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Polymorphism control of metal‐organic frameworks is highly desired for elucidating structure‐property relationships, but remains an empirical process and is usually done in a trial‐and‐error approach. We adopted the rarely used actinide cation Th4+ and a ditopic linker to construct a series of thorium‐organic frameworks (TOFs) with a range of polymorphs. The extraordinary coordination versatility of Th4+ cations and clusters, coupled with synthetic modulation, gives five distinct phases, wherein the highest degree of interpenetration (threefold) and porosity (75.9 %) of TOFs have been achieved. Notably, the O atom on the capping site of the nine‐coordinated Th4+ cation can function as a bridging unit to interconnect neighboring secondary building units (SBUs), affording topologies that are undocumented for other tetravalent‐metal‐containing MOFs. Furthermore, for the first time HCOOH has been demonstrated as a bridging unit of SBUs to further induce structural complexity. The resulting TOFs exhibit considerably different adsorption behaviors toward organic dyes, thus suggesting that TOFs represent an exceptional and promising platform for structure‐property relationship study. [ABSTRACT FROM AUTHOR]

Effective capture of radioactive iodine is of paramount importance for the safe and long‐term storage of fission products in the nuclear fuel cycle. Herein, a series of functionalized Th‐UiO‐66 MOFs was employed as a model to investigate the effects of substituents on iodine adsorption in both solution and vapor states. Sorption studies revealed that the electro‐donating amino group exhibits the most positive role on increasing the removal rate of iodine from cyclohexane and the uptake capacity of iodine vapor. Particularly, the disubstituted Th‐UiO‐66‐(NH2)2 can effectively remove 91.9 % of iodine (300 mg L−1) from cyclohexane and capture 969 mg g−1 iodine vapor, significantly higher than 59.6 % and 334 mg g−1 of untagged Th‐UiO‐66, respectively. In addition, the substituent effect on the radiolytic stability of MOFs was for the first time investigated, leading to the unearthing of one of the most radioresistant MOFs Th‐UiO‐66‐NH2 reported to date. [ABSTRACT FROM AUTHOR]

Keywords: metal coordination; metal-organic frameworks; modulator; polymorphism; thorium EN metal coordination metal-organic frameworks modulator polymorphism thorium 17504 17504 1 12/22/21 20211215 NES 211215 B The extraordinary coordination versatility b of the Th SP 4+ sp cation and the unexpected bridging role of formate allows polymorphism control of thorium-organic frameworks (TOFs) with five distinct phases, wherein the highest degree of porosity and interpenetration for TOFs have been achieved. Front Cover: Unveiling the Unique Roles of Metal Coordination and Modulator in the Polymorphism Control of Metal-Organic Frameworks (Chem. Eur. J. 70/2021) Metal coordination, metal-organic frameworks, modulator, polymorphism, thorium. [Extracted from the article]

Cover Feature: Boosting the Iodine Adsorption and Radioresistance of Th-UiO-66 MOFs via Aromatic Substitution (Chem. Eur. J. 4/2021) Keywords: iodine; metal-organic frameworks; radioresistance; substituent effects; thorium EN iodine metal-organic frameworks radioresistance substituent effects thorium 1162 1162 1 01/20/21 20210118 NES 210118 B Effective capture of radioactive iodine b is of paramount importance for the safe and long-term storage of fission products in the nuclear fuel cycle. Iodine, metal-organic frameworks, radioresistance, substituent effects, thorium. [Extracted from the article]