Preparation of Chiral Stationary Phase Co-Modified With Homochiral Secondary Amine Molecular Cages and Amylose and Its Enantiomeric Separation Performance

Abstract

In this study, reduced porous organic cages with homochiral secondary amine structure were immobilized on a silica gel surface, and a derivative of 3,5-dimethyl phenyl carbamate of amylose was coated onto the molecular cage-modified silica sphere to prepare a chiral stationary phase co-modified with amylose and homochiral secondary amine molecular cages. The prepared chiral stationary phase was characterized using techniques such as scanning electron microscopy, infrared spectroscopy, and thermogravimetric analysis. The results confirmed the successful preparation of the amylose and homochiral secondary amine molecular cages co-modified silica gel chiral stationary phase. The 10 chiral compounds were selected to systematically evaluate the enantioselective performance of the new chiral stationary phase using normal-phase chromatography for enantiomeric separation. The experimental results demonstrated that the 10 compounds were well separated on this chiral stationary phase, with complete separation achieved for trans-stilbene oxide, phenylethanol, and 1-phenyl-1-propanol, all showing a resolution greater than 1.5. In contrast, the homochiral secondary amine molecular cage-modified silica gel stationary phase showed only partial chiral separation for these compounds. The study highlights the synergistic effect of amylose and molecular cages in enhancing enantiomeric separation, demonstrating their significant potential in the development of chiral stationary phases.