An Optical Chemodosimeter Coumarin Nosylate for Probing Fluoride Ion: Synthesis, Crystal Structures, Photophysical and Theoretical Studies

To achieve selectivity for fluoride recently researchers resorted on its nucleophilic characteristics rather than its basicity. The design strategy of this kind of probe involves masking of a fluorescent moiety with NBS/DNBS masking groups. Attack of fluoride over the same leads to release of fluorescent moiety in the solution. The prime concern of this family of probes is that no crystallographic evidence is available till date in the literature to the best of our knowledge. We are reporting herein a new chemodosimeter in the form of a coumarin nosylate (CMS) as a dual channel optical probe for the smart detection of fluoride. Interestingly, we not only isolated single crystals of CMS but also successfully isolated the fluoride (F-) induced cleaved product of CMS i.e. chromenolate counter balanced with tetrabutylammonium (TBA) ion.