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N-Heterocyclic Carbene to Actinide d-Based π-bonding Correlates with Observed Metal-Carbene Bond Length Shortening Versus Lanthanide Congeners. J Am Chem Soc 2024; 146:10367-10380. [PMID: 38569081 PMCID: PMC11029940 DOI: 10.1021/jacs.3c12721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 02/23/2024] [Accepted: 02/26/2024] [Indexed: 04/05/2024]
Abstract
Comparison of bonding and electronic structural features between trivalent lanthanide (Ln) and actinide (An) complexes across homologous series' of molecules can provide insights into subtle and overt periodic trends. Of keen interest and debate is the extent to which the valence f- and d-orbitals of trivalent Ln/An ions engage in covalent interactions with different ligand donor functionalities and, crucially, how bonding differences change as both the Ln and An series are traversed. Synthesis and characterization (SC-XRD, NMR, UV-vis-NIR, and computational modeling) of the homologous lanthanide and actinide N-heterocyclic carbene (NHC) complexes [M(C5Me5)2(X)(IMe4)] {X = I, M = La, Ce, Pr, Nd, U, Np, Pu; X = Cl, M = Nd; X = I/Cl, M = Nd, Am; and IMe4 = [C(NMeCMe)2]} reveals consistently shorter An-C vs Ln-C distances that do not substantially converge upon reaching Am3+/Nd3+ comparison. Specifically, the difference of 0.064(6) Å observed in the La/U pair is comparable to the 0.062(4) Å difference observed in the Nd/Am pair. Computational analyses suggest that the cause of this unusual observation is rooted in the presence of π-bonding with the valence d-orbital manifold in actinide complexes that is not present in the lanthanide congeners. This is in contrast to other documented cases of shorter An-ligand vs Ln-ligand distances, which are often attributed to increased 5f vs 4f radial diffusivity leading to differences in 4f and 5f orbital bonding involvement. Moreover, in these traditional observations, as the 5f series is traversed, the 5f manifold contracts such that by americium structural studies often find no statistically significant Am3+vs Nd3+ metal-ligand bond length differences.
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Carbene Complexes of Plutonium: Structure, Bonding, and Divergent Reactivity to Lanthanide Analogs. J Am Chem Soc 2024; 146:4098-4111. [PMID: 38301208 PMCID: PMC10870714 DOI: 10.1021/jacs.3c12719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 12/21/2023] [Accepted: 01/08/2024] [Indexed: 02/03/2024]
Abstract
Organoplutonium chemistry was established in 1965, yet structurally authenticated plutonium-carbon bonds remain rare being limited to π-bonded carbocycle and σ-bonded isonitrile and hydrocarbyl derivatives. Thus, plutonium-carbenes, including alkylidenes and N-heterocyclic carbenes (NHCs), are unknown. Here, we report the preparation and characterization of the diphosphoniomethanide-plutonium complex [Pu(BIPMTMSH)(I)(μ-I)]2 (1Pu, BIPMTMSH = (Me3SiNPPh2)2CH) and the diphosphonioalkylidene-plutonium complexes [Pu(BIPMTMS)(I)(DME)] (2Pu, BIPMTMS = (Me3SiNPPh2)2C) and [Pu(BIPMTMS)(I)(IMe4)2] (3Pu, IMe4 = C(NMeCMe)2), thus disclosing non-actinyl transneptunium multiple bonds and transneptunium NHC complexes. These Pu-C double and dative bonds, along with cerium, praseodymium, samarium, uranium, and neptunium congeners, enable lanthanide-actinide and actinide-actinide comparisons between metals with similar ionic radii and isoelectronic 4f5 vs 5f5 electron-counts within conserved ligand fields over 12 complexes. Quantum chemical calculations reveal that the orbital-energy and spatial-overlap terms increase from uranium to neptunium; however, on moving to plutonium the orbital-energy matching improves but the spatial overlap decreases. The bonding picture that emerges is more complex than the traditional picture of the bonding of lanthanides being ionic and early actinides being more covalent but becoming more ionic left to right. Multiconfigurational calculations on 2M and 3M (M = Pu, Sm) account for the considerably more complex UV/vis/NIR spectra for 5f5 2Pu and 3Pu compared to 4f5 2Sm and 3Sm. Supporting the presence of Pu═C double bonds in 2Pu and 3Pu, 2Pu exhibits metallo-Wittig bond metathesis involving the highest atomic number element to date, reacting with benzaldehyde to produce the alkene PhC(H)═C(PPh2NSiMe3)2 (4) and "PuOI". In contrast, 2Ce and 2Pr do not react with benzaldehyde to produce 4.
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Impact of Pendent Ammonium Groups on Solubility and Cycling Charge Carrier Performance in Nonaqueous Redox Flow Batteries. Inorg Chem 2023; 62:19218-19229. [PMID: 37948607 DOI: 10.1021/acs.inorgchem.3c02396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
The synthesis, characterization, electrochemical performance, and theoretical modeling of two base-metal charge carrier complexes incorporating a pendent quaternary ammonium group, [Ni(bppn-Me3)][BF4], 3', and [Fe(PyTRENMe)][OTf]3, 4', are described. Both complexes were produced in high yield and fully characterized using NMR, IR, and UV-vis spectroscopies as well as elemental analysis and single-crystal X-ray crystallography. The solubility of 3' in acetonitrile showed a 283% improvement over its neutral precursor, whereas the solubility of complex 4' was effectively unchanged. Cyclic voltammetry indicates an ∼0.1 V positive shift for all waves, with some changes in reversibility depending on the wave. Bulk electrochemical cycling demonstrates that both 3' and 4' can utilize the second more negative wave to a degree, whereas 4' ceases to have a reversible positive wave. Flow cell testing of 3' and 4' with Fc as the posolyte reveals little improvement to the cycling performance of 3' compared with its parent complex, whereas 4' exhibits reductions in capacity decay when cycling either negative wave. Postcycling CVs indicate that crossover is the likely source of capacity loss in complexes 3, 3', and 4' because there is little change in the CV trace. Density functional theory calculations indicate that the ammonium group lowers the HOMO energy in 3' and 4', which may impart stability to cycling negative waves while making positive waves less accessible. Overall, the incorporation of a positively charged species can improve solubility, stored electron density, and capacity decay depending on the complex, features critical to high energy density redox flow battery performance.
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Synthesis and comparison of iso-structural f-block metal complexes (Ce, U, Np, Pu) featuring η6-arene interactions. Chem Sci 2023; 14:7438-7446. [PMID: 37449075 PMCID: PMC10337748 DOI: 10.1039/d3sc02194g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 06/10/2023] [Indexed: 07/18/2023] Open
Abstract
Reaction of the terphenyl bis(anilide) ligand [{K(DME)2}2LAr] (LAr = {C6H4[(2,6-iPr2C6H3)NC6H4]2}2-) with trivalent chloride "MCl3" salts (M = Ce, U, Np) yields two distinct products; neutral LArM(Cl)(THF) (1M) (M = Np, Ce), and the "-ate" complexes [K(DME)2][(LAr)Np(Cl)2] (2Np) or ([LArM(Cl)2(μ-K(X)2)])∞ (2Ce, 2U) (M = Ce, U) (X = DME or Et2O) (2M). Alternatively, analogous reactions with the iodide [MI3(THF)4] salts provide access to the neutral compounds LArM(I)(THF) (3M) (M = Ce, U, Np, Pu). All complexes exhibit close arene contacts suggestive of η6-interactions with the central arene ring of the terphenyl backbone, with 3M comprising the first structurally characterized Pu η6-arene moiety. Notably, the metal-arene bond metrics diverge from the predicted trends of metal-carbon interactions based on ionic radii, with the uranium complexes exhibiting the shortest M-Ccentroid distance in all cases. Overall, the data presents a systematic study of f-element M-η6-arene complexes across the early actinides U, Np, Pu, and comparison to cerium congeners.
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Chlorination of Pu and U Metal Using GaCl 3. Inorg Chem 2023; 62:8462-8466. [PMID: 37220066 PMCID: PMC10246562 DOI: 10.1021/acs.inorgchem.3c00522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Indexed: 05/25/2023]
Abstract
The oxidative chlorination of the plutonium metal was achieved through a reaction with gallium(III) chloride (GaCl3). In DME (DME = 1,2-dimethoxyethane) as the solvent, substoichiometric (2.8 equiv) amounts of GaCl3 were added, which consumed roughly 60% of the plutonium metal over the course of 10 days. The salt species [PuCl2(dme)3][GaCl4] was isolated as pale-purple crystals, and both solid-state and solution UV-vis-NIR spectroscopies were consistent with the formation of a trivalent plutonium complex. The analogous reaction was performed with uranium metal, generating a dicationic trivalent uranium complex crystallized as the [UCl(dme)3][GaCl4]2 salt. The extraction of [UCl(dme)3][GaCl4]2 in DME at 70 °C followed by crystallization produced [{U(dme)3}2(μ-Cl3)][GaCl4]3, a product arising from the loss of GaCl3. This method of halogenation worked on a small scale for plutonium and uranium, providing a route to cationic Pu3+ and dicationic U3+ complexes using GaCl3 in DME.
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Microstructural and Sensitivity Changes of Neat, Spray-Dried RDX. ACS OMEGA 2023; 8:1514-1522. [PMID: 36643516 PMCID: PMC9835642 DOI: 10.1021/acsomega.2c07011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 12/14/2022] [Indexed: 06/17/2023]
Abstract
Spray drying has recently gained interest in the high explosives (HE) community for the production of novel nanocomposites and well-controlled particle size distributions. However, there is a dearth of information on spray-dried, neat energetic materials. In this work, we correlate the spray drying production parameters to the resulting microstructure and handling sensitivity properties of neat RDX. We demonstrate the capability to fine-tune the particle size distributions for "nanopowder" spray-dried RDX, as well as larger particle size distributions by simply changing the spray dryer setup. We also investigate other physical and chemical changes that RDX undergoes after being processed with spray drying. We characterize these changes with scanning electron microscopy, X-ray diffraction, ultrahigh-performance liquid chromatography, and small-scale sensitivity tests. Interestingly, although the phase and chemical properties are similar before and after spray drying, small-scale sensitivity testing reveals that size reduction of RDX does not follow the typical HE desensitization trends, generally observed for other energetic materials.
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Synthesis of Trimethyltriazacyclohexane (Me 3tach) Sandwich Complexes of Uranium, Neptunium, and Plutonium Triiodides: (Me 3tach) 2AnI 3. Inorg Chem 2022; 62:5897-5905. [PMID: 36576312 DOI: 10.1021/acs.inorgchem.2c03306] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
1,3,5-Trimethyl-1,3,5-triazacyclohexane (Me3tach) readily complexes uranium triiodide to form (Me3tach)2UI3. The complex is soluble in THF and arenes and can function as a source of UI3 to form organometallic U(III) complexes. When dissolved in pyridine (py), (Me3tach)2UI3 forms (Me3tach)UI3(py)2. A related complex with the larger 1,4,7-trimethyl-1,4,7-triazacyclononane (Me3tacn) ligand, namely (Me3tacn)UI3(THF), was synthesized for comparison. Since X-ray quality crystals of (Me3tach)2UI3 can be synthesized in high yield even with small-scale reactions, the system is ideal for extension to transuranium elements. Accordingly, the neptunium and plutonium complexes (Me3tach)2NpI3 and (Me3tach)2PuI3 were synthesized in an analogous manner from NpI3(THF)4 and PuI3(THF)4, respectively.
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Hydrazine Energy Storage: Displacing N 2 H 4 from the Metal Coordination Sphere. CHEMSUSCHEM 2022; 15:e202200840. [PMID: 35864078 PMCID: PMC9804637 DOI: 10.1002/cssc.202200840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/18/2022] [Indexed: 06/15/2023]
Abstract
Hydrogen carriers, such as hydrazine (N2 H4 ), may facilitate long duration energy storage, a vital component for resilient grids by enabling more renewable energy generation. Lanthanide coordination chemistry with N2 H4 as well as efforts to displace N2 H4 from the metal coordination sphere to develop an efficient catalytic production cycle were detailed. Modeling the equilibrium of different ligand coordination, it was predicted that strong sigma donor molecules would be required to displace N2 H4 . Monitoring competition experiments with nuclear magnetic resonance confirmed that trimethyl phosphine oxide, dimethylformamide, and dimethyl sulfoxide displaced N2 H4 in large or small lanthanide complexes.
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Synthesis, solid-state, solution, and theoretical characterization of an "in-cage" scandium-NOTA complex. Dalton Trans 2022; 51:9994-10005. [PMID: 35739082 DOI: 10.1039/d1dt03887g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Developing chelators that strongly and selectively bind rare-earth elements (Sc, Y, La, and lanthanides) represents a longstanding fundamental challenge in inorganic chemistry. Solving these challenges is becoming more important because of increasing use of rare-earth elements in numerous technologies, ranging from paramagnets to luminescent materials. Within this context, we interrogated the complexation chemistry of the scandium(III) (Sc3+) trication with the hexadentate 1,4,7-triazacyclononane-1,4,7-triacetic acid (H3NOTA) chelator. This H3NOTA chelator is often regarded as an underperformer for complexing Sc3+. A common assumption is that metalation does not fully encapsulate Sc3+ within the NOTA3- macrocycle, leaving Sc3+ on the periphery of the chelate and susceptible to demetalation. Herein, we developed a synthetic approach that contradicted those assumptions. We confirmed that our procedure forced Sc3+ into the NOTA3- binding pocket by using single crystal X-ray diffraction to determine the Na[Sc(NOTA)(OOCCH3)] structure. Density functional theory (DFT) and 45Sc nuclear magnetic resonance (NMR) spectroscopy showed Sc3+ encapsulation was retained when the crystals were dissolved. Solution-phase and DFT studies revealed that [Sc(NOTA)(OOCCH3)]1- could accommodate an additional H2O capping ligand. Thermodynamic properties associated with the Sc-OOCCH3 and Sc-H2O capping ligand interactions demonstrated that these capping ligands occupied critical roles in stabilizing the [Sc(NOTA)] chelation complex.
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Abstract
![]()
Since the advent
of organotransuranium chemistry six decades ago,
structurally verified complexes remain restricted to π-bonded
carbocycle and σ-bonded hydrocarbyl derivatives. Thus, transuranium-carbon
multiple or dative bonds are yet to be reported. Here, utilizing diphosphoniomethanide
precursors we report the synthesis and characterization of transuranium-carbene
derivatives, namely, diphosphonio-alkylidene- and N-heterocyclic carbene–neptunium(III) complexes that exhibit
polarized-covalent σ2π2 multiple
and dative σ2 single transuranium-carbon bond interactions,
respectively. The reaction of [NpIIII3(THF)4] with [Rb(BIPMTMSH)] (BIPMTMSH = {HC(PPh2NSiMe3)2}1–) affords
[(BIPMTMSH)NpIII(I)2(THF)] (3Np) in situ, and subsequent treatment with the N-heterocyclic carbene {C(NMeCMe)2} (IMe4) allows
isolation of [(BIPMTMSH)NpIII(I)2(IMe4)] (4Np). Separate treatment of in situ
prepared 3Np with benzyl potassium in 1,2-dimethoxyethane
(DME) affords [(BIPMTMS)NpIII(I)(DME)] (5Np, BIPMTMS = {C(PPh2NSiMe3)2}2–). Analogously, addition of benzyl
potassium and IMe4 to 4Np gives [(BIPMTMS)NpIII(I)(IMe4)2] (6Np). The synthesis of 3Np–6Np was facilitated by adopting a scaled-down prechoreographed approach
using cerium synthetic surrogates. The thorium(III) and uranium(III)
analogues of these neptunium(III) complexes are currently unavailable,
meaning that the synthesis of 4Np–6Np provides an example of experimental grounding of 5f- vs 5f- and
5f- vs 4f-element bonding and reactivity comparisons being led by
nonaqueous transuranium chemistry rather than thorium and uranium
congeners. Computational analysis suggests that these NpIII=C bonds are more covalent than UIII=C,
CeIII=C, and PmIII=C congeners
but comparable to analogous UIV=C bonds in terms
of bond orders and total metal contributions to the M=C bonds.
A preliminary assessment of NpIII=C reactivity has
introduced multiple bond metathesis to transuranium chemistry, extending
the range of known metallo-Wittig reactions to encompass actinide
oxidation states III-VI.
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Synthesis, characterization, X-ray and electronic structures of diethyl ether and 1,2-dimethoxyethane adducts of molybdenum(IV) chloride and tungsten(IV) chloride. Dalton Trans 2022; 51:7856-7863. [PMID: 35531983 DOI: 10.1039/d2dt00787h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The bis(diethyl ether) and 1,2-dimethoxyethane (dme) adducts of molybdenum(IV) chloride and tungsten(IV) chloride are valuable starting materials for a variety of synthetic inorganic and organometallic reactions. Despite the broad utility and extensive use of these 6-coordinate complexes, their syntheses remain unoptimized, and their characterization incomplete after more than three decades. While exploring the ligand exchange behaviour of trans-MoCl4(OEt2)2, we obtained single crystals of this red-orange complex and subsequently compared its structural parameters with those of the recently reported trans-WCl4(OEt2)2. Significantly improved procedures for both MoCl4(dme) and WCl4(dme) were developed, and X-ray diffraction data were obtained and analysed. The magnetic properties of the dme adducts were probed, both with Gouy and SQUID magnetometry measurements. The magnetic moment of WCl4(dme) was smaller than that of MoCl4(dme), an observation that we attribute to the greater spin-orbit coupling of tungsten. Electronic structure studies were also conducted to probe the preferential trans configuration of the diethyl ether adducts and to assign the UV-Vis spectra of the dme adducts.
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Abstract
New coordination environments are reported for Np(III) and Pu(III) based on pilot studies of U(III) in 2.2.2-cryptand (crypt). The U(III)-in-crypt complex, [U(crypt)I2][I], obtained from the reaction between UI3 and crypt, is treated with Me3SiOTf (OTf = O3SCF3) in benzene to form the [U(crypt)(OTf)2][OTf] complex. Similarly, the isomorphous Np(III) and Pu(III) complexes were obtained similarly starting from [AnI3(THF)4]. All three complexes (1-An; An = U, Np, Pu) contain an encapsulated actinide in a THF-soluble complex. Absorption spectroscopy and DFT calculations are consistent with 5f3 U(III), 5f4 Np(III), and 5f5 Pu(III) electron configurations.
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Repair of Gauged Earlobes: Case Series and Review of Two Techniques According to Size. J Cutan Aesthet Surg 2021; 14:351-356. [PMID: 34908779 PMCID: PMC8611704 DOI: 10.4103/jcas.jcas_116_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Background Earlobe stretching is a common body modification typically performed in individuals under 30 years old. Individuals may later desire restoration of a natural earlobe contour. There is a paucity of literature regarding technique and outcomes for repair of the gauged earlobe defect. Aims and Objectives The primary aim of this study was to provide a strategy to assess stretched earlobe defects and choose between the repair techniques of de-epithelialization and closure or excision and rotation. The secondary aim of this study was to evaluate complication rates of the two techniques. Materials and Methods Retrospective review of all patients who underwent repair of stretched (gauged) earlobes at a single institution from 2012 to 2019. Patient demographics, maximum earlobe size, motivation for seeking repair, surgical technique, and complication rate were recorded. Results Fifty-three patients underwent stretched earlobe repair. The average age was 25.9 years old; 60.0% of the patients were male. Defects repaired with de-epithelialization and closure had been stretched to an average of 12.4 (SD = 3.2) mm compared to 29.3 (SD = 10.9) mm for excision and rotation. The minor complication rate was 12.5% with de-epithelialization and 10.8% for excision and rotation. Motivations for seeking repair included a desire to look more professional for work (34.0%), personal preference (30.0%), and joining the military (23.0%). Conclusion Smaller earlobe defects (<15 mm) with nonptotic lobules can be repaired with de-epithelialization and primary closure, whereas larger earlobes (>15.0 mm) with ptotic lobules require excision and rotation. Stretched earlobe repair is a well-tolerated procedure, although a significant number of patients will require minor revisions.
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[AnI 3(THF) 4] (An = Np, Pu) Preparation Bypassing An 0 Metal Precursors: Access to Np 3+/Pu 3+ Nonaqueous and Organometallic Complexes. J Am Chem Soc 2021; 143:20680-20696. [PMID: 34854294 DOI: 10.1021/jacs.1c07967] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Direct comparison of homologous molecules provides a foundation from which to elucidate both subtle and patent changes in reactivity patterns, redox processes, and bonding properties across a series of elements. While trivalent molecular U chemistry is richly developed, analogous Np or Pu research has long been hindered by synthetic routes often requiring scarcely available metallic-phase source material, high-temperature solid-state reactions producing poorly soluble binary halides, or the use of pyrophoric reagents. The development of routes to nonaqueous Np3+/Pu3+ from widely available precursors can potentially transform the scope and pace of research into actinide periodicity. Here, aqueous stocks of An4+ (An = Np, Pu) are dehydrated to well-defined [AnCl4(DME)2] (DME = 1,2-dimethoxyethane), and then a single-step halide exchange/reduction employing Me3SiI produces [AnI3(THF)4] (THF = tetrahydrofuran) in a high to nearly quantitative crystalline yield (with I2 and Me3SiCl as easily removed byproducts). We demonstrate the synthetic utility of these An-iodide molecules, prepared by metal0-free routes, through characterization of archetypal complexes including the tris-silylamide, [Np{N(SiMe3)2}3], and bent metallocenes, [An(C5Me5)2(I)(THF)] (An = Np, Pu)─chosen because both motifs are ubiquitous in Th, U, and lanthanide research. The synthesis of [Np{N(Se═PPh2)2}3] is also reported, completing an isomorphous series that now extends from U to Am and is the first characterized Np3+-Se bond.
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Pain and Opioid Consumption Following Endoscopic Sinus Surgery: A Prospective Cohort Study. Laryngoscope 2021; 132:2096-2102. [PMID: 34843110 DOI: 10.1002/lary.29967] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/28/2021] [Accepted: 11/17/2021] [Indexed: 11/08/2022]
Abstract
OBJECTIVES/HYPOTHESIS Surgeons have a critical role in the current opioid epidemic, and there is a need to prospectively understand patterns of pain and opioid use among patients undergoing endoscopic sinus surgery (ESS). STUDY DESIGN Prospective observational cohort. METHODS This was a prospective, observational cohort study that included patients undergoing ESS from November 2019 to March 2020. Demographic data were collected at baseline, as was respondent information regarding preoperative anxiety, pain, and postoperative pain expectations. Opioid use was converted to milligram morphine equivalents (MME). All patients received 10 tablets of 5 mg oxycodone (75 MME). Patients quantified postoperative pain and opioid consumption via telephone follow-up every 48 hours. The primary outcome was total MME utilized. RESULTS There were 91 patients included in the final cohort. Mean opioid use was 35.2 ± 47.3 MME. There were 29 (32%) patients who did not use any opioids after surgery, and six (7%) patients who required opioid refills. Postoperative opioid use was associated with increased preoperative anxiety (r = 0.41, P < .001), preoperative pain (r = 0.28, P = .007), and expectations for postoperative pain (r = 0.36, P < .001). Increased postoperative pain was only associated with increased opioid use on postoperative days 0-2 (r = 0.33, P = .001) and 3-4 (r = 0.59, P < .001). On multivariate regression, former smoking (β = 23.4 MME, SE = 10.1, 95% confidence interval [CI]: 3.3-43.5, P = .023) and anxiety (β = 35.9, SE = 10.2, 95% CI: 15.6-56.3, P < .001) were associated with increased MME. CONCLUSIONS The majority of patients have minimal opioid use after ESS, and pain appears to influence opioid use within the first 4 days after surgery. Additionally, patients with anxiety may benefit from alternative pain management strategies to mitigate opioid consumption. LEVEL OF EVIDENCE 3 Laryngoscope, 2021.
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Isolation and characterization of a californium metallocene. Nature 2021; 599:421-424. [PMID: 34789902 DOI: 10.1038/s41586-021-04027-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 09/15/2021] [Indexed: 11/09/2022]
Abstract
Californium (Cf) is currently the heaviest element accessible above microgram quantities. Cf isotopes impose severe experimental challenges due to their scarcity and radiological hazards. Consequently, chemical secrets ranging from the accessibility of 5f/6d valence orbitals to engage in bonding, the role of spin-orbit coupling in electronic structure, and reactivity patterns compared to other f elements, remain locked. Organometallic molecules were foundational in elucidating periodicity and bonding trends across the periodic table1-3, with a twenty-first-century renaissance of organometallic thorium (Th) through plutonium (Pu) chemistry4-12, and to a smaller extent americium (Am)13, transforming chemical understanding. Yet, analogous curium (Cm) to Cf chemistry has lain dormant since the 1970s. Here, we revive air-/moisture-sensitive Cf chemistry through the synthesis and characterization of [Cf(C5Me4H)2Cl2K(OEt2)]n from two milligrams of 249Cf. This bent metallocene motif, not previously structurally authenticated beyond uranium (U)14,15, contains the first crystallographically characterized Cf-C bond. Analysis suggests the Cf-C bond is largely ionic with a small covalent contribution. Lowered Cf 5f orbital energy versus dysprosium (Dy) 4f in the colourless, isoelectronic and isostructural [Dy(C5Me4H)2Cl2K(OEt2)]n results in an orange Cf compound, contrasting with the light-green colour typically associated with Cf compounds16-22.
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Patterns of opioid use after endoscopic sinus surgery among patients with anxiety and depression. Int Forum Allergy Rhinol 2021; 12:788-790. [PMID: 34708586 DOI: 10.1002/alr.22919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 09/27/2021] [Accepted: 10/19/2021] [Indexed: 11/07/2022]
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Complexation and redox chemistry of neptunium, plutonium and americium with a hydroxylaminato ligand. Chem Sci 2021; 12:13343-13359. [PMID: 34777753 PMCID: PMC8528073 DOI: 10.1039/d1sc03905a] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 09/03/2021] [Indexed: 11/25/2022] Open
Abstract
There is significant interest in ligands that can stabilize actinide ions in oxidation states that can be exploited to chemically differentiate 5f and 4f elements. Applications range from developing large-scale actinide separation strategies for nuclear industry processing to carrying out analytical studies that support environmental monitoring and remediation efforts. Here, we report syntheses and characterization of Np(iv), Pu(iv) and Am(iii) complexes with N-tert-butyl-N-(pyridin-2-yl)hydroxylaminato, [2-(tBuNO)py]−(interchangeable hereafter with [(tBuNO)py]−), a ligand which was previously found to impart remarkable stability to cerium in the +4 oxidation state. An[(tBuNO)py]4 (An = Pu, 1; Np, 2) have been synthesized, characterized by X-ray diffraction, X-ray absorption, 1H NMR and UV-vis-NIR spectroscopies, and cyclic voltammetry, along with computational modeling and analysis. In the case of Pu, oxidation of Pu(iii) to Pu(iv) was observed upon complexation with the [(tBuNO)py]− ligand. The Pu complex 1 and Np complex 2 were also isolated directly from Pu(iv) and Np(iv) precursors. Electrochemical measurements indicate that a Pu(iii) species can be accessed upon one-electron reduction of 1 with a large negative reduction potential (E1/2 = −2.26 V vs. Fc+/0). Applying oxidation potentials to 1 and 2 resulted in ligand-centered electron transfer reactions, which is different from the previously reported redox chemistry of UIV[(tBuNO)py]4 that revealed a stable U(v) product. Treatment of an anhydrous Am(iii) precursor with the [(tBuNO)py]− ligand did not result in oxidation to Am(iv). Instead, the dimeric complex [AmIII(μ2-(tBuNO)py)((tBuNO)py)2]2 (3) was isolated. Complex 3 is a rare example of a structurally characterized non-aqueous Am-containing molecular complex prepared using inert atmosphere techniques. Predicted redox potentials from density functional theory calculations show a trivalent accessibility trend of U(iii) < Np(iii) < Pu(iii) and that the higher oxidation states of actinides (i.e., +5 for Np and Pu and +4 for Am) are not stabilized by [2-(tBuNO)py]−, in good agreement with experimental observations. The coordination modes and electronic properties of a strongly coordinating hydroxylaminato ligand with Np, Pu and Am were investigated.Complexes were characterized by a range of experimental and computational techniques.![]()
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"MoCl 3(dme)" Revisited: Improved Synthesis, Characterization, and X-ray and Electronic Structures. Inorg Chem 2021; 60:12218-12225. [PMID: 34353020 DOI: 10.1021/acs.inorgchem.1c01398] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
"MoCl3(dme)" (dme = 1,2-dimethoxyethane) is an important precursor for midvalent molybdenum chemistry, particularly for triply Mo-Mo bonded compounds of the type Mo2X6 (X = bulky anionic ligand). However, its exact structural identity has been obscure for more than 50 years. In search of a convenient, large-scale synthesis, we have found that trans-MoCl4(Et2O)2 dissolved in dme can be cleanly reduced with dimethylphenylsilane, Me2PhSiH, to provide khaki Mo2Cl6(dme)2 in ∼90% yield. If the reduction is performed on a small scale, single crystals suitable for X-ray crystallography can be obtained. Two different crystal morphologies were identified, each belonging to the P21/n space group, but with slightly different unit cell constants. The refined structure of each form is an edge-shared bioctahedron with overall Ci symmetry and metal-metal separations on the order of 2.8 Å. The bulk material is diamagnetic as determined by both the Gouy method and SQUID magnetometry. Density functional theory calculations suggest a σ2π2δ*2 ground state for the dimer with the diamagnetism arising from a singlet diradical "broken symmetry" electronic configuration. In addition to a definitive structural assignment for "MoCl3(dme)", this work highlights the utility of organosilanes as easy to handle, alternative reductants for inorganic synthesis.
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Back Cover: Structural and Spectroscopic Comparison of Soft‐Se vs. Hard‐O Donor Bonding in Trivalent Americium/Neodymium Molecules (Angew. Chem. Int. Ed. 17/2021). Angew Chem Int Ed Engl 2021. [DOI: 10.1002/anie.202103249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Structural and Spectroscopic Comparison of Soft‐Se vs. Hard‐O Donor Bonding in Trivalent Americium/Neodymium Molecules. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202017186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Rücktitelbild: Structural and Spectroscopic Comparison of Soft‐Se vs. Hard‐O Donor Bonding in Trivalent Americium/Neodymium Molecules (Angew. Chem. 17/2021). Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202103249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Structural and Spectroscopic Comparison of Soft-Se vs. Hard-O Donor Bonding in Trivalent Americium/Neodymium Molecules. Angew Chem Int Ed Engl 2021; 60:9459-9466. [PMID: 33529478 DOI: 10.1002/anie.202017186] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Indexed: 11/06/2022]
Abstract
Covalency is often considered to be an influential factor in driving An3+ vs. Ln3+ selectivity invoked by soft donor ligands. This is intensely debated, particularly the extent to which An3+ /Ln3+ covalency differences prevail and manifest as the f-block is traversed, and the effects of periodic breaks beyond Pu. Herein, two Am complexes, [Am{N(E=PPh2 )2 }3 ] (1-Am, E=Se; 2-Am, E=O) are compared to isoradial [Nd{N(E=PPh2 )2 }3 ] (1-Nd, 2-Nd) complexes. Covalent contributions are assessed and compared to U/La and Pu/Ce analogues. Through ab initio calculations grounded in UV-vis-NIR spectroscopy and single-crystal X-ray structures, we observe differences in f orbital involvement between Am-Se and Nd-Se bonds, which are not present in O-donor congeners.
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Autologous Fat Grafting in Facial Cosmetic Surgery: A National Survey. Facial Plast Surg 2021; 37:136-138. [PMID: 33845497 DOI: 10.1055/s-0040-1721098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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A lobulated mass on the upper back with prominent vasculature: A giant basal cell carcinoma. Dermatol Reports 2021; 13:9046. [PMID: 33936576 PMCID: PMC8056320 DOI: 10.4081/dr.2021.9046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 02/11/2021] [Indexed: 11/23/2022] Open
Abstract
Basal cell carcinoma (BCC) is characterized by slow but locally invasive growth. Although there is low metastatic potential, if not treated early, these skin cancers can lead to significant morbidity and mortality. In this case report, we present a man with a neglected BCC that developed into what is termed a giant BCC or one that is greater than 5 cm. This tumor was discovered only upon workup of orthostatic lightheadedness and iron deficiency anemia. Although rare, basal cell carcinoma must be included on the differential of a large cutaneous lesion and may be a source of significant blood loss.
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Crystallographic characterization of (C 5H 4SiMe 3) 3U(BH 4). Acta Crystallogr E Crystallogr Commun 2021; 77:383-389. [PMID: 33936762 PMCID: PMC8025856 DOI: 10.1107/s2056989021002425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/03/2021] [Indexed: 05/31/2023]
Abstract
The structure of Cp′3U(BH4), (C5H4SiMe3)3U(BH4), at 112 K has triclinic (P) symmetry. It is of interest with respect to borohydride coordination modes. New syntheses have been developed for the synthesis of (borohydrido-κ3H)tris[η5-(trimethylsilyl)cyclopentadienyl]uranium(IV), [U(BH4)(C8H13Si)3] or Cp′3U(BH4) (Cp′ = C5H4SiMe3) and its structure has been determined by single-crystal X-ray crystallography. This compound crystallized in the space group P and the structure features three η5-coordinated Cp′ rings and a κ3-coordinated (BH4)− ligand.
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Advancing understanding of actinide(iii) (Ac, Am, Cm) aqueous complexation chemistry. Chem Sci 2021; 12:5638-5654. [PMID: 34168798 PMCID: PMC8179631 DOI: 10.1039/d1sc00233c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 02/22/2021] [Indexed: 01/07/2023] Open
Abstract
The positive impact of having access to well-defined starting materials for applied actinide technologies - and for technologies based on other elements - cannot be overstated. Of numerous relevant 5f-element starting materials, those in complexing aqueous media find widespread use. Consider acetic acid/acetate buffered solutions as an example. These solutions provide entry into diverse technologies, from small-scale production of actinide metal to preparing radiolabeled chelates for medical applications. However, like so many aqueous solutions that contain actinides and complexing agents, 5f-element speciation in acetic acid/acetate cocktails is poorly defined. Herein, we address this problem and characterize Ac3+ and Cm3+ speciation as a function of increasing acetic acid/acetate concentrations (0.1 to 15 M, pH = 5.5). Results obtained via X-ray absorption and optical spectroscopy show the aquo ion dominated in dilute acetic acid/acetate solutions (0.1 M). Increasing acetic acid/acetate concentrations to 15 M increased complexation and revealed divergent reactivity between early and late actinides. A neutral Ac(H2O)6 (1)(O2CMe)3 (1) compound was the major species in solution for the large Ac3+. In contrast, smaller Cm3+ preferred forming an anion. There were approximately four bound O2CMe1- ligands and one to two inner sphere H2O ligands. The conclusion that increasing acetic acid/acetate concentrations increased acetate complexation was corroborated by characterizing (NH4)2M(O2CMe)5 (M = Eu3+, Am3+ and Cm3+) using single crystal X-ray diffraction and optical spectroscopy (absorption, emission, excitation, and excited state lifetime measurements).
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Expanding the Nonaqueous Chemistry of Neptunium: Synthesis and Structural Characterization of [Np(NR 2) 3Cl], [Np(NR 2) 3Cl] -, and [Np{ N(R)(SiMe 2CH 2)} 2(NR 2)] - (R = SiMe 3). Inorg Chem 2021; 60:2740-2748. [PMID: 33539075 DOI: 10.1021/acs.inorgchem.0c03616] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Reaction of 3 equiv of NaNR2 (R = SiMe3) with NpCl4(DME)2 in THF afforded the Np(IV) silylamide complex, [Np(NR2)3Cl] (1), in good yield. Reaction of 1 with 1.5 equiv of KC8 in THF, in the presence of 1 equiv of dibenzo-18-crown-6, resulted in formation of [{K(DB-18-C-6)(THF)}3(μ3-Cl)][Np(NR2)3Cl]2 (4), also in good yield. Complex 4 represents the first structurally characterized Np(III) amide. Finally, reaction of NpCl4(DME)2 with 5 equiv of NaNR2 and 1 equiv of dibenzo-18-crown-6 afforded the Np(IV) bis(metallacycle), [{Na(DB-18-C-6)(Et2O)0.62(κ1-DME)0.38}2(μ-DME)][Np{N(R)(SiMe2CH2)}2(NR2)]2 (8), in moderate yield. Complex 8 was characterized by 1H NMR spectroscopy and X-ray crystallography and represents a rare example of a structurally characterized neptunium-hydrocarbyl complex. To support these studies, we also synthesized the uranium analogues of 4 and 8, namely, [K(2,2,2-cryptand)][U(NR2)3Cl] (2), [K(DB-18-C-6)(THF)2][U(NR2)3Cl] (3), [Na(DME)3][U{N(R)(SiMe2CH2)}2(NR2)] (6), and [{Na(DB-18-C-6)(Et2O)0.5(κ1-DME)0.5}2(μ-DME)][U{N(R)(SiMe2CH2)}2(NR2)]2 (7). Complexes 2, 3, 6, and 7 were characterized by a number of techniques, including NMR spectroscopy and X-ray crystallography.
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Abstract
We report two anionic diphosphametallocenates, [K(2.2.2-crypt)][M(PC4Me4)2] (M = Cr, 2-Cr; Fe, 2-Fe). Both are low-spin (S = ½) by EPR spectroscopy and SQUID magnetometry. This contrasts the high-spin (S = 3/2) ferrocenate, [K(2.2.2-crypt)][Fe(C5H2-1,2,4-tBu)2] (4-Fe). Quantum chemical calculations suggest this is due to significant differences in ligand field splitting of the d-orbitals which also explain structural features in the 2-M complexes.
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Monolithic Nanoporous Gold Foams with Catalytic Activity for Chemical Vapor Deposition Growth of Carbon Nanostructures. ACS APPLIED MATERIALS & INTERFACES 2021; 13:1204-1213. [PMID: 33356086 DOI: 10.1021/acsami.0c17624] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
While bulk gold is generally considered to be a catalytically inactive material, nanostructured forms of gold can in fact be highly catalytically active. However, few methods exist for preparing high-purity macroscopic forms of catalytically active gold. In this work, we describe the synthesis of catalytically active macroscopic nanoporous gold foams via combustion synthesis of gold bis(tetrazolato)amine complexes. The resulting metallically pure porous gold nanoarchitectures exhibit bulk densities of <0.1 g/cm3 and Brunauer-Emmett-Teller (BET) surface areas as high as 10.9 m2/g, making them among the lowest-density and highest-surface-area monolithic forms of gold produced to date. Thanks to the presence of a highly nanostructured gold surface, such gold nanofoams have also been found to be highly catalytically active toward thermal chemical vapor deposition (CVD) growth of carbon nanotubes, providing a novel method for direct synthesis of carbon nanostructures on macroscopic gold substrates. In contrast, analogous copper nanofoams were found to be catalytically inactive toward the growth of graphitic nanostructures under the same synthesis conditions, highlighting the unusually high catalytic propensity of this form factor of gold. The combustion synthesis process described herein represents a never-wet approach for directly synthesizing macroscopic catalytically active gold. Unlike sol-gel and dealloying approaches, combustion synthesis eliminates the time-consuming diffusion-mediated steps associated with previous methods and offers multiple degrees of freedom for tuning morphology, electrical conductivity, and mechanical properties.
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Abstract
Metal nitrides are strong refractory ceramic materials known for applications in the coatings, catalysis, and semiconductor industries. Lanthanide nitrides are difficult to prepare in high purity and often require high temperatures and sophisticated equipment. In this work, we present an approach to the synthesis of high-purity f-element nitrides through the use of simple lanthanide salts and the nitrogen-rich ligand 5,5'-bis(1H-tetrazolyl)amine (H2BTA) to form lanthanide complexes of 5,5'-bis(tetrazolato)amine (BTA2-). We have demonstrated that, when dehydrated, these types of complexes undergo a self-sustained combustion reaction under an inert atmosphere to yield nanostructured f-element nitride foams for lanthanum and cerium. The synthesis, characterization, and single-crystal X-ray crystallography of the BTA2- complexes of lanthanum, cerium, praseodymium, neodymium, and europium are also discussed.
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Case Report of Delayed Auricular Reconstruction Using a Porous Polyethylene Implant for an Advanced Skin Cancer. EAR, NOSE & THROAT JOURNAL 2020; 101:165-166. [PMID: 32809848 DOI: 10.1177/0145561320950500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Abstract
With the advent of lanthanide-based technologies, there is a clear need to advance the fundamental understanding of 4f-element chelation chemistry. Herein, we contribute to a growing body of lanthanide chelation chemistry and report the synthesis of bimetallic 4f-element complexes within an imine/hemiacetalate framework, Ln2TPTOMe [Ln = lanthanide; TPTOMe = tris(pyridineimine)(Tren)tris(methoxyhemiacetalate); Tren = tris(2-aminoethylamine)]. These products are generated from hydrolysis and methanolysis of the cage ligand tris(pyridinediimine)bis(Tren) (TPT; Tadanobu et al. Chem. Lett. 1993, 22 (5), 859-862) likely facilitated by inductive effects stemming from the Lewis acidic lanthanide cations. These complexes are interesting because they result from imine cleavage to generate two metal binding sites: one pocketed site within the macrocycle and the other terminal site capping a hemiacetalate moiety. A clear demarcation in reactivity is observed between samarium and europium, where the lighter and larger lanthanides generate a mixture of products, Ln2TPTOMe and LnTPT. Meanwhile, the heavier and smaller lanthanides generate exclusively bimetallic Ln2TPTOMe. The cleavage reactivity to form Ln2TPTOMe was extended beyond methanol to include other primary alcohols.
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Actinide 2-metallabiphenylenes that satisfy Hückel’s rule. Nature 2020; 578:563-567. [DOI: 10.1038/s41586-020-2004-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 11/20/2019] [Indexed: 11/09/2022]
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Violaceous nodules in an HIV-positive man. Dermatol Online J 2020; 26:13030/qt1b42h7nt. [PMID: 32239893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 03/26/2020] [Indexed: 06/11/2023] Open
Abstract
Plasmablastic lymphoma (PBL) is a rare and aggressive malignancy associated with immunosuppression and the oncogenic effects of the Epstein-Barr virus (EBV). We present an HIV-positive man with PBL that presented as ulcers and violaceous exophytic nodules on the legs. The clinical features, histologic appearance, and differential diagnosis of this malignancy are briefly reviewed.
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Hydration of α-UO3 following storage under controlled conditions of temperature and relative humidity. Dalton Trans 2020; 49:10452-10462. [DOI: 10.1039/d0dt01852j] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Experimental measurements and theoretical evaluation of changes in chemical speciation of α-UO3 using XRD, EXAFS, TGA, and DFT calculations.
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Single crystal structure and photocatalytic behavior of grafted uranyl on the Zr-node of a pyrene-based metal–organic framework. CrystEngComm 2020. [DOI: 10.1039/c9ce02034a] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The zirconium MOF NU-1000 was post-synthetically modified through solvothermal deposition to include the uranyl ion and characterized via single-crystal X-ray diffraction; photo-oxidation was also performed.
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Advancing Chelation Chemistry for Actinium and Other +3 f-Elements, Am, Cm, and La. J Am Chem Soc 2019; 141:19404-19414. [PMID: 31794205 DOI: 10.1021/jacs.9b10354] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A major chemical challenge facing implementation of 225Ac in targeted alpha therapy-an emerging technology that has potential for treatment of disease-is identifying an 225Ac chelator that is compatible with in vivo applications. It is unclear how to tailor a chelator for Ac binding because Ac coordination chemistry is poorly defined. Most Ac chemistry is inferred from radiochemical experiments carried out on microscopic scales. Of the few Ac compounds that have been characterized spectroscopically, success has only been reported for simple inorganic ligands. Toward advancing understanding in Ac chelation chemistry, we have developed a method for characterizing Ac complexes that contain highly complex chelating agents using small quantities (μg) of 227Ac. We successfully characterized the chelation of Ac3+ by DOTP8- using EXAFS, NMR, and DFT techniques. To develop confidence and credibility in the Ac results, comparisons with +3 cations (Am, Cm, and La) that could be handled on the mg scale were carried out. We discovered that all M3+ cations (M = Ac, Am, Cm, La) were completely encapsulated within the binding pocket of the DOTP8- macrocycle. The computational results highlighted the stability of the M(DOTP)5- complexes.
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Rücktitelbild: [Am(C
5
Me
4
H)
3
]: An Organometallic Americium Complex (Angew. Chem. 34/2019). Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201907513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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[Am(C 5 Me 4 H) 3 ]: An Organometallic Americium Complex. Angew Chem Int Ed Engl 2019; 58:11695-11699. [PMID: 31190446 DOI: 10.1002/anie.201905225] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Indexed: 11/06/2022]
Abstract
We report the small-scale synthesis, isolated yield, single-crystal X-ray structure, 1 H NMR solution spectroscopy /solid-state UV/Vis-nIR spectroscopy, and density functional theory (DFT)/ab initio wave function theory calculations on an Am3+ organometallic complex, [Am(C5 Me4 H)3 ] (1). This constitutes the first quantitative data on Am-C bonding in a molecular species.
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Back Cover: [Am(C
5
Me
4
H)
3
]: An Organometallic Americium Complex (Angew. Chem. Int. Ed. 34/2019). Angew Chem Int Ed Engl 2019. [DOI: 10.1002/anie.201907513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Oxidation of uranium(iv) mixed imido-amido complexes with PhEEPh and to generate uranium(vi) bis(imido) dichalcogenolates, U(NR) 2(EPh) 2(L) 2. Dalton Trans 2019; 48:10865-10873. [PMID: 31049520 DOI: 10.1039/c9dt00680j] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
This work provides new routes for the conversion of U(iv) into U(vi) bis(imido) complexes and offers new information on the manner in which the U(vi) compounds form. Many compounds from the series described by the general formula U(NR)2(EPh)2(L)2 (R = 2,6-diisopropylphenyl, tert-butyl; E = S, Se, Te; L = py, EPh) were synthesized via oxidation of an in situ generated U(iv) amido-imido species with Ph2E2. This synthetic sequence provides a general route into bis(imido) U(vi) chalcogenolate complexes, circumventing the need to perform problematic salt metathesis reactions on U(vi) iodides. Investigation into the speciation of the U(iv) complexes that form prior to oxidation found a significant dependence on the identity of the ancillary ligands, with tBu2bpy forming the isolable imido-(bis)amido complex, U(NDipp)(NHDipp)2(tBu2bpy)2. Together, these data are consistent with the view that the bis(imido) U(vi) motif - much like the uranyl ion, UO22+- is a thermodynamic sink into which simple ligand frameworks are unable to prevent uranium from falling when in the presence of a suitable retinue of imido proligands.
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Abstract
OBJECTIVES Laryngomalacia is an established cause of stridor and sleep-disordered breathing in children. However, the relationship between laryngomalacia and dysphagia has not been well characterized. The objectives of this study were to (1) describe the patient characteristics, symptoms, and prevalence of dysphagia in children with laryngomalacia and (2) examine the effectiveness of supraglottoplasty in improving feeding. METHODS This was a retrospective study of patients with laryngomalacia who underwent a modified barium swallow study (MBSS) at a tertiary academic pediatric medical center between March 1, 2014, and March 1, 2018. Patients were excluded if they did not undergo a MBSS. Comorbidities, airway and feedings symptoms, MBSS results, and surgical history were recorded from each patient's electronic medical record. RESULTS Forty-four children met inclusion/exclusion criteria. The median age at presentation was 96 days. There was a male predominance (66%). About one-third had a genetic or neuromuscular comorbidity. Most children had stridor (93%) and feeding difficulty (86%), while 50% had parent-reported poor weight gain. Fifty-seven percent of patients had evidence of penetration or aspiration on MBSS. All patients with a positive MBSS had dysphagia symptoms. Fifty-seven percent of patients underwent supraglottoplasty. Postoperatively, 92% reported improvement in dysphagia symptoms. CONCLUSION Dysphagia is prevalent among a subset of children with laryngomalacia. Symptomatic children may benefit from a swallow evaluation to help determine the need for further intervention. Children who undergo supraglottoplasty for laryngomalacia have improved dysphagia at follow-up, though the amount of improvement directly attributable to surgery is unclear and warrants further investigation.
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Linked Picolinamide Nickel Complexes as Redox Carriers for Nonaqueous Flow Batteries. CHEMSUSCHEM 2019; 12:1304-1309. [PMID: 30675995 DOI: 10.1002/cssc.201802985] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 01/17/2019] [Indexed: 06/09/2023]
Abstract
The use of nickel complexes utilizing non-innocent ligands based on picolinamide to function as redox carriers in flow batteries was explored. The picolinamide moiety was linked together with -CH2 CH2 - (bpen), -CH2 CH2 CH2 - (bppn), and -C6 H4 - (bpb) moieties, resulting in two, three, and four quasi-reversible waves, respectively, for the nickel complexes and >3 V difference between the outermost positive and negative waves. The redox events were theoretically modelled for each complex, showing excellent agreement (<0.3 V difference) between the experimental and modelled potentials. Bulk cycling of the most soluble complex, Ni(bppn), indicated only one of the three waves was reversible. Therefore, Ni(bppn) has the ability to act as a negative charge redox carrier in flow cells.
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Complexation of High-Valency Mid-Actinides by a Lipophilic Schiff Base Ligand: Synthesis, Structural Characterization, and Progress toward Selective Extraction. Inorg Chem 2019; 58:3559-3563. [DOI: 10.1021/acs.inorgchem.8b02849] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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A sulphur and uranium fiesta! Synthesis, structure, and characterization of neutral terminal uranium(vi) monosulphide, uranium(vi) η2-disulphide, and uranium(iv) phosphine sulphide complexes. Dalton Trans 2019; 48:50-57. [DOI: 10.1039/c8dt02932f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Three new uranium species, (C5Me5)2U(N-2,6-iPr2-C6H3)(S), (C5Me5)2U(N-2,6-iPr2-C6H3)(η2-S2), and (C5Me5)2U(N-2,6-iPr2-C6H3)(SPMe3) have been prepared.
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