Synthesis, properties and fluoride sensing of hydrazide incorporated 1,8-naththalimide Troger’s bases

We report the synthesis of novel benzohydrazide incorporated naphthalimide troger’s base systems ( 1–4 ) via condensation of naphthalimide with various aryl hydrazides in high yields (86–94%). 1–4 shows strong absorption (λ max = ~ 385 nm) and emission (λ max = ~ 490 nm, ϕ f = 13–57%) in the visible region. Compound 1 found to exhibit selective fluorescent sensing of fluoride ion. The presence of hydrazine functionality in the molecular framework undergoes deprotonation via H-bonding interactions leading to significant quenching of fluorescence. The limit of detection has been calculated to be 9.05 µM. In addition, compound 1 is highly selective towards the fluoride ions among various anions such as OH − , HSO 4 − , NO 2 − , BF 4 − , CN − and OClO 4 − tested.