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Wang et al. report here an ultra-robust imidazolium-decorated covalent organic framework (COF) conjugate fabricated by an ionizing radiation strategy for efficient capture of 99TcO4−, where tunable ReO4− uptake up to 952 mg g−1 can be achieved by simply adjusting the γ-ray dose. The COFs feature high porosity, ultra-robust nanofiber structure, and fast adsorption kinetics, thus emphasizing their advantages in terms of column experiments.

Despite that two-dimensional transition metal carbides and carbonitrides (MXenes) are burgeoning candidates for remediation of environmental pollutants, the construction of robust functionalized MXene nanosheets with a high affinity for target heavy metal ions and radionuclides remains a challenge. Here we report the successful placement of amidoxime chelating groups on Ti3C2Tx MXene surface by diazonium salt grafting. The introduction of amidoxime functional groups significantly enhances the selectivity of Ti3C2Tx nanosheets for uranyl ions and also greatly improves their stability in aqueous solution, enabling efficient, rapid, and recyclable uranium extraction from aqueous solutions containing competitive metal ions. Benefiting from the excellent conductivity of MXenes, the amidoxime functionalized Ti3C2Tx nanosheets show outstanding electrochemical performance such that when loaded on carbon cloth the application of an electric field increases the uranium adsorption capacity from 294 to 626 mg/g, outperforming all organic electrochemical sorption materials reported previously. The present work provides an effective strategy to functionalize MXene nanosheets with fundamental implications for the design of MXene-based selective electrosorption electrode materials.

Two five‐coordinate mononuclear DyIII single‐molecule magnets [(TrapenTMS)Dy(L)] (Trapen=tris(2‐aminobenzyl) amine; TMS=SiMe3; L=OPMe31, OPEt32) have been synthesized by the reaction of [(TrapenTMS)Dy(THF)] and OPMe3, OPEt3, respectively. The molecular structures of 1 and 2 were fully established by single crystal X‐ray diffraction. The centre DyIII ions of both complexes exhibit distorted triangular bipyramid geometries, varying with different neutral ligands L on the apex. The TrapenTMS ligand forms the pyramid base of the trigonal bipyramid. Subtle structural modifications of the axial O‐ligand terminal substituent result in different dynamic magnetic behaviors. Magnetic data analysis reveals that 1 and 2 exhibit the characteristic behavior of SMM without a dc field, accompanying an unambiguous quantum tunneling of the magnetization. Field‐induced slow magnetic relaxation was observed for 1 and 2 under an applied bias dc field of 1000 Oe, the relaxation energy barriers are 107 K and 88 K for 1 and 2, respectively. We have investigated the differences in magnetism and magnetic anisotropy between the two complexes by ab initio calculations. [ABSTRACT FROM AUTHOR]

A new family of low-coordinate mononuclear DyIII single-molecule magnets [(TrapenTMS)Dy(LB)] (Trapen = tris(2-aminobenzyl)amine; TMS = SiMe3; LB = THF 1, pyridine 2, ONMe33) has been synthesized and structurally characterized by single crystal X-ray diffraction. The five-coordinate DyIII ions exhibit distorted triangular bipyramidal geometries, among the different neutral ligands LB on the apex and the same TrapenTMS ligand, making the pyramid base of the trigonal bipyramid. Magnetic data analysis reveals that 1–3 are characteristic of SMM behaviors without a dc field, accompanying an unambiguous quantum tunneling of magnetization. Under an extra dc field of 500 Oe, field-induced slow magnetic relaxation behaviors occur with Raman and/or QTM processes. Ab initio calculations were also performed to rationalize the observed discrepancy in the magnetic behaviors, and the result illustrates that the SMM behavior could be effectively manipulated by the axial symmetry of the triangular bipyramidal DyIII motifs. [ABSTRACT FROM AUTHOR]

A synergistic strategy for enhancing U(VI) capture under highly acidic conditions (2 M HNO3) by radiation resistant phosphonate-functionalized two-dimensional covalent organic frameworks with tailor-made binding sites bearing a strong affinity was described. The combination of the radiation resistant characteristic with a strong acid-resistant property endows COFs with practical capabilities for actinide capture from real radioactive liquid waste. [ABSTRACT FROM AUTHOR]

A practical and scalable protocol for visible‐light‐accelerated arylation and alkylation of quinoxalin‐2(1H)‐ones with hydrazines is reported. In this protocol, a hydrazone‐based two‐dimensional covalent organic frameworks (2D‐COF‐1) was employed as the heterogeneous photocatalyst (PC). Due to its excellent photocatalytic properties, good chemical stability and heterogeneous nature, the present method exhibits high efficiency, good functional group tolerance, easy scalability and remarkable catalyst reusability. More importantly, it provides an alternative way that allows rapid access to various C3 arylated or alkylated quinoxalin‐2(1H)‐ones in a greener and sustainable manner. [ABSTRACT FROM AUTHOR]

Abstract: A copper/iron‐cocatalyzed fluoroalkylative cyclization of 1,6‐enynes with readily available iodoperfluoroalkanes reagents for the synthesis of the corresponding fluoroalkylated pyrrolidines and benzofuran derivatives is reported. This novel protocol provides a mild method for the construction of Csp3‐CF2 and exocyclic double bonds in one step with high regio‐ and stereo‐selectivities. [ABSTRACT FROM AUTHOR]

Abstract: Herein, we reported a novel method to synthesize α‐trifluoromethylated ketones from enol triflates. Involving a cascade sulfur dioxide extrusion and a CF3 (trifluoromethyl) radical addition process, this reaction proceeds at room temperature and is driven by visible light irradiation. This protocol bears good functional group compatibility, which can generate the desired products in good to excellent yields even in gram scale. It is hoped that this approach to generate CF3 radicals from enol triflates can be used in other radical‐involved reactions. [ABSTRACT FROM AUTHOR]

Benzimidazol-2-ones have various biological functions and are usually prepared by reactions of substituted benzene-1,2-diamines with carbonyl-containing compounds or intramolecular N-arylations using substrates with carbon-halogen bonds. However, the starting materials of these protocols are often not readily available. Herein, a simple and practical metal-free oxidative C-H amidation of N, N′-diarylureas has been developed that takes place at room temperature. This protocol uses readily available N, N′-diarylureas as the starting materials and inexpensive PhI(OAc)2 as the oxidant without the need of a catalyst, ligand, or the exclusion of air. The present method has a wide functional group tolerance and affords a new and practical strategy for the synthesis of N-heterocycles. [ABSTRACT FROM AUTHOR]

A transition metal-free method for the trifluoromethylation of N-allylamides has been developed, and the corresponding trifluoromethyl-containing oxazolines were prepared in moderate to good yields. The protocol uses readily available substituted N-allylamides as the starting materials, inexpensive and easily stored sodium trifluoromethanesulfinate as the trifluoromethyl source, iodobenzene diacetate as the oxidant, and the procedure involves sequential intermolecular trifluoromethylation of alkenes with sodium trifluoromethanesulfinate and intramolecular cyclization. This is the first example to prepare CF3-containing oxazolines. Therefore, the present method should afford an efficient and practical strategy for synthesis of other CF3-containing cyclic compounds. [ABSTRACT FROM AUTHOR]

Keywords: alkylation; arylation; covalent organic frameworks; quinoxalin-2(1H)-ones; visible-light-driven This protocol features high efficiency, good functional group tolerance, easy scalability and remarkable catalyst reusability. This protocol features high efficiency, good functional group tolerance, easy scalability and remarkable catalyst reusability. [Extracted from the article]

The article presents a diagram which shows the chemical structure of the metal-free oxidative C-H amidation of N,N'-diarylureas with PhI(OAc)2 and the synthesis of benzimidazol-2-one derivatives.