Chemistry Commons^™

Synthesis And Catalytic Applications Of Non-Metal Doped Mesoporous Titania, Syed Z. Islam, Suraj R. Nagpure, Doo Young Kim, Stephen E. Rankin

Chemical and Materials Engineering Faculty Publications

Mesoporous titania (mp-TiO₂) has drawn tremendous attention for a diverse set of applications due to its high surface area, interfacial structure, and tunable combination of pore size, pore orientation, wall thickness, and pore connectivity. Its pore structure facilitates rapid diffusion of reactants and charge carriers to the photocatalytically active interface of TiO₂. However, because the large band gap of TiO₂ limits its ability to utilize visible light, non-metal doping has been extensively studied to tune the energy levels of TiO₂. While first-principles calculations support the efficacy of this approach, it is challenging to …

Enzyme–Free Uric Acid Electrochemical Sensors Using Β–Cyclodextrin Modified Carboxylic Acid Functionalized Carbon Nanotubes, Mulugeta B. Wayu, Margaret A. Schwarzmann, Samuel D. Gillespie, Michael C. Leopold

Chemistry Faculty Publications

Carboxylic acid-functionalized multi-walled carbon nanotubes (COOH-MWCNT) were modified via ultrasonication with β-cyclodextrin (β-CD) to obtain a COOH-MWCNT:β-CD nanocomposite material for the purpose of developing an enzyme-free electrochemical sensor for uric acid—a clinically relevant molecule implemented in pregnancy-induced hypertension diagnosis. The nanocomposite material is deposited onto glassy carbon electrodes and subsequently capped with layers of Nafion and Hydrothane polyurethane. The surface morphology and electronic structure of the nanocomposite material were characterized using UV–Vis, TEM, and FTIR. The performance of the electrochemical sensor was measured through direct injection of UA during amperometry. With the high surface area of the COOH-MWCNT in concert …

Effect Of Zinc Cations On The Kinetics Of Supramolecular Assembly And The Chirality Of Porphyrin J-Aggregates, A. Romeo, M. A. Castriciano, R. Zagami, G. Pollicino, L Monsù Scolaro, Robert F. Pasternack

Chemistry & Biochemistry Faculty Works

Dilute aqueous solutions of anionic meso-4-sulfonatophenyl-porphyrin (TPPS) extract zinc(ii) ions from glass or quartz surfaces at room temperature and efficiently form the corresponding metal complex (ZnTPPS). The partial or complete formation of ZnTPPS has been probed by UV/Vis spectroscopy and both static and time-resolved fluorescence. The source of zinc(ii) ions has been clearly identified through inductively coupled plasma optical emission spectrometry. The presence of increasing amounts of ZnTPPS slows down the rate of TPPS J-aggregate formation in acid solution. This influences the nucleation step and has a profound impact on the onset of chirality in these species. This evidence indicates …

Selective Atomic Layer Deposition Of Transition Metal Thin Films, Marissa Marie Kerrigan

Wayne State University Dissertations

Atomic layer deposition (ALD) affords highly conformal thin films with precise thickness control due to its self-limited growth mechanism. ALD enables the increasing demands for smaller feature sizes in microelectronics devices to be met. Area-selective ALD growth is receiving attention in the fabrication of microelectronic devices, since it can eliminate complicated etching steps from the fabrication process and minimizes expensive and toxic reagent use. Selectivity can be achieved by tailoring the surface chemistry of the precursor and substrate. To date, few area-selective ALD processes have been reported for metallic films. Thin films of cobalt metal deposited selectively are of considerable …

Synthesis Of Low-Coordinate Transition Metal Bis(Alkoxide) Complexes And Their Reactivity Toward Small Molecules, Maryam Yousif

Wayne State University Dissertations

This dissertation focused on the synthesis of new transition metal complexes in bis(alkoxide) ligand environments and the investigation of their reactivity in nitrene-group transfer catalysis and small molecule activation. Treatment of Cr(N(SiMe3)2)2(THF)2 with two equivalents of HOR (OR = OCtBu2Ph) led to the formation of the chromium(II) alkoxide dimer, Cr2(OR)4. Upon the reaction with bulky aryl and alkyl azides, Cr2(OR)4 led to the stable Cr(IV) mono(imido) complexes, Cr(OR)2(NR), featuring trigonal planar metal centers. In contrast, less bulky aryl azides led to the formation of chromium (VI) bis(imido) complexes Cr(OR)2(NR)2, independent of the amount of azide used. Chromium(IV) mono(imido) species Cr(OR)2(NR) …

Ln(Ii)-Containing Cryptates: Synthesis And Properties, Akhila Nuwan Wijerathne Kuda-Wedagedara

Wayne State University Dissertations

LNII-CONTAINING CRYPTATES: SYNTHESIS AND PROPERTIES

by

AKHILA N. W. KUDA-WEDAGEDARA

May 2016

Advisor: Dr. Matthew J. Allen

Major: Chemistry

Degree: Doctor of Philosophy

Research projects described in this dissertation are focused on studying the physicochemical properties, including the photochemical, redox, and magnetic properties, of LnII-containing cryptates and how ligand structure influences metal–ligand interactions that in turn influence physicochemical properties. The results of these studies enable tailoring of the coordination properties of metal complexes that are important in applications including luminescent materials, chemical reductions, catalysis, and imaging.

A EuII-containing cryptate 2.1-EuII synthesized with an amine-rich ligand displayed bright yellow luminescence in …

Evaluation Of Earth-Abundant Monometallic And Bimetallic Complexes For Catalytic Water Splitting, Kenneth Kwame Kpogo

Wayne State University Dissertations

The development of affordable water splitting catalysts from Earth-abundant transition metal ions such as Co and Mn is of immense scientific interest. Aiming to develop an efficient water splitting catalyst, a Co(II) complex featuring an asymmetric, pentadentate quinolyl-bispyridine ligand with a phenylenediamine backbone was synthesized and characterized by spectroscopic, spectrometric, and X-ray analysis. The Co ion was selected because of its ability to undergo redox conversions from 3d5 CoIV through 3d8 CoI thereby making it a suitable catalyst that can withstand harsh structural and electronic changes during catalysis. The electrocatalytic water reduction activity of the catalyst at neutral pH gave …

Bond Length And Bond Valence Relationships For Chromium Oxides, Chromium Sulfides, Molybdenum Oxides, And Molybdenum Sulfides, J. Labrecque, F. D. Hardcastle

Journal of the Arkansas Academy of Science

Pauling determined an empirical logarithmic dependence of bond order (bond valence), s, to bond length, R, s = exp(R₀ – R/ b), where R₀ is unit bond length and b is a fitting parameter. Recently, an expression was derived for relating the b fitting parameter to theoretically derived atomic orbital exponents. With a method to calculate b, both R₀ and atomic orbital exponents can be experimentally determined through optimized fitting for Cr-O, Cr-S, Mo-O, and Mo-S. In the present study, bond length – valence relationships are found for Cr-O, Cr-S, Mo-O, and Mo-S chemical …

Bond Length And Bond Valence For Tungsten-Oxygen And Tungsten-Sulfur Bonds, F. D. Hardcastle, R. Lykins

Journal of the Arkansas Academy of Science

In 1947, Linus Pauling presented an “empirical” dependence of bond valence (s, also referred to as bond order) and bond length R: s = exp[(R₀-R)/b], where R₀ is bond length of unit valence and “b” is a fitting parameter. Recently, an expression was derived for relating the b fitting parameter to theoretically derived atomic orbital exponents. With a method to calculate b, both R₀ and atomic orbital exponents can be experimentally determined through optimized fitting for W-O and W-S bonds. In the present study, bond …

Kinetic Analysis And Mechanochemical Syntheses Of Palladium Complexes, Jonathon Zachary

Murray State Theses and Dissertations

Mechanochemical synthesis is a rapidly developing, more environmentally friendly alternative to traditional solution based syntheses. Mechanochemical methods often result in higher overall yields, minimize undesirable side reactions, and present cleaner more concise methods for compound preparation. This work will address the syntheses of three dialkyl 2,2′-bipyridyl-4,4′-dicarboxylate complexes of palladium(II) iodide and the kinetics of these reactions. Then, this work will address the improved synthesis and purification of 1,3-dimethyl-1H-benzimidazolium iodide and the synthesis of diiodo-bis(1,3-dimethyl benzimidazol-2-ylidene) palladium(II).

The successful synthesis of dialkyl 2,2′-bipyridyl-4,4′-dicarboxylate complexes of palladium(II) iodide was carried out under solvent free ball milling conditions and the kinetic analysis was …

Use Of Trispyrazolemethane In The Synthesis Of Organometallic Compounds, Claire Hazelton

Undergraduate Honors Thesis Collection

Trispyrazoleborate is a negatively charged facially coordinating tridentate ligand that has been highly researched and used in many metal complexes. The related ligand trispyrazolemethane has not been widely studied due to its difficult synthesis. The objective of this project is to determine the effects of the neutral nature of the trispyrazolemethane on the metal carbonyl complexes of molybdenum and tungsten. Besides the ligand tricarbonyl complex, iodide and hydride derivatives were synthesized. All compounds were characterized with IR and HNMR.

Chalcogenide Nanocrystal Assembly: Controlling Heterogeneity And Modulating Heterointerfaces, Jessica Davis Davis

Wayne State University Dissertations

This dissertation work is focused on developing methods to facilitate charge transport in heterostructured materials that comprise a nanoscale component. Multicomponent semiconductor materials were prepared by (1) spin coating of discrete nanomaterials onto porous silicon (pSi) or (2) self-assembly. Spin-coating of colloidal quantum dot (QD) PbS solutions was employed to create prototype PbS QD based radiation detection devices using porous silicon (pSi) as an n-type support and charge transport material. These devices were initially tested as a photodetector to ascertain the possibility of their use in high energy radiation detection. Short chain thiolate ligands (4-fluorothiophenolate) and anion passivation at the …

Water Splitting Using Cobalt-Based Amidopyridine Complexes, Habib Baydoun

Wayne State University Dissertations

As part of the ongoing search for clean energy sources, splitting water into oxygen and hydrogen has emerged as a promising source of alternative energy. We are interested in developing electrocatalysts capable of performing water reduction and water oxidation. In this dissertation, a variety of catalytic platforms based on an amidopyridine framework are studied. A novel monomeric cobalt complex in an amidopyridine ligand environment, ([CoIII(L1)(pyrr)2]PF6), was investigated for electrocatalytic water reduction and found to have an onset overpotential of 0.54 V and an observed TOF of 23 min-1. The catalytic decomposition pathway was explored with the aim of designing more …

Chemical Reduction Of Planar And Curved Polyarenes : From Group I To Group Ii Metals, Natalie Jean O'Neil

Legacy Theses & Dissertations (2009 - 2024)

To further advance energy storage materials research, the structural studies of carbonaceous compounds intercalated with alkali and alkaline earth metal ions are of great interest and importance. Structure-property relationships of electrode and superconductive materials can be better understood with the gained fundamental knowledge stemming from a synergistic use of solid state and solution studies. Due to the polymeric structures and insolubility in common solvent of intercalated carbonaceous materials, studies of structures and properties must be conducted on smaller subunits. Planar polycyclic aromatic hydrocarbons (PAHs) can serve as models for the infinite π-carbon layers of graphite or graphene, while nonplanar PAHs …

Homo- And Heterometallic Bis(Pentafluorobenzoyl)Methanide Complexes Of Copper(Ii) And Cobalt(Ii), Janell Crowder

Legacy Theses & Dissertations (2009 - 2024)

β-Diketones are well known to form metal complexes with practically every known metal and metalloid. Metal complexes of fluorinated β-diketones generally exhibit increased volatility and thermal stability compared to the non-fluorinated analogues, and thus are used extensively in various chemical vapor deposition (CVD) processes for the deposition of metal, simple or mixed metal oxides, and fluorine-doped metal oxide thin films. Furthermore, the electron-withdrawing nature of the fluorinated ligand enhances the Lewis acidity of a coordinatively unsaturated metal center which facilitates additional coordination reactions. The physical and structural properties of fluorinated β-diketonate complexes are discussed in Chapter 1 …

Design, Synthesis And Analysis Of Potential Photo-Activatable Cathepsin K Inhibitors, Khalin Evania Nisbett

Wayne State University Theses

Abstract

DESIGN, SYNTHESIS AND ANALYSIS OF POTENTIAL PHOTO-ACTIVATABLE CATHEPSIN K INHIBITORS

by

KHALIN NISBETT

May 2017

Advisor: Dr. Jeremy Kodanko

Major: Chemistry

Degree: Master of Science

Tightly regulated cysteine CA proteases play a major role in maintaining the homeostasis within cells. Subsequently, when these proteases are dysregulated and mislocalized they disrupt healthy cell dynamics and contribute to many life-threatening pathologies such arteriosclerosis, osteoporosis and cancer. As such many pharmaceutical companies and research teams are highly interested in these proteases as targets. One emergent strategy is the spatiotemporal control of biological processes. In relation to this, a series of spatiotemporally controlled …

Nitrogen-Containing Materials For Mechanochemical Synthesis, Luminescence Analysis, And Heterogeneous Catalysis, David Nash

Electronic Theses and Dissertations

Various inorganic nitrogen-containing materials have been exploited for their different properties. Several nitride materials are commercially attractive due to their mechanical properties making them suitable for ceramic industries and wide bandgaps fitting for use as semiconductor and insulator materials, as well as optoelectronics. Nitride materials can exhibit versatility in applications such as the use of gallium nitride to make blue LEDs, nitrides of titanium and silicon being utilized as medical implants for their chemical inertness and hardness, and the heavy use of boron nitride as a solid lubricant in the cosmetic industry. Amines have been used as nitrogen-containing organic ligands …

Investigation Of Host-Sensitized Luminescence Of Trivalent Lanthanide Doped Yttrium Phosphate Using Vuv Spectroscopy, Zachary Way

All Master's Theses

Host-sensitized luminescence of yttrium phosphate doped with trivalent lanthanide elements prepared via two synthetic approaches was studied using VUV spectroscopy. A correlation between an unusually intense 150 nm excitation intensity and the ground state energy level of select trivalent lanthanide elements was proposed. Using spectroscopy, the host-to-activator transfer efficiencies of YPO₄:Ln³⁺ (Ln³⁺ = Sm³⁺, Eu³⁺ and Tb³⁺) were evaluated for two synthetic approaches. Electron-hole pair trapping efficiencies and S_loss values were calculated using published kinetic models.

From Rags To Riches, From Waste To Valuables: Towards A Sustainable Fuel Additive, Jonathan Kilroy

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Efficient Integration Of Plasmonic And Excitonic Properties Of Metal And Semiconductor Nanostructures Via Sol-Gel Assembly, Dilhara Liyanage

Theses and Dissertations

Research in nanoscience has gained noteworthy interest over the past three decades. As novel chemical and physical properties that are vastly different from extended solids are realized in nanosized materials, nanotechnology has become the center of attention for material in research community. Much to our amazement, investigations in the past two decades revealed that the nanocrystalline semiconductors are “THE PRIME CANDIDATES” to meet the growing energy demand, sensor development, cellular imaging and a number of other optoelectronic applications. Nonetheless, synthesis of nanostructures with control over physical parameters is not sufficient, yet assembling them into functional nanoarchitectures with unique and tunable …

Heterogeneous Base Metal Catalyzed Oxidative Depolymerization Of Lignin And Lignin Model Compounds, John Adam Jennings

Theses and Dissertations--Chemistry

With the dwindling availability of petroleum, focus has shifted to renewable energy sources such as lignocellulosic biomass. Lignocellulosic biomass is composed of three main constituents, lignin, cellulose and hemicellulose. Due to the low value of cellulosic ethanol, utilization of the lignin component is necessary for the realization of an economically sustainable biorefinery model. Once depolymerized, lignin has the potential to replace petroleum-derived molecules used as bulk and specialty aromatic chemicals. Numerous lignin depolymerization strategies focus on cleavage of β-aryl ether linkages, usually at high temperatures and under reductive conditions.

Alternatively, selective benzylic oxidation strategies have recently been explored for …

Interactions Of Compounds Containing Group 12 And 16 Elements, Daniel Burriss

Theses and Dissertations--Chemistry

The focus of this dissertation is on the interactions of compounds containing group 12 and 16 elements. This work is presented in three major parts. First, the interaction of the synthetic dithiol N,N’-bis(2-mercaptoethyl)isophthalamide), abbreviated BDTH₂, with selenite. Second, the interaction of cysteine with Cd(II) and the biologically relevant Cd-Cysteine crystal structure. Third, the green synthesis of CdSe quantum dots (QDs).

The interaction of BDTH₂ with selenite is different from the interactions with other metals and metalloids previously studied. Under ambient conditions, BDTH₂ is oxidized to the disulfide, BDT(S-S), while selenite is reduced to elemental selenium. However, …

Arsenic Removal With A Dithiol Ligand Supported On Magnetic Nanoparticles, John Hamilton Walrod Ii

Theses and Dissertations--Chemistry

Exposure to arsenic (As) in water, the ubiquitous toxin that poses adverse health risks to tens of millions, is the result of both anthropogenic and geochemical mobilization. Despite recent publicity and an increased public awareness, the dangers associated with arsenic exposure rank among the top priorities of public health agencies globally. Existing sequestration applications mainly include reductions and adsorption with zero-valent metals and their oxides. The performance of adsorption media is known to preferentially favor aqueous As(V) over As(III) due to the charge of the dissolved oxyanion. Magnetic nanoparticles (MNP) have been the focus of multidisciplinary research efforts for the …

Exploring The Structure And Properties Of Nanomaterials Using Advanced Electron Microscopy Techniques, Yao-Jen Chang

Theses and Dissertations--Chemistry

Nowadays people are relying on all kinds of electronic devices in their daily life. All these devices are getting smaller and lighter with longer battery life due to the improvement of nanotechnology and materials sciences. Electron microscopy (EM) plays a vital role in the evolution of materials characterization which shapes the technology in today’s life. In electron microscopy, electron beam is used as the illumination source instead of visible light used in traditional optical microscopy, the wavelength of an electron is about 10⁵ times shorter than visible light. By taking this advantage, the resolving power and magnification are greatly …

Deconvolving The Steps To Control Morphology, Composition, And Structure, In The Synthesis Of High-Aspect-Ratio Metal Oxide Nanomaterials, Lei Yu

Theses and Dissertations--Chemistry

Metal oxides are of interest not only because of their huge abundance but also for their many applications such as for electrocatalysts, gas sensors, diodes, solar cells and lithium ion batteries (LIBs). Nano-sized metal oxides are especially desirable since they have larger surface-to-volume ratios advantageous for catalytic properties, and can display size and shape confinement properties such as magnetism. Thus, it is very important to explore the synthetic methods for these materials. It is essential, therefore, to understand the reaction mechanisms to create these materials, both on the nanoscale, and in real-time, to have design control of materials with desired …

Designing High Performance Overall Water Splitting Electrocatalysts From Non-Precious Metal Selenides, Abdurazag T. Swesi

Doctoral Dissertations

“The energy production has been depending mostly on fossil fuel which will be depleted someday in the near future. Aspects such as the loss of energy resources and destruction of the environment have motivated researchers for pursuing transition away from fossil fuels to renewable solar-fuels. Therefore, in order to meet the continuous increasing demand for energy, the hydrogen, with the largest energy density stored in it, can then efficiently be used in fuel cells without concern of contaminants. Water splitting reaction to generate H₂ and O₂ is one promising method of converting solar energy into fuels. The major …

Synthesis And Characterization Of Metallic Nanoparticles For Catalytic Applications, Sarah Smith

Theses and Dissertations

In recent years, research has focused on reducing the cost of catalysts in a variety of ways including using less expensive materials, improving the synthetic method, and increasing the catalytic activity, recovery, and recyclability. Typically with nanoparticles, the size, shape, composition, and surface coating have an effect on catalytic activity.^1-2 In this work, we focused on reducing the cost of precious metal based catalysts by altering the synthetic methods.

One way to lower the cost of synthesizing precious metal nanoparticles is by debasing the precious metal with a second cheaper more abundant metal. CuPd nanoparticles were synthesized in oleylamine …

Sol-Gel Chemistry: An Advanced Technique To Produce Macroscopic Nanostructures Of Metal And Semiconductor Colloids, Lamia Nahar

Theses and Dissertations

The fascinating physical properties that arise in materials limited to dimensions of 1-100 nm have gained noteworthy interest from the scientific community. Accordingly, there has been a lot of attention paid to the synthesis of discrete nanoparticles (NPs) and they are being investigated for a range of advanced technologies. Nonetheless, efficient use of nanomaterials in device applications require them to be assembled into solid state macro-structures while retaining their unique, nanoparticulate properties. To date, most commonly investigated assembling techniques include: covalent coupling of NPs surface groups, control evaporation of the solvent to produce ordered supercrystals or non-ordered glassy films, and …

Size And Shape Control In Metal Nanoparticles And Nanocomposites, Tomendro Subedi

Theses and Dissertations (Comprehensive)

This thesis describes major findings on the shape transformation of the precursor silver decahedral nanoparticles (AgDeNPs) with pentagonal symmetry and twin defects into silver pentagonal prism nanoparticles (AgPPNPs) using Br¯ as a shape selective reagent. Silica-encapsulation of the gold-plated AgDeNPs was also carried out forming ordered arrays of silica encapsulated gold-plated AgDeNPs (SiO₂@Au@AgDeNPs) of different sizes. At first, synthetic procedures for AgDeNPs (pentagonal bipyramids), silver pentagonal rod nanoparticles (AgPRNPs) and gold-plating of AgDeNPs (Au@AgDeNPs) were optimized. Gold plating enhances the chemical stability of AgDeNPs and preserves the superior plasmonic properties of silver. This thesis deals with the transformation …

Electropolymerization Of B–Cyclodextrin Onto Multi–Walled Carbon Nanotube Composite Films For Enhanced Selective Detection Of Uric Acid, Mulugeta B. Wayu, Luke T. Dipasquale, Margaret A. Schwarzmann, Samuel D. Gillespie, Michael C. Leopold

Chemistry Faculty Publications

An amperometric uric acid (UA) sensor incorporating a multi-walled carbon nanotubes (MWCNT) network in Nafion and electropolymerized β-cyclodextrin (β-CD) layer is investigated. The electrochemical sensor is comprised of a glassy carbon electrode modified with Nafion-MWCNT nanocomposite film, a β-CD polymer inner selective layer, and a Hydrothane polyurethane (HPU) outer selective coating. The surface morphology and electronic structure of the electrode material are characterized using transmission electron microscopy (TEM), scanning electron microscope (SEM), and Fourier transform infrared (FTIR) spectroscopy. The electrocatalytic activity of the sensor is studied using cyclic voltammetry (CV), chronocoulometry (CC) and differential pulse voltammetry (DPV). Analytical performance of …