Visual Detection of Triethylamine and a Dual Input/Output Logic Gate Based on a Eu³⁺-Complex

A series of Ln³⁺-metal centered complexes, Ln(TTA)₃(DPPI) (Ln = La, 1; Ln = Eu, 2; Ln = Tb, 3; or Ln = Gd, 4) [(DPPI = N-(4-(1H-imidazo [4,5-f][1,10]phenanthrolin-2-yl)phenyl)-N-phenylbenzenamine) and (TTA = 2-Thenoyltrifluoroacetone)] have been synthesized and characterized. Among which, the Eu³⁺-complex shows efficient purity red luminescence in dimethylsulfoxide (DMSO) solution, with a Commission International De L' Eclairage (CIE) coordinate at x = 0.638, y = 0.323 and Φ_Eu^L = 38.9%. Interestingly, increasing the amounts of triethylamine (TEA) in the solution regulates the energy transfer between the ligand and the Eu³⁺-metal center, which further leads to the luminescence color changing from red to white, and then bluish-green depending on the different excitation wavelengths. Based on this, we have designed the IMPLICATION logic gate for TEA recognition by applying the amounts of TEA and the excitation wavelengths as the dual input signal, which makes this Eu³⁺-complex a promising candidate for TEA-sensing optical sensors.