Chiral Periodic Mesoporous Organosilicates Based on Axially Chiral Monomers: Transmission of Chirality in the Solid State

Chiral mesoporous materials have been prepared with purely organic monomers employing an enantiomerically pure biphenyl bis-siloxane as a dopant along with simple 4,4'-bis(triethoxysilyl)biphenyl as the bulk material. Analysis of these materials by CD spectroscopy indicates the formation of new chiral aggregates in the solid state consistent with charge delocalization from adjacent aryl rings in close contact. These aggregates are only observed when the biphenyl and enantiomerically pure biaryl are both present. The red-shift resulting of the CD signal resulting from these interactions is modeled computationally using time-dependent DFT calculations.