Fluorescent Dendritic Organogels Based on 2-(2′-Hydroxyphenyl)benzoxazole: Emission Enhancement and Multiple Stimuli-Responsive Properties

A new highly efficient and versatile poly(benzyl ether) dendritic organogelator HPB‐G1 with 2‐(2′‐hydroxyphenyl)benzoxazole (HPB) at the focal point has been designed and synthesized. HPB‐G1 can form stable organogels toward various apolar and polar organic solvents. Further studies revealed that intermolecular multiple π–π stacking interactions are the main driving forces for the formation of the organogels. Notably, dendron HPB‐G1 exhibited a significantly enhanced emission in the gel state in contrast to weak emission in solution. Most interestingly, these dendritic organogels exhibited multiple stimuli‐responsive behaviors upon exposure to environmental stimuli, including temperature, sonication, shear stress, and the presence of anions, metal cations, acids/bases, thus leading to reversible sol–gel phase transitions. Smart fluorescence: A highly efficient and versatile dendron with 2‐(2′‐hydroxyphenyl)benzoxazole at the core that can form stable organogels with various apolar and polar organic solvents has been developed. These fluorescent dendritic organogels exhibit gelation‐induced enhanced fluorescence emission and multiple stimuli‐responsive behaviors (see figure).