Polyoxometalate–Organic Hybrid “Calixarenes” as Supramolecular Hosts

• Published in: Angewandte Chemie 2024-01, Vol.136 (4), p.n/a
• Main Authors: Gao, Yuan, Guo, Ji, Lai, Yuyan, Lin, Jiaheng, Liu, Junrui, Ji, Jianming, Yin, Panchao, Wang, Wei, Zhao, Hongmei, Chen, Guanying, Wang, Lei, Fang, Xikui
• Format: Article
• Language: English
• Subjects: Acetic acid; Aromatic compounds; Calixarenes; Chemistry; Host–Guest Systems; Macrocycles; Physicochemical properties; Polyoxometalates; Polyoxometallates; Substrates; Supramolecular Chemistry
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.202315691

Calixarenes are among the most useful and versatile macrocycles in supramolecular chemistry. The one thing that has not changed in the 80 years since their discovery, despite numerous derivatizations, is their fully organic, covalent scaffolds. Here, we report a new type of organic–inorganic hybrid “calixarenes” constructed by means of coordination‐driven assembly. Replacing acetate ligands on the {SiW10Cr2(OAc)2} clusters with 5‐hydroxyisophthalates allows these 95° inorganic building blocks to be linked into bowl‐shaped, hybrid “calix[n]arenes” (n=3, 4). With a large concave cavity, the metal–organic calix[4]arene can accommodate nanometer‐sized polyoxoanions in an entropically driven process. The development of hybrid variants of calixarenes is expected to expand the scope of their physicochemical properties, guest/substrate binding, and applications on multiple fronts. Organic–inorganic hybrid calix[n]arenes (n=3, 4) can be rationally constructed from the coordination‐driven assembly of polyoxometalate building blocks and dicarboxylate linkers with bite angles of 95° and 120°, respectively. With bowl‐shaped, hydrophobic cavities similar to those of organic calixarenes, these molecular containers can host nanometer‐sized Keggin and Dawson anions.