Cell permeable fluorescent colorimetric Schiff base chemoreceptor for detecting F− in aqueous solvent

A novel colorimetric hydrazine based Schiff base chemoreceptor (E)-2-((2-(perfluorophenyl)hydrazono)methyl)phenol (PMP), for detection of fluoride (F−) is reported in this work. The receptor can selectively detect F− by turning from colorless to yellow. The recognition event is further confirmed by solution state spectrophotometric measurements like UV-Vis, Fluorescence and 1H NMR titrimetric studies. The fluorescence 'turn on' phenomenon of PMP with gradual addition of F− can be well explained by inhibition of CN isomerization process. 1H NMR titration experiments of PMP with F− further support the hydrogen bonding interaction between host PMP and guest F−. Interestingly, PMP has potential toward detection of intracellular F− in cells of Candida albicans (diploid fungus) and pollen grains of Techoma stans. The recognition phenomenon is reversible and we have successfully developed two input logic network where INHIBIT gate can be considered as an AND gate with one input inverted by a NOT function. Furthermore, this logic gate represents a potential 'Write-Read-Erase-Read' memory function possessing multi writing ability.