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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]

Main observation and conclusion: The issue of covalence of actinide complexes remains controversial to date. The introduction of 2‐phosphaethynolate anion into actinide complexes is expected to investigate the reaction mode and the bonding property. Herein, we describe the functionalization of An(TrenTIPS)Cl (1: An = U; 2: An = Th) precursors with NaOCP(dioxane)2.5 through salt‐elimination method leading to the formation of the corresponding uranium and thorium phosphaethynolate species: [U(TrenTIPS)(OCP)] (3) and [Th(TrenTIPS)(OCP)] (4). These two complexes were fully characterized by nuclear magnetic resonance (NMR), FT‐IR spectrum, UV‐vis‐NIR spectroscopies as well as X‐ray crystal diffraction. Computational analyses of the two complexes reveal that the U—O bond has a more covalent bond property than the Th—O bond due to more 5f orbital contribution for U. [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]

The development of the uranyl cation as a powerful photocatalyst is seriously delayed in comparison with the advances in its fundamental and structural chemistry. However, its characteristic high oxidative capability in the excited state ([UO2]2+* (+2.6 V vs. SHE; SHE=standard hydrogen electrode) combined with blue‐light absorption (hv=380–500 nm) and a long‐lived fluorescence lifetime up to microseconds have reveals that the uranyl cation approaches an ideal photocatalyst for visible‐light‐driven organic transformations. Described herein is the successful use of uranyl nitrate as a photocatalyst to enable C(sp3)−H activation and C−C bond formation through hydrogen atom transfer (HAT) under blue‐light irradiation. In particular, this operationally simple strategy provides an appropriate approach to the synthesis of diverse and valuable diarylmethane motifs. Mechanistic studies and DFT calculations have provided insights into the detailed mechanism of the photoinduced HAT pathway. This research suggests a general platform that could popularize promising uranyl photocatalytic performance. [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]

A visible-light-induced tandem radical addition–cyclization sequence via 2-aryl phenyl isocyanides as the starting material and two-dimensional covalent organic frameworks (2D-COFs) as the photocatalyst was developed, delivering multifarious 6-substituted phenanthridines in high yields. Benefitting from the utilization of a heterogeneous photocatalyst, this protocol features easy catalyst separation and excellent recyclability. A negligible loss of the catalytic activity was observed after multiple runs. High practicability of this protocol was further demonstrated by continuous flow experiments. [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]

A new type of axially chiral cyclo-[1,1′-biphenyl]-2,2′-diol (CYCNOL) ligands with adjustable dihedral angles have been developed by varying the bridge chain length. Eight-, nine- and ten-membered cyclo-ligands were prepared and evaluated by using two representative examples: enantioselective additions of diethylzinc to aldehydes and organometallic reagents to enones. The results revealed that the fine regulation of dihedral angles through variation of the bridge chain length was effective in the asymmetric synthesis. [ABSTRACT FROM AUTHOR]

A simple, efficient and practical iron-catalyzed azidoarylthiation of alkenes has been developed at room temperature, and the corresponding products containing ortho-sited sulfide and azide units were obtained in moderate to good yields with good tolerance of functional groups. The protocol uses readily available 1-(alkylthio)pyrrolidine-2,5-diones and trimethylsilyl azide as the alkylthiation and azidation reagents, respectively, inexpensive and environmentally friendly iron chloride as the catalyst without addition of any ligand and additive. [ABSTRACT FROM AUTHOR]

A simple and efficient catalyst-free method for isothiocyanatoalkylthiation of styrenes has been developed. The protocol uses (alkylthio)pyrrolidine-2,5-diones and trimethylsilyl isothiocyanate as the isothiocyanatoalkylthiolating reagents, dimethylformamide (DMF) as the solvent, and the reactions were completed within one hour with tolerance of some functional groups. No catalyst and additive were required in the reaction system, which avoided any contamination of transition metal catalysts in the target products. Therefore, the present method provides a convenient, efficient and practical strategy for the synthesis of compounds by a combination of sulfides and isothiocyanates. [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]

A novel, efficient, and practical method for the synthesis of imidazopyridine derivatives has been developed through the copper-catalyzed aerobic oxidative CH functionalization of substituted pyridines with N-(alkylidene)-4 H-1,2,4-triazol-4-amines. The procedure occurs by cleavage of the NN bond in the N-(alkylidene)-4 H-1,2,4-triazol-4-amines and activation of an aryl CH bond in the substituted pyridines. This is the first example of the preparation of imidazopyridine derivatives by using pyridines as the substrates by transition-metal-catalyzed CH functionalization. This method should provide a novel and efficient strategy for the synthesis of other nitrogen heterocycles. [ABSTRACT FROM AUTHOR]

Efficient copper-catalyzed aerobic oxidative CH and CC functionalization of 1-[2-(arylamino)aryl]ethanones leading to acridones has been developed. The procedure involves cleavage of aromatic CH and acetyl CC bonds with intramolecular formation of a diarylketone bond. The protocol uses inexpensive Cu(O2CCF3)2 as catalyst, pyridine as additive, and economical and environmentally friendly oxygen as the oxidant, and the corresponding acridones with various functional groups were obtained in moderate to good yields. [ABSTRACT FROM AUTHOR]

The asymmetric vinylogous Mukaiyama aldol reaction between α-keto phosphonate and 2-(trimethylsilyloxy)furan was performed by using bis(oxazoline)-copper complexes as the catalyst and 2,2,2-trifluoroethanol as additive in dichloromethane. The present method is highly tolerable for functionalized α-keto phosphonates and enabled us to obtain the corresponding 3- and 4-substituted benzyl-functionalized tertiary α-hydroxy phosphonates in high yields (up to 86%) as well as high enantiostereoselectivities (up to 98% ee) and diastereoselectivities (up to 99:1, anti-selective). [ABSTRACT FROM AUTHOR]

A novel and efficient visible-light photoredox method for the synthesis of internal alkynes containing quaternary carbons has been developed via coupling reactions of N-phthalimidoyl oxalates of tert-alcohols with 1-(2-(arylsulfonyl)ethynyl)benzenes. The reactions proceeded well at room temperature with good functional group tolerability. [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]

A graphical abstract of the article "Catalyst-Free Isothiocyanatoalkylthiation of Styrenes with (Alkylthio)pyrrolidine-2,5-diones and Trimethylsilyl Isothiocyanate" by H. Tian et al. is presented.

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.

A wide range of β-alkoxy sulfides are conveniently and efficiently obtained from alkenes using readily available 1-(arylthio)pyrrolidine-2,5-diones and alcohols as the oxysulfenylation reagents. [ABSTRACT FROM AUTHOR]

The title compounds are efficiently and simply obtained using readily available 1-(arylsulfanyl)pyrrolidine-2,5-diones as arylsulfanylating reagents and inexpensive boron trifluoride etherate as catalyst. [ABSTRACT FROM AUTHOR]

The article reports on Transition Metal-Free Trifluoromethylation of N-Allylamides with Sodium Trifluoromethanesulfinate.

The article presents chemical equations related to an article copper-catalyzed aerobic oxidative C-H functionalization of substituted pyridines by J. Yu and others published in a 2013 issue of the journal "Chemistry: A European Journal."

The new protocol uses an inexpensive catalyst and an economical and environmentally friendly oxidant. [ABSTRACT FROM AUTHOR]

The present method is suitable for functionalized α-keto phosphonates (II) and allows the synthesis of α-hydroxy phosphonates (III) bearing two chiral centers in high yields as well as high enantioselectivities. [ABSTRACT FROM AUTHOR]

Although synthesis, reactivity, and bonding of U(IV) and Th(IV) complexes have been extensively studied, direct comparison of fully analogous compounds is rare. Herein, we report corresponding complexes 1-U and 1-Th , in which U(IV) and Th(IV) are supported by the tetradentate pyridine-decorated dianionic ligand N 2 NN' (1,1,1-trimethyl- N -(2-(((pyridin-2-ylmethyl)(2-((trimethylsilyl)amino)benzyl)amino)methyl)phenyl)silanamine). Although 1-U and 1-Th are structurally very similar, they display disparate reactivities with TMS 3 SiK (tris(trimethylsilyl)silylpotassium). The reaction of (N 2 NN')UCl 2 ( 1-U ) and 1 equiv of TMS 3 SiK in THF unexpectedly formed [Cl(N 2 NN')U] 2 O ( 2-U ) featuring an unusual bent U-O-U moiety. In contrast, a salt elimination reaction between (N 2 NN')ThCl 2 ( 1-Th ) and 1 equiv of TMS 3 SiK led to thorium complex 2-Th , in which the pyridyl group has undergone a 1,4-addition nucleophilic attack. Complex 2-Th serves as a synthon for preparing dimetallic bis-azide complex 3-Th by reaction with NaN 3 . The complexes were characterized by X-ray crystal diffraction, solution NMR, FT-IR, and elemental analysis. Computations of the formation mechanism of 2-U from 1-U suggest reduced U(III) as a key intermediate for promoting the cleavage of the C-O bonds of THF. The inaccessible nature of Th(III) as an intermediate oxidation state explains the very different reactivity of 1-Th versus 1-U . Given that reactants 1-U and 1-Th and products 2-U and 2-Th all comprise tetravalent actinides, this is an unusual case of very disparate reactivity despite no net change in the oxidation state. Complexes 2-U and 3-Th provide a basis for the synthesis of other dinuclear actinide complexes with novel reactivity and properties.

A new family of low-coordinate mononuclear Dy III single-molecule magnets [(Trapen TMS )Dy(L B )] (Trapen = tris(2-aminobenzyl)amine; TMS = SiMe 3 ; L B = THF 1, pyridine 2, ONMe 3 3) has been synthesized and structurally characterized by single crystal X-ray diffraction. The five-coordinate Dy III ions exhibit distorted triangular bipyramidal geometries, among the different neutral ligands L B on the apex and the same Trapen TMS 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 Dy III motifs.

Herein we present a new metalloligand, Th 6 L 12 [IHEP-10; L = 4-pyrazolecarboxylic acid (H 2 PyC)], which can be used to generate a novel multicomponent heterometallic metal-organic framework (MOF), [[Cu 3 (μ 3 -OH)(NO 3 )(H 2 O) 2 ] 2 Th 6 (μ 3 -O) 4 (μ 3 -OH) 4 (PyC) 6 (HPyC) 6 (H 2 O) 6 ](NO 3 ) 2 (IHEP-11), through further assembly with second [Cu 3 (μ 3 -OH)(PyC) 3 ] clusters. In IHEP-11, six Cu 3 clusters are connected by six NO 3 - anions to form an unprecedented annular Cu 18 cluster, which can be viewed as a 12-connected node to link with 12 Th 6 clusters, resulting a 4,12-connected shp net. Benefiting from the cationic framework and 3D porous structure, IHEP-11 can efficiently remove ReO 4 - (an analogue of radioactive 99 TcO 4 - ) from aqueous solution in a wide pH range. This work highlights the feasibility of constructing multicomponent MOFs through a step-by-step synthesis strategy based on metalloligands.

In this paper, LaCoO 3 powders were prepared by the urea combustion method and used as electrode materials for supercapacitors. The effect of the potential window and the current density on the performance degradation of LaCoO 3 electrodes during the cycling test was analyzed. The degradation mechanism of LaCoO 3 -based symmetric supercapacitors was discussed. The results of the cycling test show that: with the increase in potential window and current density, the performance degradation in the cycling test becomes more intense. The results of cyclic voltammetry tests, galvanostatic charge-discharge tests, X-ray photoelectron spectroscopy tests and KOH electrolyte concentration measurements before and after the cycling test show that the degradation of the supercapacitors is mainly caused by the occurrence and accumulation of irreversible redox reactions during the charge and discharge process, which reduces the ratio of Co 2+ /Co 3+ and the number of oxygen vacancies., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (This journal is © The Royal Society of Chemistry.)

Invited for the cover of this issue is the group of Xiaobo Yang at the Shenyang Normal University. The image depicts the covalent organic frameworks photocatalyst (2D-COF-1) acting as a bridge between the substrate and product. Read the full text of the article at 10.1002/chem.201903523., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The diastereospecific formation of δ-hydroxyalkylbutenolide phosphonate has been achieved via a vinylogous Mukaiyama aldol reaction. The reaction was performed using α-ketophosphonate 1 and 2-(trimethylsilyloxy)furan 2 mediated by Cu(OTf)(2) and 2,2,2-trifluoroethanol as additive in CH(2)Cl(2). The reaction proceeds rapidly and affords the corresponding 5-(hydroxy(aryl)methyl) furan-2(5H)-one phosphonates 3 in high yields with good to excellent diastereoselectivities (d.r. up to >99 : 1). 5-(Hydroxy(alkyl)methyl)furan-2(5H)-one phosphonates could also be obtained with good diastereoselectivities.

An enantioselective Biginelli reaction has been developed by using a bifunctional primary amine-thiourea-TfOH (BPAT·TfOH) as a chiral phase-transfer catalyst and t-BuNH(2)·TFA as an additive in saturated brine at room temperature. The corresponding dihydropyrimidines were obtained in moderate-to-good yields with up to 99% ee under mild conditions. A plausible transition state has been proposed to explain the origin of the activation and the asymmetric induction.

The diastereospecific formation of β-N-glycoside-linked α-amino-2(5H)-furanone has been achieved with high yield via a vinylogous Mannich reaction. The reaction was performed by using O-pivaloylated galactosylamine 1 as a chiral template and ZnCl(2)·Et(2)O as a promoter in Et(2)O. Imines 3 of aromatic compounds and trimethylsiloxyfuran 4 were converted to N-galactosyl α-amino-2(5H)-furanone 5, giving ratios of diastereomers higher than 20:1. This procedure provides rapid access to biologically important γ-butenolide derivatives.