Electronic Decoupling in C3‑Symmetrical Light-Responsive Tris(Azobenzene) Scaffolds: Self-Assembly and Multiphotochromism
journal contributionposted on 31.10.2018, 00:00 by Agostino Galanti, Valentin Diez-Cabanes, Jasmin Santoro, Michal Valášek, Andrea Minoia, Marcel Mayor, Jérôme Cornil, Paolo Samorì
We report the synthesis of a novel C3-symmetrical multiphotochromic molecule bearing three azobenzene units at positions 1, 3, 5 of the central phenyl ring. The unique geometrical design of such a rigid scaffold enables the electronic decoupling of the azobenzene moieties to guarantee their simultaneous isomerization. Photoswitching of all azobenzenes in solution was demonstrated by means of UV–vis absorption spectroscopy and high performance liquid chromatography (HPLC) analysis. Scanning tunneling microscopy investigations at the solid–liquid interface, corroborated by molecular modeling, made it possible to unravel the dynamic self-assembly of such systems into ordered supramolecular architectures, by visualizing and identifying the patterns resulting from three different isomers, thereby demonstrating that the multiphotochromism is retained when the molecules are confined in two dimensions.