Inorganic Chemistry Commons^™

Synthesis And Characterization Of Starburst Pseudorotaxanes And Their Metallic Derivatives, Shalini D. Kadinappulige

Masters Theses

Mechanically Interlocked Molecules (MIMs) are interlocked molecular architectures, characterized by the fact that they are linked through a mechanical bond. Catenanes, rotaxanes, molecular knots, and Borromean rings are typical examples for these molecules. Since MIMs are not connected by covalent bonds, hydrogen bonding, π- π stacking, and/or electrostatic interactions help bring the components together. Dialkyl-ammonium centers, bis(pyridinium)ethane dications, viologen species, and naphthalenediimide π-deficient groups are well known as recognition motifs for crown ethers. In the research described here, we have synthesized several pseudorotaxanes and their tricyclohexyltin metallic derivatives, based on benzobis(imidazolium) (BBI) salts as axles, in combination with the 15DN38C10 …

Development Of Supported Pd-Based Catalysts For Carbon-Carbon Cross-Coupling And Oxidation Reactions, Mrinmoy Das

Theses and Dissertations

Heterogeneous catalysts are a crucial part of chemistry used for various chemical synthesis stages, pharmaceutical, and environmental applications. The use of nanoparticles or rather nanocatalysts enhances the heterogeneous catalytic applications. Both chemical and physical methods can be used to synthesize nanocatalysts. Chemical synthesis methods require comparatively fewer instruments and can easily synthesize a large amount of nanocatalysts. Nevertheless, chemical synthesis methods require reducing agents and solvents that can be toxic or harmful materials. They often need harsh reaction conditions as well, like high temperature and pressure. On the other hand, physical synthesis methods often require complex instrument setup, but their …

Discerning The Spectroscopic Properties And Chemical Reactivity Of Bioinspired Metallocomplexes, Ashley K. Forney

Theses and Dissertations

In Nature, metalloenzymes catalyze a variety of thermodynamically demanding reactions with remarkable performance under mild, physiological conditions. This innate ability is a driving force for the development of nature inspired, synthetic analogues that are robust and can catalyze a variety of organic transformations. This work involves the successful syntheses of four coordinate, bioinspired complexes, [M^II(n-DOB)] (M = Ni, Co, and Cu; n = 12 and 13), which have been characterized by NMR, ESI-MS, UV/Vis, EPR, and CV. Spectroscopic evidence presents the generation of reactive metal-(di)oxygen species that display amphoteric reaction behavior, making these rarities among inorganic oxidants. These …

Mixed-Valent Heterometallic Molecular Precursors : Expansion Into 4d Transition Metals, Jesse Caleb Carozza

Legacy Theses & Dissertations (2009 - 2024)

Hydrogen fuel can provide an ideal carbon-free energy carrier wherever water is available, be that on Earth or throughout the solar system. The use of water electrolysis to split water molecules into contaminant-free hydrogen gas, suitable for use in fuel cells, and oxygen gas allows also for storage of excess electrical energy during periods of high production and low demand, and an easy path to release that stored energy when demand is high and active supply is low. However, liberating hydrogen from water is an energy-intensive process, and effective electrocatalysts that reduce the amount of energy wasted by the reaction …

Reactions Of First-Row Transition Metal Complexes In Bis(Alkoxide) Ligand Environments With Diazoalkanes: Formation Of Carbenes Versus Reductive Coupling To Form Bridging Tetrazenes, Amanda Grass

Wayne State University Dissertations

This dissertation focuses on the design and reactions of novel late transition metal carbene complexes featuring alkoxide ligand environments. The high-valent cobalt carbene Co(OR)2(=CPh2) (OR = OCtBu2Ph), featuring short Co=C bond of 1.773(3) Å, was previously reported from the reaction of Co(OR)2(THF)2 with diphenyldiazoalkane. Magnetic and spectroscopic (EPR) studies demonstrated Co(OR)2(=CPh2) to be a low-spin S = ½ complex. Computational studies, in agreement with experimental data, suggested that the electronic structure of Co(OR)2(=CPh2) lies between intermediate spin Co(III) anti-ferromagnetically coupled to a carbene radical and a Co(IV) alkylidene. This dissertation began with investigation of this complex in carbene transfer reactivity. …

Greener Synthesis Of Chlorophosphazenes, Andrew Mcgee

Williams Honors College, Honors Research Projects

This project will attempt to synthesize chlorophosphazene molecules in the absence of solvents by using mechanochemical techniques in order to create a more environmentally friendly synthesis route. In this pursuit, various parameters will be changed including the milling ball to reagent ratios, the molar ratios of the reactants, and the addition of different catalysts. The products of each reaction will be characterized in order to determine success. This work builds upon existing efforts to utilize mechanochemical techniques in main group chemistry. The output of this project will be a report in ACS style and a poster to be presented for …

Design Of Pigments For Use In “Cool” Coatings, Tyler Laughorn

Williams Honors College, Honors Research Projects

This project was focused on the development and testing of several novel pigments that exhibit high NIR-reflectance and therefore show potential for use in “cool” coatings. A “cool” coating will reflect more solar radiation than other standard coatings, and so a coated structure would require less energy to keep cool. Four sets of pigments were synthesized: Co_1-xMg_xCr₂O₄ (teal), Co_0.25Mg_0.75Cr_2-yAl_yO₄ (blue), Ti_1-x-yNi_xSb_yO₂ (yellow), and Cr_2-xFe_xO₃ (black). NIR and TSR values were then measured …

Synthesis, Magnetic And Adsorption Of Dye Onto The Surface Of Nio Nanoparticles, Islam Gomaa, Nasser M. Hosny

Nanotechnology Research Centre

NiO was synthesized simply via thermal decomposition of nickel ascorbate, which resulted from semi-solid reaction of nickel acetate and ascorbic acid. The prepared precursor was characterized by elemental, thermal and spectral analyses. The precursor was decomposed at 700 °C producing cubic NiO with average size 50 nm as indicated from XRD and TEM. FESEM indicated the formation of macroporous NiO. Magnetic parameters (saturation magnetization (Ms), remanence (Mr) and coercivity (Hc)) of NiO nanoparticles and its precursor were determined and compared with the bulk nickel. Zeta potential measurements at different pH values indicated that NiO is negatively charged. Adsorption of ponceau …

Uncovering Structure-Property Relationships Of Inorganic Nanomaterials Via Transmission Electron Microscopy, Melonie Thomas

Theses and Dissertations--Chemistry

The rapid increase of research in nanoscale devices and nanotechnology in the past few decades has revealed that nanomaterials may possess exceptional properties that are significantly different from the bulk counterpart, due to local rearrangements of the atoms at surfaces and defects. Transmission electron microscopy (TEM) is an indispensable tool when it comes to the characterization of nanomaterials, primarily due to its ability to resolve the local-structure of materials at the atomic-scale. To study dynamic processes, however, regular TEM experiments are inadequate, as they provide only before and after information rather than the real-time data essential to understanding a reaction …

Synthesis Of Metal Oxide Surface And Interface Arrays By A Combined Solid-Liquid- Vapor/Vapor-Liquid-Solid Approach, Alexandra J. Riddle

Theses and Dissertations--Chemistry

This project was motivated by an in situ heating experiment in the transmission electron microscope (TEM) in which gold (Au) nanoparticles were observed to dissolve tin dioxide (SnO2) nanowires (NWs) under vacuum. The explanation for this observation was that the high-temperature and low-pressure environment of the TEM caused the reverse reaction of the well-known vapor-liquid-solid (VLS) method commonly used to grow NWs. In the VLS process, a metal catalyst absorbs reactant vapor until it becomes supersaturated. The precipitation of the NW occurs at the liquid-solid interface, which ceases when there is no longer reactant vapor, and the diameter of the …

Designing Metal-Halide Perovskites With Enhanced Optical Properties And Stability Using Surface Ligands, Md Aslam Uddin

Theses and Dissertations--Chemistry

Metal-halide perovskites (MHPs), with formula ABX₃ (A = methylammonium, formamidinium, or Cs⁺; B = Sn²⁺ or Pb²⁺; and X = Cl^-, Br^-, or I^-) are versatile and attractive materials because of their tunable optical and electronic properties. These optical and electronic properties include tunable direct band gaps, high absorption coefficients, low exciton binding energies, relatively high electron and hole mobilities, narrow emission line-widths, and high photoluminescence (PL) quantum yields (Φ_PL). Much of the initial excitement around organic metal-halide perovskites focused on their application in photovoltaics (PVs) …

Identification Of Adsorbate Ft-Ir Bands Using In-Situ Techniques: Pd Speciation And Adsorption Chemistry Of Pd-Zeolites For Passive Nox Adsorption, Robert Bruce Pace Iii

Theses and Dissertations--Chemistry

To meet increasingly stringent automotive emissions standards, further improvements in catalytic converter design are necessary. Current automotive catalyst systems are effective at eliminating emission of nitrogen oxides (NO_x) once the catalyst reaches operational temperature (~200 °C). NO_x emitted at lower catalyst temperatures now comprises most of the NO_x released during a typical test cycle. Referred to as “the cold start problem” this issue has come to the forefront of automotive catalyst development, as mitigating these emissions is necessary to further reduce automotive emissions. Passive NO_x adsorbers present an appealing solution to the cold start problem, …

Heparan Sulfate. A Ligand For Coordination Compounds., Eric Ginsburg

Theses and Dissertations

Heparan sulfate (HS), a type of glycosaminoglycan (GAG), has been identified as a ligand for interactions with polynuclear platinum complexes (PPCs). HS is involved in numerous biological processes, and often considered to be extracellular DNA. PPCs interact with HS through the formation of a “sulfate clamp”, where multiple anionic sulfate groups cluster around the cationic PPC. The masking of HS results in the inhibition of enzymatic activity, protein-HS interactions, and other biological processes. PPCs use HS proteoglycans as an method of cellular internalization. By targeting sulfated-GAGs, PPCs can offer precision medicine not currently observed with the FDA approved platinum therapies. …

Electrocatalytic Cathodes For Advanced Lithium–Sulfur Batteries, Ahmed Abdelkader

Theses and Dissertations

Energy demands are anticipated to increase in the next decades with the consumption of fossil fuels predicted to grow from the current levels. This will place an enormous burden on the non–renewable reserves of our energy sources and add to the preexisting environmental crisis with the emission of greenhouse gases like carbon dioxide (CO₂). Electrical energy storage (EES) is considered one of the most crucial needs of modern society to circumvent this crisis and potential applications include electric vehicles and devices, as well as storage systems for solar and wind sources.Lithium–ion batteries (LIBs) have proven to be …

Structure, Morphology And Composition-Property Elucidation Of Ni–Mo And Ni−Mo−P Nanocrystals For Water Splitting Reactions And Group Iv Alloy And Silicate Nanocrystals For Visible To Near Ir Optoelectronics, Ebtesam Hassan Abuelenein Eladgham

Theses and Dissertations

Abstract

Structure, Morphology and Composition-Property Elucidation of Ni–Mo and Ni−Mo−P Nanocrystals for Water Splitting Reactions and Group IV Alloy and Silicate Nanocrystals for Visible to Near IR Optoelectronics

by

Ebtesam Hassan Abuelenein Eladgham

A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University.

Advisor: Indika U Arachchige

Associate Professor, Department of Chemistry

Nanomaterials have gained a great attention because of their unique physical properties with size intermediate between molecular materials and extended solids. They have a large surface to volume ratio and display size tunable physical properties that was not …

Investigation Into The Reaction Profile Of A Bioinspired Nickel Complex, Denver Heitger

Theses and Dissertations

Metal complexes that can activate natural oxidants like H₂O₂ and O₂ have become a key research topic in many labs in hope of mimicking nature, by generating a bioinspired complex that can perform unique chemistry through green processes. To prepare the perfect catalyst, this has lead scientists to explore numerous avenues, including the use of both natural and artificial oxidants, to tease apart the reaction pathway taking place. A ligand system dear to the Lucas Lab (13-DOB) has been metalated with nickel, a cheap and earth abundant transition metal. Our bioinspired metal-(di)oxygen adducts can be formed …

Investigations Of Graphene-Supported Single-Atom Catalyst Model Ions In The Gas Phase, Michael Borrome

Theses and Dissertations

Recent developments in heterogeneous catalysis has led to the conception of single-atom catalysts (SACs), a class of catalysts based on isolated metal atoms anchored to a support scaffold. SACs are often much more reactive and can offer better selectivity when compared to nano-scale catalysts. In order to realize the full potential of SACs, a sound understanding of the underlying catalytic mechanisms is required. However, surface analysis tools can become less effective in studying catalytic mechanisms at the atomic scale. Mass spectrometry has proven to be a robust technique for studying organometallic catalytic mechanisms at the single-molecule level. Using mass spectrometry, …

Transition Metal Chalcogenide Hybrid Systems As Catalysts For Energy Conversion And Biosensing, Siddesh Umapathi

Doctoral Dissertations

"Generation of hydrogen and oxygen through catalyst-aided water splitting which has immense applications in metal air batteries, PEM fuel cells and solar to fuel energy production, has been one of the critical topics in recent times. The state of art oxygen evolution reaction (OER), oxygen reduction reaction (ORR), hydrogen evolution reaction (HER) catalysts are mostly comprised of precious metals. The current challenge lies in replacing these precious metal-based catalysts with non-precious earth-abundant materials without compromising catalytic efficiency.

This research explores mixed metal selenides containing Fe-Ni, Fe-Co and RhSe which were hydrothermally synthesized and/or electrodeposited and tested for OER and ORR …

Cobalt-Catalyzed Aerobic Oxidative Cyclization Reactions Of Bisnucleophiles: New Methodologies And The Role Of Bisnucleophiles In O2 Activation, Jiaqi Liu

Graduate Theses, Dissertations, and Problem Reports (ETD)

Over the past few decades, transition metals have found wide applications in the development of selective oxidative transformations mediated by molecular oxygen. Due to the benign nature of molecular oxygen as an oxidant and an increasing awareness of green chemistry practice, tremendous progress has been made towards the development of Cu-and Pd-catalyzed aerobic oxidation reactions. As a first-row transition metal alternative to copper, cobalt has been employed in aerobic catalytic transformations for its cost-efficiency and earth abundance; however, redox-active mediators such as benzoquinone (BQ), N-hydroxyphthalimide (NHPI) or salen-type ligands are usually required. To date, reactions mediated by Co/O₂ catalytic …

Synthesis And Characterization Of Pyridine Dipyrrolide Iron Complexes Relevant To Nitrene And Carbene Group Transfer, Brett M. Hakey

Graduate Theses, Dissertations, and Problem Reports (ETD)

The synthesis and electronic structures of the square-planar high-spin Fe^II complexes (^MesPDP^Ph)Fe(OEt₂) and (^MesPDP^Ph)Fe(thf) were investigated. Analysis of these compounds using a combination of ¹H NMR and ⁵⁷Fe Mössbauer spectroscopies, in conjunction with computational analysis, has resulted in a rationalization for their unusual electronic structures, which arise from the unique coordination environment enforced by the pyridine dipyrrolide chelate ligand.

The reactivity of (^MesPDP^Ph)Fe(thf) with organic azides has been probed and resulted in the isolation of an array of products that are consistent with …