Aggregation-induced emission logic gates based on metal ion sensing of phenanthroline–tetraphenylethene conjugates

Abstract

Phenanthroline–tetraphenylethene (Phen–1TPE) was synthesized by a typical Suzuki coupling. The aggregation-induced emission (AIE) properties and interactions with metal ions in THF–water (f_w = 90%) and in THF were investigated. Aggregation-induced emission logic gates were fabricated based on the metal ion sensing of Phen–1TPE conjugates via control of the metal ions and solvents. In THF–water with f_w = 90%, Phen–1TPE exhibits a strong AIE effect, while the fluorescence is almost totally quenched upon the addition of Cu²⁺ compared to other metal ions. Phen–1TPE works as an “INHIBIT” logic gate, with Cu²⁺ and aggregation (“Agg”) as the inputs and the fluorescence as the output. The fluorescence can also be quenched in f_w = 90% by the addition of metal ions (Cd²⁺, Zn²⁺, Sn²⁺ and In³⁺). In THF, Phen–1TPE exhibits a metal ion–ligand charge transfer (MLCT)-caused fluorescence enhancement by the addition of metal ions (Cd²⁺, Zn²⁺, Sn²⁺ and In³⁺). Thus it is established that Phen–1TPE works as a dual “XOR” logic gate with metal ions (Cd²⁺, Zn²⁺, Sn²⁺ and In³⁺) and “Agg” as the inputs. The INHIBIT and XOR logic gates were manipulated by utilizing different metal ions and water–THF volume ratios as the inputs, and the fluorescence of Phen–1TPE as the output.