Manipulating the Isomerization of a Tris-azobenzene Cage by Anion Binding
Huibin Shan, Wei Zhao, Ji Wang, Yougang Yao, Hongwei Ma, Kanglei Liu, Xiao‐Juan Yang, Biao Wu
Abstract
Here, we report a C 3 -symmetric tris-azobenzene cage 1 comprising azobenzene cores and bis(urea) units. This system demonstrates efficient reversible photoisomerization and unprecedented anion-mediated switching modes. Specifically, the phosphate anion induces a concerted ZZZ → EEE isomerization with prolonged thermal relaxation ( t 1/2 = 37.5 h at 298 K). In contrast, the bulky benzene-1,3,5-tricarboxylate anion enforces a stepwise pathway ( ZZZ → EZZ → EEZ → EEE ) with rapid thermal relaxation ( t 1/2 = 54.4, 44.5, and 12.9 min for each step). This study represents the first demonstration of selective control over stepwise and concerted multi-azobenzene switch, mimicking biological adaptability through environmental changes.