Chiral NH-Controlled Supramolecular Metallacycles
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- 作者：Jinqiao Dong ; Chunxia Tan ; Kang Zhang ; Yan Liu ; Paul J. LowJianwen Jiang ; Yong Cui
- 刊名：Journal of the American Chemical Society
- 出版年：2017
- 出版时间：February 1, 2017
- 年：2017
- 卷：139
- 期：4
- 页码：1554-1564
- 全文大小：1043K
- ISSN：1520-5126
文摘
Chiral NH functionalities-based discrimination is a key feature of Nature’s chemical armory, yet selective binding of biologically active molecules in synthetic systems with high enantioselectivity poses significant challenges. Here we report the assembly of three chiral fluorescent Zn6L6 metallacycles from pyridyl-functionalized Zn(salalen) or Zn(salen) complexes. Each of these metallacycles has a nanoscale hydrophobic cavity decorated with six, three, or zero chiral NH functionalities and packs into a three-dimensional supramolecular porous framework. The binding affinity and enantioselectivity of the metallacycles toward α-hydroxycarboxylic acids, amino acids, small molecule pharamaceuticals (l-dopa, d-penicillamine), and chiral amines increase with the number of chiral NH moieties in the cyclic structure. From single-crystal X-ray diffraction, molecular simulations, and quantum chemical calculations, the chiral recognition and discrimination are attributed to the specific binding of enantiomers in the chiral pockets of the metallacycles. The parent metallacycles are fluorescent with the intensity of emission being linearly related to the enantiomeric composition of the chiral biorelevant guests, which allow them to be utilized in chiral sensing. The fact that manipulation of chiral NH functionalities in metallacycles can control the enantiorecognition of biomolecular complexes would facilitate the design of more effective supramolecular assemblies for enantioselective processes.