title: Chiral NH-Controlled Supramolecular Metallacycles.
abstract: 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 Zn6L6metallacycles 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.
authors.affiliation: School of Chemistry and Chemical Technology and State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University , Shanghai 200240, China.
authors.forename: Jinqiao
authors.initials: J
authors.lastname: Dong
authors.affiliation: School of Chemistry and Chemical Technology and State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University , Shanghai 200240, China.
authors.forename: Chunxia
authors.initials: C
authors.lastname: Tan
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore , 4 Engineering Drive 4, 117576 Singapore.
authors.forename: Kang
authors.initials: K
authors.lastname: Zhang
authors.affiliation: School of Chemistry and Chemical Technology and State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University , Shanghai 200240, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: School of Chemistry and Biochemistry, University of Western Australia , 35 Stirling Highway, Crawley, WA 6009, Australia.
authors.forename: Paul J
authors.identifier: 0000-0003-1136-2296
authors.initials: PJ
authors.lastname: Low
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore , 4 Engineering Drive 4, 117576 Singapore.
authors.forename: Jianwen
authors.identifier: 0000-0003-1310-9024
authors.initials: J
authors.lastname: Jiang
authors.affiliation: School of Chemistry and Chemical Technology and State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University , Shanghai 200240, China.|Collaborative Innovation Center of Chemical Science and Engineering , Tianjin 300072, China.
authors.forename: Yong
authors.identifier: 0000-0003-1977-0470
authors.initials: Y
authors.lastname: Cui