A novel water-soluble 1,8-naphthalimide as a fluorescent pH-probe and a molecular logic circuit

A novel highly water-soluble fluorescence sensing 1,8-naphthalimide is synthesized and investigated. The novel compound is designed on the “fluorophore-receptor1-spacer-receptor2” model as a molecular fluorescence probe for determination of ions in 100% aqueous media. The novel probe comprising hydrazide and N-methylpiperazine substituents is capable of operating simultaneously via ICT and PET signaling mechanism and of recognizing selectively protons and hydroxyl anions over the representative metal ions and anions. Due to the remarkable fluorescence changes as a function of pH the system is able to act as a three output combinatorial logic circuit with two chemical inputs. Two INHIBIT gates in fluorescence and absorption mode as well as an IMPLICATION logic gate are obtained. Because of the parallel action of both INHIBIT gates a magnitude digital comparator is achieved for the first time in this way.