Post‐Assembly Modification of Homochiral Titanium–Organic Cages for Recognition and Separation of Molecular Isomers

• Published in: Angewandte Chemie International Edition Vol. 62; no. 16; pp. e202300726 - n/a
• Main Authors: Chen, Guang‐Hui, He, Yan‐Ping, Yu, Yinghua, Lv, Hong, Li, Shangda, Wang, Fei, Gu, Zhi‐Gang, Zhang, Jian
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 11.04.2023
• Edition: International ed. in English
• Subjects: Assembly; Cages; Chiral Cage-Based Frameworks; Isomers; Post-Assembly Modification; Recognition; Recognition and Separation; Separation; Supramolecular compounds; Titanium; Titanium–Organic Cages; Post-Assembly Modification; Chiral Cage-Based Frameworks; Recognition and Separation; Titanium-Organic Cages
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202300726

A chiral metal–organic cage (MOC) was extended and fixed into a porous framework using a post‐assembly modification strategy, which made it easier to study the host–guest chemistry of the solid‐state MOC using a single‐crystal diffraction technique. Anionic Ti4L6 (L=embonate) cage can be used as a 4‐connecting crystal engineering tecton, and its optical resolution was achieved, thus homochiral ΔΔΔΔ‐ and ΛΛΛΛ‐[Ti4L6] cages were obtained. Accordingly, a pair of homochiral cage‐based microporous frameworks (PTC‐236(Δ) and PTC‐236(Λ)) were easily prepared by a post‐assembly reaction. PTC‐236 has rich recognition sites provided by the Ti4L6 moieties, chiral channels and high framework stability, affording a single‐crystal‐to‐single‐crystal transformation for guest structure analyses. Thus it was successfully utilized for the recognition and separation of isomeric molecules. This study provides a new approach for the orderly combination of well‐defined MOCs into functional porous frameworks. A chiral metal–organic cage has been extended and introduced into a porous framework by using a post‐assembly modification strategy. The microporous frameworks were successfully utilized for the recognition and separation of isomeric molecules, including aromatic compounds, nitriles, and chiral aromatic alcohols.