Recent endeavors on design, synthesis, fluorescence mechanisms and applications of benzazole-based molecular probes toward miscellaneous species

Owing to their much more accessible structural diversity and recognition mechanism, the fluorescent probes with small molecular scaffold are significant, and they have been broadly investigated in the cutting edge of materials and biological chemistry. Known as the facile synthesis, expedient structural modification, good molecular stability, admirable fluorescence properties, multiple binding sites and excellent environmental compatibility, the benzazole moieties are under growing attraction in fluorescent probes for efficient detection of different species, such as cations (H+, Al3+, Hg2+, Cu2+, etc.), anions (HSO3-, F-, OH-, CN- , etc.), biomolecules (thiols, amino acids, etc.) and explosives (picric acid and TNT, etc.). In this review, benzimidazole-, benzoxazole- and benzothiazole-based fluorescent probes that have been reported in the recent three years (2017-2019) are refined to elucidate the progress of benzazole-based probes by combining their design strategy, synthetic route, sensing mechanism and applications. We wish that it may afford valuable recommendation to the construction of intelligent and versatile fluorescent probes based on benzazole derivatives.