Strategy for Chitosan containing azobased Schiff bases for Colorimetric Sensing of Anions

By : Nidhi Nigam, Santosh Kumar, P. K. Dutta, Tamal Ghosh

Page No: 137-148

Abstract
The present investigation deals with the anion sensing studies of prepared chitosan/methyl red dye: chitosan/hydroxy nitro azobenzaldehyde (CHNAB) and chitosan/hydroxy methyl azobenzaldehyde (CHMAB) derivatives under mild conditions. These derivatives were synthesized by 79% and  90% deacetylated chitosan, in isopropyl alcohol/water mixture and dimethyl sulfoxide. The polymers were well characterized by thermal analysis (differential scanning calorimetry, DSC and thermogravimetric analysis,TGA), FTIR, 1 H-NMR, ESI-Mass spectra, birefringence and antibacterial activity and reported elsewhere. The optical property of the derivatives is an advantageous property prompted us to evaluate its anion sensing properties by UV-titrimetric method. UV–visible titration was carried out in DMSO to evaluate the binding affinities toward a set of anions (F- , Cl- , Br- , I- , CN- , AcO- , HSO4 - and H2 PO4 - ). In the present study, it is observed that cyanide is mainly operating as a nucleophile. These cyanide anion sensing phenomena were analyzed by UV–vis titration in dimethyl sulfoxide. The plausible sensing mechanism of the chitosan derivative for CN-recognition was established. The study on the novel design strategy may be used for sensing anions.

Authors :
Nidhi Nigam, Santosh Kumar, P.K.Dutta, and Tamal Ghosh : Department of Chemistry, Motilal Nehru National Institute of Technology, Allahabad-211004, India.
 

DOI: https://doi.org/10.32381/JPM.2018.35.01.10