Synthesis and Photophysical Properties of Symmetrical Phenolphthalein Derivatives

Abstract

Novel phenolphthalein based compounds was synthesized and potentially used for detection of Hg2+ ions in CH3CN as solvent calorimetrically. Compound 3 exhibited absorption maxima at 290 nm, which showed a red shift to 480 nm in CH3CN. 3 displayed fast colour change from colorless to reddish brown in the presence of Hg2+ ions. The binding constant for 3.Hg2+ was found to be 3.2 × 104 M-1. The lowest detection limit of 3 for Hg2+ ions was determined to be 7.2 × 10-8 M. Compound 5 showed three absorption peaks at 480 nm, 350 nm and 240 nm. Compound 5 also showed strong emission at 550 nm.