[The Ion Identification and Molecular Logic Gate of a Thiacalix[4]arene Fluorescent Probe]

A disubstituted phthalimide-based thiacalix[4] arene derivative (probe s1) was synthesized from cone 1, 3-thiacalix[4] arene and hydroxyethyl phthalimide, with benzyl appended the lower edge of thiacalix[4]-arene by triazole ring in the 2,4 position. The relative fluorescence quantum yield of probe s1 is 0.43 in CH3CN solvent. The strong fluorescence emission of probe s1 at 390 nm wavelength can be selectively quenched by Fe3+ in DMF/H2O solution. Similarly, the presence of I- also induced a significant fluorescence quenching of probe s1 at 310 nm wavelength in CH3CN solution. Spectral titration and isothermal titration calorimetry were showed that probe s1 with Fe3+ or I- both form 1 : 1 complexes, the binding constants up to 10(5) and coordinate process were spontaneous. The linear ranges of fluorescence detect Fe3+ or I- were 1.0 x 10(-7) - 1.6 x 10(-4) mol x L(-1) and 1.0 x 10(-7) - 8.5 x 10(-5) mol x L(-1), detection limits were up to 2.30 x 10(-8) mol x L(-1) and 1.17 x 10(-8) mol x L(-1), respectively. Meanwhile, take advantage of identification and coordination action, a logic circuit constructed at the molecular level by controlling two input signals of Fe3+ and F-, which causing probe s1 cycling of fluorescence emission or quenching. IR spectrum speculated that the nitrogen atoms of triazole groups are involved in the complexation with Fe3+, while the hydrogen atoms of triazole groups were complexed with I- by hydrogen bonding.