Spectroscopic and TD-DFT studies on the dual mode fluorescent chemosensors based on pyrene thiosemicarbazones, and its application as molecular-scale logic devices

The newly synthesised thiocarbazone derivates used as an effective and selective colourimetric and “turn on” fluorescence sensor for copper ion and 'turn off' for fluoride and cyanide anion. The presence and absence of ions were considered as input signals and the corresponding absorption and emission responses were consired as output. The proton transfer from the nitrogen adjacent to pyrene moiety, and which takes place at the excited state (ESPT).123