Construction and investigation of photo-switch property of azobenzene-bridged pillar[5]arene-based [3]rotaxanes

Series of azobenzene-bridged pillar[5]arene-based [3]rotaxanes with different alkyl chain length of guest molecules were constructed by threading-endcapping method with alkylenetriazole as axile and tetrahydrochromene as endcapping group. The encapsulation of pillar[5]arenes were proved by high-resolution mass, H-1 NMR and NOESY spectra. The photo-responsive property were examined by irradiation of the synthesized [3]rotaxanes with 365 nm and blue light LED, which caused trans to cis and cis to trans isomerization, respectively. Irradiation of corresponding model guest compounds without pillar[5]arene encapsulation resulted in near completely trans to cis and cis to trans isomerization, indicating the existence of pillar[5]arenes is the determining factor for the comprised photo isomerization efficiency. (C) 2020 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.

Automated summary

A series of azobenzene-bridged pillar[5]arene-based [3]rotaxanes with different alkyl chain length of guest molecules were constructed and the encapsulation of pillar[5]arenes was verified experimentally. The photo-responsive property of these compounds was demonstrated with the presence of pillar[5]arenes playing a key role in the photo isomerization efficiency.