Novel hydroxyl-substituted perylene-3,4,9,10-tetracarboxylic acid diimides for selective recognition of fluoride

Two novel highly fluorescent hydroxyl-substituted perylene diimides derivatives, N,N-dicyclohexyl-1-hydroxyperylenediimide (1) 2,9-dicyclohexyl-5,5-dimethyl-12-hydroxy-5,6-dihydropyreno[2,1,10-def:7,8,9-d′e′f′]diisoquinoline-6-oxa-1,3,8,10(2H,9H)-tetraone (2) were designed and efficiently synthesized through a single aromatic nucleophilic displacement reaction. The physical properties of the as-prepared compounds had been fully studied. Both receptors have shown no affinity for other anions, such as Cl⁻, Br⁻, I⁻ SO₄⁻, PF₆⁻, H₂PO₄⁻, BF₄⁻, AcO⁻, ClO₄⁻ (as salt of tetra-n-butylammonia) and ammonium hydroxide. Interestingly, they can be served as colorimetric and fluorescent chemodosimeter for fluoride ion using hydroxyl as binding sites, which was the first report of hydroxyl-modified PDIs based photodetector of fluoride ion. Upon addition of F⁻ anion to compound 2 solution, dramatic color change and fluorescence quenching were observed. Furthermore, the red-shifted maximum absorption wavelength reached 207 nm to the far-red region, which was the maximal spectrum bathochromic-shift of PDIs used in fluoride detection. In addition, the two fluoride sensor can be used under illumination from a laboratory hand-held UV lamp. These results demonstrated that using facile synthetic routes to constructing PDIs molecules with hydroxyl moiety was a useful strategy for designing high performance fluoride recognization.