Synthesis and Characterization of Functional, Chiral Periodic Mesoporous Organosilica Materials
High-surface-area materials are ideal for recyclable supports and solid phases for heterogeneous catalysis and for chromatography because they allow for a large number of substrate-surface interactions. Such synthetic materials can be precisely tuned in terms of pore size and shape, particle shape, hydrophobicity, and functionality at the surface. Periodic mesoporous organosilica (PMO) materials offer the stability of a silicon framework; the functionality of an organic compound, ligand or complex; and the opportunity for all of the aforementioned properties to be highly controlled. Additionally, these materials can have chirality on the molecular or particle scale, through the use of chiral building blocks during their synthesis. In the work described herein, we have shown that molecular chirality can be installed within PMO materials through the use of chiral organic monomers doped into the material bulk phase. The chiral dopants and other functional dopants can be chemically manipulated within the solid-state material, and we have shown that the deprotection of masked biphenol groups yields free diols that can be subsequently modified into new functionalities, such as phosphoric acid residues. By cleaving the chiral auxiliary of the chiral dopants within the solid-state material, we can remove the physical barrier to racemization; and yet, the dopant does not lose its chiral information, even after hydrothermal treatment. This work demonstrates the potential for multifunctional PMOs as heterogeneous catalysts, where selective functionalization of embedded dopants can establish different types of active sites within the material. Lastly, the synthesis of new bulk phase monomers is investigated with the idea that the complimentary quadrupole polarities of perfluorinated and nonfluorinated arenes will facilitate the self-assembly of the bulk and dopant monomers by increasing electrostatic interactions during material synthesis.