Fluorescent sensor for alpha,omega-dicarboxylate anions

The synthesis and photophysical behavior of several naphthylurea derivative s used as chemosensors for detecting anionic species is reported. In partic ular, compound 3 shows a photoinduced electron transfer (PET) process. The photophysical properties of 3 upon the addition of dicarboxylate anions hav e been studied. Results show that fluorescence quenching of the naphthyl mo iety and appearance of a new emission is induced by the formation of a comp lex. The obtained fluorescence and H-1-NMR data indicate that a 1 : 1 stoic hiometry complex is formed between compound 3 and dicarboxylate anions thro ugh a hydrogen-bonding interaction. The selectivity of 3 for recognition of different dicarboxylates depends on the chain length of the anionic specie s.