Anisotropic flexibility and rigidification in a TPE-based Zr-MOFs with scu topology

• Published in: Nature communications 2023-09, Vol.14 (1), p.5347-5347, Article 5347
• Main Authors: Meng, Sha-Sha, Xu, Ming, Guan, Hanxi, Chen, Cailing, Cai, Peiyu, Dong, Bo, Tan, Wen-Shu, Gu, Yu-Hao, Tang, Wen-Qi, Xie, Lan-Gui, Yuan, Shuai, Han, Yu, Kong, Xueqian, Gu, Zhi-Yuan
• Format: Article
• Language: English
• Subjects: 140/131; 147/143; 639/301/357/404; 639/638/263/915; 639/638/298/921; Anisotropy; Dicarboxylic acids; Directional control; Flexibility; Humanities and Social Sciences; Ligands; Metal-organic frameworks; Motion stability; multidisciplinary; NMR; Nuclear magnetic resonance; Porosity; Science; Science (multidisciplinary); Separation; Topology; Zirconium
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-41055-6

Tetraphenylethylene (TPE)-based ligands are appealing for constructing metal-organic frameworks (MOFs) with new functions and responsiveness. Here, we report a non-interpenetrated TPE-based scu Zr-MOF with anisotropic flexibility, that is, Zr-TCPE (H 4 TCPE = 1,1,2,2-tetra(4-carboxylphenyl)ethylene), remaining two anisotropic pockets. The framework flexibility is further anisotropically rigidified by installing linkers individually at specific pockets. By individually installing dicarboxylic acid L 1 or L 2 at pocket A or B, the framework flexibility along the b -axis or c -axis is rigidified, and the intermolecular or intramolecular motions of organic ligands are restricted, respectively. Synergistically, with dual linker installation, the flexibility is completely rigidified with the restriction of ligand motion, resulting in MOFs with enhanced stability and improved separation ability. Furthermore, in situ observation of the flipping of the phenyl ring and its rigidification process is made by 2 H solid-state NMR. The anisotropic rigidification of flexibility in scu Zr-MOFs guides the directional control of ligand motion for designing stimuli-responsive emitting or efficient separation materials. Metal-organic frameworks (MOFs) with adjustable porosity and tunable functionality have attracted considerable attention, but the directional control of intermolecular and intramolecular motion of TPE-based ligands in the non-interpenetrated flexible MOFs has not yet been studied. Here, the authors report a non-interpenetrated tetraphenylethylene-based MOF with anisotropic flexibility.