4-Amino-1,8-dicyanonaphthalene derivatives as novel fluorophore and fluorescence switches: efficient synthesis and fluorescence enhancement induced by transition metal ions and protons

A new electronic push–pull fluorophore, 4-amino-1,8-dicyanonaphthalene, and its derivatives have been synthesized efficiently. They can be used as photo-induced electron transfer fluorescence switches which exhibit considerable fluorescence enhancement induced by transition metal ions Cr3+ and Fe3+ and also respond to pH values very sensitively.