Synthesis and characterization of rod-like periodic mesoporous organosilica with the 1,4-diureylenebenzene moieties

Highly ordered periodic mesoporous organosilicas (PMOs) with the 1,4-diureylenebenzene moieties incorporated into the silica framework walls were synthesized through co-condensation of bissilylated 1,4-diureylenebenzene and tetraethyl orthosilicate using triblock copolymer P123 as a structure-directing agent in acidic solutions. These PMOs were characterized by powder X-ray diffraction, N2 adsorption/desorption measurements, 13C and 29Si solid state NMR spectra, FT-IR, SEM, TEM and elemental analysis. It is observed that the PMOs containing 1,4-diureylenebenzene groups inside the pore walls possess large surface area ranging from 423 to 223 m2/g and uniform mesopores between 4.7 and 6.2 nm. With the increasing component of the bissilylated precursor to 10 mol%, PMOs with a rod-like morphology were obtained. When the fraction of the bridged organosilane exceeds 10 mol% in the start mixture, the orderness of the PMOs decreases and the mesoporous wall structure collapses under the adopted synthetic conditions.