Chemistry Commons^™

Design, Synthesis, Characterization, And Applications Of Matrix Free Polymer Nanocomposites, Yucheng Huang

Theses and Dissertations

This dissertation focuses on the design, synthesis, characterization and application of matrix free polymer nanocomposites. Reversible addition-fragmentation chain transfer (RAFT) polymerization was used to synthesize block copolymers and polymer grafted silica nanoparticles with precise control over architectures.

In the first chapter, thermoplastic elastomer (TPE) grafted nanoparticles were prepared by grafting block copolymer poly(styrene-block-(n-butyl acrylate)) onto silica nanoparticles (NPs) (~15nm) via surface initiated RAFT polymerization. The effects of polymer chain length and graft density on the mechanical properties were investigated using films made solely from the grafted NPs. The ultimate tensile stress and elastic modulus increased with the increase of PS …

Synthesis And Reactivity Of Carborane Backbone Pincer Complexes, Bennett J. Eleazer

Theses and Dissertations

In organometallic chemistry, boron-centered ligand systems represent a powerful synthetic strategy for the promotion of a variety of catalytic transformations. These ligands offer a versatile array of bonding motifs, which can function as borane, boratrane, boryl, borate, or borylenes type ligands, and are likely the strongest σ-donors in the anionic series of ligands based on boron, carbon, nitrogen, and oxygen. Carboranes, which are icosahedral boron clusters of the type C2B10H12, offer unique potential as metal ligands, such as their bonding to exohedral metal centers being dominated by two-center-two-electron σ-bond interactions, their three-dimensional cluster structure providing considerable steric shielding to a …

Synthesis And Characterization Of Polydiene-Grafted Nanoparticles, Zaid Mohammed Abbas Alajeeli

Theses and Dissertations

This dissertation presents the design, synthesis, and characterization of polydiene grafted nanoparticles as a way to tailor nanocomposite interfaces and properties via interface design. The polymerization of dienes was done via reversible addition fragmentation chain transfer (RAFT) polymerization. The grafting of polymer chains on the surface of silica nanoparticles can be controlled through the molecular design of the RAFT agents attached to the nanoparticles surface. The properties of the nanocomposites largely depended on the interface between the particles and the polymer matrix. In the first part of this work, the polymerization of diene monomers was done on 15 nm diameter …

Synthesis And Characterization Of A Novel Platinum Ligand Complex ((Κ-N,C,N- 2,6-Bis(Diethylaminomethyl)Phenyl)(4- Tert-Butylphenyl) Platinum(Ii)), Carly Roleder

CMC Senior Theses

A novel platinum ligand complex (NCN)PtAr, ((κ-N,C,N- 2,6-bis (diethylaminomethyl)phenyl)(4- tert-butylphenyl) platinum(II)), was synthesized. A reaction of 1-Bromo-4-tert-butylbenzene Grignard with (NCN)PtCl, (where NCN = 2,6-bis(diethylaminomethyl)phenyl) yielded the (NCN)PtAr (where Ar = 4-tert­-butylphenyl). The product was then characterized with NMR spectra through ¹H NMR, ¹³C NMR, COSY, HSQC, and HMBC to verify it structure.

Substituted Hydroxylamines As Nitrogen Transfer Reagents: Direct Synthetic Pathways To Structurally Rich Heteroatomic Scaffolds, Dylan John Quinn

Theses and Dissertations

Nitrogen is found in virtually all valuable chemical compounds. The abundance of atmospheric nitrogen however, is rendered inaccessible because of the strong N-N triple bond, ultimately preventing its practical utilization in synthetic organic synthesis. The development of powerful nitrogen transfer reagents, such as substituted hydroxylamine derivatives, have played an important role in the introduction of nitrogen into valuable chemical scaffolding.

Herein is reported the methodological development of synthetic nitrogen placement into a range of valuable heteroatomic compounds. This work shows that O-Substituted Hydroxylamine can be used to furnish small heteroatomic compounds, particularly nitriles. Whereas, N-Substituted Hydroxylamine can be employed to …

Hydroformylation And Aldehyde-Water Shift Catalysis By Dirhodium Tetraphosphine Complexes, Marshall Douglas Moulis

LSU Doctoral Dissertations

The use of a unique tetraphosphine ligand (et,ph-P4) allows for the chelating of two rhodium centers to perform bimetallic coopertivity in hydroformylation reactions to better the yields the linear aldehyde product. The proposed catalyst is [Rh₂(μ-H)₂(CO)₄(rac-et,ph-P4)]²⁺ and has been studied by in situ FT-IR and NMR. When tested in a polar phasic acetone/water (30 % by vol.), the catalyst forms a monocationic system [Rh₂(μ-H)₂(CO)₄(rac-et,ph-P4)]⁺ that has an initial TOF of 26 min^-1, selectivity of 27:1 L:B, and low byproducts of …

A Novel Method For Synthesis Of Hydroxytyrosol, Emmanuel Onobun

Electronic Theses and Dissertations

Hydroxytyrosol, 3,4-dihydroxyphenolethanol, a naturally occurring polyphenol most common in olive tree (Olea europaea), is one of the most effective member of the polyphenols family, because of its remarkable antioxidant activity, its ability to inhibit oxidation of low density lipids (LDL), and its protection against DNA oxidative damage. Hydroxytyrosol, which is widely used in cosmetics and food supplements industries, can be purchased as an olive oil extract that contains low concentration of hydroxytyrosol besides other polyphenols. The price and low natural abundance of hydroxytyrosol make alternative synthetic sources very attractive. In this research, a novel method for the synthesis of pure …

Design And Synthesis Of Selective Estrogen Receptor Β Agonists And Their Pharmacology, K. L. Iresha Sampathi Perera

Dissertations (1934 -)

Estrogens (17β-estradiol, E2) have garnered considerable attention in influencing cognitive process in relation to phases of the menstrual cycle, aging and menopausal symptoms. However, hormone replacement therapy can have deleterious effects leading to breast and endometrial cancer, predominantly mediated by estrogen receptor-alpha (ERα) the major isoform present in the mammary gland and uterus. Further evidence supports a dominant role of estrogen receptor-beta (ERβ) for improved cognitive effects such as enhanced hippocampal signaling and memory consolidation via estrogen activated signaling cascades. Creation of the ERβ selective ligands is challenging due to high structural similarity of both receptors. Thus far, several ERβ …

Synthesis Of Pyranobenzopyrans, Sumiea B. Eltayeb

Seton Hall University Dissertations and Theses (ETDs)

Carbohydrates and their derivatives are involved in a wide array of biological processes and are crucial for the survival of living entities. As a result, sugar-based compounds have become attractive scaffolds for drug design. In addition, pyranobenzopyran derivatives have shown promise in the treatment of numerous health conditions such as anticoagulants, antifungal, and anti-inflammatory agents. They have also shown important properties as antibiotics anti-AIDS agents) and antitumor drugs. The main point of our research was to determine and develop a synthetic method for the preparation of pyranobenzopyrans and carbohydrate fused heterocyclic compounds. This was accomplished via a [4+2] cycloaddition reaction …

Silver Nanoparticles As A Potential Solar Absorber, Benjamin Hardy

Honors Projects

This work reports the development of Silver nanoparticles implanted into a polymer as a solar absorber. The plasmonic nature of silver nanoparticle allows for adjustments to be made in its UV-VIS-NIR absorbance spectrum. A combination of different sized/shaped particles could result in ideal absorption of the majority of the solar spectrum. Allotting this with the stability of a polymer leads to potential solids or solutions that could work as a solar absorber. Tests were also performed to determine whether or not UV-C irradiation during synthesis effects the characteristics of silver nanoparticles, in particular the absorbance. Successful synthesis of silver nanoparticle …

Volatile Technetium Oxides: Implications For Nuclear Waste Vitrification, Bradley Covington Childs

UNLV Theses, Dissertations, Professional Papers, and Capstones

From 1943 to 1987, the Hanford site was the primary location for the production of Pu for military applications in the United States. Decades of Pu production have been accompanied by generation of large amounts of liquid and solid radioactive waste. One of radioelements present in the Hanford wastes is Tc, principally the isotope 99Tc (1500 kg). In the waste, it is primarily present in the heptavalent state as TcO4 - . One option for the management of Tc at the Hanford site is its vitrification into a borosilicate glass. The behavior of Tc during vitrification is problematic, as it …

Controlled Synthesis And Utilization Of Metal And Oxide Hybrid Nanoparticles, Cameron Cowgur Crane

Graduate Theses and Dissertations

This dissertation reports the development of synthetic methods concerning rationally-designed, hybrid, and multifunctional nanomaterials. These methods are based on a wet chemical, solution phase approach that utilizes the knowledge of synthetic organic and inorganic chemistry to generate building blocks in solution for the growth of nanocrystals and hybrid nanostructures. This work builds on the prior knowledge of shape-controlled synthesis of noble metal nanocrystals and expands into the challenging realm of the more reactive first row transition metals. Specifically, a microemulsion sol-gel method was developed to synthesize Au-SiO2 dimers as precursors for the synthesis of segmented heterostructures of noble metals that …

Photochemical Properties And Structure-Activity Relationships Of RuIi Complexes With Pyridylbenzazole Ligands As Promising Anticancer Agents, Dmytro Havrylyuk, David K. Heidary, Leona Nease, Sean Parkin, Edith C. Glazer

Chemistry Faculty Publications

Ruthenium complexes capable of light‐triggered cytotoxicity are appealing potential prodrugs for photodynamic therapy (PDT) and photoactivated chemotherapy (PACT). Two groups of (polypyridyl)Ru^II complexes with 2‐(2‐pyridyl)benzazole ligands were synthesized and investigated for their photochemical properties and anticancer activity to compare strained and unstrained systems that are likely to have different biological mechanisms of action. The structure–activity relationship was focused on the benzazole‐core bioisosterism and replacement of coligands in Ru^II complexes. Strained compounds rapidly ejected the 2‐(2‐pyridyl)benzazole ligand after light irradiation, and possessed strong toxicity in the HL‐60 cell line both under dark and light conditions. In contrast, unstrained Ru …

Isocoumarins And 3,4-Dihydroisocoumarins, Amazing Natural Products: A Review, Aisha Saddiqa, Osman Çakmak, Muhammad Usman

Turkish Journal of Chemistry

The isocoumarins are naturally occurring lactones that constitute an important class of natural products exhibiting an array of biological activities. A wide variety of these lactones have been isolated from natural sources and, due to their remarkable bioactivities and structural diversity, great attention has been focused on their synthesis. This review article focuses on their structural diversity, biological applications, and commonly used synthetic modes.

Efficient Multicomponent Synthesis Of 1,2,3-Triazoles Catalyzed By Cu(Ii) Supported On Pei@Fe$_{3}$O$_{4}$ Mnps In A Water/Peg$_{300}$ System, Zeinab Hassanpour, Aziz Maleki, Morteza Hosseini, Lena Gorgannezhad, Vajihe Nejadshafiee, Ali Ramazani, Ismaeil Haririan, Abbas Shafiee, Mehdi Khoobi

Turkish Journal of Chemistry

A highly dispersible and magnetically recoverable Cu-PEI@Fe$_{3}$O$_{4}$ MNPs catalyst was prepared and successfully applied in one-pot three-component coupling of terminal alkynes, sodium azide, and alkyl bromides/chlorides in water to give 1,4-disubstituted 1,2,3-triazoles with good to excellent yields. The catalyst was fully characterized with FT-IR, TGA, TEM, SEM, VSM, EDX, cyclic voltammetry, and ICP-AES spectroscopic techniques. Furthermore, the catalyst was easily recycled by an external magnet and successfully reused six times in the reaction without significant loss of its catalytic activity and copper leaching. The large-scale reaction was also carried out in the absence of any base and reducing agent even …

Deep Eutectic Solvents Synthesis, Characterization And Applications In Pretreatment Of Lignocellulosic Biomass, Ganesh Degam

Electronic Theses and Dissertations

There has been an increased interest in green solvents and biofuels with the growing environmental awareness across the globe. Conventional methods of biofuel production involve the use of large quantities of molecular solvents and ionic liquids (ILs), but they have the drawbacks of high vapor pressure (organic solvents), toxicity, and recyclability in terms of a sustainability point of view. Deep eutectic solvents (DESs) have recently emerged as green alternatives to molecular solvents and ionic liquids (ILs). They are defined as eutectic mixtures formed between quaternary ammonium, phosphonium or sulfonium salts and hydrogen bond donors (HBDs) with the freezing temperature lower …

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.

Iodine-Initiated Hydration Of Internal Alkynes, Nicholas J. Shuber, Karelle Aiken

Honors College Theses

The iodine-initiated hydration of internal alkynes is a novel, green, and inexpensive synthetic pathway in comparison with the commonly used transition metal catalyzed reactions. This can be a useful alternative in many fields, academic or industrial. This experimental design has been used successfully on terminal alkynes and is now being extended to internal alkynes. Through systematic probing of the reaction conditions, we have gleaned sufficient information to determine a strong mechanistic hypothesis based on neighboring group participation. Here in, we will report our result with a series of internal, keto alkynes reacted under ambient conditions with iodine in “wet” solvent. …

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 …

The Synthesis Of Symmetric Polycyclic Aromatic Hydrocarbons And The Mesomorphic Properties Of Their Brominated Derivatives, Vanessa Bellemore

Theses and Dissertations (Comprehensive)

In this thesis, the synthesis of a series of brominated alkoxy-substituted trinaphthylenes was developed using a nickel-mediated Yamamoto coupling as the main step. Characterization of these compounds led to the discovery of a new set of broad range liquid crystals. They were found to undergo higher order transitions (i.e. glass phases/soft crystals/liquid crystal) via DSC, and also to decompose before reaching an isotropic liquid, as verified via thermogravimetric analysis. Polarized optical microscopy showed a texture characteristic of a columnar hexagonal mesophase. In addition, the aggregation in solution was studied using concentration dependent NMR studies, and the brominated-derivatives were determined to …

The Synthesis And Characterization Of Photoluminescent Conjugated Frameworks Containing Silicon And Germanium, Douglas William Hammerstroem

Dissertations

Siloles and 9-heterofluorenes (Si, Ge) are conjugated π-electron systems containing Group 14 atoms which demonstrate unique properties such as high electron affinity, mobility, and bathochromically shifted optical spectra relative to their all-carbon analogs. This is due to their low-lying lowest-unoccupied molecular orbital (LUMO) which is resultant of the σ*-π* conjugation between the exocyclic groups at the Group 14 center and the butadiene unit of the ring. As a consequence, they have received considerable attention for their use as components for a wide variety of optical and electronic applications such as organic light emitting diodes (OLEDs), photovoltaic devices, field-effect transistors (FETs), …

Synthesis And Performance Of Novel Supramolecular Tools For Single-Particle Cryogenic Electron Microscopy And Drug And Gene Delivery, Kyle J. Wright

Open Access Dissertations

High-resolution biomacromolecular structure elucidation is fundamentally important to structure-based drug design and basic research into complex biochemical processes. Cryo-EM is an emerging alternative to XRD and NMR that is complementary in many ways relative to XRD and NMR. Materials approaches to cryo-EM are anticipated to greatly facilitate the cryo-EM process, allowing progress toward a more high-throughput application of cryo-EM to address challenges in structural biology. ^ Various affinity-based approaches inspired by approaches previously introduced for 2D crystallization were developed for facilitation of cryo-EM. A library of affinity lipopolymer constructs were synthesized consisting of lipopolymers of various PEG molecular weights conjugated …

I. Synthesis Of Diverse Structures From Quinone Monoketal And Quinone Imine Ketal With Efficiency And Control Ii. Synthetic Study Of Phalarine, Zhiwei Yin

Dissertations, Theses, and Capstone Projects

Quinonoids are quinone derivatives that have carbonyl or carbonyl equivalent and even number of double bonds embedded in six member rings. As a result of the intrinsic α,β-unsaturated ketone or imine structures, quinonoids, such as quinone monoketals, quinols, quinol ethers and quinone imine ketals, can accommodate a wide range of reactions including 1,2-additon, 1,4-addtion, SN2’ reaction (allylic substitution) to the α-carbon of the carbonyl or imine and cycloaddition reactions (e.g. Diels-Alder reaction). Quinonoids are effective building blocks for synthesizing heterocycles, which are ubiquitous in pharmaceutically useful agents. Developing new quinonoid based methodologies is essential to expanding the boundary of synthetic …

Anodic Electrochemistry: Controlling The Reactivity Of Radical Cation Intermediates, Robert John Perkins

Arts & Sciences Graduate Student Theses and Dissertations

Radical cations are highly reactive intermediates which when formed can lead to a variety of interesting and efficient synthetic transformation. Electrochemical oxidations may be used to generate radical cations from electron rich, nucleophilic functional groups, triggering intramolecular cyclization reactions. These intramolecular anodic olefin coupling reactions are a powerful synthetic tool for coupling electron-rich olefins with a second nucleophile to form complex ring systems. However, they do not all work well. The main focus of this dissertation research is to diagnose the main causes of failed anodic olefin coupling reactions, devise new methods to overcome or circumvent these causes, and then …

Shining Light On Beta-Lactam Synthesis: The Photochemical Synthesis Of 3-Oh-Beta-Lactams, Tyler L. Morse

Arts & Sciences Graduate Student Theses and Dissertations

No abstract provided.

Templated Oligosaccharide Synthesis, Jia Guang Xiao

Dissertations

Glycosyl transfer within the active site of an enzyme involves the arrangement of the gly-cosyl donor and glycosyl acceptor in close proximity to each other. To mimic this pro-cess, intramolecular glycosylations are carried out where the donor and acceptor are linked together via a spacer. Correct orientation, rigidity and position of the spacer play a vital role in the selectivity and yield of reactions in this “molecular clamp method”. Though current methodologies show promising results in terms of yield and selectivity, the need to synthesize different complexes to ensure selectivities in all types of glycosidic linkages is a large deterrent …

Calculating The Energy Barriers Required To Join Metal-Organic Framework Synthesis Intermediates With Non-Equilibrium Molecular Simulation, Marcus A. Tubbs, David Cantu, Roger Rousseau, Vassiliki-Alexandra Glezakou

STAR Program Research Presentations

Metal organic frameworks are synthetic porous materials with great capacity for adsorption of carbon dioxide and methane. They chemically appear as a chain-link fence with nodes of metal connected by organic linkers. The pores between the nodes define the characteristics of the material, allowing gas particles of specific size to pass through while blocking larger particulates. While there has been success in synthesizing small amounts of metal organic frameworks, the mechanistic details behind their assembly remain unknown. Understanding the synthesis mechanism is necessary to understand the kinetics involved and be able to produce this useful material on an industrial scale. …

Synthesis And Topochemical Manipulation Of New Layered Perovskites, Lea Gustin

LSU New Orleans Theses and Dissertations

Metastable layered perovskites containing interlayer transition metals can readily be obtained by simple ion exchange reactions on receptive hosts, such as those of the Dion-Jacobson and Ruddlesden-Popper structure types. In this work, we focused on adding to the library of layered perovskites by not only creating new compounds, but by also showing their ability to be further manipulated, and by studying the stability of the series through thermal behavior studies.

The reactions with transition metal halides are particularly interesting since they often lead to novel architectures and magnetic behavior. On subsequent heat treatment, these exchange products typically decompose to thermodynamically …

Ruthenium Hydride Catalyzed Silylvinylation Of Terminal And Internal Alkynes And Synthesis Of Poly(Trimethylenecarbonate) And Poly(Dimethylacrylamide) Block Copolymer, Alec Beaton Jr.

Renée Crown University Honors Thesis Projects - All

Various propargyl alcohols were synthesized via Grignard reactions. These alkynic alcohols are tethered with dimethyl and biphenyl silicon tethers. These terminal alkyne substrates are reacted with RuHCl(CO)(H₂IMes)(PPh₃) as a catalyst under high pressure (80 psi) ethylene atmosphere to afford the 5-exo-dig trans-silylvinylation product in poor yield. Internal alkyne substrates are found to be much more efficiently transformed into the silylvinylation product, favoring one cycloisomer product over the other.

Preparation Parameters Optimization And Electrocatalytic Properties Of Supported Au Nanoparticles, Rui Yao, Yu-Jiang Song, Huan-Qiao Li, Jia Li, Jian-Guo Liu

Journal of Electrochemistry

Due to interesting size effect, physical and chemical properties, nano-scale gold materials have been commonly used to catalytic reactions. However, the application of gold nanomaterials in the field of electrocatalysis is limited. Herein, we report the synthesis of gold nanparticles supported on carbon through chemical reduction of HAuCl₄ by NaBH₄ under mild conditions in the presence of surfactants as soft templates, carbon black or graphene as a support. We investigated a series of key reaction parameters, including reagent concentration, temperature, the types of carbon supports and surfactants. With the optimum synthetic parameters, we successfully obtained supported 1 ~ …