Study Of Novel β-cyclodextrin Bonded Hydride Silica Chiral Stationary Phases

The special structure of cyclodextrin (CDs) gives rise to their remarkable ability informing inclusion complexes with a variety of molecules by some interactions, includingpolar-polar and hydrogen-bonding interactions. Combining with the advantages of–C=N-and improve its stability, our research group has designed a series of cyclodextrinderivatives with chiral oxazoline substituents, and chemically bonded it to silica gel. Thiskind of CSPs applied to chiral separation progress achieved good performances. On thebasis of the strong electrostatic interaction and its special characteristic in mobile phases,we designed and synthesized an oxazoline ionic salt derivative β-CD:6-deoxy-6-R-(+)-(4-pyridin-1-ium-4-methyl-benzenesulphonate)-4,5-dihydrooxazolinyl–β-cyclodextrin (R-POTPHDOCD). Researches show that, this ionic liquid modified CSP hasgreat superiority in separating analytis with strong polarity groups, such as amino andcarboxyl，so it greatly strengthen the interaction between the chiral stationary phases andthe analytes.This kind of ionic salt derivative stationary phase can not achieve satisfactoryseparation results with some aromatic organic compounds although it has many advantages.We have been introduced many acting sites in our cyclodextrin selectors, so to furtherimprove the CSP, we are begin to thinking about changing the polarity of the silica gelcarrier to increase the affinity with the organic compounds. In order to solve this problem,we introduced hydride sillca to this CSP，designed and sythesised two kinds of β-CDbonded hydride silica CSPs: natural β-CD bonded hydride silica CSP (hydride NCD) and6-deoxy-6-R-(+)-(4-pyridin-1-ium-4-methyl-benzenesulphonate)-4,5-dihydrooxazolinyl–β–cyclodextrin bonded hydride silica CSP (hydride R-POTPHDOCD).22rac-β-nitro-ethanols,5ferrocene derivatives,11mandelic acid and amino acid compounds,6oxazolinylderivatives were separated in polar organic mobile phase mode and reversed phase mode bythe three CSPs. The separation data showed that hydride R-POTPHDOCD with relativelyweak polarity possessed the advantages of both R-POTPHDOCD and hydride NCD. It hasstrong affinity with the analytes, and can be suitable for a wide range of pH value.Meanwhile, on the reversed phase mode. The solvent with smaller polarity in the highconcentration solution tend to achieve the best separation results. Therefore, the hydrideR-POTPHDOCD CSP expands the separation application scope.