Co-reporter:Zhi-Hui Zhang, Ganna A. Senchyk, Yi Liu, Tyler Spano-Franco, Jennifer E. S. Szymanowski, and Peter C. Burns
Inorganic Chemistry November 6, 2017 Volume 56(Issue 21) pp:13249-13249
Publication Date(Web):October 17, 2017
DOI:10.1021/acs.inorgchem.7b02019
By varying solvent systems, the solvothermal treatment of uranyl nitrate and methylenediphosphonic acid (H4PCP) afforded three new porous uranyl-organic frameworks (UOFs). All were structurally characterized by single-crystal X-ray diffraction and formulated as (Et2NH2)2[(UO2)3(PCP)2](H2O)2.5 (1), (MeNH3)(H3O)[(UO2)3(PCP)2(H2O)3] (2), and [Na(H2O)4](H3O)[(UO2)3(PCP)2(H2O)2](H2O)5 (3). These compounds crystallize with three-dimensional anionic frameworks containing U(VI) and distinct cationic species due to in situ solvent hydrolysis. The solvent systems diethylformamide (DEF), N-methyl-2-pyrrolindone (NMP), and the additive sodium vanadate (Na3VO4) significantly impact the resultant structures, affording diethyl ammonium, methyl ammonium, and sodium cations captured in channels of the anionic frameworks of 1–3. In 1, a trinuclear U3O18 unit formed by three uranyl polyhedra that share edges is connected into a three-dimensional framework. Compound 2 has a three-dimensional framework formed from a uranyl-methylenediphosphonate layer that is pillared by UO7 pentagonal bipyramids. With the inclusion of sodium cations, 3 is a porous framework containing UO7 pentagonal bipyramids within a layer, with sodium cations and UO6 square bipyramids linking the adjacent layers. Compounds 1–3 feature the uranyl/ligand ratio of 3:2, but present diverse structural building units ranging from edge-shared trinuclear to heteronuclear assemblies. The compounds have been characterized by infrared (IR), Raman, and UV–vis spectroscopies, X-ray diffraction, and thermogravimetric analysis.
Co-reporter:Mateusz Dembowski, Christopher A. Colla, Sarah Hickam, Anna F. Oliveri, Jennifer E. S. Szymanowski, Allen G. Oliver, William H. Casey, and Peter C. Burns
Inorganic Chemistry May 1, 2017 Volume 56(Issue 9) pp:5478-5478
Publication Date(Web):April 10, 2017
DOI:10.1021/acs.inorgchem.7b00649
Herein, we report a new salt of a pyrophosphate-functionalized uranyl peroxide nanocluster {U24Pp12} (1) exhibiting Oh molecular symmetry both in the solid and solution. Study of the system yielding 1 across a wide range of pH by single-crystal X-ray diffraction, small-angle X-ray scattering, and a combination of traditional 31P and diffusion-ordered spectroscopy (DOSY) NMR affords unprecedented insight into the amphoteric chemistry of this uranyl peroxide system. Key results include formation of a rare binary {U24}·{U24Pp12} (3) system observed under alkaline conditions, and evidence of acid-promoted decomposition of {U24Pp12} (1) followed by spatial rearrangement and condensation of {U4} building blocks into the {U32Pp16} (2) cluster. Furthermore, 31P DOSY NMR measurements performed on saturated solutions containing crystalline {U32Pp16} show only trace amounts (∼2% relative abundance) of the intact form of this cluster, suggesting a complex interconversion of {U24Pp12}, {U32Pp16}, and {U4Pp4–x} ions.
Co-reporter:Mateusz Dembowski;Varinia Bernales;Jie Qiu;Sarah Hickam;Gabriel Gaspar;Laura Gagliardi
Inorganic Chemistry February 6, 2017 Volume 56(Issue 3) pp:1574-1580
Publication Date(Web):January 11, 2017
DOI:10.1021/acs.inorgchem.6b02666
Combination of uranium, peroxide, and mono- (Na, K) or divalent (Mg, Ca, Sr) cations under alkaline aqueous conditions results in the rapid formation of anionic uranyl triperoxide monomers (UTs), (UO2(O2)3)4–, exhibiting unique Raman signatures. Electronic structure calculations were decisive for the interpretation of the spectra and assignment of unexpected signals associated with vibrations of the uranyl and peroxide ions. Assignments were verified by 18O isotopic labeling of the uranyl ions supporting the computational-based interpretation of the experimentally observed peaks and the assignment of a novel asymmetric vibration of the peroxide ligands, v2(O22–).
Co-reporter:Travis A. Olds, Mateusz Dembowski, Xiaoping Wang, Christina Hoffman, Todd M. Alam, Sarah Hickam, Kristi L. Pellegrini, Junhong He, and Peter C. Burns
Inorganic Chemistry August 21, 2017 Volume 56(Issue 16) pp:9676-9676
Publication Date(Web):August 7, 2017
DOI:10.1021/acs.inorgchem.7b01174
Single-crystal time-of-flight neutron diffraction has provided atomic resolution of H atoms of H2O molecules and hydroxyl groups, as well as Li cations in the uranyl peroxide nanocluster U60. Solid-state magic-angle-spinning nuclear magnetic resonance (MAS NMR) spectroscopy was used to confirm the dynamics of these constituents, revealing the transportation of Li atoms and H2O through cluster walls. H atoms of hydroxyl units that are located on the cluster surface are involved in the transfer of H2O and Li cations from inside to outside and vice versa. This exchange occurs as a concerted motion and happens rapidly even in the solid state. As a consequence of its large size and open hexagonal pores, U60 exchanges Li cations more rapidly compared to other uranyl nanoclusters.
Co-reporter:Mateusz Dembowski, Christopher A. Colla, Ping Yu, Jie Qiu, Jennifer E. S. Szymanowski, William H. Casey, and Peter C. Burns
Inorganic Chemistry August 21, 2017 Volume 56(Issue 16) pp:9602-9602
Publication Date(Web):August 7, 2017
DOI:10.1021/acs.inorgchem.7b01095
Understanding the stability fields and decomposition products of various metal- and actinide-oxide nanoclusters is essential for their development into useful materials for industrial processes. Herein, we explore the spontaneous transformation of the sulfate-centered, phosphate functionalized uranyl peroxide nanocluster {U20P6} to {U24} under aqueous ambient conditions using time-resolved small-angle X-ray scattering, Raman, and 31P NMR spectroscopy. We show that the unusual μ-η1:η2 bridging mode of peroxide between uranyl ions observed in {U20P6} may lead to its rapid breakdown in solution as evidenced by liberation of phosphate groups that were originally present as an integral part of its cage structure. Remarkably, the uranyl peroxide moieties present after degradation of {U20P6} undergo cation-mediated reassembly into the {U24} cluster, demonstrating the propensity of the uranyl peroxide systems to preserve well-defined macro-anions.
Co-reporter:Ewa A. Dzik, Haylie L. Lobeck, Lei Zhang, Peter C. Burns
The Journal of Chemical Thermodynamics 2017 Volume 114(Volume 114) pp:
Publication Date(Web):1 November 2017
DOI:10.1016/j.jct.2017.07.007
•10 uranyl phosphate samples were synthesized using slow mixing by a diffusion method.•Enthalpies of formation were determined using high temperature calorimetry.•Acid-base interactions become more exothermic with decreasing NCDA.•NCDA is used to relate crystal chemical stability to thermodynamic properties.Samples of synthetic analogs of uranyl phosphate minerals have been prepared at room temperature by slow mixing of reactants by a diffusion method. Reaction products were analyzed using powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), inductively coupled plasma optical emission spectrophotometry (ICP-OES), and inductively coupled plasma mass spectrometry (ICP-MS). Calorimetric measurements have been performed in a Calvet-type twin calorimeter using sodium molybdate (3Na2O-4MoO3) solvent at 976 K as a flux. The enthalpy of formation from the binary oxides, ΔHf-ox, at 298 K was calculated for each compound from the respective drop solution enthalpies, ΔHds. Calculated standard enthalpies of formation from the elements, ΔH0f, at 298 K are −3425 ± 9 kJ/mol for meta-ankoleite (KUP), −6233 ± 17 kJ/mol for meta-autunite (CaUP), −6921 ± 13 kJ/mol for meta-torbernite (CuUP), −7254 ± 17 kJ/mol for meta-saléeite (MgUP), −3264 ± 12 kJ/mol for Rb-meta-autunite (RbUP), −3580 ± 7 kJ/mol for meta-natro-autunite (NaUP), −3692 ± 11 kJ/mol for Li-meta-autunite (LiUP), −6402 ± 5 kJ/mol for meta-uranocircite (BaUP), −3277 ± 6 kJ/mol for Cs-meta-autunite (CsUP), and −7109 ± 19 kJ/mol for Co-meta-autunite (CoUP). The results exhibit trends of the thermodynamic stability of these compounds. The normalized charge deficiency per anion (NCDA) approach relates the thermodynamic stability of these compounds to their crystal structures. The thermodynamic stability of uranyl phosphate minerals is important for understanding their formation in Nature, as well as their fate in a geological repository for nuclear waste, and their existence in the subsurface of anthropogenically contaminated environments.
Co-reporter:Jie Qiu, Tyler L. SpanoMateusz Dembowski, Alex M. Kokot, Jennifer E. S. Szymanowski, Peter C. Burns
Inorganic Chemistry 2017 Volume 56(Issue 4) pp:
Publication Date(Web):January 30, 2017
DOI:10.1021/acs.inorgchem.6b02429
Two novel hybrid uranyl peroxide phosphate cage clusters, designated U20P6 and U20P12, contain peroxide bridges between uranyl in an unusual μ–η1:η2 configuration, as well as the common μ–η2:η2 configuration. These appear to be the only high-nuclearity metal peroxide complexes containing μ–η1:η2 peroxide bridges, and they are unique among uranyl peroxide cages. Both clusters contain 20 uranyl polyhedra, and U20P6 and U20P12 contain 6 and 12 phosphate tetrahedra, respectively. The 20 uranyl polyhedra in both cages are arranged on the vertices of distorted topological dodecahedrons (20 vertex fullerenes). Each cage is completed by phosphate tetrahedra and is templated by a sulfate-centered Na12 cluster with the Na cations defining a regular convex isocahedron. Whereas μ–η2:η2 peroxides are essential features of uranyl peroxide cages, where they form equatorial edges of uranyl hexagonal bipyramids, the μ–η1:η2 peroxide groups in U20P6 and U20P12 are associated with strong distortions of the uranyl polyhedra. Formation of U20P6 and U20P12 is a further demonstration of the pliable nature of uranyl polyhedra, which contributes to the tremendous topological variability of uranyl compounds. Despite the unusual structure and highly distorted polyhedral geometries of U20P6, small-angle X-ray scattering and Raman spectra suggest its stability in the aqueous solution and solid state.
Co-reporter:Kathryn M. Peruski, Varinia Bernales, Mateusz Dembowski, Haylie L. Lobeck, Kristi L. Pellegrini, Ginger E. Sigmon, Sarah Hickam, Christine M. Wallace, Jennifer E. S. Szymanowski, Enrica Balboni, Laura GagliardiPeter C. Burns
Inorganic Chemistry 2017 Volume 56(Issue 3) pp:
Publication Date(Web):January 11, 2017
DOI:10.1021/acs.inorgchem.6b02435
Uranium concentrations as high as 2.94 × 105 parts per million (1.82 mol of U/1 kg of H2O) occur in water containing nanoscale uranyl cage clusters. The anionic cage clusters, with diameters of 1.5–2.5 nm, are charge-balanced by encapsulated cations, as well as cations within their electrical double layer in solution. The concentration of uranium in these systems is impacted by the countercations (K, Li, Na), and molecular dynamics simulations have predicted their distributions in selected cases. Formation of uranyl cages prevents hydrolysis reactions that would result in formation of insoluble uranyl solids under alkaline conditions, and these spherical clusters reach concentrations that require close packing in solution.
Co-reporter:Mateusz Dembowski; Travis A. Olds; Kristi L. Pellegrini; Christina Hoffmann; Xiaoping Wang; Sarah Hickam; Junhong He; Allen G. Oliver
Journal of the American Chemical Society 2016 Volume 138(Issue 27) pp:8547-8553
Publication Date(Web):June 20, 2016
DOI:10.1021/jacs.6b04028
The first neutron diffraction study of a single crystal containing uranyl peroxide nanoclusters is reported for pyrophosphate-functionalized Na44K6[(UO2)24(O2)24(P2O7)12][IO3]2·140H2O (1). Relative to earlier X-ray studies, neutron diffraction provides superior information concerning the positions of H atoms and lighter counterions. Hydrogen positions have been assigned and reveal an extensive network of H-bonds; notably, most O atoms present in the anionic cluster accept H-bonds from surrounding H2O molecules, and none of the surface-bound O atoms are protonated. The D4h symmetry of the cage is consistent with the presence of six encapsulated K cations, which appear to stabilize the lower symmetry variant of this cluster. 31P NMR measurements demonstrate retention of this symmetry in solution, while in situ 31P NMR studies suggest an acid-catalyzed mechanism for the assembly of 1 across a wide range of pH values.
Co-reporter:Samuel O. Odoh, Jacob Shamblin, Christopher A. Colla, Sarah Hickam, Haylie L. Lobeck, Rachel A. K. Lopez, Travis Olds, Jennifer E. S. Szymanowski, Ginger E. Sigmon, Joerg Neuefeind, William H. Casey, Maik Lang, Laura Gagliardi, and Peter C. Burns
Inorganic Chemistry 2016 Volume 55(Issue 7) pp:3541-3546
Publication Date(Web):March 14, 2016
DOI:10.1021/acs.inorgchem.6b00017
Recent accidents resulting in worker injury and radioactive contamination occurred due to pressurization of uranium yellowcake drums produced in the western U.S.A. The drums contained an X-ray amorphous reactive form of uranium oxide that may have contributed to the pressurization. Heating hydrated uranyl peroxides produced during in situ mining can produce an amorphous compound, as shown by X-ray powder diffraction of material from impacted drums. Subsequently, studtite, [(UO2)(O2)(H2O)2](H2O)2, was heated in the laboratory. Its thermal decomposition produced a hygroscopic anhydrous uranyl peroxide that reacts with water to release O2 gas and form metaschoepite, a uranyl-oxide hydrate. Quantum chemical calculations indicate that the most stable U2O7 conformer consists of two bent (UO2)2+ uranyl ions bridged by a peroxide group bidentate and parallel to each uranyl ion, and a μ2-O atom, resulting in charge neutrality. A pair distribution function from neutron total scattering supports this structural model, as do 1H- and 17O-nuclear magnetic resonance spectra. The reactivity of U2O7 in water and with water in air is higher than that of other uranium oxides, and this can be both hazardous and potentially advantageous in the nuclear fuel cycle.
Co-reporter:Jie Qiu, Mateusz Dembowski, Jennifer E. S. Szymanowski, Wen Cong Toh, and Peter C. Burns
Inorganic Chemistry 2016 Volume 55(Issue 14) pp:7061-7067
Publication Date(Web):June 29, 2016
DOI:10.1021/acs.inorgchem.6b00918
Combining reactants in water under ambient conditions results in the assembly and crystallization of 2.6 nm diameter cage clusters designated U48V6P48 within 3 weeks. These consist of 24 uranyl hexagonal bipyramids, 24 uranyl pentagonal bipyramids, six vanadyl square pyramids, and 48 phosphate tetrahedra. Peroxide-bridged dimers of uranyl hexagonal bipyramids are linked directly to vanadyl-stabilized tetramers of uranyl pentagonal bipyramids to form the cage, with phosphate tetrahedra providing additional linkages between these two units. Time-resolved small-angle X-ray scattering and Raman spectroscopy indicate that the combination of the reactants initially resulted in simultaneous formation of smaller uranyl peroxide cages and vanadyl peroxide complexes. The disappearance of the smaller uranyl peroxide cages from solution coincides with the diminution of uncoordinated peroxide, both of which occurred before the assembly of the relatively peroxide-poor U48V6P48, which clearly occurred in solution prior to its crystallization.
Co-reporter:Ginger E. Sigmon, Jennifer E. S. Szymanowski, Korey P. Carter, Christopher L. Cahill, and Peter C. Burns
Inorganic Chemistry 2016 Volume 55(Issue 6) pp:2682-2684
Publication Date(Web):February 29, 2016
DOI:10.1021/acs.inorgchem.6b00207
A cage cluster consisting of 31 uranyl and 9 Sm3+ polyhedra self-assembles in an alkaline aqueous peroxide solution and crystallizes (U31Sm9). Trimers of Sm3+ polyhedra are templated by μ3-η2:η2:η2-peroxide groups and link to oxo atoms of uranyl ions. Three such trimers link into a ring through uranyl hexagonal bipyramids, and these are attached through six polyhedra to a unit consisting of 21 uranyl hexagonal bipyramids to complete the cage. Luminescence spectra collected with an excitation wavelength of 420 nm reveal fine structure, which is not observed for a cluster containing only uranyl polyhedra.
Co-reporter:Ernest M. Wylie, Kathryn M. Peruski, Sarah E. Prizio, Andrea N.A. Bridges, Tracy S. Rudisill, David T. Hobbs, William A. Phillip, Peter C. Burns
Journal of Nuclear Materials 2016 Volume 473() pp:125-130
Publication Date(Web):May 2016
DOI:10.1016/j.jnucmat.2016.02.013
•Nanoscale control in irradiated fuel reprocessing.•Ultrafiltration to recover uranyl cage clusters.•Alternative to solvent extraction for uranium purification.Current separation and purification technologies utilized in the nuclear fuel cycle rely primarily on liquid–liquid extraction and ion-exchange processes. Here, we report a laboratory-scale aqueous process that demonstrates nanoscale control for the recovery of uranium from simulated used nuclear fuel (SIMFUEL). The selective, hydrogen peroxide induced oxidative dissolution of SIMFUEL material results in the rapid assembly of persistent uranyl peroxide nanocluster species that can be separated and recovered at moderate to high yield from other process-soluble constituents using sequestration-assisted ultrafiltration. Implementation of size-selective physical processes like filtration could results in an overall simplification of nuclear fuel cycle technology, improving the environmental consequences of nuclear energy and reducing costs of processing.
Co-reporter:Dr. Lei Mei;Dr. Qun-yan Wu;Dr. Li-yong Yuan;Dr. Lin Wang;Shu-wen An;Zhen-ni Xie;Dr. Kong-qiu Hu; Zhi-fang Chai; Peter C. Burns; Wei-qun Shi
Chemistry - A European Journal 2016 Volume 22( Issue 32) pp:11329-11338
Publication Date(Web):
DOI:10.1002/chem.201601506
Abstract
The hierarchical assembly of well-organized submoieties could lead to more complicated superstructures with intriguing properties. We describe herein an unprecedented polyrotaxane polythreading framework containing a two-fold nested super-polyrotaxane substructure, which was synthesized through a uranyl-directed hierarchical polythreading assembly of one-dimensional polyrotaxane chains and two-dimensional polyrotaxane networks. This special assembly mode actually affords a new way of supramolecular chemistry instead of covalently linked bulky stoppers to construct stable interlocked rotaxane moieties. An investigation of the synthesis condition shows that sulfate can assume a vital role in mediating the formation of different uranyl species, especially the unique trinuclear uranyl moiety [(UO2)3O(OH)2]2+, involving a notable bent [O=U=O] bond with a bond angle of 172.0(9)°. Detailed analysis of the coordination features, the thermal stability as well as a fluorescence, and electrochemical characterization demonstrate that the uniqueness of this super-polyrotaxane structure is mainly closely related to the trinuclear uranyl moiety, which is confirmed by quantum chemical calculations.
Co-reporter:Yunyi Gao;Jennifer E. S. Szymanowski;Xinyu Sun;Dr. Peter C. Burns;Dr. Tianbo Liu
Angewandte Chemie International Edition 2016 Volume 55( Issue 24) pp:6887-6891
Publication Date(Web):
DOI:10.1002/anie.201601852
Abstract
An actinyl peroxide cage cluster, Li48+mK12(OH)m[UO2(O2)(OH)]60 (H2O)n (m≈20 and n≈310; U60), discriminates precisely between Na+ and K+ ions when heated to certain temperatures, a most essential feature for K+ selective filters. The U60 clusters demonstrate several other features in common with K+ ion channels, including passive transport of K+ ions, a high flux rate, and the dehydration of U60 and K+ ions. These qualities make U60 (a pure inorganic cluster) a promising ion channel mimic in an aqueous environment. Laser light scattering (LLS) and isothermal titration calorimetry (ITC) studies revealed that the tailorable ion selectivity of U60 clusters is a result of the thermal responsiveness of the U60 hydration shells.
Co-reporter:Yunyi Gao;Jennifer E. S. Szymanowski;Xinyu Sun;Dr. Peter C. Burns;Dr. Tianbo Liu
Angewandte Chemie 2016 Volume 128( Issue 24) pp:7001-7005
Publication Date(Web):
DOI:10.1002/ange.201601852
Abstract
An actinyl peroxide cage cluster, Li48+mK12(OH)m[UO2(O2)(OH)]60 (H2O)n (m≈20 and n≈310; U60), discriminates precisely between Na+ and K+ ions when heated to certain temperatures, a most essential feature for K+ selective filters. The U60 clusters demonstrate several other features in common with K+ ion channels, including passive transport of K+ ions, a high flux rate, and the dehydration of U60 and K+ ions. These qualities make U60 (a pure inorganic cluster) a promising ion channel mimic in an aqueous environment. Laser light scattering (LLS) and isothermal titration calorimetry (ITC) studies revealed that the tailorable ion selectivity of U60 clusters is a result of the thermal responsiveness of the U60 hydration shells.
Co-reporter:Jennifer A. Soltis; Christine M. Wallace; R. Lee Penn
Journal of the American Chemical Society 2015 Volume 138(Issue 1) pp:191-198
Publication Date(Web):December 28, 2015
DOI:10.1021/jacs.5b09802
Self-assembly of ([UO2(O2)OH]60)60– (U60), an actinide polyoxometalate with fullerene topology, can be induced by the addition of mono- and divalent cations to aqueous U60 solutions. Dynamic light scattering and small-angle X-ray scattering lend important insights into assembly in this system, but direct imaging of U60 and its assemblies via transmission electron microscopy (TEM) has remained an elusive goal. In this work, we used cryogenic TEM to image U60 and secondary and tertiary assemblies of U60 to characterize the size, morphology, and rate of formation of the secondary and tertiary structures. The kinetics and final morphologies of the secondary and tertiary structures strongly depend on the cation employed, with monovalent cations (Na+ and K+) leading to the highest rates and largest secondary and tertiary structures.
Co-reporter:G. A. Senchyk, E. M. Wylie, S. Prizio, J. E. S. Szymanowski, G. E. Sigmon and P. C. Burns
Chemical Communications 2015 vol. 51(Issue 50) pp:10134-10137
Publication Date(Web):19 May 2015
DOI:10.1039/C5CC01524C
Hybrid uranyl–vanadium oxide clusters intermediate between transition metal polyoxometalates and uranyl peroxide cage clusters were obtained by dissolving uranyl nitrate in the ionic liquid 3-ethyl-1-methylimidazolium ethyl sulfate mixed with an aqueous solution containing vanadium. Where sulfate was present, wheel-shaped {U20V20} crystallized and contains ten sulfate tetrahedra, and in the absence of added sulfate, {U2V16}, a derivative of {V18}, was obtained.
Co-reporter:Jie Qiu, Bess Vlaisavljevich, Laurent Jouffret, Kevin Nguyen, Jennifer E.S. Szymanowski, Laura Gagliardi, and Peter C. Burns
Inorganic Chemistry 2015 Volume 54(Issue 9) pp:4445-4455
Publication Date(Web):April 13, 2015
DOI:10.1021/acs.inorgchem.5b00248
The self-assembly of uranyl peroxide polyhedra into a rich family of nanoscale cage clusters is thought to be favored by cation templating effects and the pliability of the intrinsically bent U–O2–U dihedral angle. Herein, the importance of ligand and cationic effects on the U–O2–U dihedral angle were explored by studying a family of peroxide-bridged dimers of uranyl polyhedra. Four chemically distinct peroxide-bridged uranyl dimers were isolated that contain combinations of pyridine-2,6-dicarboxylate, picolinate, acetate, and oxalate as coordinating ligands. These dimers were synthesized with a variety of counterions, resulting in the crystallographic characterization of 15 different uranyl dimer compounds containing 17 symmetrically distinct dimers. Eleven of the dimers have U–O2–U dihedral angles in the expected range from 134.0 to 156.3°; however, six have 180° U–O2–U dihedral angles, the first time this has been observed for peroxide-bridged uranyl dimers. The influence of crystal packing, countercation linkages, and π–π stacking impact the dihedral angle. Density functional theory calculations indicate that the ligand does not alter the electronic structure of these systems and that the U–O2–U bridge is highly pliable. Less than 3 kcal·mol–1 is required to bend the U–O2–U bridge from its minimum energy configuration to a dihedral angle of 180°. These results suggest that the energetic advantage of bending the U–O2–U dihedral angle of a peroxide-bridged uranyl dimer is at most a modest factor in favor of cage cluster formation. The role of counterions in stabilizing the formation of rings of uranyl ions, and ultimately their assembly into clusters, is at least as important as the energetic advantage of a bent U–O2–U interaction.
Co-reporter:Pius O. Adelani;Nicholas A. Martinez;Nathaniel D. Cook
European Journal of Inorganic Chemistry 2015 Volume 2015( Issue 2) pp:340-347
Publication Date(Web):
DOI:10.1002/ejic.201402764
Abstract
A series of phosphonate-based uranyl–organic hybrids has been assembled based on the reaction of uranyl cations with 2,5-dihydroxy-1,4-benzenediphosphonic acid in the presence of a variety of alkali metal and organoammonium cations: K[(UO2)2F2{H0.5O3PC6H2(OH)2PO3H0.5}](H2O)2 (1), Cs[(UO2)2{H0.75O3PC6H2(OH)2PO3H0.75}](H2O)4·2H2O (2), [(CH3)4N]2[UO2{HO3PC6H2(OH)2PO3H}2] (3), [(CH3CH2)4N][UO2F{HO3PC6H2(OH)2PO3H}] (4), and [(CH3CH2)2N(CH3)2][UO2F{HO3PC6H2(OH)2PO3H}] (5). In compounds 1, 4, and 5, chains of UO5F2 pentagonal bipyramids are linked by the hydroxyphosphonate moiety into three-dimensional frameworks, and compound 4 is isostructural with 5. However, the structures of 2 and 3 are composed of monomeric UO7 pentagonal bipyramids assembled to form layered structural units. Additional steric influences from the –OH groups appended on the diphosphonate species play a vital role in directing the structure topologies.
Co-reporter:Yunyi Gao;Fadi Haso;Jennifer E. S. Szymanowski;Jing Zhou;Lang Hu;Dr. Peter C. Burns;Dr. Tianbo Liu
Chemistry - A European Journal 2015 Volume 21( Issue 51) pp:18785-18790
Publication Date(Web):
DOI:10.1002/chem.201503773
Abstract
The precise guidance to different ions across the biological channels is essential for many biological processes. An artificial nanopore system will facilitate the study of the ion-transport mechanism through nanosized channels and offer new views for designing nanodevices. Herein we reveal that a 2.5 nm-sized, fullerene-shaped molecular cluster Li48+mK12(OH)m[UO2(O2)(OH)]60−(H2O)n (m≈20 and n≈310) (U60) shows selective permeability to different alkali ions. The subnanometer pores on the water–ligand-rich surface of U60 are able to block Rb+ and Cs+ ions from passing through, while allowing Na+ and K+ ions, which possess larger hydrated sizes, to enter the interior space of U60. An interestingly high entropy gain during the binding process between U60 and alkali ions suggests that the hydration shells of Na+/K+ and U60 are damaged during the interaction. The ion selectivity of U60 is greatly influenced by both the morphologies of the surface nanopores and the dynamics of the hydration shells.
Co-reporter:Brendan T. McGrail ; Laura S. Pianowski
Journal of the American Chemical Society 2014 Volume 136(Issue 13) pp:4797-4800
Publication Date(Web):March 17, 2014
DOI:10.1021/ja502425t
Sunlight photolysis of uranyl nitrate and uranyl acetate solutions in pyridine produces uranyl peroxide complexes. To answer longstanding questions about the origin of these complexes, we conducted a series of mechanistic studies and demonstrate that these complexes arise from photochemical oxidation of water. The peroxo ligands are easily removed by protonolysis, allowing regeneration of the initial uranyl complexes for potential use in catalysis.
Co-reporter:Ernest M. Wylie, Kathryn M. Peruski, Jacob L. Weidman, William A. Phillip, and Peter C. Burns
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 1) pp:473
Publication Date(Web):December 6, 2013
DOI:10.1021/am404520b
Uranyl peroxide cluster species were produced in aqueous solution by the treatment of uranyl nitrate with hydrogen peroxide, lithium hydroxide, and potassium chloride. Ultrafiltration of these cluster species using commercial sheet membranes with molecular mass cutoffs of 3, 8, and 20 kDa (based on polyethylene glycol) resulted in U rejection values of 95, 85, and 67% by mass, respectively. Ultrafiltration of untreated uranyl nitrate solutions using these membranes resulted in virtually no rejection of U. These results demonstrate the ability to use the filtration of cluster species as a means for separating U from solutions on the basis of size. Small-angle X-ray scattering, Raman spectroscopy, and electrospray ionization mass spectrometry confirmed the presence of uranyl peroxide cluster species in solution and were used to characterize their size, shape, and dispersity.Keywords: membranes; nanoscale control; nuclear technology; ultrafiltration; uranyl peroxide nanocluster;
Co-reporter:Pius O. Adelani, Nathaniel D. Cook, Jean-Marie Babo, and Peter C. Burns
Inorganic Chemistry 2014 Volume 53(Issue 8) pp:4169-4176
Publication Date(Web):April 4, 2014
DOI:10.1021/ic500220d
Three new multidimensional polymetallic uranyl diphosphonates were crystallized under mild hydrothermal conditions: [Cu(H2O)]2{(UO2)4F2[(PO3C6H4)(C6H4PO3H)3]2(bipym)}·6H2O (1), [Cu(H2O)]2{(UO2)4[(C6H4PO3)(C6H4PO3H)]4(bipym)} (2), and Cu{(UO2)(C6H4PO3)2(bipym)}·H2O (3). Compound 1 consists of UO6F pentagonal bipyramids connected by diphosphonate moieties into a tubular channel. The Cu2+ cations are stabilized between the nanotubular subunits by 2,2′-bipyrimidine (bipym). The structure of 2 is similar to 1, except that it consists of relatively rare UO6 tetragonal bipyramids bridged by diphosphonate groups. Compound 3 also contains UO6 tetragonal bipyramids. Unlike compounds 1 and 2, only two of the tetradentate N atoms of the binucleating bipym group are coordinated. All three compounds show luminescent properties under ambient conditions, with evidence of the characteristic vibronically coupled charge-transfer based uranyl cation emissions.
Co-reporter:Jie Qiu, Jie Ling, Claire Sieradzki, Kevin Nguyen, Ernest M. Wylie, Jennifer E. S. Szymanowski, and Peter C. Burns
Inorganic Chemistry 2014 Volume 53(Issue 22) pp:12084-12091
Publication Date(Web):October 28, 2014
DOI:10.1021/ic5018906
The first four uranyl peroxide compounds containing ethylenediaminetetra-acetate (EDTA) were synthesized and characterized from aqueous uranyl peroxide nitrate solutions with a pH range of 5–7. Raman spectra demonstrated that reaction solutions that crystallized [NaK15[(UO2)8(O2)8(C10H12O10N2)2(C2O4)4]·(H2O)14] (1) and [Li4K6[(UO2)8(O2)6(C10H12O10N2)2(NO3)6]·(H2O)26] (2) contained excess peroxide, and their structures contained oxidized ethylenediaminetetraacetate, EDTAO24–. The solutions from which [K4[(UO2)4(O2)2(C10H13O8N2)2(IO3)2]·(H2O)16] (3) and LiK3[(UO2)4(O2)2(C10H12O8N2)2(H2O)2]·(H2O)18 (4) crystallized contained no free peroxide, and the structures incorporated intact EDTA4–. In contrast to the large family of uranyl peroxide cage clusters, coordination of uranyl peroxide units in 1–4 by EDTA4– or EDTAO24– results in isolated tetramers or dimers of uranyl ions that are bridged by bidentate peroxide groups. Two tetramers are bridged by EDTAO24– to form octamers in 1 and 2, and dimers of uranyl polyhedra are linked through iodate groups in 3 and EDTA4– in 4, forming chains in both cases. In each structure the U–O2–U dihedral angle is strongly bent, at ∼140°, consistent with the configuration of this linkage in cage clusters and other recently reported uranyl peroxides.
Co-reporter:Brendan T. McGrail, Ginger E. Sigmon, Laurent J. Jouffret, Christopher R. Andrews, and Peter C. Burns
Inorganic Chemistry 2014 Volume 53(Issue 3) pp:1562-1569
Publication Date(Web):January 14, 2014
DOI:10.1021/ic402570b
Strategies for interpreting mass spectrometric and Raman spectroscopic data have been developed to study the structure and reactivity of uranyl peroxide cage clusters in aqueous solution. We demonstrate the efficacy of these methods using the three best-characterized uranyl peroxide clusters, {U24}, {U28}, and {U60}. Specifically, we show a correlation between uranyl–peroxo–uranyl dihedral bond angles and the position of the Raman band of the symmetric stretching mode of the peroxo ligand, develop methods for the assignment of the ESI mass spectra of uranyl peroxide cage clusters, and show that these methods are generally applicable for detecting these clusters in the solid state and solution and for extracting information about their bonding and composition without crystallization.
Co-reporter:Jie Ling, Franklin Hobbs, Steven Prendergast, Pius O. Adelani, Jean-Marie Babo, Jie Qiu, Zhehui Weng, and Peter C. Burns
Inorganic Chemistry 2014 Volume 53(Issue 24) pp:12877-12884
Publication Date(Web):December 1, 2014
DOI:10.1021/ic5018449
Transition-metal based polyoxometalate clusters have been known for decades, whereas those built from uranyl peroxide polyhedra have more recently emerged as a family of complex clusters. Here we report the synthesis and structures of six nanoscale uranyl peroxide cage clusters that contain either tungstate or molybdate polyhedra as part of the cage, as well as phosphate tetrahedra. These transition-metal–uranium hybrid clusters exhibit unique polyhedral connectivities and topologies that include 6-, 7-, 8-, 10-, and 12-membered rings of uranyl polyhedra and uranyl ions coordinated by bidentate peroxide in both trans and cis configurations. The transition-metal polyhedra appear to stabilize unusual units built of uranyl polyhedra, rather than templating their formation.
Co-reporter:Zhehui Weng, Zhi-hui Zhang, Travis Olds, Marcin Sterniczuk, and Peter C. Burns
Inorganic Chemistry 2014 Volume 53(Issue 15) pp:7993-7998
Publication Date(Web):July 16, 2014
DOI:10.1021/ic5007814
Two copper–uranium heterometallic compounds, [(UO2)3CuIIO2(C6NO2)5] (1) and [(UO2)CuI(C6NO2)3] (2), have been synthesized by the reaction of uranyl acetate with copper salts in the presence of isonicotinic acid. Both compounds have been characterized by single-crystal X-ray diffraction, IR, Raman, and UV–vis spectroscopy. In compound 1, interactions between copper and uranium centers occur and result in a three-dimensional pillar layered structure. Compound 1 is also the first example of a heterometallic uranyl organic framework with a trinuclear U3O18 building block. Compound 2 is the first uranyl organic framework that contains monovalent copper, which arises from the reaction of Cu(II) chloride and is assumed to be due to the oxidation of chloride at low pH.
Co-reporter:P. A. Smith and P. C. Burns
CrystEngComm 2014 vol. 16(Issue 31) pp:7244-7250
Publication Date(Web):12 Jun 2014
DOI:10.1039/C4CE00512K
Ionothermal methods were employed in the synthesis of two novel uranyl coordination compounds: [C5H6N]2 [UO2(C7H7SO3)4(H2O)] (1) and UO2(HAsO4)(NC5H11O2) (2), using pyridinium and betainium class ionic liquids. The results show novel ionic liquid incorporation and uranyl structural topologies, providing insight into the development of low-dimensionality uranyl complexes beyond traditional hydrothermal methods.
Co-reporter:E. M. Wylie, P. A. Smith, K. M. Peruski, J. S. Smith, M. K. Dustin and P. C. Burns
CrystEngComm 2014 vol. 16(Issue 31) pp:7236-7243
Publication Date(Web):14 Mar 2014
DOI:10.1039/C4CE00270A
Ionothermal reactions of uranyl salts in several ionic liquids containing cyclic cations produced single crystals of five new uranyl compounds. (C4H7N2)[(UO2)(AsO4)] (1), (C8H15N2)2[(UO2)4(SeO3)5] (2), (C6H11N2)2[(UO2)3(C2H5PO4)4] (3), and (C5H5N)2[(UO2)2(SeO4)3] (4) are each comprised of two-dimensional structural units. (C4H7N2)[(UO2)5(PO4)3(HPO4)(H2O)2]·3H2O (5) is composed of a three-dimensional network. While the uranyl structural units in all five compounds are directly related to ones found in either uranyl minerals or compounds produced in aqueous media, each contain cyclic ionic liquid constituents as charge-balancing agents. These results suggest that the cation selectivity of these structural units is low, even under various solvation conditions and templating effects from cyclic cations donated from ionic liquid media.
Co-reporter:Pius O. Adelani, Nathaniel D. Cook, and Peter C. Burns
Crystal Growth & Design 2014 Volume 14(Issue 11) pp:5692-5699
Publication Date(Web):October 12, 2014
DOI:10.1021/cg500972w
Three new multidimensional bimetallic UO22+-3d three-dimensional complexes were crystallized in high yield under mild hydrothermal conditions: [Mn(H2O)]2[(UO2)4(PO3C6H4PO3)3(bipym)]·2H2O (1), [Ni(H2O)]2[(UO2)3(O3PC6H4PO3)(O3PC6H4PO3H)2(bipym)]·6H2O (2), and Zn[(UO2)(HO3PC6H4PO3)(HO3PC6H4PO3H)0.5(bipym)0.5] (3), where bipym = 2,2-bipyrimidine. The structure of 1 is composed of edge-sharing dimers of uranyl pentagonal bipyramids that are linked by rigid phenyl spacers to form pillared three-dimensional networks. This compound is remarkable in that the [Mn2(H2O)2(bipym)]4+ moiety is incorporated within the uranyl phosphonate frameworks without reducing the dimensionality of the overall structure. Compound 2 consists of uranyl tetragonal and pentagonal bipyramids that are linked by phosphonate groups to form a pillared three-dimensional framework with channels that are occupied by the [Ni2(H2O)2(bipym)2]4+ moiety. In compound 3, edge-sharing dimers of uranyl pentagonal bipyramids are connected through the phosphonate ligand to create corrugated uranyl-phosphonate chains. The incorporated [Zn2(bipym)]4+ subunits are located within the interlayer of the uranyl-phosphonate chains. All three compounds are characterized by absorption, fluorescence, and infrared spectroscopy.
Co-reporter:Jie Qiu and Peter C. Burns
Chemical Reviews 2013 Volume 113(Issue 2) pp:1097
Publication Date(Web):October 24, 2012
DOI:10.1021/cr300159x
Co-reporter:Pius O. Adelani, Ginger E. Sigmon, and Peter C. Burns
Inorganic Chemistry 2013 Volume 52(Issue 11) pp:6245-6247
Publication Date(Web):May 16, 2013
DOI:10.1021/ic400827h
Nanoscopic uranyl coordination cages have been prepared by a facile route involving self-assembly via temperature and solvent-driven, in situ ligand synthesis. The synthesis of hydrogen arsenate and pyroarsonate ligands in situ enhances flexibility, which is an important factor in producing these compounds.
Co-reporter:Pius O. Adelani, Michael Ozga, Christine M. Wallace, Jie Qiu, Jennifer E. S. Szymanowski, Ginger E. Sigmon, and Peter C. Burns
Inorganic Chemistry 2013 Volume 52(Issue 13) pp:7673-7679
Publication Date(Web):June 13, 2013
DOI:10.1021/ic4008262
Two new hybrid uranyl-carboxyphosphonate cage clusters built from uranyl peroxide units were crystallized from aqueous solution under ambient conditions in approximately two months. The clusters are built from uranyl hexagonal bipyramids and are connected by employing a secondary metal linker, the 2-carboxyphenylphosphonate ligand. The structure of cluster A is composed of a ten-membered uranyl polyhedral belt that is capped on either end of an elongated cage by five-membered rings of uranyl polyhedra. The structure of cluster B consists of 24 uranyl cations that are arranged into 6 four-membered rings of uranyl polyhedra. Four of the corresponding topological squares are fused together to form a sixteen-membered double uranyl pseudobelt that is capped on either end by 2 topological squares. Cluster A crystallizes over a wide pH range of 4.6–6.8, while cluster B was isolated under narrower pH range of 6.9–7.8. Studies of their fate in aqueous solution upon dissolution of crystals by electrospray ionization mass spectrometry (ESI-MS) and small-angle X-ray scattering (SAXS) provide evidence for their persistence in solution. The well-established characteristic fingerprint from the absorption spectra of the uranium(VI) cations disappears and becomes a nearly featureless peak; nonetheless, the two compounds fluoresce at room temperature.
Co-reporter:Jie Qiu ; Kevin Nguyen ; Laurent Jouffret ; Jennifer E. S. Szymanowski
Inorganic Chemistry 2013 Volume 52(Issue 1) pp:337-345
Publication Date(Web):December 11, 2012
DOI:10.1021/ic3020817
Two chiral cage clusters built from uranyl polyhedra and (HPO3)2– groups have been synthesized in pure yield and characterized structurally and spectroscopically in the solid state and aqueous solution. Synthesis reactions under ambient conditions in mildly acidic aqueous solutions gave clusters U22PO3 and U28PO3 that contain belts of four uranyl peroxide pentagonal and hexagonal bipyramids, in contrast to earlier reported uranyl peroxide cage clusters that are built from four-, five-, and six-membered rings of uranyl hexagonal bipyramids. U22PO3 and U28PO3 are also the first chiral uranyl-based cage clusters, the first that contain uranyl pentagonal bipyramids that contain no peroxide ligands, and the first that incorporate (HPO3)2– bridges between uranyl ions. They are built from 22 uranyl polyhedra and 20 (HPO3)2– groups, or 28 uranyl polyhedra and 24 (HPO3)2– groups, with the outer and inner surfaces of the cages passivated by the O atoms of uranyl ions. Small-angle X-ray scattering (SAXS) profiles demonstrated that U22PO3 clusters formed in solution within 1 h after mixing of reactants, and remained in solution for 2 weeks prior to crystallization. Time-resolved electrospray ionization mass spectrometry and SAXS demonstrated that U28PO3 clusters formed in solution within 1 h of mixing the reactants, and remained in solution 1 month before crystallization. Crystallization of U22PO3 and U28PO3 is accelerated by addition of KNO3. Clusters of U22PO3 with and without encapsulated cations exhibit markedly different aqueous solubility, reflecting the importance of cluster surface charge in fostering linkages through counterions to form a stable solid.
Co-reporter:Zuolei Liao, Jie Ling, Laura R. Reinke, Jennifer E. S. Szymanowski, Ginger E. Sigmon and Peter C. Burns
Dalton Transactions 2013 vol. 42(Issue 19) pp:6793-6802
Publication Date(Web):05 Mar 2013
DOI:10.1039/C3DT33025G
The family of cage clusters built by uranyl ions bridged through bidentate peroxide groups has been expanded by incorporation of 1-hydroxyethane-1,1-diphosphonic (etidronic) acid ligands. Six cage clusters containing from 16 to 64 uranyl ions, as well as from eight to 32 etidronic acid ligands have been synthesized and characterized. Incorporation of etidronic acid ligands introduces both new cluster topologies and organic functional groups to this class of nanoscale materials. The anionic clusters were crystallized from aqueous solution under ambient conditions for structural characterization, with the resulting cluster size and polyhedral connectivity influenced by the presence of Li, Na and/or K counter ions. The association of these counter ions with four and five membered rings of edge-sharing uranyl hexagonal bipyramids, such that they are coordinated by the O atoms of uranyl ions, is at times notably either consistent or inconsistent with local energetics predicted by density functional theory in earlier studies.
Co-reporter:Ernest M. Wylie, Megan K. Dustin, Jeremy S. Smith, Peter C. Burns
Journal of Solid State Chemistry 2013 Volume 197() pp:266-272
Publication Date(Web):January 2013
DOI:10.1016/j.jssc.2012.08.045
Ionothermal reactions of uranyl nitrate with various salts in methylimidazolium-based ionic liquids have produced single crystals of three uranyl compounds that incorporate imidazole derivatives as charge-balancing cations. (C4H7N2)[(UO2)(PO3F)(F)] (1) crystallizes in space group C2, a=17.952(1) Å, b=6.9646(6) Å, c=8.5062(7) Å, β=112.301(1)°, (C6H11N2)2[(UO2)(SO4)2] (2) crystallizes in space group C2/c, a=31.90(1) Å, b=9.383(5) Å, c=13.770(7) Å, β=93.999(7)° and (C6H11N2)[(UO2)2(PO4)(HPO4) (3) crystallizes in space group P21/n, a=9.307(2), b=18.067(4), c=9.765(2), β=93.171(2). The U6+ cations are present as (UO2)2+ uranyl ions coordinated by three O atoms and two F atoms in 1 and five O atoms in 2 and 3 to give pentagonal bipyramids. The structural unit in 1 is composed of F-sharing dimers of uranyl pentagonal bipyramids linked into sheets through corner-sharing fluorophosphate tetrahedra. The structural unit in 2 is composed of uranyl pentagonal bipyramids with one chelating sulfate tetrahedron linked into chains by three other corner-sharing sulfate tetrahedra. In 3, the structural unit is composed of chains of uranyl pentagonal bipyramids linked into sheets through edge- and corner-sharing phosphate and hydrogen phosphate tetrahedra. N-methylimidazolium cations occupy the interstitial space between the uranyl fluorophosphate sheets in 1, whereas 1-ethyl-3-methylimidazolium cations link the uranyl sulfate and phosphate units in 2 and 3 into extended structures.Graphical abstractThe synthesis of uranyl compounds by ionothermal treatment is explored, and provides three novel compounds and insights concerning the role of water in controlling the structural units.Highlights► Ionothermal syntheses have produced three new uranyl compounds. ► Imidazole derivatives are incorporated as charge-balancing agents. ► X-ray and spectroscopic analyses reveal variability between imidazole derivatives. ► This method offers synthetic insight in the absence of water at low temperatures.
Co-reporter:Bess Vlaisavljevich;Dr. Pere Miró;Dr. Dongxia Ma;Dr. Ginger E. Sigmon;Dr. Peter C. Burns;Dr. Christopher J. Cramer;Dr. Laura Gagliardi
Chemistry - A European Journal 2013 Volume 19( Issue 9) pp:2937-2941
Publication Date(Web):
DOI:10.1002/chem.201204149
Co-reporter:May Nyman and Peter C. Burns
Chemical Society Reviews 2012 vol. 41(Issue 22) pp:7354-7367
Publication Date(Web):13 Jun 2012
DOI:10.1039/C2CS35136F
While the d0 transition-metal POMs of Group V (V5+, Nb5+, Ta5+) and Group VI (Mo6+, W6+) have been known for more than a century, the actinyl peroxide POMs, specifically those built of uranyl triperoxide or uranyl dihydroxidediperoxide polyhedra, were only realized within the last decade. While virtually every metal on the Periodic Table can form discrete clusters of some type, the actinyls are the only—in addition to the transition-metal POMs– whose chemistry is dictated by the prevalence of the ‘yl’ oxygen ligand. Thus this emerging structural, solution, and computational chemistry of actinide POMs warrants comparison to the mature chemistry of transition-metal POMs. This assessment between the transition-metal POMs and actinyl POMs (uranyl peroxide POMs, specifically) has provided much insight to the similarities and differences between these two chemistries. We further break down the comparison between the alkaline POMs of Nb and Ta; and the acidic POMs of V, Mo and W. This more indepth literature review and discussion reveals that while an initial evaluation suggests the actinyl POMs are more akin to the alkaline transition-metal POMs, they actually share characteristics unique to the acidic POMs as well. This tutorial review is meant to provide fodder for deriving new POM chemistries of both the familiar transition-metals and the emerging actinides, as well as fostering communication and collaboration between the two scientific communities.
Co-reporter:Daniel J. Grant, Zhehui Weng, Laurent J. Jouffret, Peter C. Burns, and Laura Gagliardi
Inorganic Chemistry 2012 Volume 51(Issue 14) pp:7801-7809
Publication Date(Web):July 5, 2012
DOI:10.1021/ic3008574
The compound Na4[(UO2)(S2)3](CH3OH)8 was synthesized at room temperature in an oxygen-free environment. It contains a rare example of the [(UO2)(S2)3]4– complex in which a uranyl ion is coordinated by three bidentate persulfide groups. We examined the possible linkage of these units to form nanoscale cage clusters analogous to those formed from uranyl peroxide polyhedra. Quantum chemical calculations at the density functional and multiconfigurational wave function levels show that the uranyl–persulfide–uranyl, U–(S2)–U, dihedral angles of model clusters are bent due to partial covalent interactions. We propose that this bent interaction will favor assembly of uranyl ions through persulfide bridges into curved structures, potentially similar to the family of nanoscale cage clusters built from uranyl peroxide polyhedra. However, the U–(S2)–U dihedral angles predicted for several model structures may be too tight for them to self-assemble into cage clusters with fullerene topologies in the absence of other uranyl-ion bridges that adopt a flatter configuration. Assembly of species such as [(UO2)(S2)(SH)4]4– or [(UO2)(S2)(C2O4)4]4– into fullerene topologies with ∼60 vertices may be favored by use of large counterions.
Co-reporter:Zhehui Weng, Shuao Wang, Jie Ling, Jessica M. Morrison, and Peter C. Burns
Inorganic Chemistry 2012 Volume 51(Issue 13) pp:7185-7191
Publication Date(Web):June 11, 2012
DOI:10.1021/ic300240s
A uranyl triazole (UO2)2[UO4(trz)2](OH)2 (1) (trz = 1,2,4-triazole) was prepared using a mild solvothermal reaction of uranyl acetate with 1,2,4-triazole. Single-crystal X-ray diffraction analysis of 1 revealed it contains sheets of uranium–oxygen polyhedra and that one of the U(VI) cations is in an unusual coordination polyhedron that is intermediate between a tetraoxido core and a uranyl ion. This U(VI) cation also forms cation–cation interactions (CCIs). Infrared, Raman, and XPS spectra are provided, together with a thermogravimetric analysis that demonstrates breakdown of the compound above 300 °C. The UV–vis–NIR spectrum of 1 is compared to those of another compound that has a range of U(VI) coordination enviromments.
Co-reporter:Pere Miró, Jie Ling, Jie Qiu, Peter C. Burns, Laura Gagliardi, and Christopher J. Cramer
Inorganic Chemistry 2012 Volume 51(Issue 16) pp:8784-8790
Publication Date(Web):August 2, 2012
DOI:10.1021/ic3005536
A new wheel-shaped polyoxometalate {[W5O21]3[(UVIO2)2(μ-O2)]3}30– has been synthesized and structurally characterized. The calculated electrostatic potential reveals the protonation of several μ-oxo bridges reducing the polyoxometalate total charge. A protonated structure computed at the density functional level of theory (DFT) is in good agreement with the experimental fit. This species presents a classical polyoxometalate electronic structure with well-defined metal and oxo bands belonging to its U/W and oxo/peroxo constituents, respectively. Furthermore, fragment calculations indicate that the electronic structures of the uranyl–peroxide and polyoxotugstate fragments are little affected by the nanowheel assembly.
Co-reporter:Pius O. Adelani and Peter C. Burns
Inorganic Chemistry 2012 Volume 51(Issue 20) pp:11177-11183
Publication Date(Web):September 24, 2012
DOI:10.1021/ic301783q
A uranyl-2,2′-bipyridine coordination polymer, (UO2)2(2,2′-bpy)(CH3CO2)(O)(OH) (1; 2,2′-bpy = 2,2′-bipyridine) has been synthesized hydrothermally at 165 °C and characterized via single-crystal X-ray diffraction and UV–vis–near-IR, fluorescence, and IR spectroscopies. The structure consists of two uranyl pentagonal bipyramids that are linked through cation–cation interactions (CCIs) to form chains that are truncated in the second and third dimensions by 2,2′-bpy. These chains of uranyl polyhedra consist of a rare case of CCIs through the edge-sharing polyhedral connection mode instead of the more common corner-sharing connection mode. 1 is the first uranium(VI) compound reported that contains CCIs in which the structural unit is one-dimensional, although lower-dimensional structural units with CCIs are known for pentavalent actinides.
Co-reporter:Pius O. Adelani, Laurent J. Jouffret, Jennifer E. S. Szymanowski, and Peter C. Burns
Inorganic Chemistry 2012 Volume 51(Issue 21) pp:12032-12040
Publication Date(Web):October 25, 2012
DOI:10.1021/ic301942t
Three new uranium arsonate compounds, UO2(C6H5)2As2O5(H2O) (UPhAs-1), UO2(HO3AsC6H4AsO3H)(H2O)·H2O (UPhAs-2), and UO2(HO3AsC6H4NH2)2·H2O (UPhAs-3) have been synthesized under mild hydrothermal conditions. UPhAs-1 is constructed from UO7 pentagonal bipyramids that are chelated by the pyroarsonate moiety, [PhAs(O2)OAs(O2)Ph]2–, forming chains of layered uranyl polyhedra. Two of the phenylarsonic acids are condensed in situ to form the fused tetrahedra of the pyroarsonate moiety through a metal-mediated, thermally induced condensation process. The structure of UPhAs-2 consists of UO7 pentagonal bipyramids that are chelated by phenylenediarsonate ligands, forming one-dimensional chains of uranyl polyhedra. UPhAs-3 consists of a rare UO6 tetragonally distorted octahedron (D4h) that is on a center of symmetry and linked to two pairs of adjacent 4-aminophenylarsonate ligands. This linear chain structure is networked through hydrogen bonds between the lattice water molecules and the −NH2 moiety. All three of these compounds fluoresce at room temperature, showing characteristic vibronically coupled charge-transfer based emission.
Co-reporter:Jie Ling, Michael Ozga, Megan Stoffer and Peter C. Burns
Dalton Transactions 2012 vol. 41(Issue 24) pp:7278-7284
Publication Date(Web):17 Apr 2012
DOI:10.1039/C2DT30229B
Two complex cage clusters built from uranyl hexagonal bipyramids and multiple types of bridges between uranyl ions, U30Py10Ox5 and U38Py10Nt4, were crystallized from aqueous solution under ambient conditions. These are built from 30 uranyl hexagonal bipyramids, 10 pyrophosphate groups, and five oxalate bridges in one case, and 38 uranyl hexagonal bipyramids, 10 pyrophosphate groups, and four nitrate groups in the other. The crystal compositions are (H3O)10Li18K22[(UO2)30(O2)30(P2O7)10(C2O4)5](H2O)22 and Li24K36[(UO2)38(O2)40(OH)8(P2O7)10(NO3)4](NO3)4(H2O)n for U30Py10Ox5 and U38Py10Nt4, respectively. Cluster U30Py10Ox5 crystallizes over a narrow range of solution pH that encourages incorporation of both oxalate and pyrophosphate, with incorporation of oxalate only being favored under more acidic conditions, and pyrophosphate only under more alkaline conditions. Cluster U38Py10Nt4 contains two identical lobes consisting of uranyl polyhedra and pyrophosphate groups, with these lobes linked into the larger cluster through four nitrate groups. The synthesis conditions appear to have prevented closure of these lobes, and a relatively high nitrate concentration in solution favored formation of the larger cluster.
Co-reporter:Daniel K. Unruh, Andrew Quicksall, Laura Pressprich, Megan Stoffer, Jie Qiu, Kirill Nuzhdin, Weiqiang Wu, Mariya Vyushkova, Peter C. Burns
Journal of Solid State Chemistry 2012 Volume 191() pp:162-166
Publication Date(Web):July 2012
DOI:10.1016/j.jssc.2012.03.006
The mixed-valence chromium uranyl compounds Li5[(UO2)4(Cr(V)O5)(Cr(VI)O4)4](H2O)17 (1), (Mg(H2O)6)5[(UO2)8(Cr(V)O5)2(Cr(VI)O4)8] (2) and (NH4)5[(UO2)4(Cr(V)O5)(Cr(VI)O4)2]H2O11 (3) have been synthesized and characterized. Each contains an identical sheet of cation-centered polyhedra. Central to the connectivity of the sheet are four uranyl pentagonal bipyramids that share some of their equatorial vertices, giving a four-membered ring. The Cr(V) cation located near the center of this ring is coordinated by O atoms in a square pyramidal arrangement. The Cr(VI) is tetrahedrally coordinated by O atoms, and these tetrahedra link the four-membered rings of bipyramids. The mixed-valence nature of the sheet was verified by XANES, an EPR spectrum, and bond-valence analysis. Low-valence cations and H2O groups reside between the sheets of uranyl and chromate polyhedra, where they provide linkages between adjacent sheets.Graphical abstractThree uranyl chromate compounds contain both pentavalent and hexavalent chromium. The unusual topology of the uranyl chromate sheet contains unusual pentavalent chromium in a square pyramidal coordination environment.Highlights► The first uranyl compounds with mixed Cr valences are reported. ► A sheet of uranyl polyhedra stabilizes pentavalent chromium. ► Uranyl and chromate polyhedra form a topologically novel sheet.
Co-reporter:Ernest M. Wylie, Colleen M. Dawes, Peter C. Burns
Journal of Solid State Chemistry 2012 Volume 196() pp:482-488
Publication Date(Web):December 2012
DOI:10.1016/j.jssc.2012.07.020
Single crystals of Zn4(OH)2[(UO2)(PO4)2(OH)2(H2O)] (UZnP), Cs[(UO2)(HPO4)NO3] (UCsP), and In3[(UO2)2(PO4)4OH(H2O)6].2H2O (UInP) were obtained from hydrothermal reactions and have been structurally and chemically characterized. UZnP crystallizes in space group Pbcn, a=8.8817(7), b=6.6109(5), c=19.569(1) Å; UCsP crystallizes in P−1, a=7.015(2), b=7.441(1), c=9.393(2) Å, α=72.974(2), β=74.261(2), γ=79.498(2); and UInP crystallizes in P−1, a=7.9856(5), b=9.159(1), c=9.2398(6) Å α=101.289(1), β=114.642(1), γ=99.203(2). The U6+ cations are present as (UO2)2+ uranyl ions coordinated by five O atoms to give pentagonal bipyramids. The structural unit in UZnP is a finite cluster containing a uranyl pentagonal bipyramid that shares corners with two phosphate tetrahedra. The structural unit in UCsP is composed of uranyl pentagonal bipyramids with one chelating nitrate group that are linked into chains by three bridging hydrogen phosphate tetrahedra. In UInP, the structural unit contains pairs of edge-sharing uranyl pentagonal bipyramids with two chelating phosphate tetrahedra that are linked into chains through two bridging phosphate tetrahedra. Indium octahedra link these uranyl phosphate chains into a 3-dimensional framework. All three compounds exhibit unique structural units that deviate from the typical layered structures observed in uranyl phosphate solid-state chemistry.Graphical abstractThree new uranyl phosphates with unique structural units are reported. Highlights► Three new uranyl phosphates have been synthesized hydrothermally. ► Single crystal analyses reveal unique structural units. ► The dimensionality of these compounds deviate from typical U6+ layered structures
Co-reporter:Daniel K. Unruh, Michelle Baranay, Laura Pressprich, Megan Stoffer, Peter C. Burns
Journal of Solid State Chemistry 2012 Volume 186() pp:158-164
Publication Date(Web):February 2012
DOI:10.1016/j.jssc.2011.11.033
Eight uranyl chromates have been crystallized from aqueous solution and characterized: Mg(H2O)6[(UO2)2(CrO4)2(OH)2](H2O)3 (1), (NH4)2[(UO2)2(CrO4)2(OH)2](H2O)3, Rb2[(UO2)2(CrO4)2(OH)2](H2O)3 (3), Cs[(UO2)(CrO4)(OH)]H2O (4), Rb[(UO2)(CrO4)(OH)]H2O (5) Co(H2O)4(Co(H2O)6)2[(UO2)4(CrO4)6(OH)2](H2O)4 (6), Li2[(UO2)2(CrO4)3](H2O)7 (7), and Zn(H2O)6[(UO2)2(CrO4)3](H2O)3 (8). The structural units of 1 through 8 each consist of a sheet of uranyl pentagonal bipyramids and (Cr(VI)O4)2− tetrahedra. In each case two uranyl pentagonal bipyramids share an equatorial edge, giving a dimer that is linked into the sheet through vertex sharing with (Cr(VI)O4)2− tetrahedra. The sheets are based upon three distinct sheet anion topologies, and the sheets based on a given anion topology can differ in the orientations of the non-bridging O atoms of (CrO4)2− tetrahedra. The interlayers of these compounds contain either monovalent or divalent cations, as well as H2O groups that are either bonded to the interlayer cation or are held in place by H bonding only. We explore the relationships between sheet topologies and interlayer configuration in these compounds.Graphical abstractEight uranyl chromate compounds containing sheet structural units built from uranyl pentagonal bipyramids and (CrO4)2− tetrahedra are reported. Relationships between sheet topologies and interstitial constituents is examined.Highlights► Eight uranyl Cr(VI) compounds with sheet structural units are reported. ► Relationships between the topology of the uranyl chromate sheets and interlayers are examined. ► Uranyl and chromate polyhedra form a topologically novel sheet.
Co-reporter:Peter C. Burns;Alexandra Navrotsky;Rodney C. Ewing
Science 2012 Volume 335(Issue 6073) pp:1184-1188
Publication Date(Web):09 Mar 2012
DOI:10.1126/science.1211285
Co-reporter:Jie Qiu ; Jie Ling ; Audrey Sui ; Jennifer E. S. Szymanowski ; Antonio Simonetti
Journal of the American Chemical Society 2011 Volume 134(Issue 3) pp:1810-1816
Publication Date(Web):December 20, 2011
DOI:10.1021/ja210163b
A complex core–shell cluster consisting of 68 uranyl peroxo polyhedra, 16 nitrate groups, and ∼44 K+ and Na+ cations was obtained by self-assembly in alkaline aqueous solution under ambient conditions. Crystals formed after a month and were characterized. The cluster, designated as {U1⊂U28⊂U40R}, contains a fullerene-topology cage built from 28 uranyl polyhedra. A ring consisting of 40 uranyl polyhedra linked into five-membered rings and 16 nitrate groups surrounds this cage cluster. Topological pentagons in the cage and ring are aligned, and their corresponding rings of uranyl bipyramids are linked through K+ cations located between the two shells. A partially occupied U site is located at the center of the cluster. Time-resolved small-angle X-ray scattering and electrospray ionization mass spectrometry demonstrated that the U28 cage cluster formed in solution within an hour, whereas the U40R shell formed around the cage cluster after more than several days.
Co-reporter:Ginger E. Sigmon
Journal of the American Chemical Society 2011 Volume 133(Issue 24) pp:9137-9139
Publication Date(Web):May 24, 2011
DOI:10.1021/ja2013449
Clusters built from 32 uranyl peroxide polyhedra self-assemble and crystallize within 15 min after combining uranyl nitrate, ammonium hydroxide, and hydrogen peroxide in aqueous solution under ambient conditions. These novel crown-shaped clusters are remarkable in that they form so quickly, have extraordinarily low aqueous solubility, form with at least two distinct peroxide to hydroxyl ratios, and form in very high yield. The clusters, which have outer diameters of 23 Å, topologically consist of eight pentagons and four hexagons. Their rapid formation and low solubility in aqueous systems may be useful properties at various stages in an advanced nuclear energy system.
Co-reporter:Jessica M. Morrison ; Laura J. Moore-Shay
Inorganic Chemistry 2011 Volume 50(Issue 6) pp:2272-2277
Publication Date(Web):February 3, 2011
DOI:10.1021/ic1019444
The isomorphous compounds NH4[(UO6)2(UO2)9(GeO4)(GeO3(OH))] (1), K[(UO6)2(UO2)9(GeO4)(GeO3(OH))] (2), Li3O[(UO6)2(UO2)9(GeO4)(GeO3(OH))] (3), and Ba[(UO6)2(UO2)9(GeO4)2] (4) were synthesized by hydrothermal reaction at 220 °C. The structures were determined using single crystal X-ray diffraction and refined to R1 = 0.0349 (1), 0.0232 (2), 0.0236 (3), 0.0267 (4). Each are trigonal, P3̅1c. 1: a = 10.2525(5), c = 17.3972(13), V = 1583.69(16) Å3, Z = 2; 2: a = 10.226(4), c = 17.150(9), V = 1553.1(12) Å3, Z = 2; 3: a = 10.2668(5), c = 17.0558(11), V = 1556.94(15) Å3, Z = 2; 4: a = 10.2012(5), c = 17.1570(12), V = 1546.23(15) Å3, Z = 2. There are three symmetrically independent U sites in each structure, two of which correspond to typical (UO2)2+ uranyl ions and the other of which is octahedrally coordinated by six O atoms. One of the uranyl ions donates a cation−cation interaction, and accepts a different cation−cation interaction. The linkages between the U-centered polyhedra result in a relatively dense three-dimensional framework. Ge and low-valence sites are located within cavities in the framework of U-polyhedra. Chemical, thermal, and spectroscopic characterizations are provided.
Co-reporter:Daniel K. Unruh ; Jie Ling ; Jie Qiu ; Laura Pressprich ; Melissa Baranay ; Matthew Ward
Inorganic Chemistry 2011 Volume 50(Issue 12) pp:5509-5516
Publication Date(Web):May 19, 2011
DOI:10.1021/ic200065y
Five cage clusters that self-assemble in alkaline aqueous solution have been isolated and characterized. Each is built from uranyl hexagonal bipyramids with two or three equatorial edges occupied by peroxide, and three also contain phosphate tetrahedra. These clusters contain 30 uranyl polyhedra; 30 uranyl polyhedra and six pyrophosphate groups; 30 uranyl polyhedra, 12 pyrophosphate groups, and one phosphate tetrahedron; 42 uranyl polyhedra; and 40 uranyl polyhedra and three pyrophosphate groups. These clusters present complex topologies as well as a range of compositions, sizes, and charges. Two adopt fullerene topologies, and the others contain combinations of topological squares, pentagons, and hexagons. An analysis of possible topologies further indicates that higher-symmetry topologies are favored.
Co-reporter:Jie Ling, Matthew Ward, Peter C. Burns
Journal of Solid State Chemistry 2011 Volume 184(Issue 2) pp:401-404
Publication Date(Web):February 2011
DOI:10.1016/j.jssc.2010.12.007
Two uranyl tellurates, AgUO2(HTeO5) (1) and Pb2UO2(TeO6) (2), were synthesized under hydrothermal conditions and were structurally, chemically, and spectroscopically characterized. 1 crystallizes in space group Pbca, a=7.085(2) Å, b=11.986(3) Å, c=13.913(4) Å, V=1181.5(5) Å3, Z=8; 2 is in P2(1)/c, a=5.742(1) Å, b=7.789(2) Å, c=7.928(2) Å, V=90.703(2) Å3, and Z=2. These are the first structures reported for uranyl compounds containing tellurate. The U6+ cations are present as (UO2)2+ uranyl ions that are coordinated by O atoms to give pentagonal and square bipyramids in compounds 1 and 2, respectively. The structural unit in 1 is a sheet consisting of chains of edge-sharing uranyl pentagonal bipyramids that are one bipyramid wide, linked through the dimers of TeO6 octahedra. In 2, uranyl square bipyramids share each of their equatorial vertices with different TeO6 octahedra, giving a sheet with the autunite-type topology. Sheets in 1 and 2 are connected through the low-valence cations that are located in the interlayer region. The structures of 1 and 2 are compared to those of uranyl compounds containing octahedrally coordinated cations.Graphical abstractTwo hydrothermally synthesized uranyl tellurates, AgUO2(HTeO5) and Pb2UO2(TeO6), contain sheets built from uranyl pentagonal or square bipyramids, as well as tellurate octahedra.Research highlights► Compounds AgUO2(HTeO5) and Pb2UO2(TeO6) are the first uranyl tellurate compounds. ► The structure of AgUO2(HTeO5) consists of sheets of uranyl pentagonal bipyramids and TeO6 octahedra. ► The structure of Pb2UO2(TeO6) contains sheets of TeO6 octahedra and uranyl square bipyramids.
Co-reporter:Dr. Jie Ling;Dr. Jie Qiu;Jennifer E. S. Szymanowski; Peter C. Burns
Chemistry - A European Journal 2011 Volume 17( Issue 9) pp:2571-2574
Publication Date(Web):
DOI:10.1002/chem.201003481
Co-reporter:Jie Ling ; Jie Qiu ; Ginger E. Sigmon ; Matthew Ward ; Jennifer E. S. Szymanowski
Journal of the American Chemical Society 2010 Volume 132(Issue 38) pp:13395-13402
Publication Date(Web):September 2, 2010
DOI:10.1021/ja1048219
Despite potential applications in advanced nuclear energy systems, nanoscale control of uranium materials is in its infancy. In its hexavalent state, U occurs as (UO2)2+ uranyl ions that are coordinated by various ligands to give square, pentagonal, or hexagonal bipyramids. Creation and design of nanostructured uranyl materials requires interruption of the tendency of uranyl bipyramids to share equatorial edges to form infinite sheets that occur in extended structures. Where a bidentate peroxide group bridges uranyl bipyramids, the configuration is inherently bent, fostering formation of cage clusters. Here the bent configurations of four- and five-membered rings of uranyl peroxide hexagonal bipyramids are bridged by pyrophosphate or methylenediphosphonate, creating eight chemically complex cage clusters with specific topologies. Chemical complexity in such clusters provides opportunities for the tuning of cage sizes, pore sizes, and properties such as aqueous solubility. Several of these are topological derivatives of simpler clusters that contain only uranyl bipyramids, whereas others exhibit new topologies.
Co-reporter:Bess Vlaisavljevich ; Laura Gagliardi
Journal of the American Chemical Society 2010 Volume 132(Issue 41) pp:14503-14508
Publication Date(Web):September 24, 2010
DOI:10.1021/ja104964x
Quantum chemical calculations were performed to understand the formation of nanoscale cage clusters based on uranyl ions. We investigated the uranyl−peroxide−uranyl interaction and compared the geometries of clusters with and without such interactions. We show that a covalent interaction along the U−Operoxo bonds causes the U−O2−U dihedral angle to be bent, and it is this inherent bending of the configuration that encourages curvature and cage cluster formation. The U−O2−U dihedral angle of the peroxo bridge is tuned by the size or electronegativity of the counterion present.
Co-reporter:Jie Ling ; Jessica M. Morrison ; Matthew Ward ; Kelsey Poinsatte-Jones
Inorganic Chemistry 2010 Volume 49(Issue 15) pp:7123-7128
Publication Date(Web):July 7, 2010
DOI:10.1021/ic1010242
Three uranyl germanates, Cs2[(UO2)(Ge2O6)](H2O) (1), Ag[(UO2)2(HGe2O7)](H2O) (2), and Ag2[(UO2)3(GeO4)2](H2O)2 (3) were synthesized under hydrothermal conditions, and their structures were determined by single crystal X-ray diffraction. Compound 1 crystallizes in space group P21/n, a = 7.9159(2) Å, b = 21.5949(5) Å, c = 12.4659(3) Å, β = 96.964(1)°, V = 2115.24(9) Å3, Z = 8; 2 is orthorhombic Ama2, a = 7.124(1) Å, b = 10.771(2) Å, c = 14.024(1) Å, V = 1076.2(4) Å3, Z = 4; 3 is orthorhombic Pnma, a = 10.0462(6) Å, b = 7.4699(5) Å, c = 17.776(1) Å, V = 1334.0(2) Å3, Z = 4. These compounds are frameworks of uranyl square (1) or pentagonal (2, 3) bipyramids and four-membered rings of germanate tetrahedra (1), dimers of germanate tetrahedra (2), or chains of GeO5 triangular bipyramids (3). There are channels through each of the frameworks that contain the low-valence cations and the H2O groups. Compound 1 dehydrates upon heating, but the framework remains intact to at least 900 °C.
Co-reporter:Daniel K. Unruh ; Michelle Baranay ; Melissa Baranay
Inorganic Chemistry 2010 Volume 49(Issue 15) pp:6793-6795
Publication Date(Web):June 28, 2010
DOI:10.1021/ic100871z
The synthesis and structural characterization of the compounds K[(UO2)2(UO4)(OH)(NO3)2]H2O (1) and Ba[(UO2)4(UO4)2(OH)2(NO3)4]H2O (2) have revealed that each contains sheets that are based upon the β-U3O8-type topology and that these sheets are linked through low-valence interlayer cations. Consistent with other uranium(VI) compounds that have topologically identical sheets, one of the uranium(VI) sites exhibits a highly unusual (UO4)2− tetraoxido core that is further coordinated by two bidentate (NO3)− groups.
Co-reporter:Daniel K. Unruh, Alicia Burtner, Laura Pressprich, Ginger E. Sigmon and Peter C. Burns
Dalton Transactions 2010 vol. 39(Issue 25) pp:5807-5813
Publication Date(Web):25 May 2010
DOI:10.1039/C0DT00074D
Four self-assembling clusters of uranyl peroxide polyhedra have been formed in alkaline aqueous solutions and structurally characterized. These clusters consist of 28, 30, 36 and 44 uranyl polyhedra and exhibit complex new topologies. Each has a structure that contains topological squares, pentagons and hexagons. Analysis of possible topologies within boundary constraints indicates a tendency for adoption of higher symmetry topologies in these cases. Small angle X-ray scattering data demonstrated that crystals of one of these clusters can be dissolved in ultrapure water and that the clusters remain intact for at least several days.
Co-reporter:Ginger E. Sigmon, Peter C. Burns
Journal of Solid State Chemistry 2010 Volume 183(Issue 7) pp:1604-1608
Publication Date(Web):July 2010
DOI:10.1016/j.jssc.2010.04.042
The structures and infrared spectra of six novel thorium compounds are reported. Th(NO3)2(OH)2(H2O)2 (1) crystallizes in space group C2/c, a=14.050(1), b=8.992(7), c=5.954(5) Å, β=101.014(2)°. K2Th(NO3)6 (2), P-3, a=13.606(1), c=6.641(6) Å. (C12H28N)2Th(NO3)6 (3), P21/c, a=14.643(4), b=15.772(5), c=22.316(5) Å, β=131.01(1)°. KTh(NO3)5(H2O)2 (4), P21/c, a=10.070(8), b=12.731(9), c=13.231(8) Å, β=128.647(4)°. Th(CrO4)2(H2O)2 (5), P21/n, a=12.731(1), b=9.469(8), c=12.972(1) Å, β=91.793(2)°. K2Th3(CrO4)7(H2O)10 (6), Ama2, a=19.302(8), b=15.580(6), c=11.318(6) Å. The coordination polyhedra about Th in these structures are diverse. Th is coordinated by 9 O atoms in 5 and 6, seven of which are from monodentate (CrO4) tetrahedra and two are (H2O). The Th in compound 1 is coordinated by ten O atoms, four of which are O atoms of two bidentate (NO3) triangles and six of which are (OH) and (H2O). In compounds 2, 3 and 4 the Th is coordinate by 12 O atoms. In 2 and 3 there are six bidentate (NO3) triangles, and in 4 ten of the O atoms are part of five bidentate (NO3) triangles and the others are (H2O) groups. The structural units of these compounds consist of a chain of thorium and nitrate polyhedra (1), isolated thorium hexanitrate clusters (2, 3), an isolated thorium pentanitrate dihydrate cluster (4), and a sheet (6) and framework (5) of thorium and chromate polyhedra. These structures illustrate the complexity inherent in the crystal chemistry of Th.Graphical AbstractThe structures and infrared spectra of four new Th nitrates and two Th chromates are reported. The coordination numbers of the Th cations range from nine to 12 in these compounds. Structural units consist of isolated clusters, chains, sheets and frameworks.
Co-reporter:Dr. Jie Ling;Christine M. Wallace;Jennifer E. S. Szymanowski; Peter C. Burns
Angewandte Chemie International Edition 2010 Volume 49( Issue 40) pp:7271-7273
Publication Date(Web):
DOI:10.1002/anie.201003197
Co-reporter:Dr. Jie Ling;Christine M. Wallace;Jennifer E. S. Szymanowski; Peter C. Burns
Angewandte Chemie 2010 Volume 122( Issue 40) pp:7429-7431
Publication Date(Web):
DOI:10.1002/ange.201003197
Co-reporter:Ginger E. Sigmon ; Jie Ling ; Daniel K. Unruh ; Laura Moore-Shay ; Matthew Ward ; Brittany Weaver
Journal of the American Chemical Society 2009 Volume 131(Issue 46) pp:16648-16649
Publication Date(Web):October 30, 2009
DOI:10.1021/ja907837u
Uranyl peroxide polyhedra are known to self-assemble into complex closed clusters with fullerene and other topologies containing as many as 60 polyhedra. Here clusters containing 20 uranyl pentagonal triperoxides have been isolated and characterized that assume the smallest possible fullerene topology consisting only of 12 pentagons. Oxalate has been used to crystallize fragments of larger uranyl peroxide clusters, and these fragments and other known structures indicate that the U−O2−U dihedral angle is inherently bent. Such bending is thought to be essential in directing the self-assembly of uranyl peroxide polyhedra into closed clusters.
Co-reporter:Daniel K. Unruh, Alicia Burtner and Peter C. Burns
Inorganic Chemistry 2009 Volume 48(Issue 6) pp:2346-2348
Publication Date(Web):February 17, 2009
DOI:10.1021/ic8024217
Uranyl peroxides have been intensively studied recently because they form topologically complex structures including spherical clusters containing tens of uranyl polyhedra. In all uranyl peroxides reported to date, the coordination of U6+ cations by peroxide is bidentate. The compound K2(Mg(H2O)6)4[(UO2)3(O2)8]·2H2O has been synthesized and characterized and contains a trimer of linked uranyl peroxide polyhedra. The central U6+ cation is linked to two peroxide groups in a μ-η2:η1 configuration. Inclusion of this mode of linkage could dramatically increase the flexibility and topological complexity of uranyl peroxide nanoscale clusters.
Co-reporter:Ginger E. Sigmon ; Brittany Weaver ; Karrie-Ann Kubatko
Inorganic Chemistry 2009 Volume 48(Issue 23) pp:10907-10909
Publication Date(Web):October 26, 2009
DOI:10.1021/ic9020355
Bowl (U16) and crown-shaped clusters (U20R and U24R) containing 16, 20, and 24 uranyl peroxide polyhedra self-assemble in alkaline aqueous solution under ambient conditions. Structural analyses of crystallized clusters provided details of their topologies. Each contains uranyl hexagonal bipyramids in which two cis edges are peroxide, with a third edge defined by two OH groups, as well as hexagonal bipyramids in which three edges are peroxide. These are the first open uranyl peroxide clusters reported, and they join a growing family of complex cluster topologies based on uranium that hold promise for nanoscale control of chemistry in nuclear energy cycles.
Co-reporter:Jie Ling, Ginger E. Sigmon, Peter C. Burns
Journal of Solid State Chemistry 2009 Volume 182(Issue 2) pp:402-408
Publication Date(Web):February 2009
DOI:10.1016/j.jssc.2008.11.013
Five hybrid organic–inorganic uranyl selenates have been synthesized, characterized and their structures have been determined. The structure of (C2H8N)2[(UO2)2(SeO4)3(H2O)] (EthylAUSe) is monoclinic, P21, a=8.290(1), b=12.349(2), c=11.038(2) Å, β=104.439(4)°, V=1094.3(3) Å3, Z=2, R1=0.0425. The structure of (C7H10N)2[(UO2)(SeO4)2(H2O)]H2O (BenzylAUSe) is orthorhombic, Pna21, a=24.221(2), b=11.917(1), c=7.4528(7) Å, V=2151.1(3) Å3, Z=4, R1=0.0307. The structure of (C2H10N2)[(UO2)(SeO4)2(H2O)](H2O)2 (EDAUSe) is monoclinic, P21/c, a=11.677(2), b=7.908(1), c=15.698(2) Å, β=98.813(3)°, V=1432.4(3) Å3, Z=4, R1=0.0371. The structure of (C6H22N4)[(UO2)(SeO4)2(H2O)](H2O) (TETAUSe) is monoclinic, P21/n, a=13.002(2), b=7.962(1), c=14.754(2) Å, β=114.077(2)°, V=1394.5(3) Å3, Z=4, R1=0.0323. The structure of (C6H21N4)[(UO2)(SeO4)2(HSeO4)] (TAEAUSe) is monoclinic, P21/m, a=9.2218(6), b=12.2768(9), c=9.4464(7) Å, β=116.1650(10)°, V=959.88(12) Å3, Z=2, R1=0.0322. The inorganic structural units in these compounds are composed of uranyl pentagonal bipyramids and selenate tetrahedra. In each case, tetrahedra link bipyramids through vertex-sharing, resulting in chain or sheet topologies. The charge-density matching principle is discussed relative to the orientations of the organic molecules between the inorganic structural units.The structures of five new inorganic–organic hybrid uranyl selenates present new structural topologies based upon chains and sheets of uranyl pentagonal bipyramids and selenate tetrahedra.
Co-reporter:T.Z. Forbes, P.C. Burns
Journal of Solid State Chemistry 2009 Volume 182(Issue 1) pp:43-48
Publication Date(Web):January 2009
DOI:10.1016/j.jssc.2008.08.032
The compound (NpO2)2(SO4)(H2O)4 was synthesized by evaporation of a Np5+ sulfate solution. The crystal structure was determined using single crystal X-ray diffraction and refined to an R1=0.0310. (NpO2)2(SO4)(H2O)4 crystallizes in triclinic space group P-1, a=8.1102(7) Å, b=8.7506(7) Å, c=16.234(1) Å, α=90.242(2)°, β=92.855(2)°, γ=113.067(2)°, V=1058.3(2) Å3, and Z=2. The structure contains neptunyl pentagonal bipyramids that share vertices through cation–cation interactions to form a sheet or cationic net. The sheet is decorated on each side by vertex sharing with sulfate tetrahedra, and adjacent sheets are linked together through hydrogen bonding. A graphical representation of (NpO2)2(SO4)(H2O)4 was constructed to facilitate the structural comparison to similar Np5+ compounds. The prevalence of the cationic nets in neptunyl sulfate compounds related to the overall stability of the structure is also discussed.(NpO2)2(SO4)(H2O)4 was synthesized by hydrothermal methods and its structure determined. A graphical representation of the compound was constructed to facilitate the structural comparison to similar Np5+ compounds and the prevalence of the cationic nets in neptunyl sulfate compounds related to the overall stability of the structure is discussed.
Co-reporter:GingerE. Sigmon;DanielK. Unruh;Jie Ling;Brittany Weaver;Matthew Ward;Laura Pressprich;Antonio Simonetti ;PeterC. Burns
Angewandte Chemie International Edition 2009 Volume 48( Issue 15) pp:2737-2740
Publication Date(Web):
DOI:10.1002/anie.200805870
Co-reporter:GingerE. Sigmon;DanielK. Unruh;Jie Ling;Brittany Weaver;Matthew Ward;Laura Pressprich;Antonio Simonetti ;PeterC. Burns
Angewandte Chemie 2009 Volume 121( Issue 15) pp:2775-2778
Publication Date(Web):
DOI:10.1002/ange.200805870
Co-reporter:ToriZ. Forbes Dr.;J.Gregory McAlpin;Rachel Murphy;PeterC. Burns
Angewandte Chemie 2008 Volume 120( Issue 15) pp:2866-2869
Publication Date(Web):
DOI:10.1002/ange.200705563
Co-reporter:ToriZ. Forbes Dr.;J.Gregory McAlpin;Rachel Murphy;PeterC. Burns
Angewandte Chemie International Edition 2008 Volume 47( Issue 15) pp:
Publication Date(Web):
DOI:10.1002/anie.200890063
Co-reporter:ToriZ. Forbes Dr.;J.Gregory McAlpin;Rachel Murphy;PeterC. Burns
Angewandte Chemie 2008 Volume 120( Issue 15) pp:
Publication Date(Web):
DOI:10.1002/ange.200890063
Co-reporter:ToriZ. Forbes Dr.;J.Gregory McAlpin;Rachel Murphy;PeterC. Burns
Angewandte Chemie International Edition 2008 Volume 47( Issue 15) pp:2824-2827
Publication Date(Web):
DOI:10.1002/anie.200705563
Co-reporter:T.Z. Forbes, P.C. Burns
Journal of Solid State Chemistry 2007 Volume 180(Issue 1) pp:106-112
Publication Date(Web):January 2007
DOI:10.1016/j.jssc.2006.09.026
The compound K4(NpO2)3Cl7(H2O)4 was synthesized by evaporation of a Np5+-bearing solution. The crystal structure was determined by single crystal X-ray diffraction and refined to R1=0.0374. The compound is triclinic, P−1, a=8.882(1) Å, b=12.082(2) Å, c=12.403(2) Å, α=65.855(2)°, β=69.604(2)°, γ=74.432(2)°, V=1126.0(3) Å3, and Z=2. The structure contains dimers of edge sharing Np5+ pentagonal bipyramids that are linked into infinite chains through cation–cation interactions with an additional Np5+ pentagonal bipyramid. The structural units are linked through bonds to interstitial K cations and by H bonding. A graphical representation for neptunyl structural units including cation–cation interactions is introduced.The structure of K4(NpO2)3Cl7(H2O)4 contains neptunyl pentagonal bipyramids that are linked into chains through cation–cation interactions.
Co-reporter:Tori Z. Forbes, Peter C. Burns
Journal of Solid State Chemistry 2005 Volume 178(Issue 11) pp:3445-3452
Publication Date(Web):November 2005
DOI:10.1016/j.jssc.2005.08.017
Four Np5+ sulfates, X4[(NpO2)(SO4)2]Cl (X=K, Rb) (KS1, RbS1), Na3[(NpO2)(SO4)2](H2O)2.5 (NaS1), and CaZn2[(NpO2)2(SO4)4](H2O)10 (CaZnS1) were synthesized by evaporation of solutions derived from hydrothermal treatment. Their structures were solved by direct methods and refined on the basis of F2 for all unique data collected with MoKα radiation and a CCD-based detector to agreement indices (KS1, RbS1, NaS1, CaZnS 1) R1=0.0237R1=0.0237, 0.0593, 0.0363, 0.0265 calculated for 2617, 2944, 2635, 2572 unique observed reflections, respectively. KS1 crystallizes in space group P2/n , a=10.0873(4)a=10.0873(4), b=4.5354(2)b=4.5354(2), c=14.3518(6)c=14.3518(6), β=103.383(1)°β=103.383(1)°, V=638.76(5)Å3, Z=2Z=2. RbS1 is also monoclinic, P2/n , with a=10.5375(8)a=10.5375(8), b=4.6151(3)b=4.6151(3), c=16.0680(12)c=16.0680(12), β=103.184(1)°β=103.184(1)°, V=699.33(9)Å3, Z=2Z=2. NaS1 is monoclinic, P21/m , with a=7.6615(5)a=7.6615(5), b=7.0184(4)b=7.0184(4), c=11.0070(7)c=11.0070(7), β=90.787(1)°β=90.787(1)°, V=591.81(6)Å3, Z=4Z=4. CaZnS1 is monoclinic, P21/m, with a=8.321(2)a=8.321(2), b=7.0520(2)b=7.0520(2), c=10.743(3)c=10.743(3), β=91.758(5)°β=91.758(5)°, V=630.1(3)Å3, Z=2Z=2. The structures of KS1 and RbS1 contain chains of edge-sharing neptunyl hexagonal bipyramids, with sulfate tetrahedra attached to either side of the chain by sharing edges with the bipyramids. NaS1 and CaZnS1 both contain chains of neptunyl pentagonal bipyramids and sulfate tetrahedra in which each bipyramid is linked to four tetrahedra, three by sharing vertices and one by sharing an edge. Bipyramids are bridged by sharing vertices with sulfate tetrahedra. Each of these structures exhibits significant departures from those of uranyl sulfates.The structures of four Np5+ sulfates, X4[(NpO2)(SO4)2]Cl (X=K, Rb), Na3[(NpO2)(SO4)2](H2O)2.5, and CaZn2[(NpO2)2(SO4)4](H2O)10 contain chains formed by the sharing of edges and vertices between neptunyl polyhedra and sulfate tetrahedra. These structures exhibit significant departures from those of uranyl sulfates.
Co-reporter:Peter C. Burns ;Karrie-Ann Kubatko;Ginger Sigmon;Brian J. Fryer Dr.;Joel E. Gagnon;Mark R. Antonio Dr.;L Soderholm Dr.
Angewandte Chemie International Edition 2005 Volume 44(Issue 14) pp:
Publication Date(Web):22 MAR 2005
DOI:10.1002/anie.200462445
Waste not: Actinyl nanospheres self-assembled from alkaline solutions have been shown to be composed of 24, 28, and 32 actinyl peroxide polyhedra (for example, see picture of the uranyl peroxide polyhedra (U-28)). The nanospheres represent a new class of polyoxometalates, and their formation in nuclear waste may have an impact on the mobility of actinides in the environment.
Co-reporter:Peter C. Burns ;Karrie-Ann Kubatko;Ginger Sigmon;Brian J. Fryer Dr.;Joel E. Gagnon;Mark R. Antonio Dr.;L Soderholm Dr.
Angewandte Chemie International Edition 2005 Volume 44(Issue 14) pp:
Publication Date(Web):22 MAR 2005
DOI:10.1002/anie.200590044
Co-reporter:Peter C. Burns ;Karrie-Ann Kubatko;Ginger Sigmon;Brian J. Fryer Dr.;Joel E. Gagnon;Mark R. Antonio Dr.;L Soderholm Dr.
Angewandte Chemie 2005 Volume 117(Issue 14) pp:
Publication Date(Web):22 MAR 2005
DOI:10.1002/ange.200462445
Nicht vergeuden: Actinyl-Nanokugeln, die sich in alkalischen Lösungen bilden, bestehen aus 24, 28 und 32 Actinylperoxid-Polyedern (als Beispiel sind die Uranylperoxid-Polyeder (U-28) gezeigt). Die Nanokugeln bilden eine neue Klasse von Polyoxometallaten, und ihre Bildung in Nuklearabfällen könnte einen Einfluss auf die Mobilität von Actinoiden in der Umwelt haben.
Co-reporter:Peter C. Burns ;Karrie-Ann Kubatko;Ginger Sigmon;Brian J. Fryer Dr.;Joel E. Gagnon;Mark R. Antonio Dr.;L Soderholm Dr.
Angewandte Chemie 2005 Volume 117(Issue 14) pp:
Publication Date(Web):22 MAR 2005
DOI:10.1002/ange.200590044
Co-reporter:Karrie-Ann Hughes Kubatko;Katheryn B. Helean;Alexandra Navrotsky
Science 2003 Vol 302(5648) pp:1191-1193
Publication Date(Web):14 Nov 2003
DOI:10.1126/science.1090259
Abstract
Minerals containing peroxide are limited to studtite, (UO2)O2(H2O)4, and metastudtite, (UO2)O2(H2O)2. High-temperature oxide-melt solution calorimetry and solubility measurements for studtite (standard enthalpy of formation at 298 kelvin is –2344.7 ± 4.0 kilojoules per mole from the elements) establishes that these phases are stable in peroxide-bearing environments, even at low H2O2 concentrations. Natural radioactivity in a uranium deposit, or the radioactivity of nuclear waste, can create sufficient H2O2 by alpha radiolysis of water for studtite formation. Studtite and metastudtite may be important alteration phases of nuclear waste in a geological repository and of spent fuel under any long-term storage, possibly at the expense of the commonly expected uranyl oxide hydrates and uranyl silicates.
Co-reporter:Sergey V. Krivovichev, Peter C. Burns
Journal of Solid State Chemistry 2003 Volume 170(Issue 1) pp:106-117
Publication Date(Web):January 2003
DOI:10.1016/S0022-4596(02)00033-6
Two new mixed organic–inorganic uranyl molybdates, (C6H14N2)3[(UO2)5(MoO4)8](H2O)4 (1) and (C2H10N2)[(UO2)(MoO4)2] (2), have been obtained by hydrothermal methods. The structure of 1 [triclinic, , Z=1, a=11.8557(9), b=11.8702(9), c=12.6746(9) Å, α=96.734(2)°, β=91.107(2)°, γ=110.193(2)°, V=1659.1(2) Å] has been solved by direct methods and refined on the basis of F2 for all unique reflections to R1=0.058, which was calculated for the 5642 unique observed reflections (|Fo|⩾4σF). The structure contains topologically novel sheets of uranyl square bipyramids, uranyl pentagonal bipyramids, and MoO4 tetrahedra, with composition [(UO2)5(MoO4)8]6−, that are parallel to (−101). H2O groups and 1,4-diazabicyclo [2.2.2]-octane (DABCO) molecules are located in the interlayer, where they provide linkage of the sheets. The structure of 2 [triclinic, , Z=2, a=8.4004(4), b=11.2600(5), c=13.1239(6) Å, α=86.112(1)°, β=86.434(1)°, γ=76.544(1)°, V=1203.14(10) Å] has been solved by direct methods and refined on the basis of F2 for all unique reflections to R1=0.043, which was calculated for 5491 unique observed reflections (|Fo|⩾4σF). The structure contains topologically novel sheets of uranyl pentagonal bipyramids and MoO4 tetrahedra, with composition [(UO2)(MoO4)2]2−, that are parallel to (110). Ethylenediamine molecules are located in the interlayer, where they provide linkage of the sheets. All known topologies of uranyl molybdate sheets of corner-sharing U and Mo polyhedra can be described by their nodal representations (representations as graphs in which U and Mo polyhedra are given as black and white vertices, respectively). Each topology can be derived from a simple black-and-white graph of six-connected black vertices and three-connected white vertices by deleting some of its segments and white vertices.
Co-reporter:Yaping Li, Peter C Burns
Journal of Nuclear Materials 2001 Volume 299(Issue 3) pp:219-226
Publication Date(Web):December 2001
DOI:10.1016/S0022-3115(01)00702-4
Single crystals of two sodium uranyl phases, Na2[(UO2)3O3(OH)2] and Na4(UO2)2(Si4O10)2(H2O)4 (designated NAUOH and NAURSI, respectively), were hydrothermally synthesized. Na uranyl oxyhydroxide (NAUOH) is monoclinic, space group P21/n, a=0.70476(3) nm, b=1.14126(6) nm, c=1.20274(6) nm, β=90.563(1)°, . The structure of NAUOH was solved by direct methods and refined on the basis of F2 for 4027 unique reflections measuring using Mo Kα X-radiation and a CCD-based Smart APEX detector. The agreement index (R1) is 2.7%, calculated using 2955 unique observed reflections (|Fo|⩾4σF), and the goodness-of-fit is 0.68. The structure contains uranyl pentagonal bipyramids that share vertices and edges, forming sheets parallel to (0 1 0). The sheets are linked by double chains of Na polyhedra located in the interlayer. NAUOH is a Na analogue of the mineral compreignacite, and may correspond to the Na uranyl oxide hydrate formed in studies of the oxidative dissolution of spent nuclear fuel. The phase Na4(UO2)2(Si4O10)2(H2O)4 (NAURSI) is the Na analogue of KNa3(UO2)2(Si4O10)2(H2O)4, which was found as an alteration phase on hydrothermally treated actinide-bearing borosilicate waste glass. It is monoclinic, space group C2/m, a=1.2770(1) nm, b=1.3610(1) nm, c=0.82440(8) nm, β=119.248(2)°, . The structure of NAURSI was solved by direct methods and refined on the basis of F2 for 1483 unique reflections measured with Mo Kα X-radiation and a CCD-based Smart 1 K detector. The agreement index (R1) is 1.9%, calculated using 1333 unique observed reflections (|Fo|⩾4σF), and the goodness-of-fit is 1.08. The structure is based on a uranyl silicate framework, with Na cations and H2O groups located in interstitial sites. The structure is closely related to that of KNa3(UO2)2(Si4O10)2(H2O)4.
Co-reporter:Peter C Burns, Rudolph A Olson, Robert J Finch, John M Hanchar, Yves Thibault
Journal of Nuclear Materials 2000 Volume 278(2–3) pp:290-300
Publication Date(Web):April 2000
DOI:10.1016/S0022-3115(99)00247-0
Vapor hydration experiments on a U-doped borosilicate waste glass at 200°C produced a novel uranium silicate. Single crystal X-ray structure analysis of this phase indicate the ideal formula KNa3(UO2)2(Si4O10)2(H2O)4, although the compound shows some compositional variability. It is monoclinic, space group C2, Z=2,a=1.2782(1), b=1.3654(1),c=0.82677(8) nm, β=119.240(1)°. The structure was solved by direct methods and refined to an agreement index (R) of 3.6% for 2239 unique observed (|F0|⩾4σF) reflections and a goodness-of-fit of 1.05. The structure contains vertex-sharing silicate tetrahedra arranged in four and eight-membered rings that are linked to give sheets parallel to (0 0 1). The sheets are cross-linked by vertex-sharing with UrO4 square bipyramids [Ur=(UO2)2+ uranyl ion], forming a framework of polyhedra of higher bond-valence. The title phase is the major sink for U during glass corrosion at 200°C after approximately 60 days in a saturated vapor environment. Consideration of the structural sites reveals the potential of this compound to incorporate radionuclides from a variety of nuclear-waste glasses over a wide range of environmental conditions.
Co-reporter:Jie Ling ; Jie Qiu
Inorganic Chemistry () pp:
Publication Date(Web):February 1, 2012
DOI:10.1021/ic202380g
Cage clusters built from uranyl hexagonal bipyramids and oxalate ligands crystallize from slightly acidic aqueous solution under ambient conditions, facilitating structure analysis. Each cluster contains uranyl ions coordinated by peroxo ligands in a bidentate configuration. Uranyl ions are bridged by shared peroxo ligands, oxalate ligands, or through hydroxyl groups. U50Ox20 contains 50 uranyl ions and 20 oxalate groups and is a topological derivative of the U50 cage cluster that has a fullerene topology. U120Ox90 contains 120 uranyl ions and 90 oxalate groups and is the largest and highest mass cluster containing uranyl ions that has been reported. It has a core–shell structure, in which the inner shell (core) consists of a cluster of 60 uranyl ions and 30 oxalate groups, identical to U60Ox30, with a fullerene topology. The outer shell contains 12 identical units that each consist of five uranyl hexagonal bipyramids that are linked to form a ring (topological pentagon), with each uranyl ion also coordinated by a side-on nonbridging oxalate group. The five-membered rings of the inner and outer shells (the topological pentagons) are in correspondence and are linked through K cations. The inner shell topology has therefore templated the location of the outer shell rings, and the K counterions assume a structure-directing role. Small-angle X-ray scattering data demonstrated U50Ox20 remains intact in aqueous solution upon dissolution. In the case of clusters of U120Ox90, the scattering data for dissolved crystals indicates the U60Ox30 core persists in solution, although the outer rings of uranyl bipyramids contained in the U120Ox90 core–shell cluster appear to detach from the cluster when crystals are dissolved in water.
Co-reporter:G. A. Senchyk, E. M. Wylie, S. Prizio, J. E. S. Szymanowski, G. E. Sigmon and P. C. Burns
Chemical Communications 2015 - vol. 51(Issue 50) pp:NaN10137-10137
Publication Date(Web):2015/05/19
DOI:10.1039/C5CC01524C
Hybrid uranyl–vanadium oxide clusters intermediate between transition metal polyoxometalates and uranyl peroxide cage clusters were obtained by dissolving uranyl nitrate in the ionic liquid 3-ethyl-1-methylimidazolium ethyl sulfate mixed with an aqueous solution containing vanadium. Where sulfate was present, wheel-shaped {U20V20} crystallized and contains ten sulfate tetrahedra, and in the absence of added sulfate, {U2V16}, a derivative of {V18}, was obtained.
Co-reporter:Daniel K. Unruh, Alicia Burtner, Laura Pressprich, Ginger E. Sigmon and Peter C. Burns
Dalton Transactions 2010 - vol. 39(Issue 25) pp:NaN5813-5813
Publication Date(Web):2010/05/25
DOI:10.1039/C0DT00074D
Four self-assembling clusters of uranyl peroxide polyhedra have been formed in alkaline aqueous solutions and structurally characterized. These clusters consist of 28, 30, 36 and 44 uranyl polyhedra and exhibit complex new topologies. Each has a structure that contains topological squares, pentagons and hexagons. Analysis of possible topologies within boundary constraints indicates a tendency for adoption of higher symmetry topologies in these cases. Small angle X-ray scattering data demonstrated that crystals of one of these clusters can be dissolved in ultrapure water and that the clusters remain intact for at least several days.
Co-reporter:Jie Ling, Michael Ozga, Megan Stoffer and Peter C. Burns
Dalton Transactions 2012 - vol. 41(Issue 24) pp:NaN7284-7284
Publication Date(Web):2012/04/17
DOI:10.1039/C2DT30229B
Two complex cage clusters built from uranyl hexagonal bipyramids and multiple types of bridges between uranyl ions, U30Py10Ox5 and U38Py10Nt4, were crystallized from aqueous solution under ambient conditions. These are built from 30 uranyl hexagonal bipyramids, 10 pyrophosphate groups, and five oxalate bridges in one case, and 38 uranyl hexagonal bipyramids, 10 pyrophosphate groups, and four nitrate groups in the other. The crystal compositions are (H3O)10Li18K22[(UO2)30(O2)30(P2O7)10(C2O4)5](H2O)22 and Li24K36[(UO2)38(O2)40(OH)8(P2O7)10(NO3)4](NO3)4(H2O)n for U30Py10Ox5 and U38Py10Nt4, respectively. Cluster U30Py10Ox5 crystallizes over a narrow range of solution pH that encourages incorporation of both oxalate and pyrophosphate, with incorporation of oxalate only being favored under more acidic conditions, and pyrophosphate only under more alkaline conditions. Cluster U38Py10Nt4 contains two identical lobes consisting of uranyl polyhedra and pyrophosphate groups, with these lobes linked into the larger cluster through four nitrate groups. The synthesis conditions appear to have prevented closure of these lobes, and a relatively high nitrate concentration in solution favored formation of the larger cluster.
Co-reporter:Zuolei Liao, Jie Ling, Laura R. Reinke, Jennifer E. S. Szymanowski, Ginger E. Sigmon and Peter C. Burns
Dalton Transactions 2013 - vol. 42(Issue 19) pp:NaN6802-6802
Publication Date(Web):2013/03/05
DOI:10.1039/C3DT33025G
The family of cage clusters built by uranyl ions bridged through bidentate peroxide groups has been expanded by incorporation of 1-hydroxyethane-1,1-diphosphonic (etidronic) acid ligands. Six cage clusters containing from 16 to 64 uranyl ions, as well as from eight to 32 etidronic acid ligands have been synthesized and characterized. Incorporation of etidronic acid ligands introduces both new cluster topologies and organic functional groups to this class of nanoscale materials. The anionic clusters were crystallized from aqueous solution under ambient conditions for structural characterization, with the resulting cluster size and polyhedral connectivity influenced by the presence of Li, Na and/or K counter ions. The association of these counter ions with four and five membered rings of edge-sharing uranyl hexagonal bipyramids, such that they are coordinated by the O atoms of uranyl ions, is at times notably either consistent or inconsistent with local energetics predicted by density functional theory in earlier studies.
Co-reporter:May Nyman and Peter C. Burns
Chemical Society Reviews 2012 - vol. 41(Issue 22) pp:NaN7367-7367
Publication Date(Web):2012/06/13
DOI:10.1039/C2CS35136F
While the d0 transition-metal POMs of Group V (V5+, Nb5+, Ta5+) and Group VI (Mo6+, W6+) have been known for more than a century, the actinyl peroxide POMs, specifically those built of uranyl triperoxide or uranyl dihydroxidediperoxide polyhedra, were only realized within the last decade. While virtually every metal on the Periodic Table can form discrete clusters of some type, the actinyls are the only—in addition to the transition-metal POMs– whose chemistry is dictated by the prevalence of the ‘yl’ oxygen ligand. Thus this emerging structural, solution, and computational chemistry of actinide POMs warrants comparison to the mature chemistry of transition-metal POMs. This assessment between the transition-metal POMs and actinyl POMs (uranyl peroxide POMs, specifically) has provided much insight to the similarities and differences between these two chemistries. We further break down the comparison between the alkaline POMs of Nb and Ta; and the acidic POMs of V, Mo and W. This more indepth literature review and discussion reveals that while an initial evaluation suggests the actinyl POMs are more akin to the alkaline transition-metal POMs, they actually share characteristics unique to the acidic POMs as well. This tutorial review is meant to provide fodder for deriving new POM chemistries of both the familiar transition-metals and the emerging actinides, as well as fostering communication and collaboration between the two scientific communities.
.jpg)
![Dibenzo[b,e][1,4]dioxin,pentachloro-](http://img.cochemist.com/ccimg/36100/36088-22-9.png)
![Dibenzo[b,e][1,4]dioxin,pentachloro-](http://img.cochemist.com/ccimg/36100/36088-22-9_b.png)
![Dibenzo[b,e][1,4]dioxin,hexachloro-](http://img.cochemist.com/ccimg/34500/34465-46-8.png)
![Dibenzo[b,e][1,4]dioxin,hexachloro-](http://img.cochemist.com/ccimg/34500/34465-46-8_b.png)
![Dibenzo[b,e][1,4]dioxin,1,2,3,7,8,9-hexachloro-](http://img.cochemist.com/ccimg/19500/19408-74-3.png)
![Dibenzo[b,e][1,4]dioxin,1,2,3,7,8,9-hexachloro-](http://img.cochemist.com/ccimg/19500/19408-74-3_b.png)
![hydrogen dioxo[phosphato(3-)-O,O']uranate(1-)](http://img.cochemist.com/ccimg/18500/18433-48-2.png)
![hydrogen dioxo[phosphato(3-)-O,O']uranate(1-)](http://img.cochemist.com/ccimg/18500/18433-48-2_b.png)
![Tungstate(3-),tetracosa-m-oxododecaoxo[m12-[phosphato(3-)-kO:kO:kO:kO':kO':kO':kO'':kO'':kO'':kO''':kO''':kO''']]dodeca-,hydrogen (1:3)](http://img.cochemist.com/ccimg/1400/1343-93-7.png)
![Tungstate(3-),tetracosa-m-oxododecaoxo[m12-[phosphato(3-)-kO:kO:kO:kO':kO':kO':kO'':kO'':kO'':kO''':kO''':kO''']]dodeca-,hydrogen (1:3)](http://img.cochemist.com/ccimg/1400/1343-93-7_b.png)
![Dibenzo[b,e][1,4]dioxin,1,2,3,6,7,8-hexachloro-](http://img.cochemist.com/ccimg/57700/57653-85-7.png)
![Dibenzo[b,e][1,4]dioxin,1,2,3,6,7,8-hexachloro-](http://img.cochemist.com/ccimg/57700/57653-85-7_b.png)
![Dibenzo[b,e][1,4]dioxin,1,2,3,4,6,7,8-heptachloro-](http://img.cochemist.com/ccimg/35900/35822-46-9.png)
![Dibenzo[b,e][1,4]dioxin,1,2,3,4,6,7,8-heptachloro-](http://img.cochemist.com/ccimg/35900/35822-46-9_b.png)
![2,3,7,8-Tetrachlorodibenzo[b,e][1,4]dioxine](http://img.cochemist.com/ccimg/1800/1746-01-6.png)
![2,3,7,8-Tetrachlorodibenzo[b,e][1,4]dioxine](http://img.cochemist.com/ccimg/1800/1746-01-6_b.png)
