Periodic mesoporous organosilicas possessing molecularly mixed pyridine and benzene moieties in the frameworks

Periodic mesoporous organosilicas (PMOs) were synthesized from precursor mixtures of bridged organosilanes containing various ratios of divinylbenzene (vPh) and divinylpyridine (vPy) under basic conditions. The bi-functional vPh-vPy-PMOs exhibited ordered mesoporous structures and molecular scale periodicity to form crystal-like pore walls. With an increase in the vPy content, the diffraction peak due to the molecular-scale periodicity was gradually shifted from 14.75 degrees to 14.95 degrees along with a gradual change in external morphology of the PMO particles from spherical to rod-like shapes. Moreover, the fluorescence from vPh was largely quenched by vPy in vPh-vPy-PMOs compared to the physical mixtures of vPh-PMO and vPy-PMO. These results strongly suggest that the vPh and vPy units were homogeneously distributed within the PMO framework. To the best of our knowledge, this is the first study to demonstrate the homogeneous distribution of different organic bridges in multifunctional PMOs.