Kim Minkyu, Han Moon Jong, Lee Hansol, Flouda Paraskevi, Bukharina Daria, Pierce Kellina J, Adstedt Katarina M, Buxton Madeline L, Yoon Young Hee, Heller William T, Singamaneni Srikanth, Tsukruk Vladimir V
School of Materials Science & Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
Angew Chem Int Ed Engl. 2023 Jul 24;62(30):e202305646. doi: 10.1002/anie.202305646. Epub 2023 Jun 20.
Chiral metal-organic frameworks (MOFs) have gained rising attention as ordered nanoporous materials for enantiomer separations, chiral catalysis, and sensing. Among those, chiral MOFs are generally obtained through complex synthetic routes by using a limited choice of reactive chiral organic precursors as the primary linkers or auxiliary ligands. Here, we report a template-controlled synthesis of chiral MOFs from achiral precursors grown on chiral nematic cellulose-derived nanostructured bio-templates. We demonstrate that chiral MOFs, specifically, zeolitic imidazolate framework (ZIF), unc-[Zn(2-MeIm) , 2-MeIm=2-methylimidazole], can be grown from regular precursors within nanoporous organized chiral nematic nanocelluloses via directed assembly on twisted bundles of cellulose nanocrystals. The template-grown chiral ZIF possesses tetragonal crystal structure with chiral space group of P4 , which is different from traditional cubic crystal structure of I-43 m for freely grown conventional ZIF-8. The uniaxially compressed dimensions of the unit cell of templated ZIF and crystalline dimensions are signatures of this structure. We observe that the templated chiral ZIF can facilitate the enantiotropic sensing. It shows enantioselective recognition and chiral sensing abilities with a low limit of detection of 39 μM and the corresponding limit of chiral detection of 300 μM for representative chiral amino acid, D- and L- alanine.
手性金属有机框架材料（MOFs）作为用于对映体分离、手性催化和传感的有序纳米多孔材料，已受到越来越多的关注。其中，手性MOFs通常是通过复杂的合成路线，使用有限的几种具有反应活性的手性有机前体作为主要连接体或辅助配体来制备的。在此，我们报道了一种模板控制合成手性MOFs的方法，该方法以在向列型手性纤维素衍生的纳米结构生物模板上生长的非手性前体为原料。我们证明，手性MOFs，具体来说，沸石咪唑酯骨架材料（ZIF），即unc-[Zn(2-MeIm)₂，2-MeIm = 2-甲基咪唑]，可以通过在纳米多孔有序向列型手性纳米纤维素内的规则前体，在纤维素纳米晶体的扭曲束上定向组装而生长。模板生长的手性ZIF具有四方晶体结构，手性空间群为P4，这与自由生长的传统ZIF-8的I-43m立方晶体结构不同。模板化ZIF晶胞的单轴压缩尺寸和晶体尺寸是这种结构的特征。我们观察到，模板化的手性ZIF可以促进对映体传感。对于代表性的手性氨基酸D-和L-丙氨酸，它表现出对映选择性识别和手性传感能力，检测下限低至39 μM，相应的手性检测限为300 μM。
