A fluoride-selective colorimetric and fluorescent chemosensor and its use for the design of molecular-scale logic devices

A simple and efficient chemosensor 1 was synthesized by reacting thiosemicarbazide with 1-naphthaldehyde. It was found that the sensor is highly selective toward fluoride anions in both UV–vis and fluorescence channels in DMSO solution. Especially, the spectral responses of the sensor along with a visible color change can be switched back and forth by successively adding F − and HSO 4 − anions into the DMSO solution, which may be represented by a complementary “IMPLICATION/INHIBIT” logic gate at molecular level employing both the ions as the chemical inputs. Based on such a reversible and reproducible sensing system, we designed a molecular-scale sequential memory unit displaying “Writing-Reading-Erasing-Reading” and “Multi-write” functions in the form of binary logic.