Dual channel detecting of CO in a metal complex gel system: Phase transition and fluorescence enhancement

A C3 symmetric molecule BTBM bearing benzimidazole moiety was design and synthesized. BTBM could form supramolecular gel in glacial acetic acid and exhibit fluorescent emission. By complexing with Pd2+, metal organic gel could be obtained and the fluorescent intensity of the benzimidazole moiety was weaken. When the metal organic gel was placed in CO gas atmosphere, the metal organic gel was collapsed and the fluorescence recovered again. This work provide a dual channel method including the phase transition and fluorescent intensity change to detect CO gas by naked eyes.