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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]

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 direct 1,6-addition route of p-QMs to diarylmethanes was catalyzed by uranyl ion. • Abundant, and sequestrable depleted uranium made the reaction more sustainable. • Moderate to high yields with broad scope and functional group tolerance. • Facile operation and mild conditions as a practical and attractive protocol. A direct 1,6-addition route of p -QMs to synthesize substituted diarylmethanes catalyzed by uranyl ion was developed. In our approach, the salient feature of this transformation is that abundant, underexploited, neglected and sequestrable depleted uranium made the reaction more sustainable. Moreover, diarylmethane derivatives were delivered in moderate to high yields with broad scope and functional group tolerance. Facile operation and mild conditions offer a practical and attractive protocol. [ABSTRACT FROM AUTHOR]

[Display omitted] • Phosphorylated TzDa-Phos fabricated for the U(VI) and Pu(IV) adsorption. • q m (U) at pH 4.0 and 3 M HNO 3 : 394 and 56 mg/g, respectively; K d (Pu): 9.7 × 103 mL/g. • Phosphonic group P–O− responsible for the coordination with U at pH 4.0. • Nonprotonated P O maintains the removal capacity for U and Pu from 3 M HNO 3. Uranium and plutonium are typical actinides tightly associated with nuclear fuel cycle. In this work we rationally design and fabricate a phosphonic group-decorated covalent organic framework, TzDa-Phos, for highly selective removal of uranium [U(VI)] and plutonium [Pu(IV)]. The saturation adsorption capacity for U(VI) can reach 394 mg/g at pH 4.0, and even maintains 40 mg/g in 1–4 M HNO 3 solutions. The distribution coefficient of Pu(IV) with TzDa-Phos is recorded up to 9.7 × 103 mL/g at 3 M HNO 3. The excellent adsorption performance of TzDa-Phos for U(VI) and Pu(IV) is reasonably attributed to phosphonic groups decorated in TzDa. Specifically, the strong complexation of P O with uranium nitrate species (e.g., UO 2 (NO 3)+, UO 2 (NO 3) 2 0) is indicated at high acidities, in contrary to the coordination of P-O− with uranium at pH 4.0 as evidenced by FT-IR, XPS and EXAFS analyses. This work provides a promising adsorbent to recover uranium and plutonium from various wastewaters via a solid-phase extraction approach. [ABSTRACT FROM AUTHOR]