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

Abstract

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.