1-(2-Naphthalenyl)benzimidazolium based fluorescent probe for acetate ion in 90% aqueous buffer

A new fluorescent probe 9,10-bis[1-(2-naphthalenylbenzimidazolium)-3-methyl]anthracene 1 has been synthesized which shows highly selective fluorescence quenching with only acetate ions in 90% aqueous buffer at pH 7.4. The structure optimization (DFT) of probe 1 and its 1:1 complex with acetate anion, shows that probe 1 is pre-organized and has to undergo minimal spatial reorganization during complexation with acetate anion.