Inorganic Chemistry Commons^™

Influence Of Platinum Nanoparticles On Ionic Transport And Hydrogen Reactivity Of Yttria-Stabilized Zirconia Thin Films, Firas Mahyob

Electronic Theses and Dissertations

Yttria-stabilized zirconia (YSZ) is a widely used ceramic material in solid oxide fuel cells, oxygen sensors, and sensing applications due to its high ionic conductivity, chemical inertness, and thermal stability. YSZ is promising active coating for use in miniaturized harsh environment wireless surface acoustic sensors to monitor gases such as H₂. Adding catalytic Pt nanoparticles can enhance gas reactivity and lead to associated film conductivity changes.

In this work, thin films with an (8% Y₂O₃ - 92% ZrO₂) composition were deposited onto piezoelectric langasite substrates using RF magnetron sputtering in Ar:O₂ - …

Gold (I) Tetrathiomolybdate Clusters: Synthesis, Characterization, Computational Studies, And Reactivity With Thiophenol And Selenophenol, Dhirgam Humaidy

Electronic Theses and Dissertations

This thesis describes the synthesis and reactivity of heterometallic complexes containing medicinally active Au(I) and tetrathiomolybdate, [MoS₄]^2-. The research is motivated by the idea of multifunctional drugs, which are designed to treat diseases through two or more mechanisms of action. Five clusters of the general form, [MoS₄(AuL)₂] were prepared: C-1 (L=IPr), C-2 (L=IBzMe), C-3 (L=IMes), C-4 (L=PPh₃), and C-5 (L=PEt₃). The clusters with NHC ligands, C-1, C-2, and C-3 were prepared for the first time and thoroughly characterized by ¹H NMR,¹³C{¹H} …

Synthesis And Evaluation Of Water-Dispersed Aryl-Gold Nanoparticles And Applications In Catalysis, Ahmad Al Ahmad

Electronic Theses and Dissertations

Gold nanoparticles have been used in environmental remediation as catalysts through biological and chemical redox reactions of many types of industrial waste including nitroarenes, organic dyes, carbon monoxide, and others. These reactions occur in harsh environmental conditions (e.g. changing temperature, presence of salts, extreme pH solutions) which require robust nanoparticles that can keep their activity and resist aggregation. This thesis describes the synthesis, characterization, and investigation of the catalytic activity of gold-aryl nanoparticles. Gold–aryl nanoparticles (AuNPs-COOH) fabricated using a mild reduction process of a molecular aryldiazonium gold(III) salt [HOOC-4-C6H4N≡N]AuCl4 showed high stability in the presence of high ionic strength salt, …

Synthesis And Characterization Of Heteronuclear Inorganic Complexes For The Photodegradation Of Persistant Organic Pollutants, Matthew A. Moyet

Electronic Theses and Dissertations

The focus of this thesis is to investigate the structural modification and characterization potential of common photocatalysts that have various uses for environmental remediation purposes. Pollution involving organic chemicals is one of the most common scenarios found in communities throughout the country. Efforts to rid contaminated drinking water supplies of these chemicals include physical and chemical filters, which have limited ability and efficacy. This lack of efficient filtration services has led to an increased demand for more effective treatment methods. Chemical species that react in the presence of light are known as photocatalysts and have been used in previous studies …

Development Of Bismuth Oxyhalide Photocatalysts For Environmental And Industrial Applications, Robert Arthur

Electronic Theses and Dissertations

Heterogeneous semiconductor photocatalysis, of interest for water splitting and environmental remediation applications, uses light to drive reactions. Metal oxide and sulfide semiconductors have been previously studied but have limitations that include large band gap energies and high rates of recombination. Bismuth oxyhalides (BiOX) are an emerging class of photocatalysts with tunable band gaps and low rates of recombination due to their unique crystal structures. Studies of BiOX photocatalytic activity have largely focused on removal of azo dyes from aqueous solutions, with little attention paid to degradation byproducts. Furthermore, these catalysts have not been explored as a means to conduct organic …

Optical Memory Behavior, Metallophilic Luminescence, And Chemical Sensing Ability Of Inorganic And Organometallic Complexes: Development Of Optoelectronic Materials, Aaron D. Nicholas

Electronic Theses and Dissertations

This dissertation is divided into three sections: (1) optical memory, (2) metallophilic-based luminescence, and (3) chemical sensors. (1) Optical memory behavior of d¹⁰metal Cu(I) thiocyanate salts are investigated to explore their potential use in the development of digital data storage devices. From this study we have discovered a new class of CuSCN(3-BrPy)₂optical memory material which undergo a reduction in emission intensity upon laser irradiation. This loss of emission intensity can be reversed simply by heating the sample to room temperature. The mechanism by which this emission loss occurs has been studied, revealing a migrating Br atom …

Luminescence Antenna Behavior In Lanthanide Complexes And Luminescence Sensing In Group 11 Iodides, Francis Barnes

Electronic Theses and Dissertations

In this thesis luminescent materials are studied. The luminescent materials studied are lanthanide complexes and group 11 iodide sensing abilities. Emission intensity of the lanthanide complexes through direct excitation of the lanthanide ion are relatively weak. To overcome this, three unique organic ligands were utilized to synthesize lanthanide nitrate complexes in which higher emission intensity can be observed via the antenna effect. Increased emission intensity resulted for Eu^III and Tb^III complexes for each ligand except triphenylphosphane oxide (only the Tb^III complex demonstrated increased emission intensity). Latva’s empirical rule allows for the antenna effect to occur, in which …

Synthesis And Characterization Of Mesoporous Silica Membranes Modified By Atomic And Molecular Layer Deposition, David Emmett Cassidy

Electronic Theses and Dissertations

Inorganic membranes offer a means for chemical separations in a variety of applications including chemical processing, drug delivery systems, battery separators and fuel cells. There is currently a “pore size gap” in silica membranes between 1-2 nanometers. Synthesizing membranes with a fine control of the pore size and distribution within that gap is a significant challenge. This thesis reports findings on using atomic and molecular layer deposition as new synthesis approaches to controlling pore size and chemical functionality of silica membranes. Mesoporous silica membranes, prepared using surfactant-templates with pore diameters ~4nm, were modified using atomic layer deposition and molecular layer …

Photophysical And Photochemical Investigations Of New Tunable Luminescent Metal-Metal Bonded D8-D10 Exciplexes, Howard H. Patterson

University of Maine Office of Research Administration: Grant Reports

This award in the Inorganic, Bioinorganic and Organometallic Chemistry program supports Dr. Howard Patterson at the University of Maine at Orono to investigate d8-d10 exciplexes exhibiting multiple excimeric emissions that can be tuned across the UV and visible regions by: site-selective excitation, temperature, varying the concentration in solution or the solid state (alkali halide hosts), and/or controlled laser irradiation that leads to reversible write/read/erase changes. Photophysical, photochemical, and computational studies will be performed in order to assess the factors that are important for establishing structure-luminescence relationships in tunable systems. The broad tunability previously observed in d10-d10 complexes will be extended …

Metallophilic Interactions In Closed-Shell Metal-Metal Bonded Luminescent Systems And Their Tunability For Excited State Energy Transfer, Howard H. Patterson

University of Maine Office of Research Administration: Grant Reports

Howard Patterson, University of Maine, is supported by the Inorganic, Bioinorganic and Organometallic Chemistry Program for photochemical studies of metal-metal bonded excimers and exciplexes. In solution or in the solid state, dicyanoaurate(I) and dicyanoargentate(I) ions oligomerize. The oligomers show complex photochemistry, including luminescence caused by metallophilic interactions. These systems can be tuned over 18,000 wavenumbers by doping or by adding various donor ions. This research project will look in detail at lifetime and time-resolved studies, vibrational analysis by Raman scattering and infrared, structural studies by x-ray and neutron diffraction, and theoretical analyses. The research will provide insight into metallophilic interactions …

Modification Of Semi-Metal Oxide And Metal Oxide Powders By Atomic Layer Deposition Of Thin Films, Mark Q. Snyder

Electronic Theses and Dissertations

This work describes two methods of modifying, and the subsequent characterizing of, oxide nanopowders. The first method, atomic layer deposition, or ALD, is a series of surface-limited reactions that are repeated to deposit a thin, inorganic film on the surface of the nanopowder. Deposition of a thin film is a useful method to alter the surface properties of a material while retaining its bulk properties. Part of this thesis concerns the understanding of the growth mechanism of thin film titanium nitride (a material known for thermal and chemical stability as well as electronic conductivity) on silica through the ALD process. …

U.S.-Russia Cooperative Research: Designing Gold(I) Complexes For New Materials, Alice E. Bruce, Mitchell Bruce, Dmitri Lemenosvsii, Victor Dyadchenko,

University of Maine Office of Research Administration: Grant Reports

This award in International Programs and the Inorganic, Bioinorganic, and Organometallic Chemistry Program supports collaborative research by Dr. Alice E. Bruce of the University of Maine and Dr. Dmitri Lemenovskii of Moscow State University (Russia). The goal of the project is to design gold complexes that will be useful in new materials, such as liquid crystals. Organogold compounds containing rod-shaped molecules will be synthesized and structurally characterized. Lattice effects in liquid and solid phases formed from the compounds will be studied. Both groups are experienced in the synthetic aspects of the research, but will take advantage of the University of …

Self-Assembly Of Inorganic Membranes: Attachment Of Gold Nanoparticles To A Mesoporous Silica Membrane, Jennifer K. Saucier

Honors College

The purpose of this study was to investigate the self-assembly of gold nanoparticles to create thin, densely packed structures several monolayers thick for the synthesis of a membrane. Silica membrane synthesis was examined as a support for deposition of the nanoparticles. Pore size formation and thickness were controlled to promote high flux, defect free layer formation while providing for optimum separation. Silica mesoporous membranes were created through the acid-catalyzed hydrolysis of tetraethyl orthosilicate. An ionic block co-polymer was used to control a networked pore formation. The silica sols were dip coated on macroporous alumina supports. The silica membranes were characterized …

Surface Interactions Of Mercury On Gold Foil Electrodes In Electrodeposition And Stripping And ; An Investigation Of Free Thiolate Ions From Metal-Thiolate Chalcogenides, Charles Martin Watson

Electronic Theses and Dissertations

Mercury, a highly toxic metal, whose environmental concentration magnifies with ascension of the food chain, is monitored in our waters, food and air. Monitoring mercury is generally done by sample collection, transport to the laboratory; followed by: digestion of the sample, separation of the mercury and detection of the mercury: mostly by cold vapor atomic absorption or, cold vapor atomic fluorescence. These monitoring methods, preclude, routine, in-the-field mercury determination. New analytical techniques have been proposed for in the field determination of mercury. They consist of mercury adsorption onto a sensor or electrode and measuring how much is there either as …

Reactions Of Alcohols And Organophosphonates On Tungsten Trioxide Epitaxial Films, Shuguo Ma

Electronic Theses and Dissertations

The adsorption, diffusion, reactions, and desorption of water, alcohols, ethers, and an organophosphonate were studied using calibrated thermal desorption spectroscopy (CTDS) on thin film WO₃(OOl) surfaces grown epitaxially on a single crystal α- Al₂O₃(li02) (sapphire) substrate. The studies were conducted on oxidized and reduced surfaces, which were characterized by x-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). The desorption spectra for molecular desorption of all of these molecules shifted to lower temperature with increasing coverage, and had overlapping tails on the high temperature side. Monte Carlo simulations show that this typical desorption shape …

Simulation Of Structure, Dynamics And Electron Diffraction Patterns Of Heterogeneous Clusters Armn2N, W. H. Jinasena

Electronic Theses and Dissertations

The nitrogen-argon system provides a useful paradigm for studying segregation and mixing behavior in heterogeneous clusters. Using three realistic pair potentials corresponding to argon-argon, nitrogen-nitrogen and argon-nitrogen interactions, the structures and thermodynamics of Ar_m(N₂)_n, clusters are investigated. Comparison of these results to previous simulation results on neat argon and nitrogen clusters is made. The initial focus of the study is the series of thirteen particle clusters of Ar_m(N₂)_13-m (0 ≤ m ≤ 13); molecular dynamics in the microcanonical ensemble is the principle simulation tool. The icosahedral nitrogen-argon clusters …

Stabilization Of Rutile-Related Thin Film On Tio2 Substrates, Youngnam Cho

Electronic Theses and Dissertations

Conducting metal oxide thin films are of broad interest because they have a wide variety of magnetic and electronic properties. Materials exist that range from superconducting to insulating, are ferromagnetic and are ferroelectric. These properties make thin conducting oxide films attractive for many industrial applications. A class of metal oxides exists that adapt the rutile crystal structure; the structure of the mineral rutile, TiO₂. These metal oxides have the general formula MO₂ where M is a metal cation of valence +4. Metal oxides crystallizing in the rutile structure also display a wide variety of physical properties. The …

Synthesis And Reactivity Of Gold Thiolate Cluster Complexes, Hanan Abdou

Electronic Theses and Dissertations

Chemical oxidation of dinuclear gold(I) thiolates of the formula LLAu₂(SC₆H₄CH₃)₂ [LL= dppp, bis(dipheny1phosphine)propane and dppb, bis(dipheny1phosphine)butane] and dinuclear gold(I) thiolate complexes with bridging a propane dithiolate ligand of the formula LLAu₂(SC₃H₆S) [LL = dppp and dppb] was carried out using the mild oxidizing agent, ferrocenium, [Cp₂Fe]PF6). Spectroscopic studies and elemental analysis showed the formation of gold(I) clusters, disulfide, and ferrocene as products of this oxidation reaction. The clusters, [(dppp)AU₂(SC₆H₄CH₃)](PF₆) and [(dppb)Au₂(SC …