Fluorometric and colorimetric detection of hypochlorous acid and hypochlorite by a naphthalimide - dicyanoisophorone conjugate

A naphthalimide-dicyanoisophorone conjugate (1) was synthesized and used as a chemodosimeter for fluorometric and colorimetric detection of hypochlorous acid (HClO) and hypochlorite (OCl-) in aqueous media. This molecule shows a strong reddish-purple color and a weak fluorescence, but HClO/OCl--selective oxidative decomposition of the dicyanoisophorone moiety promotes a color fading and a fluorescence enhancement. Ab initio calculation revealed that these responses to HClO/OCl- originate from the suppression of intramolecular electron transfer from the photoexcited naphthalimide moiety by the decomposition of the dicyanoisophorone moiety. These colorimetric and fluorometric responses facilitate relatively rapid (similar to 5 min), selective, and sensitive detection of HClO/OCl- as low as similar to 1.3 mu M under physiological conditions.

Automated summary

A new naphthalimide-dicyanoisophorone conjugate has been synthesized for the detection of hypochlorous acid and hypochlorite, showing selective fluorescence enhancement and color fading. This chemodosimeter allows for rapid, selective, and sensitive detection of HClO/OCl- at concentrations as low as 1.3 μM under physiological conditions.