Highly Luminescent Organic−Inorganic Hybrid Mesoporous Silicas Containing Tunable Chemosensor inside the Pore Wall

Abstract

New multifunctional luminescent hybrid mesoporous silicas (LHMS) containing a tunable chemosensor diimine moiety inside the pore wall have been synthesized. XRD and TEM image analyses indicate the formation of highly ordered 2D hexagonal mesophase from a 1:3 mixture of diimine organosilica and tetraethyl orthosilicate (TEOS) assisted by the supramolecular assembly of cetyltrimethylammonium bromide (CTAB); the use of diimine organosilica precursor alone leads to disordered mesophase. 13C CP MAS, 29Si MAS NMR, and UV−visible spectroscopic data show the incorporation of bridging organic diimine in the solid mesoporous materials. N2 sorption data suggest high BET surface areas together with type IV isotherms for the LHMS samples. These hybrid mesoporous materials show very strong affinity for metal cations (Fe3+, Zn2+, etc.), which could be utilized for possible application to metal ion chemosensors. All the LHMS samples exhibit very strong photoluminescence at room temperature and strong dependence of emission on exogenous ions. The highly ordered sample has the advantage over the disordered sample synthesized over pure diimine precursor, because its ion-exchange efficiency is high and it is synthesized with a small amount of diimine chemosensor precursor.