A Photoactivated Molecular Gate

An o-nitrobenzyl ester derivative bearing a cyclodextrin moiety that was selectively opened by the addition of specific enzymes and by UV irradiation was prepared. On methoxybenzylamine fragment, a compound, which , other than the photo-cleavable group, contained two bulky tert-butyl moieties to obtain effective pore blockage in the final hybrid material, as well as one trialkoxysilane moiety for anchoring on the external mesoporous silica nanoparticles (MSN) surface, was obtained. The TEM images show the typical porosity associated with the inorganic support and their spherical form of about 100 nm in diameter. The release of the ruthenium dye in the absence of light is completely inhibited. The photolysis of the methoxybenzylamine group diminished the steric crowding around the pore outlets, which accounts for the dye delivery and the emission enhancement observed.