ESIPT based dual fluorescent sensor and concentration dependent reconfigurable boolean operators

Abstract

Probes 1 and 2 (CH₃CN–H₂O; 4 : 1) at pH 7.0 ± 0.1 (10 mM, HEPES) selectively bind with Zn²⁺ ions and give a new emission band at 490 nm. These can estimate 20 nM Zn²⁺ ions as the lowest detection limit. The determination of Zn²⁺ ions by probe 1 is not interfered by the presence of other metal ions viz. Na⁺, K⁺, Mg²⁺, Ca²⁺, Sr²⁺, Fe²⁺, Co²⁺, Ni²⁺, Cd²⁺, Ag⁺, Hg²⁺. However, in the case of probe 2 Cu²⁺ causes only the fluorescence quenching. In acetonitrile, the addition of different concentrations of Cu²⁺ (2 μM, 5 μM, 10 μM) and a fixed amount of F⁻ (25 μM) to a solution of 2 (0.25 μM, CH₃CN) elaborates Cu²⁺ ion concentration dependent NOR, INH and AND Boolean operators with three distinct emission channels at 585, 515 and 400 nm, respectively.