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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.

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.)

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 ([UO 2 ] 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(sp 3 )-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., (© 2020 Wiley-VCH GmbH.)

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.)

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., (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

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)-4H-1,2,4-triazol-4-amines. The procedure occurs by cleavage of the N-N bond in the N-(alkylidene)-4H-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., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

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., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)