Controlled Construction of Heteroleptic [Pd2(LA)2(LB)(LC)]4+ Cages: A Facile Approach for Site‐Selective endo‐Functionalization of Supramolecular Cavities

• Published in: Angewandte Chemie International Edition 2023-02, Vol.62 (6), p.e202217215-n/a
• Main Authors: Liu, Yan, Liao, Shou‐Heng, Dai, Wen‐Tao, Bai, Qixia, Lu, Shuai, Wang, Heng, Li, Xiaopeng, Zhang, Zhe, Wang, Pingshan, Lu, Wei, Zhang, Qi
• Format: Article
• Language: English
• Subjects: Cages; Cavities; Construction; Endo-Functionalization; Functional groups; Heteroleptic Assemblies; Metal-Ligand Supramolecular Structures; Supramolecular Chemistry
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202217215

Construction of supramolecular structures with internal functionalities is a promising approach to build enzyme‐like cavities. The endo‐functionalized [Pd12L24] and [Pd2L4] coordination cages represent the most successful systems in this regard. However, these systems mainly contain one type of endo‐moiety. We herein provide a solution for the controlled endo‐functionalization of [Pd2L4] cages. Site‐selective introduction of the endo‐functional group was achieved through the formation of heteroleptic [Pd2(LA)2(LB)(LC)] cages. Using two orthogonal steric control elements is the key for the selective formation of the hetero‐assemblies. We demonstrated the construction of two hetero‐cages with a single internal functional group as well as a hetero‐cage with two distinct endohedral functionalities. The endo‐functionalized hetero‐cages bound sulfonate guests with fast‐exchange dynamics. This strategy provides a new solution for the controlled endo‐functionalization of supramolecular cavities. Unprecedented heteroleptic [Pd2 (LA)2 (LB) (LC)] supramolecular cages were selectively constructed by taking advantage of a pair of orthogonal steric control elements encoded in distinct ligands. This strategy allows the site‐selective introduction of distinct endo‐functionalities into the cavity of the heteroleptic cage.