3D Covalent Organic Framework with “the” Topology

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 20; no. 20; pp. e2307666 - n/a
• Main Authors: Das, Saikat, Mabuchi, Haruna, Irie, Tsukasa, Sasaki, Kohki, Nozaki, Mika, Tomioka, Rina, Wen, Dan, Zhao, Yu, Ben, Teng, Negishi, Yuichi
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.05.2024
• Subjects: Covalence; covalent organic framework; Degree of crystallinity; Density functional theory; Dipoles; Iodine; iodine capture; radioactive waste; Recyclability; reticular design; Structural design; Structural integrity; Symmetry; the net topology; Topology; the net topology; iodine capture; radioactive waste; covalent organic framework; reticular design
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202307666

Discovery of new topology covalent organic frameworks (COFs) is a mainstay in reticular chemistry and materials research because it not only serves as a stepwise guide to the designed construction of covalent‐organic architectures but also helps to comprehend function from structural design point‐of‐view. Proceeding on this track, the first 3D COF, TUS‐38, with the topology is constructed by reticulating a planar triangular 3‐c node of D3h symmetry with a tetragonal prism 8‐c node of D2h symmetry via [3 + 8] reversible imine condensation reaction. TUS‐38 represents a twofold interpenetrated multidirectional pore network with a high degree of crystallinity and structural integrity. Interestingly, stemming from the nitrogen‐rich s‐triazine rings with electron‐deficient character and ─C ═ N─ linkages composing the TUS‐38 framework that benefit to the charge–transfer and hence dipole–dipole electrostatic interactions between the framework and iodine in addition to exclusive topological characteristics of the exotic the net, TUS‐38 achieves an exemplary capacity for iodine vapor uptake reaching 6.3 g g−1. Recyclability studies evidence that TUS‐38 can be reused at least five times retaining 95% of its initial adsorption capacity; while density functional theory (DFT) calculations have heightened the understanding of the interactions between iodine molecules and the framework. The first‐ever COF featuring an unprecedented 3,8‐connected “the” net topology, TUS‐38, is crystallized with Im‐3 space group by linking a planar triangular 3‐c building block of D3h symmetry with a tetragonal prism 8‐c building block of D2h symmetry following reversible imine bonding.