A fluorescent chemosensor for detection of perchlorate ions in water

1-(4-Biphenyl)benzimidazolium based dipodal system acts as a highly selective fluorescent chemosensor for determination of perchlorate ions in aqueous buffer and in drinking water at concentrations lower than that permissible by EPA. 1H NMR titration studies, Job's plot, X-ray crystal structure and theoretical studies reveal cavity based recognition.