Anthraimidazoledione Derivatives in Fluoride Sensing Ensuing Si-O Bond Cleavage in Organic and Aqueous Medium

Anthraimidazoledione derivatives 1 and 2 containing silyl groups have been synthesized and characterized. Anion binding properties with reference to Si-O bond cleavage are documented in organic and aqueous medium. Both compounds 1 and 2 selectively sense F- ion over a series of other anions by exhibiting ratiometric change in UV-vis spectra in CH3CN. In fluorescence, significant quenching of emission of both 1 and 2 occurs in presence of F-. Other anions in this event are silent. Compounds are also found working in aqueous CH3CN. Both show quenching of emission while aqueous solution of KF is added to their acetonitrile solutions. Importantly, Si-O bond cleavage in 1 and 2 follows first order kinetics and the cleavage is more facile in 1 than 2. The detection limits for fluoride with compounds 1 and 2 were found to be 49.6 mu M and 20.1 mu M, respectively.