Structural Complexity and Magnetic Orderings in a Large Family of 3d-4f Heterobimetallic Sulfates.

The synthesis of a large family of heterobimetallic lanthanide copper sulfates was realized via stoichiometric hydrothermal reactions among LnO, CuO, and HSO, giving rise to four distinct phases, namely LnCu(SO)(OH) (Ln = Sm-Ho) (), LnCu(SO)(OH) (Ln = Tm-Lu) (), LnCu(SO)(OH) (Ln = Nd-Gd, except Pm) (), and LnCu(SO)(OH) (Ln = Dy-Lu) (), with completely different topologies. The passage from and to and across the 4f series, respectively, can be ascribed to the effect of lanthanide contraction, which progressively induces shrinking of the Ln-O distance, reduction in the Ln coordination number, and eventually structural transitions. The incorporation of identical 3d-4f metal ions into different spin-lattices, in conjunction with substitution of diverse Ln cations within the same spin-lattice, gives rise to tunable magnetic properties varying from ferromagnetic ordering in and to antiferromagnetic ordering in , and to paramagnetic correlations found in and .

Employing Lewis Acidity to Generate Bimetallic Lanthanide Complexes.

With the advent of lanthanide-based technologies, there is a clear need to advance the fundamental understanding of 4f-element chelation chemistry. Herein, we contribute to a growing body of lanthanide chelation chemistry and report the synthesis of bimetallic 4f-element complexes within an imine/hemiacetalate framework, [Ln = lanthanide; TPT = tris(pyridineimine)(Tren)tris(methoxyhemiacetalate); Tren = tris(2-aminoethylamine)]. These products are generated from hydrolysis and methanolysis of the cage ligand tris(pyridinediimine)bis(Tren) (; Tadanobu et al.

Trivalent f-Element Squarates, Squarate-Oxalates, and Cationic Materials, and the Determination of the Nine-Coordinate Ionic Radius of Cf(III).

The synthesis, structure, and solid-state UV-vis-NIR spectroscopy of four new f-element squarates, M(CO)(HO) (M = Eu, Am, Cf) and Sm(CO)(COOH)(HO)·0.5HO, four new cationic lanthanide squarate chlorides, [M(CO)(HO)]Cl·5HO (M = Eu, Dy, Ho Er), and two new actinide squarate oxalates, M(CO)(CO)(HO) (M = Am, Cf), are presented. All of the metal centers are trivalent.

Electron Beam Irradiation as a General Approach for the Rapid Synthesis of Covalent Organic Frameworks under Ambient Conditions.

Crystalline porous materials such as covalent organic frameworks (COFs) are advanced materials to tackle challenges of catalysis and separation in industrial processes. Their synthetic routes often require elevated temperatures, closed systems with high pressure, and long reaction times, hampering their industrial applications. Here we use a traditionally unperceived strategy to assemble highly crystalline COFs by electron beam irradiation with controlled received dosage, contrasting sharply with the previous observation that radiation damages the crystallinity of solids.

Evidence of Alpha Radiolysis in the Formation of a Californium Nitrate Complex.

Well-characterized complexes of transplutonium elements are scarce because of the experimental challenges of working with these elements and the rarity of the isotopes. This leads to a lack of structural and spectroscopic data needed to understand the nature of chemical bonds in these compounds. In this work, the synthesis of Cf(DOPO ) (NO )(py) (DOPO =2,4,6,8-tetra-tert-butyl-1-oxo-1H-phenoxazin-9-olate; py=pyridine) is reported, in which the nitrate anion is hypothesized to form through the α-radiolysis-induced reaction of pyridine and/or the ligand.

Examination of Molten Salt Reactor Relevant Elements Using Hydrothermal Synthesis.

The structural chemistry of elements relevant to the FLiBe molten salt reactor, Th, U, Np, and Zr, including Ce and Nd (as analogues for Pu and Am, respectively), have been examined using hydrothermal synthesis at 200 °C. These reactions serve to model the reaction of molten salts under hydrolysis conditions. The results show that U and Np formed , while Ce formed .

Gas-Phase Complexes of Americium and Lanthanides with a Bis-triazinyl Pyridine: Reactivity and Bonding of Archetypes for F-Element Separations.

Bis-triazinyl pyridines (BTPs) exhibit solution selectivity for trivalent americium over lanthanides (Ln), the origins of which remain uncertain. Here, electrospray ionization was used to generate gas-phase complexes [ML], where M = La, Lu, or Am and L is EtBTP 2,6-bis(5,6-diethyl-1,2,4-triazin-3-yl)-pyridine. Collision-induced dissociation (CID) of [ML] in the presence of HO yielded a protonated ligand [L(H)] and hydroxide [ML(OH)] or hydrate [ML(L-H)(HO)], where (L-H) is a deprotonated ligand.

Structural and Spectroscopic Investigation of Two Plutonium Mellitates.

The aqueous reaction of mellitic acid (Hmell) with PuBr·HO forms two plutonium mellitates, Pu(mell)(HO)·HO () and Pu(mell)(HO)·2HO (). These compounds are compared to the isomorphous lanthanide mellitates with similar ionic radii via bond length analysis. Both plutonium compounds form three-dimensional metal-organic frameworks, with having two unique metal centers and having one.

Probing a variation of the inverse-trans-influence in americium and lanthanide tribromide tris(tricyclohexylphosphine oxide) complexes.

The synthesis, characterization, and theoretical analysis of meridional americium tribromide tris(tricyclohexylphosphine oxide), , has been achieved and is compared with its early lanthanide (La to Nd) analogs. The data show that homo ligands display significantly shorter bonds than the or hetero ligands. This is particularly pronounced in the americium compound.

Structure, Spectroscopy, and Theoretical Analysis of Zero- and Three-Dimensional Lithium Plutonium Fluorides: LiPuF and LiPuF.

The reaction of PuO with HF and LiF under hydrothermal conditions results in the formation of LiPuF and LiPuF. These compounds were structurally characterized using single-crystal X-ray diffraction, and UV-vis-near-IR absorption spectroscopy was employed to confirm the oxidation state of the plutonium in the compounds as 4+. The structure of LiPuF consists of [PuF] anions that adopt a bicapped trigonal-prismatic geometry with approximate symmetry.

[LnO] Cluster-Encapsulating Polyplumbites as New Polyoxometalate Members and Record Inorganic Anion-Exchange Materials for ReO Sequestration.

Various types of polyoxometalates (POMs) have been synthesized since the 19th century, but their assortment has been mostly limited to Groups 5 and 6 metals. Herein, a new family of POMs composed of a carbon group element as the addenda atoms with two distinct phases, (Ln = Sm to Ho, Y) and (Ln = Er and Tm) is reported. Both structures are built from [LnO] rare-earth metal hexamers being incorporated in [PbO]/[PbO] polyplumbites, and unbound perchlorates as charge-balancing anions.

Origins of the odd optical observables in plutonium and americium tungstates.

A series of trivalent f-block tungstates, MWO(OH)(HO) (M = La, Ce, Pr, Nd, and Pu) and AmWO(OH), have been prepared in crystalline form using hydrothermal methods. Both structure types take the form of 3D networks where MWO(OH)(HO) is assembled from infinite chains of distorted tungstate octahedra linked by isolated MO bicapped trigonal prisms; whereas AmWO(OH) is constructed from edge-sharing AmO square antiprisms connected by distorted tungstate trigonal bipyramids. PuWO(OH)(HO) crystallizes as red plates; an atypical color for a Pu(iii) compound.

Electrochemical Studies of Selected Lanthanide and Californium Cryptates.

Efforts to quantitatively reduce Cf → Cf in solution as well as studies of its cyclic voltammetry have been hindered by its scarcity, significant challenges associated with manipulating an unusually intense γ emitter, small reaction scales, the need for nonaqueous solvents, and its radiolytic effects on ligands and solvents. In an effort to overcome these impediments, we report on the stabilization of Cf by encapsulation in 2.2.

[Am(C Me H) ]: An Organometallic Americium Complex.

We report the small-scale synthesis, isolated yield, single-crystal X-ray structure, H NMR solution spectroscopy /solid-state UV/Vis-nIR spectroscopy, and density functional theory (DFT)/ab initio wave function theory calculations on an Am organometallic complex, [Am(C Me H) ] (1). This constitutes the first quantitative data on Am-C bonding in a molecular species.

Synthesis, Spectroscopy, and Theoretical Details of Uranyl Schiff-Base Coordination Complexes.

Two uranyl Schiff-base coordination complexes, and {L = ,'-bis[(4,4'-diethylamino)salicylidene]-1,2-phenylenediamine}, have been synthesized that feature a rigid phenyl backbone. These complexes have been characterized by structural, spectroscopic, and theoretical analysis to offer an electronic structure basis to explain the bonding parameters and stability. Single-crystal X-ray analysis reveals that adopts the typical "soft taco confirmation" characteristic of uranyl salophen complexes, whereas features an unusual neutral ligand coordination that contains an internal hydrogen bond between the phenol and imine.

Contemporary Chemistry of Berkelium and Californium.

The merging of small-scale syntheses and rapid crystallization methods have provided access to crystalline samples of berkelium (Z=97) and californium (Z=98) coordination complexes and compounds that can be interrogated with a suite of spectroscopic tools and structural elucidation approaches that have come online over the last 20 years. The combination of this experimental data with relativistic theoretical methods that capture the effects of spin-orbit coupling and scalar relativistic effects have allowed us to understand the electronic structure of berkelium and californium compounds at a level of detail that was not previously possible. The harbinger of this new era of post-curium chemistry was the synthesis and characterization of [Cf{B O (OH) }].

Redetermination of the crystal structure of tetra-lithium octa-fluorido-zirconate(IV), LiZrF, from single-crystal X-ray data.

Presented herein is the crystal-structure redetermination of LiZrF from single-crystal X-ray data. Alkali zirconium fluorides are important in nuclear-relevant technologies, and zirconium is commonly employed as an analogue for tetra-valent -block elements. The previous structure report of this species is based on powder X-ray data [Dugat (1995 ▸).

Molecular and Electronic Structure, and Hydrolytic Reactivity of a Samarium(II) Crown Ether Complex.

The reaction of SmI with dibenzo-30-crown-10 (DB30C10), followed by metathesis with [BuN][BPh], allows for the isolation of [Sm(DB30C10)][BPh] as bright-red crystals in good yield. Exposure of [Sm(DB30C10)] to solvents containing trace water results in the conversion to the dinuclear Sm complex, Sm(DB30C10)(OH)I. Structural analysis of both complexes shows substantial rearrangement of the crown ether from a folded, Pac-Man form with Sm to a twisted conformation with Sm.

Tailored Perovskite Waste Forms for Plutonium Trapping.

Perovskite ceramics have been extensively studied as host matrixes for radionuclide entrapment for nuclear waste disposal. As an expansion of these investigations, cerium, neodymium, and plutonium were incorporated into a perovskite phase, ACuFeTiO (A = Nd, Ce, Pu), using sol-gel methods under oxidizing and reducing atmospheres. The targeted materials contained varying levels of Ce and Nd on the A site, yielding potential compositions of NdCe CuFeTiO ( x = 0, 0.

Soft-donor dipicolinamide derivatives for selective actinide(iii)/lanthanide(iii) separation: the role of S- vs. O-donor sites.

Selectivity for An(iii) vs. Ln(iii) binding and extraction using dipicolinamide analogs containing the C[double bond, length as m-dash]O vs. C[double bond, length as m-dash]S groups was investigated in solution and the gas-phase, and by DFT calculations.

Origin of Selectivity of a Triazinyl Ligand for Americium(III) over Neodymium(III).

[M(EtBTP) ][BPh ] ⋅3 CH CN (M=Nd, Am; EtBTP=2,6-bis(5,6-diethyl-1,2,4-triazin-3-yl)pyridine) have been synthesized from reactions of MCl ⋅n H O with EtBTP in acetonitrile followed by anion metathesis. Structural analysis reveals that these compounds contain M cations bound by tridentate EtBTP ligands to create a tricapped trigonal prismatic geometry around the metal centers. Collection of high-resolution, single-crystal X-ray diffraction data also allowed reduction in bond lengths esd's, such that a slight contraction of Δ=0.

Synthesis and Characterization of Tris-chelate Complexes for Understanding f-Orbital Bonding in Later Actinides.

An isostructural family of f-element compounds (Ce, Nd, Sm, Gd; Am, Bk, Cf) of the redox-active dioxophenoxazine ligand (DOPO; DOPO = 2,4,6,8-tetra- tert-butyl-1-oxo-1 H-phenoxazin-9-olate) was prepared. This family, of the form M(DOPO), represents the first nonaqueous isostructural series, including the later actinides berkelium and californium. The lanthanide derivatives were fully characterized using H NMR spectroscopy and SQUID magnetometry, while all species were structurally characterized by X-ray crystallography and electronic absorption spectroscopy.

Electronic, Magnetic, and Theoretical Characterization of (NH)UF, a Simple Molecular Uranium(IV) Fluoride.

The simple system of tetraammonium octafluorouranate is employed to derive a fundamental understanding of the uranium-fluorine interaction. The structure is composed of isolated molecules, enabling a detailed examination of the U ( f) ion. Characterization of single-crystals by X-ray diffraction, absorption spectroscopy, and magnetic analysis up to 45 T is combined with extensive theoretical treatment by CASSCF.