Inorganic Chemistry Commons^™

Synthesis And Characterization Of Support-Modified Nanoparticle-Based Catalysts And Mixed Oxide Catalysts For Low Temperature Co Oxidation, Andrew Justin Binder

Doctoral Dissertations

Heterogeneous catalysts are responsible for billions of dollars of industrial output and have a profound, if often understated, effect on our everyday lives. New catalyst technologies and methods to enhance existing catalysts are essential to meeting consumer demands and overcoming environmental concerns. This dissertation focuses on the development of catalysts for low temperature carbon monoxide oxidation. CO [carbon monoxide] oxidation is often used as a probe reaction to test overall oxidation activity of a given catalyst and is an important reaction in the elimination of toxic pollutants from automotive exhaust streams. The work included here presents three new heterogeneous catalysts …

Studies Of Metalloporphyrins And Tantalum Amide Imide Compounds, Seth Carlton Hunter

Doctoral Dissertations

The focus of this dissertation is on two different subjects. The first examines the magnetic and structural properties of metalloporphyrins. In these studies, neutrons were used to probe the magnetic properties of metalloporphyrins. Insight on the structural properties of metalloporphyrins was also gained by examining the intermolecular interactions in the solid state. The second subject is the synthesis and characterization of new tantalum complexes and studies of their reactions with O₂ [dioxygen]. These complexes are potential precursors to make metal oxide and metal nitride thin films.

In the first part of this dissertation, the zero-field parameters D have been …

An Investigation Of Inorganic Compound Scattering., Karl Jay Bernstein

Doctoral Dissertations

Raman and its associated forms of spectroscopy are powerful tools that have been under-utilized. Presented within are three inorganic compounds studied with some form of Raman spectroscopy: normal Raman, hyper-Raman (HR), surface-enhanced Raman spectroscopy (SERS), surface-enhanced hyper-Raman spectroscopy (SEHRS), or resonance Raman spectroscopy (RR).

The first study involves the investigation of phosphine binding with silver metal. Phosphines find wide use in synthetic circles yet have had little study into their method of binding, unlike similar compounds comprised of sulfur. In order to understand the binding of phosphines, several tertiary phosphines, secondary phosphines and secondary phosphine oxides are examined with SERS. …

Oxygen Reduction Reaction By Copper Complex Based Electrocatalysts, Congling Zhang

Doctoral Dissertations

My research focuses on catalysis of oxygen reduction reaction (ORR) by a series of Cu(II) [copper with positive two valence] -1,2,4-triazole complex-based electrocatalysts at the cathode of PEMFC (polymer electrolyte membrane fuel cell), an efficient and environmental friendly energy conversion system compared to internal combustion engines in use today. The sluggish kinetics of ORR considerably limited the performance of PEMFCs. Understanding of ORR mechanism is important for developing affordable, active and durable ORR catalysts for such devices.

The first part of my work focused on improving the ORR performance of Cu(II)-1,2,4-triazole complex-based catalysts in an acidic environment by exploring synthesis …

Synthesis And Thermodynamic Analysis Of Volatile Beta-Diketone Complexes Of Select Lanthanides Via Gas-Phase Separations, Daniel Hanson

Doctoral Dissertations

Rapid separation techniques for fission and activation products have long been desired to supplant the slow solution-based methodologies currently used. In this work, rare earth elements were derivatized with β [beta]-diketones to synthesize rare earth complexes with high volatility suitable for gas-phase separations. Rare earth elements samarium and dysprosium were combined with hfac (1,1,1,5,5,5-hexafluoro-2,4-pentadione) and fod (6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedione) and analyzed using a gas-phase separation technique. Rare earth elements praseodymium and europium were combined with dpm (2,2,6,6-tetra-methyl-3,5-heptanedione) and similarly analyzed. Employing the data from the separations, the entropy (Δ [delta] S) and enthalpy (Δ [delta] H) of adsorption were evaluated mathematically based …

Synthesizing Strong Donor Macrocyclic Tetracarbene Metal Complexes For Catalytic Aziridination, Steven Alan Cramer

Doctoral Dissertations

A small ringed macrocyclic tetracarbene ligand was developed due to the inherent ability of N-heterocyclic carbenes (NHCs) to stabilize high oxidation states of transition metals. This new strong donor ligand was prepared by first synthesizing an 18-atom ringed macrocyclic tetraimidazolium ligand precursor. The tetraimidazolium can be prepared by a two-step procedure. This ligand precursor was deprotonated to prepare a monomeric platinum tetracarbene complex.

A new iron macrocyclic tetra-carbene complex was synthesized by an in situ strong base deprotonation strategy of the ligand precursor. The iron tetracarbene complex was found to catalyze the aziridination of a wide array of functionalized aryl …

Double-Hinged Di-1,2,4-Triazoles For Synthesis Of Breathing Mofs, Christopher Ray Murdock

Doctoral Dissertations

Employing semi-rigid di-1,2,4-triazoles as ligands has led to the formation of a plethora of Metal-Organic Framework (MOF) architectures. The ability for the ligands to exhibit multiple conformations through a “hinge” effect allows for the formation of a multitude of MOF topologies and dimensionalities. Employment of a di-triazole containing a central trans-butene moiety was initially studied and led to the formation of two three-dimensional copper MOFs. The frameworks can be synthesized independently, but a reaction occurs in water wherein the kinetic product is used as a reagent to synthesize the topologically distinct thermodynamic product.

Additional testing of reaction conditions with …

Syntheses And Reactions Of Early Transition Metal Amidinate Compounds, Adam Christopher Lamb

Doctoral Dissertations

Homoleptic Groups 4 and 5 metal amide compounds have been used as precursors in CVD/ALD processes to make microelectronic metal oxide thin films. These compounds are often very air sensitive. Ancillary ligands such as amidinates have been used to reduce their air sensitivity and to make their handling easier. Reactions of amidinates with dioxygen and water have thus been used to make metal oxide thin films. Studies of these reactions are important in order to make better precursors and purer thin films. This dissertation focuses on the following areas: (a) Syntheses of zirconium and Group 5 amidinate amides; (b) Studies …

Synthesis Of A Bifunctional Heterogeneous Catalyst For The Conversion Of Lignocellulosic Biomass Into Precursors For Alternative Fuels And Fine Chemicals, Matthew David Dembo

Masters Theses

The overall goal of the research described here is to develop synthetic routes to bifunctional reagents that can be tethered into silicate matrices derived from the tin functionalized cube, Si₈O₂₀(SnMe₃)₈. The critical functional group required for reaction with cubic silicate building block is a chlorosilane, and we additionally wish to incorporate both acid and ionic liquid groups. Once in hand, a crosslinking metathesis reaction will incorporate these reagents into porous silicate matrices derived from the Si₈O₂₀ cube, creating platforms with both acid and ionic liquid groups tethered to their …

The Development Of Lithium Tetraborate Compounds For Thermal Neutron Detection, John David Auxier Ii

Doctoral Dissertations

Due to the shortage of ³He [helium-3], the goal of this project was to develop replacement materials for slow neutron detection in mixed radiation fields. The U.S. Department of Homeland Security (DHS) indicated that replacement materials should have an absolute neutron efficiency of 2.5 cps/ng of ²⁵²Cf (Californium-252) and a neutron/gamma discrimination intrinsic efficiency of 1 x 10^-6 [one gamma-ray response in a million counts]. In this work, the use of amorphous lithium tetraborate (Li₂B₄O₇:Ce) is analyzed as a thermal neutron detector. Also discussed is the synthesis of the lithium tetraborate, …

Developing 16- And 18-Atom Ringed Macrocyclic Tetracarbene Complexes, Heather Marie Bass

Doctoral Dissertations

Stabilizing metal-ligand multiple bonds is important for the understanding of biological intermediates, as well as, for their use in group transfer reactions. Two considerations to make when developing a ligand system to support metal-ligand multiple bonds are the strength of the ligand and the symmetry of the ligand. Herein, our group has proposed a class of four-coordinate, strong σ-donor ligands by synthesizing macrocyclic tetraimidazoliums that form tetracarbenes upon deprotonation. By examining group theory, these systems should allow for the formation of complexes with metal-ligand multiple bonds in a bent square pyramidal geometry that exhibit high oxidation states and novel spin …

Syntheses, Characterization And Reactions Of Early Transition Metal Guanidinate And Imide Compounds, Bhavna Sharma

Doctoral Dissertations

Early transition metal compounds and their reactions have been widely used in catalysis and preparation of advanced materials such as metal oxides in microelectronic devices. Studies of the compounds and their reactions provide a fundamental understanding of chemistry of the compounds and are critical to their applications. This dissertation focuses on the following areas: (a) Reactions of Group 4 amide guanidinates with dioxygen or water; (b) Formation of a tantalum imide complex through an unusual α [alpha]-SiMe₃ [trimethylsilyl] abstraction. Reactions of the amide guanidinates with either dioxygen or water yield products that are identified to be dimers and polymers …

Synthesis Of Palladium-Based Electrocatalysis—From Pure Metal To Bimetallic Nanoparticles, Haijun Gao

Masters Theses

This thesis focuses on synthesis and characterization of palladium-based nanoparticles. Background information of the research in this thesis is provided in Chapter 1. Preparation and characterization of pure palladium nanoparticles are presented in Chapter 2. A fast and convenient method to prepare ultra small Pd nanoparticles via Pluronic P123 reduction is discussed in detail. Impregnation method and poly method are also studied in this chapter. Chapter 3 reports the studies of these methods to prepare ultra small bimetallic (bimetallic means a mixture of two metals) palladium-based nanoparticles. Oleylamine-mediated method used Pd nanoparticles prepared via P123 reduction as precursor. Ultra small …

The Synthesis And Characterization Of Novel Group 13 Nanostructured Building Block Heterogeneous Silicate Catalysts, Joshua G. Abbott

Doctoral Dissertations

A building block approach and sequential addition methodology were utilized to prepare heterogeneous silicate catalysts containing atomically dispersed group 13 metal (B, Al, Ga) centers. The octa(trimethyltin) silsequioxane, Si8[sub]O12[sub](OSnMe3[sub])8[sub], was used as the building block for the synthesis of these materials. Reaction of the building block with a variety of group 13 metal chlorides led to the formation of cross-linked matrices. All prepared materials were characterized by gravimetric analysis, gas absorption, IR, and NMR. In addition, aluminum and boron samples where characterized by 27[sup]Al and 11[sup]B solid state NMR, and gallium samples were studied using x-ray absorption techniques.

Studies found …

Novel Single-Site Titanosilicates With Targeted Connectivity And Nuclearity Of Titanium(Iv): Synthesis, Characterization And Catalytic Properties In Alkylphenol Oxidation, Nan Chen

Doctoral Dissertations

Titanosilicates are a family of porous materials that have shown excellent catalytic activity in olefin epoxidation and many other selective oxidation reactions. These materials have been extensively studied in the past few decades. One of the central questions in these investigations has been to define the catalytically active centers. The traditional synthesis of wet impregnation followed by calcination often produces more than one type of catalytic center within the same matrix, i.e. different coordination, connectivity and nuclearity. Each type potentially possesses unique catalytic activity. Co-existence of multiple catalytic centers makes it impossible to establish the relationship between the structure of …

The Itinerant Position Of Yttrium As Evidenced By Carboxylic Acid Extractions, Dustin C Collier

Doctoral Dissertations

The rare-earth elements Y and La-Lu share many similar physical and chemical properties. These similarities are reflected by the difficulty in the complete separation of the rare earths, often requiring hundreds to thousands of stages for the production of pure rare earths. Yttrium, traditionally known to be separated with Ho, has also been observed to be separated with other elements within the lanthanide series, and even outside the bounds of the lanthanide series itself. Previous publications by several authors have indicated that steric factors could influence the position of Y in solvent extractions of the rare earths using carboxylic acid …

The Synthesis And Characterization Of Novel Titanosilicates For Next Generation Hydrogen Storage, James R. Humble

Chancellor’s Honors Program Projects

No abstract provided.

Targeted Synthesis And Characterization Of Nanostructured Silicate Building Block Supports And Heterogeneous Catalysts With Tungsten(Vi) Or Zirconium(Iv) Centers, Michael Edward Peretich

Doctoral Dissertations

Catalysts play a vital role in almost every aspect of our lives and are used in the production of fuels, polymers, chemicals, foods, and pharmaceuticals. One challenge facing the heterogeneous catalysis community is the targeted synthesis of dispersed catalyst ensembles.

The Barnes research group has developed a general methodology for the synthesis of nanostructured silicate building block supports and heterogeneous catalysts. This methodology provides researchers with the ability to control the dispersion of surface functionality, the dispersion of metal cation centers, the number of linkages from the metal cation center to the support, the surface area of the support, and …

Targeted Synthesis And Characterization Of Isolated Zirconium (Iv) Centers In A Silicate Building Block Matrix, Katherine P. Sharp

Chancellor’s Honors Program Projects

No abstract provided.

New Electrochemical And Optical Detection Methods For Biological And Environmental Applications, Royce Nicholas Dansby-Sparks

Doctoral Dissertations

Detection of chromium and vanadium is of interest for biomedical and environmental applications. The two metals have narrow limits between being essential and toxic for humans. Ultra-sensitive techniques have been studied to measure Cr and V at low concentrations found in human blood and environmental samples. Bismuth film and mercury-alloy electrodes have been developed as alternatives to traditional Hg-based electrodes for Cr and V detection. While catalytic adsorptive stripping voltammetry (CAdSV) has been used to detect Cr and V, little is known about the process. The mechanisms of CAdSV have been probed to provide a better understanding of its exceptional …