Preparation of Mesoporous 1,4‐Phenylene‐silica Nanorings through a Dual‐templating Approach

Mesoporous 1,4-phenylene-silica nanorings were prepared using cetyltrimethylammonium bromide (CTAB) and (S)-2-methyl-1-butanol as a chiral dopant in concentrated aqueous NH3 solutions. Transmission electron microscopy images of the samples indicated that the nanorings were formed by bending nanorods 360 degrees. With increasing the stirring speed or the (S)-2-methyl-1-butanol/CT Lambda B molar ratio, the morphologies of mesoporous 1,4-phenylene-silicas changed from helical nanofibers to nanorings, and then to nano-saddles. Circular dichroism spectra of these hybrid silicas indicated that they were chiral.