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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-Uand 1-Th, in which U(IV) and Th(IV) are supported by the tetradentate pyridine-decorated dianionic ligand N2NN′ (1,1,1-trimethyl-N-(2-(((pyridin-2-ylmethyl)(2-((trimethylsilyl)amino)benzyl)amino)methyl)phenyl)silanamine). Although 1-Uand 1-Thare structurally very similar, they display disparate reactivities with TMS3SiK (tris(trimethylsilyl)silylpotassium). The reaction of (N2NN′)UCl2(1-U) and 1 equiv of TMS3SiK in THF unexpectedly formed [Cl(N2NN′)U]2O (2-U) featuring an unusual bent U–O–U moiety. In contrast, a salt elimination reaction between (N2NN′)ThCl2(1-Th) and 1 equiv of TMS3SiK led to thorium complex 2-Th, in which the pyridyl group has undergone a 1,4-addition nucleophilic attack. Complex 2-Thserves as a synthon for preparing dimetallic bis-azide complex 3-Thby reaction with NaN3. The complexes were characterized by X-ray crystal diffraction, solution NMR, FT-IR, and elemental analysis. Computations of the formation mechanism of 2-Ufrom 1-Usuggest 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-Thversus 1-U. Given that reactants 1-Uand 1-Thand products 2-Uand 2-Thall comprise tetravalent actinides, this is an unusual case of very disparate reactivity despite no net change in the oxidation state. Complexes 2-Uand 3-Thprovide a basis for the synthesis of other dinuclear actinide complexes with novel reactivity and properties.

Actinide metallacycles are an emerging class of functional coordination assemblies, but multi-level assembly from metallacycle units toward hierarchical supramolecular structures are still rarely investigated. In this work, we put forward a novel supramolecular inclusion-based method through introducing two macrocyclic hosts, cucurbit[7]uril (CB[7]) and cucurbit[8]uril (CB[8]) to facilitate hierarchical assembly of uranyl metallacycles with higher complexity, and successfully prepare two different kinds of uranyl metallacycle-based complexes with intriguing hierarchical structures, a CB[7]-based four-member molecular necklace ([4]MN) and a CB[8]-involved ring-in-ring supramolecular polymer chain. The results obtained here prove the feasibility of supramolecular inclusion for regulating coordination assembly of uranyl metallacycles and related hierarchical structures. It is believed that this method can be used to achieve the construction of actinide coordination assemblies with higher structural complexity.

Herein we present a new metalloligand, Th6L12[IHEP-10; L = 4-pyrazolecarboxylic acid (H2PyC)], which can be used to generate a novel multicomponent heterometallic metal–organic framework (MOF), [[Cu3(μ3-OH)(NO3)(H2O)2]2Th6(μ3-O)4(μ3-OH)4(PyC)6(HPyC)6(H2O)6](NO3)2(IHEP-11), through further assembly with second [Cu3(μ3-OH)(PyC)3] clusters. In IHEP-11, six Cu3clusters are connected by six NO3–anions to form an unprecedented annular Cu18cluster, which can be viewed as a 12-connected node to link with 12 Th6clusters, resulting a 4,12-connected shp net. Benefiting from the cationic framework and 3D porous structure, IHEP-11 can efficiently remove ReO4–(an analogue of radioactive 99TcO4–) 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.

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 Ti3C2TxMXene surface by diazonium salt grafting. The introduction of amidoxime functional groups significantly enhances the selectivity of Ti3C2Txnanosheets 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 Ti3C2Txnanosheets 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.

An environmentally benign Biginelli reaction for the large-scale preparation of substituted 3,4- dihydropyrimidin-2(1H)-ones using protic acids as a catalyst has been achieved. These mechanochemical reactions proceed efficiently in the absence of organic solvent, with the assistance of infrared lamp irradiation.

The diastereospecific formation of dihydropyrimidines DHPMs has been achieved in moderate to high yields with up to 99% eeby a Biginelli reaction. The reaction was performed by using a combined catalyst consisting of a chiral bifunctional primary aminethiourea 9fand a Brønsted acid with tertbutylammonium trifluoroacetate tBuNH2⋅TFA as additive in dichloromethane at room temperature. The possible mechanism for the reaction has been proposed to explain the origin of the activation and the asymmetric induction.

The diastereospecific formationof β‐N‐glycoside‐linked α‐amino phosphonic acid derivatives has been achieved in high yield by a Mannich‐type reaction. The reaction was performed by using O‐pivaloylated galactosylamine as a chiral template and SnCl4as a promoter in THF (see scheme).

A wide range of stereoselective novel functionalized tertiary α‐hydroxy phosphonates are obtained in high yields with good to excellent diastereoselectivities.

An environmentally benign Biginelli reaction using aqueous HCl as catalyst is reported.

Asymmetric Biginelli reaction of β‐ketoester (I) with urea (II) and a range of aromatic aldehydes (III) is efficiently catalyzed by a catalyst system consisting of bifunctional glucose‐derived amine—thiourea (BPAT), tBuNH2·TFA and triflic acid.

A new and efficient asymmetric access to a number of γ‐butenolide derivatives is presented.

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