Optical chemosensor for Ag+, Fe3+, and cysteine: information processing at molecular level.

A thiacalix[4]arene based chemosensor 3 bearing two pyrene groups has been synthesized which demonstrates ratiometric sensing with Ag(+) and fluorescence quenching with Fe(3+) ions in mixed aqueous media. The 'in situ' prepared Ag(+) and Fe(3+) complexes showed high selectivity toward cysteine. The molecular switching between three chemical inputs (Ag(+), Fe(3+), cysteine) results in various molecular logic gates which have been integrated sequentially to generate a sequential information processing device.