Chemistry Commons^™

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 …

Separation Of Nitrito- And Nitropentamminecobalt (Iii) Chloride By High Performance Liquid Chromatography, Tisha Hutchinson

Seton Hall University Dissertations and Theses (ETDs)

Reversed phase high performance liquid chromatography, chosen because of its ability to collect many data points over a long period of time with minimal involvement, was used to separate pentaamminenitritocobalt(III) chloride and pentaamminenitrocobalt(III) chloride. Pentaamminenitritocobalt(III) chloride was prepared, made into a concentrated solution, divided into aliquots and allowed to isomerize to pentaamminenitrocobalt(III) chloride over a period of twelve to eighteen hours. An injection was made approximately every forty-five minutes. The samples were analyzed at three wavelengths, 254 nm, 460 nm and 490 nm. The absorbance was collected and was used to determine the kinetics of the reaction.

The isomerization from …

Synthesis Of Metal-Containing Phosphines And Their Use In Coordination, Polymer, And Materials Chemistry, Amir Rabiee Kenaree

Electronic Thesis and Dissertation Repository

This thesis describes the investigation of a novel strategy for the synthesis of metal-containing small molecules, polymers, and nanomaterials. In this context, a new family of air-stable, homo- and heterometallic primary, secondary, and tertiary phosphines were prepared via the radical-initiated hydrophosphination reaction of PH₃ with vinylferrocene and/or vinylruthenocene. The full characterization of the phosphines confirmed their targeted structures and proved that the properties of the starting metallocenes are reflected in those of the resulting phosphines.

To study the coordination behavior of this family of phosphines, primary, secondary, and tertiary ethylferrocene phosphines were reacted with Group 6 metal carbonyl adducts …

Creating Functional Materials With Phosphorus, Tyler John Cuthbert

Electronic Thesis and Dissertation Repository

Understanding the relationship between small molecules or polymers and how they affect the properties of materials they compose is the basis of materials science. Using unique and versatile components can impart useful and interesting properties to materials. Here, we aimed to extend this understanding to phosphorus, and the known properties it possesses. This included the production of photopolymerizable coatings containing phosphonium molecules and polymers for antifouling and antibacterial applications. The synthesis and characterization of these phosphonium components was completed and materials were produced utilizing UV curing technology. Addition of these components produced coatings that could resist bacteria attachment and efficiently …

Synthesis Of Metal-Containing Polymers And Stable Organic Radical-Containing Polymers And Their Use As Advanced Functional Materials, Joseph A. Paquette

Electronic Thesis and Dissertation Repository

The work presented in this thesis details the synthesis and characterization of two different families of multifunctional polymers. The first family involved the incorporation of stable 6-oxoverdazyl radicals into polymer scaffolds. This was originally achieved by the polymerization of the radical precursors, phenyl- and isopropyl-6-oxotetrazanes, followed by post-polymerization oxidation to afford the phenyl- and isopropyl-6-oxoverdazyl polymers. A second methodology involved the direct polymerization of isopropyl-6-oxoverdazyl radicals using ring-opening metathesis polymerization (ROMP) to afford polymers with controlled molecular weights and narrow molecular weight distributions. The polymers were characterized by the close comparison of the physical and spectroscopic properties …

Over Or Under: Hydride Attack At The Metal Versus The Coordinated Nitrosyl Ligand In Ferric Nitrosyl Porphyrins., E G. Abucayon, R L. Khade, D R. Powell, Michael J. Shaw, Y Yang, G B. Richter-Addo

SIUE Faculty Research, Scholarship, and Creative Activity

Hydride attack at a ferric heme–NO to give an Fe–HNO intermediate is a key step in the global N--‐cycle. We demonstrate differential reactivity when six--‐ and five--‐coordinate ferric heme--‐NO models react with hydride. Although Fe–HNO formation is thermodynamically favored from this reaction, Fe–H formation is kinetically favored for the 5C case.

Synthesis, Reactivity, And Nmr Trends Of Early Transition Metal Compounds, Tabitha Marie Cook

Doctoral Dissertations

This dissertation focuses of three different subjects. The first is the synthesis and characterization of heptacoordinate amidinate compounds. Heptacoordinate compounds are not common, but their structures have been studied. Group 4 amidinate compounds have been used as precursors in the CVD/ ALD processes. Ancillary ligands, such as amidinates, have been used to reduce air-sensitivity of complexes. Reactions of these complexes with water have been used to make metal oxide thin films.

In the first study, the complexes Zr[MeC(NⁱPr)₂]₃Cl [zirconium trisamidinate chloride], Hf[MeC(NⁱPr)₂]₃Cl [hafnium trisamidinate chloride], Zr[MeC(NⁱPr) …

Redox-Active Ligand Uranium Complexes For Approaches To Multi-Electron Chemistry, John J. Kiernicki

Open Access Dissertations

While transition metal complexes are known to participate in multi-electron redox chemistry to facilitate important organometallic transformations, actinides, due to their low redox potentials, have a propensity to perform single electron chemistry. Because of its highly reducing nature, the ability to control the electronics of low-valent uranium is highly sought after as this may lead to unprecedented reactivity. Our lab has specifically been interested in mediating multi-electron transformations at uranium by employing redox-active ligands. Redox-active ligands can be used to facilitate multi-electron processes such as oxidative addition and reductive elimination at single metal centers. Using primarily 2,6-((Mes)N=CMe)2C5H3N) ( MesPDIMe) as …

Development Of An F-Element Separation Chemistry Using Solid Electrolytes, Kristian Guy Myhre

Doctoral Dissertations

The f‒elements (lanthanides and actinides) have numerous applications and are critically important to many industries, including the energy, security, and medical industries. One of the barriers to increased use and availability of the f‒elements is the difficulty in separating them from each other due to their similar chemistries. This is especially true of the trivalent f‒elements (lanthanides and minor actinides). The development of separation techniques that maximize the differences in the physicochemical properties of the f‒elements is therefore an important area of research. For these reasons, an effort was undertaken to explore the use of solid …

Design And Synthesis Of Novel Octacarboxy Porphyrinic Metal-Organic Frameworks, Jacob A. Johnson

Department of Chemistry: Dissertations, Theses, and Student Research

Metal-Organic Frameworks (MOFs) are a class of nanoporous crystalline materials constructed via the interconnection between metal-ions/inorganic clusters and organic ligands. Since the surface area, pore size and distribution, and chemical functionalities of MOFs are highly tunable via the judicious combinations of inorganic clusters and organic ligands, MOFs have attracted intensive interests for a variety of applications including gas adsorption and separation, catalysis, chemical sensing, and drug delivery among others. Porphyrin based ligands are of particular interest for building functional MOFs due to their unique photo-, electro-, and catalytic properties. In addition, the four-fold symmetry of porphyrin ligands offers an effective …

Synthesis And Characterization Of Novel Ligand For Use On Rhodium Paddlewheel Complexes, Gavin J. Rustin

Masters Theses

Dirhodium (II) paddlewheel complexes have proven to be useful catalysts in many transformations including C-H insertions, cyclopropanation, and silane insertion reactions. One deficiency of these catalysts is the inability to modulate the enantioselectivity with reactive diazo compounds. One avenue for potential improvement of paddlewheel complexes is coordinating ligands in the axial site to increase enantioselectivity. The axial site has been occupied by various ligands including Nheterocyclic carbenes, nitrogen compounds, and phosphorous compounds. This work examines compounds that can be used as ligands on dirhodium complexes that have a pendant chain containing a dibenzyl phosphite and dibenzyl phosphate, both of which …

Specific Phosphate Sorption Mechanisms Of Unaltered And Altered Biochar, Kathryn D. Szerlag

Masters Theses

Biochar has been shown to act as an effective sorbent for many organic and inorganic contaminants (including phosphate) and can help to improve the quality of our fresh water resources by preventing eutrophication. Most of the high efficiency biochar phosphate-adsorbent feedstocks are modified with chemical pretreatment, phytoremediation or anaerobic digestion to accumulate desired elements. The main objectives of this project were to first engineer magnesium (Mg) and calcium (Ca) altered biochar by chemical pretreatment followed by pyrolysis at either 350 or 550°C and evaluate their phosphate adsorption rate and potential as compared to their unaltered counterparts. Determination of surface physiochemical …

Metal-Organic Frameworks As Potential Platforms For Carbon Dioxide Capture And Chemical Transformation, Wenyang Gao

USF Tampa Graduate Theses and Dissertations

The anthropogenic carbon dioxide (CO₂) emission into the atmosphere, mainly through the combustion of fossil fuels, has resulted in a balance disturbance of the carbon cycle. Overwhelming scientific evidence proves that the escalating level of atmospheric CO₂ is deemed as the main culprit for global warming and climate change. It is thus imperative to develop viable CO₂ capture and sequestration (CCS) technologies to reduce CO₂ emissions, which is also essential to avoid the potential devastating effects in future. The drawbacks of energy-cost, corrosion and inefficiency for amine-based wet-scrubbing systems which are currently used in industry, …

Solvothermal Preparation And Characterization Of Superstructures Of Nanoscopic Cds And Cdse, Tetyana Levchenko

Electronic Thesis and Dissertation Repository

Micrometer-sized superparticles, self-assembled from metallic or semiconducting nanoclusters, can be used as convenient building blocks for preparing functional materials, utilizing the electronic and photophysical properties resulting from the quantum confinement as well as from the coupling between individual nanoscopic constituents.

This research aimed at developing a novel approach utilizing the conversion of a cadmium phenylchalcogenolate precursor (Me₄N)₂[Cd(EPh)₄] (where E = S or Se) under solvothermal conditions for the preparation of nanoscopic CdE, including both crystalline superlattices of large discrete nanoclusters and superstructures with more complex morphology. In particular, 3D cubic superlattices of molecular CdS …

The Investigation Of The Electrical Control Of Hemimicelles And Admicelles On Gold For Analyte Preconcentration, Dheyaa Hussein Al-Karawi

Masters Theses & Specialist Projects

Hemimicelles and admicelles are well-investigated wonders in modern science; they are surfactant monolayers and surface adsorbed micelles, respectively. Capacitance measurements for monitoring the formation of dodecyl sulfate (DS) surfactant monolayer on positively charged gold substrates (planar gold) and the adsorbance of 2-naphthol onto DS surfactant monolayer were performed. The investigation of the electrical control of DS at various concentrations (4, 6, 16, and 32 mM) below and above the critical micelle concentration (CMC= 8 mM) on gold surfaces for analyte preconcentration, prior to chromatographic analysis, is presented. Charged ionic surfactants, such as DS, drawn to a surface of opposite charge …

Visible-Light Generation Of High-Valent Metal-Oxo Intermediates And A Biomimetic Oxidation Catalyzed By Manganese Porphyrins With Iodobenzene Diacetate, Ka Wai Kwong

Masters Theses & Specialist Projects

High-valent iron-oxo intermediates play central roles as active oxidants in enzymatic and synthetic catalytic oxidations. Many transition metal catalysts are designed for biomimetic studies of the predominant oxidation catalysts in Nature, the cytochrome P450 enzymes.

In this work, a new photochemical method to generate high-valent iron-oxo porphyrin models was discovered. As controlled by the electronic nature of porphyrin ligands, iron(IV)-oxo porphyrin radical cations (Compound I model) and iron(IV)-oxo porphyrin derivatives (Compound II model) were produced. These observations indicate that the photochemical reactions involve a heterolytic cleavage of O-Br in precursors to give a putative iron(V)-oxo intermediate, which might relax to …

Engineering Nanoarchitectures From Nanosheets, Nanoscrolls, And Nanoparticles, Taha Rostamzadeh

University of New Orleans Theses and Dissertations

The ability to encapsulate/insert different kinds of nanoparticles (NPs) in scrolled nanosheets (NSs) may lead to the formation of new nanocomposite materials that yield novel properties. These nanostructures resemble “peapods” that consist of NPs chains (“peas”) located in a hollow space of desired nanoscrolls (“pods”). Depending on different combinations of “peas” and “pods” diverse families of nanopeapods (NPPs) can be synthesized which may exhibit interesting properties not accessible from the individual components. Though there exist various synthetic methods for the formation of NPPs, more development in terms of simplicity, flexibility, and productivity of synthetic approaches are needed so that different …

Synthesis And Characterization Of Imidazolo 3,1- Tetrakis (N-Phenylacetamidato) Dirhodium (Ii) And A Crystallographic Study Of A Copper And Two Molybdenum Model Cofactors, Gabriel I.G. Thompson

Electronic Theses and Dissertations

Imidazole was reacted with 3,1-tetrakis (N-phenlyacetamidato) dirhodium (II) to explore the chemistry of asymmetric dirhodium catalysts. The imidazolo 3,1-tetrakis (Nphenlyacetamidato) dirhodium (II) complex was synthesized and then characterized by Nuclear Magnetic Resonance and Ultraviolet-Visible spectroscopies as well as by single crystal X-ray Diffraction. Additionally, one copper and two molybdenum model cofactors were characterized by XRD to better understand their structure/function relationships. NMR results gave evidence of the formation of the 3,1-imidazole complex, and UV-Vis indicated that even in large excess imidazole was coordinated only to one axial site. The structure of the 3,1-imidazole complex was confirmed by XRD with the …

The Synthesis Of Chemosensors For Toxic Analytes, Johnathan Hugh Broome

Dissertations

A number of chemosensors have been designed and synthesized to target cations (Zn²⁺ions), neutral molecules (cathinones), charged molecules (aminoindanes), and anions. The Zn²⁺ ion sensor featured bistriazole designed binding unit and ferrocene signaling units. Characterization of Zn²⁺ ion binding was carried out with electrochemical techniques (CV and DPV), ¹H-NMR, mass spectrometry, and molecular modelling. It exhibited a 1:1 binding stoichiometry with Zn²⁺ and had an affinity for ZnCl₂ (Log K_1:1 = 4.1 ± 0.02) over other Zn²⁺ salts.

The cathinone probe was designed to selectively bind mephedrone over common street drugs …

A Library Of Coumarin-Enaminone Chemodosimeters For The Detection Of Analytes, Aaron Berrell Davis

Dissertations

Many anions and metal ions are of biological and environmental importance. This work describes our attempts to synthesize molecular probes to specifically target cyanide, zinc, cadmium and mercury as these species can often result in negative effects to the environment and the human body.

The work in this dissertation, describes the synthesis of a family of coumarin-enamine chemodosimeters, in a straightforward synthetic procedure, the reaction between 7-(diethylamino)-4-hydroxycoumarin and a primary amine. The work presented in this dissertation demonstrates that these molecules can play dual roles and therefore the work is split into two distinct parts: Part 1 describes one role …

Mida Boronates Are Hydrolysed Fast And Slow By Two Different Mechanisms, Jorge A. Gonzalez, O. Maduka Ogba, Gregory F. Morehouse, Nicholas Rosson, Kendall N. Houk, Andrew G. Leach, Paul H.-Y. Cheong, Martin D. Burke, Guy C. Lloyd-Jones

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

MIDA boronates (N-methylimidodiacetic boronic acid esters) serve as an increasingly general platform for building-block-based small molecule construction, largely due to the dramatic and general rate differences with which they are hydrolysed under various basic conditions. Yet the mechanistic underpinnings of these rate differences have remained unclear, hindering efforts to address current limitations of this chemistry. Here we show that there are two distinct mechanisms for this hydrolysis: one is base-mediated and the other neutral. The former can proceed more than three orders of magnitude faster, and involves rate-limiting attack at a MIDA carbonyl carbon by hydroxide. The alternative ‘neutral’ hydrolysis …

Corn Stalk Nitrate Interpretation, John E. Sawyer

John E. Sawyer

You’ve gotten results from corn stalk nitrate samples collected this fall. (Corn stalk nitrate analysis form.) Now, what do the results mean? The stalk nitrate test is based on the concentration of nitrate-N in the lower corn stalk (8 inch segment from 6 to 14 inches above the ground) when the plant reaches maturity (See Cornstalk testing to evaluate nitrogen management, PM 1584). In general, a larger amount of plant-available N in the soil during the time period before plant maturity results in a greater concentration of nitrate in the lower stalk. However, the stalk nitrate-N concentration …

Corn Stalk Nitrate Interpretation, John E. Sawyer

John E. Sawyer

You’ve gotten results from corn stalk nitrate samples collected this fall. (Corn stalk nitrate analysis form.) Now, what do the results mean? The stalk nitrate test is based on the concentration of nitrate-N in the lower corn stalk (8 inch segment from 6 to 14 inches above the ground) when the plant reaches maturity (See Cornstalk testing to evaluate nitrogen management, PM 1584). In general, a larger amount of plant-available N in the soil during the time period before plant maturity results in a greater concentration of nitrate in the lower stalk. However, the stalk nitrate-N concentration can be greatly …

Magnetic Doping Of Semiconductor Molecular Models And Colloidal Nanocrystals, Swamy Pittala

Doctoral Dissertations

Spin-based electronics use the spins of electrons in addition to their charges and have potential applications to create a next generation of quantum computers, capable of storing vast amounts of data in an energy-efficient way. Diluted magnetic semiconductor quantum dots (DMS-QDs) have shown great promise as ideal materials for application in spin-based electronics. However, doping impurities into quantum confined colloidal nanocrystals (NCs) has been a great challenge due to the lack of control over the dopant reactivity during the specific stages of nucleation and growth. The mechanism of dopant incorporation into nanocrystals is complex and well-defined and atomically precise molecular …

Challenges In Catalytic Hydrophosphination, Christine A. Bange, Rory Waterman

College of Arts and Sciences Faculty Publications

Despite significant advances, metal-catalyzed hydrophosphination has ample room for discovery, growth, and development. Many of the key successes in metal-catalyzed hydrophosphination over the last decade have indicated what is needed and what is yet to come. Reactivity that is absent from the literature also speaks to the challenges in catalytic hydrophosphination. This Concept article discusses and highlights recent developments that address the ongoing challenges, and identifies areas in metal-catalyzed hydrophosphination that are underdeveloped. Advances in product selectivity, catalyst design, and both unsaturated and phosphine substrates illustrate the ongoing development of the field. Like all catalytic transformations, the benefits are realized …

Electrochemistry And Spectroscopy Of A Molybdenum Porphyrin Compound, Jay S. Bhanot, Kyle A. Grice

DePaul Discoveries

Carbon dioxide has been a problematic greenhouse gas since the beginning of the industrial age. In an effort to remediate its effects on the climate, multiple techniques have been utilized in the chemical and electrochemical reduction of CO₂. Homogeneous electrocatalysis for carbon dioxide reduction has been a topic of increasing interest. However, a full examination of the catalytic performance of early transition metals supported by macroligands has yet to be done. The research reported involves synthesis of a chelate of molybdenum within a tetraphenylporphyrin, and then synthesis, purification, and characterization of its ability to reduce carbon dioxide. The …

Synthesis And Studies Of Cyclopentadienyl Molybdenum Complexes, Cesar Saucedo, Kyle A. Grice

DePaul Discoveries

The synthesis and electrochemical responses of [CpMo(CO)₃]₂, CpMo(CO)₃I, CpMo(CO)₃(OTf), and [CpMo(bpy)(CO)₂] (Cp = cyclopentadienyl, bpy = 2,2’-bipyridine, OTf = trifluoromethansulfonate) in organic solvent are reported. Transition metal compounds such as Re(bpy)(CO)₃Cl have been shown to be effective carbon dioxide reduction catalysts. The molybdenum metal complexes studied herein were examined under argon and carbon dioxide gas for the potential reduction of carbon dioxide. Proton Nuclear Magnetic Resonance (NMR) spectroscopy, infrared (IR) spectroscopy and an electrochemical method know as cyclic voltammetry were used to gather data on the complexes. Electrochemical …

Layered Xerogel Films Incorporating Monolayer Protected Cluster Networks On Platinum Black Modified Electrodes For Enhanced Sensitivity In 1st Generation Uric Acid Biosensing, Mulugeta B. Wayu, Michael J. Pannell, Michael C. Leopold

Chemistry Faculty Publications

Amperometric uric acid (UA) biosensing schemes incorporating networks of alkanethiolate‐protected gold nanoparticles, monolayer protected clusters (MPCs), and platinum black (Pt‐B) electrode modification through the layer‐by‐layer construction of xerogels are investigated. MPC doping and Pt‐B augmentation are implemented within hydroxymethyltriethoxysilane xerogel bilayers at platinum electrodes. The first xerogel adlayer is doped with an MPC network and houses uricase for the enzymatic reaction required for first‐generation schemes. Polyluminol–aniline and polyurethane are used as selective/stabilizing interfacial layers. The sensing performance with and without Pt‐B and/or MPC doping is assessed by amperometry with standardized UA injections. The use of each individual material results in …

Synthesis And Applications Of Lanthanide Sulfides And Oxides, Christopher Marin

Department of Chemistry: Dissertations, Theses, and Student Research

This dissertation focuses on two of the key fields where lanthanides find ready application: as optically active materials with a focus on the lanthanide sulfides, and as catalytic materials with a focus on cerium oxide.

The lanthanide sulfides have attracted considerable interest for their potential as solar energy conversion materials, pigments, infrared window materials, and phosphor host media. However, applications of these materials remain limited due to their synthetic difficulty along with their not well understood properties compounded by both their difficulty in manufacturing as well as in simulating largely due to the need to take into account f-shell electrons. …

Synthetic Investigation On The Biomimetic Metal-Catalyzed Sulfoxidations And Photochemical Generation Of A Highly Reactive Ruthenium(V)-Oxo Porphyrin, Weilong Luo

Masters Theses & Specialist Projects

Catalytic oxidation plays a crucial role in current chemical and pharmaceutical industries which is also a leading technology for green chemical processes. In Nature, the ubiquitous cytochrome P450 enzymes can catalyze a wide variety of oxidation reactions with high efficiency and selectivity. Many transition metal catalysts are designed as the biomimetic model of cytochrome P450 enzymes. In this work, series of metalloporphyrins and metallocorroles have been successfully synthesized to investigate and develop catalytic selective oxidation of sulfides to sulfoxides.

Manganese(III) porphyrin complexes (2) and manganese(III) corrole complexes (6) with iodobenzene diacetate [PhI(OAc)2] as a mild oxygen source exhibited remarkable catalytic …