Structural Snapshots of Cluster Growth from {U6} to {U38} During the Hydrolysis of UCl4

Chatelain, Lucile; Faizova, Radmila; Fadaei‐Tirani, Farzaneh; Pécaut, Jacques; Mazzanti, Marinella

doi:10.1002/ange.201812509

Cited by 13 publications

(17 citation statements)

References 69 publications

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“…In one study, two thiolate capped Au 28 clusters exhibited ligand-induced reversible isomerization, which resulted in different efficacies in the catalytic oxidation of CO over a CeO 2 support . In addition to thiol groups, carboxylate-based capping groups can stabilize metallic clusters. − Recent work by Chatelain et al isolated a series of U 6 , U 10 , U 13 , U 16 , U 24 , and U 38 -oxo clusters, which suggested that the thermodynamically assisted condensation of isolated U 24 and U 6 clusters can access a large nuclearity U 38 motif …”

Section: Introductionmentioning

confidence: 99%

Supramolecular Porous Assemblies of Atomically Precise Catalytically Active Cerium-Based Clusters

et al. 2020

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Atomically precise metallic clusters offer total structural information lacking in metal oxide and nanoparticle catalysts. However, their use as heterogeneous catalysts requires accessible and robust catalytic sites, yet directing clusters into ordered and porous assemblies through functional control remains elusive. Herein, we report a supramolecular strategy to induce permanent porosity within assemblies of two cerium oxide clusters through the capping ligands used. Single-crystal X-ray crystallography and density functional theory calculations revealed cluster assemblies with accessible channels, while adsorption isotherms showed permanent porosity. The clusters exhibited a bulk modulus >5 GPa in variable pressure diffraction studies. X-ray photoelectron spectroscopy, electron paramagnetic resonance spectroscopy, and Raman spectroscopy demonstrated mixed valency (Ce3+/Ce4+) and oxygen vacancies in the clusters. We benchmarked catalytic activities through the photooxidation of 2-propanol.

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Section: Introductionmentioning

confidence: 99%

Supramolecular Porous Assemblies of Atomically Precise Catalytically Active Cerium-Based Clusters

et al. 2020

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“…On the basis of large isolatable clusters including U 38 − and Np 38 (in addition to numerous examples of hexamers, i.e., refs and – ), the polymerization of U IV and Np IV appear to be more similar to Pu IV than Th IV . Unlike Pu 38 , Np 38 and U 38 isolation required organic media that slow olation–oxolation reactions . In addition, neither the Np IV 2 nor U IV 2 dimer has been isolated, from either water or organic media.…”

Section: Introductionmentioning

confidence: 99%

“…Unlike Pu 38 , Np 38 and U 38 isolation required organic media that slow olation−oxolation reactions. 36 In addition, neither the Np IV 2 nor U IV 2 dimer has been isolated, from either water or organic media. In 1973, however, the dihydroxide-bridged U 2 dimer was proposed in X-ray scattering analysis of uranium(IV) perchlorate solutions.…”

Section: ■ Introductionmentioning

confidence: 99%

Bridging the Transuranics with Uranium(IV) Sulfate Aqueous Species and Solid Phases

2020

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Isolating isomorphic compounds of tetravalent actinides (i.e., Th IV , U IV , Np IV , and Pu IV ) improve our understanding of the bonding behavior across the series, in addition to their relationship with tetravalent transition metals (Zr and Hf) and lanthanides (Ce). Similarities between these tetravalent metals are particularly illuminated in their hydrolysis and condensation behavior in aqueous systems, leading to polynuclear clusters typified by the hexamer [M IV 6O4(OH)4] 12+ building block. Prior studies have shown the predominance and coexistence of smaller species for Th IV (monomers, dimers, and hexamers) and larger species for U IV , Np IV , and Pu IV (including 38-mers and 70-mers). We show here that aqueous uranium(IV) sulfate also displays behavior similar to that of Th IV (and Zr IV ) in its isolated solid-phase and solution speciation. Two single-crystal X-ray structures are described: a dihydroxide-bridged dimer (U2) formulated as U2(OH)2(SO4)3(H2O)4 and a monomer-linked hexamer framework (U-U6) as (U(H2O)3.5)2U6O4(OH)4(SO4)10(H2O)9. These structures are similar to those previously described for Th IV . Moreover, cocrystallization of monomer and dimer and of dimer and monomer-hexamer phases for both Th IV (prior) and U IV (current) indicates the coexistence of these species in solution. Because it was not possible to effectively study the sulfate-rich solutions via X-ray scattering from which U2 and U-U6 crystallized, we provide a parallel solution speciation study in low sulfate conditions, as a function of the pH. Raman spectroscopy, UV-vis spectroscopy, and small-angle X-ray scattering of these show decreasing sulfate binding, increased hydrolysis, increased species size, and increased complexity, with increasing pH. This study describes a bridge across the first half the actinide series, highlighting U IV similarities to Th IV , in addition to the previously known similarities to the transuranic elements.

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“…This is best evidenced in the number of ligand-decorated building units, ranging from mononuclear species to nanosized clusters . Despite the identification of a growing number of U(IV) structural units, the effects of ligand complexation on actinide speciation remain unclear; speciation is notably further complicated by solution conditions, which are likewise known to have a sizable impact on phase formation. ,, A survey of the literature shows that ligands broadly play one of three roles: (1) competing with and/or thwarting hydrolysis and condensation, (2) directing and/or modulating the formation of larger polynuclear clusters, and (3) enabling the isolation of unique structural units that are otherwise absent from descriptions of actinide structural chemistry. Moreover, previous work has indicated that there are distinct differences between coordinating ligands (i.e., carboxylates) and noncoordinating organic species, the latter for which supramolecular interactions such as π–π stacking and hydrogen bonding may have a notable impact on speciation. , …”

Section: Introductionmentioning

confidence: 99%

“…The goals of this work are to further examine the effects of hydrolysis and condensation, ligand complexation, and solution conditions on actinide phase formation through a systematic study of U(IV) complexation by aliphatic dicarboxylates. To date, most studies have focused on either small, monanionic ligand sets (i.e., formate, − acetate, and simple amino acids , ) or those with rigid, aromatic backbones (i.e, benzoates, , pyridinedicarboxylates, terephthalates, , and furoates). Moving away from these monoanionic and/or rigid, aromatic linkers, the coordination of aliphatic dicarboxylates with U(IV) was examined under room temperature conditions.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterization, and Solid-State Structural Chemistry of Uranium(IV) Aliphatic Dicarboxylates

Murray

Wacker

Bertke

et al. 2021

Crystal Growth & Design

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Examinations of uranium(IV) complexation by aliphatic dicarboxylates, ranging from the three-carbon malonate to the six-carbon adipate, yielded six novel phases. Single crystals of the compounds were prepared through either evaporation or solvent layering, and the structures were determined via single-crystal X-ray diffraction. The compounds were further characterized via IR and Raman spectroscopies. For the phases synthesized via solvent layering, correlations between the solution- and solid-state speciation were probed using UV–visible absorption spectroscopy. In the presence of malonate (MA), [U(MA)2(H2O)3] n (U-1a) was isolated. As the crystals were not suitable for structure determination, reactions of MA with thorium were pursued. These efforts yielded polymorphs, Th-1a and Th-1b; in both An-1a (An = Th, U) and Th-1b, the An(IV) metal centers are bridged via the MA ligands into 2D sheets. Upon increasing the length of the aliphatic backbone, monodentate and bridging bidentate binding modes are observed. Two distinct ligand-bridged extended networks that vary in metal ion nuclearity were observed for succinate (SA): [UCl2(SA)(H2O)2] n (U-2) and [U6O4(OH)4(SA)4(H2O)10]·4Cl·mH2O (U-3). Whereas U-2 consists of mononuclear U(IV) atoms that are bridged through the organic carboxylate into a 3D network, U-3 is built from hexanuclear U(IV)-hydroxo-oxo clusters that are further bridged into a 3D network. From glutarate (GA) ligand systems, two phases were isolated including [UCl2(HGA)2(H2O)2] n (U-4) that consists of ligand-bridged one-dimensional chains and [U2Cl6(HGA)2(H2O)2] n (U-5), which is built from chloride-bridged {U2Cl2} dimers that are further linked via GA into two-dimensional sheets. Finally, in the presence of adipate (AA), [U6O4(OH)4(AA)4(H2O)8]·4Cl·7(H2O) (U-6) is observed; the structure consists of hexameric [U6O4(OH)4]12+ clusters that are propagated into one-dimensional chains via the AA and uranium-bound water molecules that directly link adjacent clusters. Taken together, this work provides a systematic examination of the influence of the identity of the dicarboxylate backbones on actinide structural chemistry and highlights the role that the organic ligand plays in stabilizing unique tetravalent actinide structural units.

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Structural Snapshots of Cluster Growth from {U₆} to {U₃₈} During the Hydrolysis of UCl₄

Cited by 13 publications

References 69 publications

Supramolecular Porous Assemblies of Atomically Precise Catalytically Active Cerium-Based Clusters

Supramolecular Porous Assemblies of Atomically Precise Catalytically Active Cerium-Based Clusters

Bridging the Transuranics with Uranium(IV) Sulfate Aqueous Species and Solid Phases

Synthesis, Characterization, and Solid-State Structural Chemistry of Uranium(IV) Aliphatic Dicarboxylates

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