College of Chemistry, Key Laboratory of Molecular Sensing and Harmful Substances Detection Technology, Zhengzhou University, Kexue Avenue 100, Zhengzhou, Henan, 450001, PR China.
College of Chemistry, Key Laboratory of Molecular Sensing and Harmful Substances Detection Technology, Zhengzhou University, Kexue Avenue 100, Zhengzhou, Henan, 450001, PR China.
Talanta. 2020 Oct 1;218:121155. doi: 10.1016/j.talanta.2020.121155. Epub 2020 May 11.
Chiral metal-organic frameworks (CMOFs) have been explored as potential chiral stationary phases (CSPs) for chiral high performance liquid chromatography (HPLC). However, their application is still hindered by the low column efficiency, high back pressure and the difficulty in column packing due to the irregular shapes and wide size distributions of CMOF particles. Here we report an efficient one-pot method for the immobilization of chiral MOF [Cu((+)-Cam)Dabco] (CuCD) onto microspheric silica particles, generating a uniform core-shell microsphere with SiO@CMOF@CMOF morphology as CSP packing material. Significantly, the shell thickness and the corresponding column efficiency could be rationally regulated by controlling the growth cycles of [Cu((+)-Cam)Dabco]. The structure of developed core-shell microspheres were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), powder X-ray diffraction (PXRD), N adsorption experiments, infrared spectroscopy (FT-IR) and thermogravimetric analysis. Mechanism involved in the chromatographic separation is the multi-interactions including hydrophobic and hydrogen-bonding, etc. Based on these interactions, successful separation could be achieved among different types of racemic compounds such as carboxylic acid, ketones and phenols under normal phase liquid chromatography (NPLC) condition. In addition, the relative standard deviation (RSD%) value of the retention time for TNPTO was below 1.1% (n = 5), indicating the good repeatability and stability of the chiral SiO@CuCD-2 column for HPLC enantioseparation. The results reveal that the CMOF coating approach is convenient to fabricate CSP with pre-designed functions of good recognition performance and to facilitate the evolution of CSP in chiral HPLC. Furthermore, the SiO@CuCD-2 column was successfully employed for the determination of the enantiomeric excess value for TNPTO in the asymmetric Michael addition reaction.
手性金属有机骨架（CMOFs）已被探索作为手性高效液相色谱（HPLC）的潜在手性固定相（CSP）。然而，由于 CMOF 颗粒的不规则形状和较宽的尺寸分布，它们的应用仍然受到柱效低、背压高和柱装填困难的限制。在这里，我们报告了一种高效的一锅法，将手性 MOF [Cu((+)-Cam)Dabco]（CuCD）固定在微球硅胶颗粒上，生成具有 SiO@CMOF@CMOF 形态的均匀核壳微球作为 CSP 填充材料。显著地，通过控制[Cu((+)-Cam)Dabco]的生长循环，可以合理调节壳层厚度和相应的柱效。所开发的核壳微球的结构通过扫描电子显微镜（SEM）、能谱（EDS）、粉末 X 射线衍射（PXRD）、N 吸附实验、红外光谱（FT-IR）和热重分析（TGA）进行了表征。色谱分离涉及的机制是多种相互作用，包括疏水作用和氢键等。基于这些相互作用，可以在正相液相色谱（NPLC）条件下实现不同类型的外消旋化合物（如羧酸、酮和酚）的成功分离。此外，TNPTO 的保留时间的相对标准偏差（RSD%）值低于 1.1%（n=5），表明 SiO@CuCD-2 柱在 HPLC 对映体分离中具有良好的重复性和稳定性。结果表明，CMOF 涂层方法方便地制备了具有良好识别性能的预设计功能的 CSP，并促进了 CSP 在手性 HPLC 中的发展。此外，SiO@CuCD-2 柱成功地用于测定不对称迈克尔加成反应中 TNPTO 的对映体过量值。
