High azobenzene functionalization enhances stability of the cis isomer: Periodic mesoporous organosilica network on the way to new light triggered applicable materials

Azobenzene and its derivatives are in the focus of research for the application as molecular switch for medical uses or industrial processes. An optical switchable azobenzene molecule was covalently anchored on the pore walls of a benzene molecule bridged periodic mesoporous organosilica material (abbreviated bz-PMO). The two step synthesis allowed the preparation of a hybrid material with a very high switch density exhibiting an extraordinary long half-life time of 87 h of the cis-isomer. The material was thoroughly characterized applying UV/Vis- and solid state NMR-spectroscopy demonstrating the successful covalent anchoring of the switch onto the pore walls. (C) 2016 Elsevier Inc. All rights reserved.