Induction of Chirality in a Metal–Organic Framework Built from Achiral Precursors

Abstract

Induction of chirality from an achiral assembly system remains a huge challenge related to the origin of life. Here, induction of chirality in a metal–organic framework (MOF) built from achiral precursors has been realized. Assembling achiral H3BTB ligands and ZnII/CdII clusters leads to a 2D coordination polymer (FJI‐H16), while introduction of achiral pyridine into such assembly system leads to a 3D chiral MOF (FJI‐H27 (M) or (P)). The driven force for chiral generation has been proved to be a pyridine participated kinetic‐control assembly process, which can be controlled by changing the amount of pyridine and temperature, from no induction to partial induction to complete induction. The chiral generation process has been identified in detail through a pyridine‐involved key intermediate (FJI‐H28). The targeted modification of pyridine can selectively lead to FJI‐H27 (M) or FJI‐H27 (P), making the chiral orientation and distribution of bulk FJI‐H27 samples can be controlled. Our work not only represents a new chiral induction process that may relate to the chiral origin in nature, but also firstly reveals how achiral external stimuli generate chirality from achiral precursors, and offers a guide for rational preparation of chiral MOFs.

Emerging Homochiral Porous Materials for Enantiomer Separation

“…The first demonstration of chirality-induced MOF for chiral separation was reported by Das et al [27f ] Asymmetric crystallization of Eu(BTC)-(H 2 O)•DMF (BTC = 1,3,5-benzenetricarboxylate) was induced by using enantiopure 2-amino-1-butanol as chiral dopant, resulting in the enrichment of one 11). [53] By replacing the achiral pyridine with enantiopure (1-hydroxyethyl)pyridine, enantiopure MOF crystals can be obtained. It was found that chiral induction of this MOF is dominated by the formation of a pyridine meditated intermediate during the crystallization of MOF, which represents a new category of chiral induction phenomenon.…”

“…b) Chiral generation of MOFs by induction of pyridine.c,d) Generation of enantiopure MOFs by homochiral pyridine. Reproduced with permission [53]. Copyright 2020, WILEY-VCH.…”

Metal‐Organic Frameworks as a New Platform for Enantioselective Separations

“…An intermediate FJIÀ H28 could be isolated from the chiral generation transition state, providing insights into the chiral generation mechanism of FJIÀ H27. [41]…”

Two Unexpected Temperature-Induced Supermolecular Isomers from Multi-Topic Carboxylic Acid: Hydrogen Bonding Layer or Helix Tube

“…It has been confirmed in a kinetic model that an achiral artificial assembly system could spontaneously produce chirality [33]. However, without inducing the chiral chemical regents (as reactants or template), the coordinated or covalent enantiomers are commonly observed in the spontaneous resolution system [34][35][36][37]. Although 1-H should contain two different enantiomer single crystals, unfortunately, the attempt to pick out and solve the left-helix structure of single-crystal X-ray crystallography failed.…”