Surface-modified mesoporous silica with ferrocene derivatives and its ultrasound-triggered functionality

Novel ferrocene derivatives designed as gatekeepers were successfully composed on the pore outlet of amino-functionalized mesoporous silica by post-synthesis grafting where the peptide bond of the amine group (–NH2) of mesoporous silica was linked with the carboxylic acid group (–COOH) of both ends of the ferrocene derivatives. The materials of the amine-functionalized mesoporous silica (NH2–MS) and ferrocene-functionalized mesoporous silica (Fc–CONH–MS) were characterized using X-ray diffractions (XRD), Fourier-transform infrared (FT-IR), N2 sorption isotherms, solid-state NMR spectra, scanning electron microscopy (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), and UV–vis absorption spectra. The ferrocene attached to the mesoporous silica pore outlet was cleavaged by ultrasound irradiation, which opened the closed-pore outlets, suggesting a possible application for controlled release drug carrier.