A dual-responsive anthrapyridone-triazole-based probe for selective detection of Ni2+ and Cu2+: A mimetic system for molecular logic gates based on color change

A newly synthesized anthrapyridone-based probe (probe 1) with a pyrene-1-triazole unit as a pendant exhibited selective and sensitive detection of Cu2+ and Ni2+ among various metal ions. Dramatic color changes were observed for the chromo-fluorogenic probe 1 upon addition of Cu2+ (yellowish-green to pink) or Ni2+ (yellowish-green to magenta), enabling naked-eye detection of each metal ion. The limit of detection (LOD) of the probe based on a ratiometric method of determining an absorbance ratio was 0.5 mu M for both metal ions. In addition, probe 1 complexed with Ni2+ (i.e., a [probe 1 + Ni2+]-complex) was alternatively used to detect Cu2+ with high selectivity and sensitivity (LOD = 0.5 mu M). A fluorescence study showed that probe 1 gave rise to green emission, but in the presence of the metal ion, this fluorescence emission was completely (Cu2+) or partially (Ni2+) quenched, resulting in notable LODs of 0.2/0.5 mu M (Cu2+/Ni2+). Probe 1 therefore possesses a dual responsiveness to the presence of Cu2+ or Ni2+: color change or fluorescence quenching. The combined result with Ni2+ and Cu2+ indicates that the anthrapyridone-based probe serves as 'YES, INHIBIT, AND' logic gates. The current system was extensively analyzed by density functional theory calculations, nuclear magnetic resonance, high-resolution mass spectrometry, ultraviolet-visible light, and fluorescence spectroscopies.