Photoresponsive porous organosilicas*

Novel structured functional hybrid materials can be obtained by incorporating photoresponsive organic components into the silicate walls of periodic mesoporous silicates. Two such materials are described, containing either viologens or stilbene analogs. Thermal or photochemical activation of viologen units generates the corresponding radical cations, whose lifetime can vary from months to milliseconds, depending on the surfactant content of the solid. In a second example, the porosity and tortuosity of the silicate can be modulated by irradiation of an organosilica containing a stilbene-like moiety.