Fluorescent chemosensor for Al3 + and resultant complex as a chemosensor for perchlorate anion: First molecular security keypad lock based on Al3 + and ClO4− inputs

A dipodal sensor detects Al3 + in HEPES buffered THF/H2O (7:3, v/v) through excited state proton transfer, representing a quenching at 355 nm and enhancement at 480 nm. The resulting aluminium complex (1.Al3 +) displays a highly selective response to perchlorate anion over other anions through the emergence of a new band at 428 nm. The chemical inputs of Al3 + and ClO4− satisfies the conditions of AND molecular logic gates and in a sequential manner generates an output which mimics the functions of a security keypad lock.