关键词: 对映异构体, 纤维素-三(4-甲基苯甲酸酯)(Chiralcel OJ), 相互作用, 分子模拟, 洗脱顺序

Abstract:

The interaction between the enantiomers of two chiral imidazole derivates and polysaccharide-based chiral stationary phase cellulose tris(4-methylbenzoate)(Chiralcel OJ) was studied via molecular simulation. The result shows that the solvent effect has significant influence on the interaction. In the solvent A with strong polarity, the complexes between R-enantiomer of the compounds and the stationary phase are more stable than those of S-enantiomer, which leads to S-enantiomer eluting firstly and R-enantiomer following. The result is accordant with the separation experiment reported in the reference. Under the condition of solvent B with weak polarity, the binding energies are similar between R and S enantiomers of the two compounds and the stationary phase, which can not make R and S enantiomers separated effectively. The analysis on the simulation result demonstrates that the enantiomers and the stationary phase repulse each other under long-distance effect. In the strong polar solvent, the long-distance electrostatic interaction is weakened, which is beneficial to distinguish the difference of the steric interaction between the enantiomers and the stationary phase and further separate the enantiomers. The analysis of energy shows that the intermolecular van der Waals energy, especially dispersion energy determines whether the enantiomers separated effectively or not on the stationary phase.

Key words: Enantiomer, Cellulose tris(4-methylbenzoate)(Chiralcel OJ), Interaction, Molecular simulation, Elution order