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Some of the material in is restricted to members of the community. By logging in, you may be able to gain additional access to certain collections or items. If you have questions about access or logging in, please use the form on the Contact Page.
Kinetics of dioxouranium(VI) ion reduction at polyelectrolyte - solution interfaces
Description:
The rates of reduction of the dioxouranium(VI) ion by 4, 4$\sp\prime$-dipropylsulfonate-2, 2$\sp\prime$ bipyridinium radical anions (ZV$\sp-$ radicals) were determined in the presence of the synthetic polyelectrolytes polyvinylsulfate (PVS... In addition, kinetic data for the reduction of the dioxoactinide(VI) ions, UO$\sb2\sp{2+}$, NpO$\sb2\sp{2+}$, and PuO$\sb2\sp{2+}$ by ZV$\sp-$ radicals were determined at pH 4.0. The measured rate parameters for the reduction of UO$\sb2...
In comparison to their lanthanide counterparts, the actinide elements are woefully understudied. This is especially true for the trans-plutonium actinides. Known isotopes of the heavier, later actinides possess, in most cases, shorter...
BONDING STUDIES IN SOME TRANSITION METAL COMPLEXES: PART I, ORIGINS OF ELECTRIC FIELD GRADIENTS IN CESIUM TRICHLORO-NICKELATE(II), CESIUM TRICHLORO-CUPRATE(II), POTASSIUM TRICHLORO-CUPRATE(II); PART II, PARAMAGNETIC RESONANCE STUDY OF BONDING IN SOME PENTAMMINECHROMIUM(III) COMPLEXES
Competitive complexation studies of europium(III) and uranium(VI) complexation by aqueous orthosilicic acid
Description:
The environmental chemistry of actinide elements is of considerable interest since the release of actinides into the environment is considered the primary long-term hazard of nuclear waste disposal in geological repositories. While... Ligand competition experiments were employed to measure the stability constants of these f-element-orthosilicate complexes. Europium-orthosilicate complexation was studied by solvent extraction and laser-induced fluorescence spectroscopy... Speciation calculations show that europium orthosilicate complexes are important inorganic species for waters between pcH 6 and 7.5 that are in equilibrium with atmospheric carbon dioxide and contain at least 0.03 mM orthosilicate....
SYNTHESIS, CHARACTERIZATION, AND REACTIONS OF EARLY TRANSITION METAL COMPLEXES WITH A TETRAAZA-MACROCYCLIC LIGAND
Description:
My work involved the synthesis, physical characterization, and studies into the chemical reactivity of various titanium, vanadium and chromium complexes of the macro-cyclic ligand (C(, 22)H(, 22)N(, 4))('2-). These compounds were... The reaction of vanadyl acetate with the free ligand yields VO(C(, 4)), which was structurally characterized. The vanadyl oxygen may subsequently be removed to give an extremely reactive (very water and oxygen sensitive)... The analogous Ti(C(, 4))Cl(, 2) complex, prepared from TiCl(, 4) and the free ligand, is less readily hydrolyzed than V(C(, 2)(.)HCl. An X-ray diffraction analysis of the structure revealed cis coordination of... Studies of chromium reaction chemistry in this ligand are currently being completed. The chromium chemistry is complicated by sensitivity to H(, 2)O and O(, 2), leading to irreversibly oxidized and decomposition products. The reaction of... chelate ring to produce a pentadentate macrocyclic ligand can beisolated as the SCN('-) adduct, (' )Cr(C(, 4))(-C=N)NCS. (VBAR) CH(, 3)
This dissertation seeks to determine the differences in the lanthanides and later actinides in non-aqueous media. Research in the f-elements is significantly understudied compared to the other metals of the periodic table. Even more so...
THE HEXAVALENT ACTINIDES: SOME NEW DIRECTIONS IN THE STUDY OF REDOX KINETICS AND COMPLEXATION THERMODYNAMICS
Description:
The environmental behavior of the actinide elements will depend on their redox and complexation chemistries. Chapter I of this Dissertation briefly reviews actinide solution chemistry on the fundamental and applied (i.e. environmental)... Solvent extraction by thenoyltrifluoracetone was found suitable for investigation of tracer-level actinide redox reactions. This technique was employed in the study of reactions of Np(VI) with water-soluble carboxylates, phenols, and... Chapter III describes the development and characteristics of a coated-wire electrode specific for actinyl cations. The electrode was found to respond rapidly and reproducibly to 10('-5) - 10('-2) M U(VI) with a slope almost twice that... The results of an investigation of the thermodynamics of Pu(VI) complexation by bicarbonate at pH 8 are presented in Chapter IV. From the previously determined 1:1 stability constant and from calorimetric data, the stability constant for...
This dissertation focuses on probing the fundamental chemistry of the actinide series, specifically the structure and bonding in complexes of transuranium elements. The actinides consist of the elements from actinium to lawrencium in the...
Distinguishing Förster resonance energy transfer and solvent-mediated charge-transfer relaxation dynamics in a zinc(II) indicator: a femtosecond time-resolved transient absorption spectroscopic study
A bifluorophoric molecule (1) capable of intramolecular Förster Resonance Energy Transfer (FRET) is reported. The emission intensity of the FRET acceptor in 1 depends on the molar absorptivity of the donor, which is a function of zinc(II...
Spectroscopy and electrochemistry of uranium complexes in aluminum chloride-1-ethyl-3-methylimidazolium chloride
Description:
The redox chemistry of UCl$\sb4$ was investigated in the solvent AlCl$\sb3$-1-ethyl-3-methylimidazolium chloride (AlCl$\sb3$-EMIC), a room temperature ionic liquid. In basic solutions (
The pressure behavior of the actinides, like the rest of the chemistry of the actinides, is not well studied or understood. Chapter 1 gives a brief description of the prior work that has gone into studying the pressure behavior of the...
Molecular photophysics and metal coordination chemistry are the two fundamental pillars that support the development of fluorescent cation indicators. In this article, we describe how Zn(II)-coordination alters various ligand-centered...
GROUND STATE PROPERTIES OF CESIUM COBALT TRICHLORIDE AND OPTICAL SELECTION RULES FOR EXCITONS AND MAGNONS IN MAGNETIC PHASES OF CESIUM COBALT TRICHLORIDE AND CESIUM NICKEL TRICHLORIDE
Flux synthesis is a very powerful and versatile technique for the exploratory synthesis of rare earth intermetallics. Reactions of rare earth metals and alkali earth elements with silicon in a Mg/Al flux or a Mg/Zn flux have yielded...
This PhD thesis is devoted to investigation of inorganic materials with low-dimensional structures. Such materials attract significant fundamental and applied interest due to the potential to achieve highly anisotropic properties, which...
The first chapter serves as an introduction to nuclear science. Nuclear weapons are briefly discussed, but more focus is given to the intricacies of fission and traditional nuclear reactors. In order to better understand nuclear waste, a...
The periodic table of the elements, derived from numerous attempts in the 1800s to systematically examine the chemistry found in nature, has seen a stark evolution over the last century. The elements of the actinide series are the...
The actinide series is of great importance, possessing applications in clean energy, space travel, medicinal use, and even household smoke detectors. Despite everyday applications, our knowledge of the actinides is severely limited...
The design and investigation of bimetallic ruthenium complexes exhibiting proton-coupled intramolecular electron transfer
Description:
The development and investigation of bimetallic systems that undergo proton-coupled intramolecular electron-transfer are reported. Initial studies involved the synthesis of a new family of synthetically versatile ruthenium complexes...
An improved method has been developed for the preparation of 5-iodo-1, 2, 3-triazoles directly from organic azides and terminal alkynes by a reaction mediated by copper(I) and iodinating agents generated in situ. The major methodological...
Itinerant magnetism occurs in materials that exhibit a spontaneous polarization of the electronic structure due to the destabilization effect of a large peak in the Density of States at the Fermi level. This itinerancy is difficult to...
Flux synthesis of new complex compounds uses an excess of molten metals or salts as a reaction medium. This solution-based method is a valuable tool in materials synthesis, enabling the solid-state chemist to achieve reactivity at...
Out of interest in better exploring the nature of actinide bonding, investigations have been undertaken which confront the problem of the unusual character of covalency as it occurs in the 5f elements by utilizing multiple analytical...
N-Alkyl-N, N-di(2-pyridylmethyl)amines are ligands commonly used by supramolecular chemists in molecular recognition and sensing applications. The metal coordination complexes of these ligands, in particular those with 2:1 (ligand:metal)...
In this work, various transition and main group metals were heated in a low temperature molten sulfur/iodine flux to produce metal sulfides and metal sulfide iodides, in a one-pot synthesis method that eliminates the use of toxic or...
Selective crystallization offers new opportunities for separating lanthanide elements, which have considerable importance in advanced materials. The first part is the second and third chapters, which investigated that the coordination...
As of 2014, there is an expected 69, 000 metric tons of nuclear waste sitting in storage in the U.S. Little efforts have been made to deal with the radiotoxicity of the spent nuclear fuel (SNF). The problem arises from the complex mixture...
The knowledge of actinide chemistry significantly lags behind the rest of the periodic table. Understanding the fundamental behavior of these elements is crucial for actinide separations and nuclear waste storage. Many separation...
Studies of lanthanide interactions with polyoxometalates: Evaluation as magnetic resonance imaging agents
Description:
A series of lacunary (XM$\sb{11}$O$\sb{39}\sp{\rm n-}$ and P$\sb2$M$\sb{11}$O$\sb{61}\sp{10-}$) and plenary (SiW$\sb{12}$O$\sb{40}\sp{4-}$ and P$\sb2$M$\sb{18}$O$\sb{62}\sp{6-}$) polyoxometalates (POM) were synthesized, analyzed and... For elemental analysis of POM, quantitative methods were developed using ICP-AES for the determination of B, Si, Ge, P and Mo and atomic absorption spectroscopy for Na. The two-step procedure minimizes interelement interferences using... The thermodynamics parameters of complexation ($\Delta$G, $\Delta$H, and $\Delta$S) of Eu(III) with POM were studied at 1 M ionic strength. pK$\sb{\rm a}$ values for the lacunary POM indicate weak basicity with two protonations between... In addition, the $\sp7$F$\sb0 \to \sp5\rm D\sb0$ selective excitation spectra of Eu(III)-polyoxometalate complexes were evaluated qualitatively. Based on the number of peaks, the number of inner sphere H$\sb2$O molecules and the known... The Gd(POM)$\sb2$ complexes were kinetically unstable in Sprague-Dawley rat serum. In vitro challenges to Gd(POM)$\sb2$ by metal cations, DTPA, and DTPA-doped serum suggest instability in serum is due primarily to a transmetalation...
Spin crossover (SCO) is a physical phenomenon where certain transition metal ions exhibit a change in their electronic configuration and magnetic state under the influence of external stimuli such as temperature, pressure, or light. SCO...
Despite their discovery during the 1940's, there are still many unanswered questions surrounding the elements past uranium, or transuranic elements. In the recent years more evidence is emerging that suggest the bonding and structure of...
SYNTHESES AND STRUCTURAL STUDIES OF TRANSITION METAL COMPLEXES: PART I: 2,2'-BIPYRIDINE-N,N'-DIOXIDE. PART II: AMINOMETHANESULFONIC ACID AND 2-AMINOETHANESULFONIC ACID
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