Rational Design and Synthesis of Hexanuclear Rare Earth <b>the</b>-<b>a</b> Metal–Organic Frameworks Platform Based on RE₆O₄(OH)₄(COO)₈ Clusters

A series of hexanuclear RE­(III) metal–organic frameworks, UPC-68, with the-a topology, have been successfully designed and synthesized by topology guidance (RE = rare earths). It is worth mentioning that the synthetic RE­(III)-MOFs are constructed by a stable D4h 8-connected RE6 cluster, which is reported first, and a D3h 3-connected ligand (H3CTTA). The results indicate that UPC-68-Tb shows the characteristic recognition of 4-nitroaniline (4-NA), 2-nitroaniline (2-NA), and 4-nitrophenol (4-NP), and iodine adsorption capacity