Post‐Assembly Modification of Homochiral Titanium–Organic Cages for Recognition and Separation of Molecular Isomers
Guang‐Hui Chen, Yan‐Ping He, Yinghua Yu, Hong Lv, Shangda Li, Fei Wang, Zhi‐Gang Gu, Jian Zhang
Abstract
Abstract 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 Ti 4 L 6 (L=embonate) cage can be used as a 4‐connecting crystal engineering tecton, and its optical resolution was achieved, thus homochiral ΔΔΔΔ‐ and ΛΛΛΛ‐[Ti 4 L 6 ] 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 Ti 4 L 6 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.