Abstract

SYNTHESIS AND SPECTRAL ANALYSIS OF COLORIMETRIC RECEPTORS FOR THE DETECTION OF FLOURIDE AND ACETATE IONS

Hari Prasad Vanam, Kalathuru Sasidhar Reddy, Dr. Bharath kumar Momidi and A. Sarangapani*

ABSTRACT

Colorimetric receptors R1, and R3 possessing –OH functionality as binding site and –NO2 as signaling unit has been designed and synthesized by simple Schiff base condensation reaction. Receptors R1 and R3 showed selective response towards F- AcO – ion among other interfering monovalent anions viz., Cl–, Br –, I–, NO3–, HSO4– and H2PO4–. Receptor R1 showed color change from colorless to blue in the presence of organic fluoride and acetate ion. Receptor R3 showed color change from colorless to pale pink and pale orange in the presence of organic fluoride and acetate ion respectively. The receptor R1 effectively binds with fluoride ion and acetate ion and the binding constant was found to be 5×104M, 4.4×104M, 3.75×102M with TBAF, NAF and TBAOAc respectively. The binding constant of receptor R3 with TBAF and TBAOAc was found to be 4×104M and 3.25×102M respectively.

Keywords: Schiff base; colorimetric sensors; Anions; job's plots; B-H method.