Fluorescence signalling of transition metal ions by multi-component systems comprising 4-chloro-1,8-naphthalimide as fluorophore

Fluorescence of 1a and 1b is 'switched on' by the quenching transition meta l ions and the extent of fluorescence enhancement is found to be considerab ly higher than that expected on the basis of photoinduced intramolecular el ectron transfer in the systems. The observation has been rationalised takin g into account the hydrated nature of the transition metal salts and prefer ential solvation of the fluorophore by the water molecules. (C) 2000 Elsevi er Science Ltd. All rights reserved.