Physical Sciences and Mathematics Commons^™

Morphology Controlled Synthesis Of Copper Based Multimetallic Nanostructures And Their Electrocatalytic Properties For Methanol Oxidation Reaction, Leanne Elizabeth Mathurin

Graduate Theses and Dissertations

This research focuses on the development of shape-controlled synthesis of Cu NM, Cu-based bimetallic and trimetallic nanostructures, and their electrocatalytic properties for methanol oxidation reaction (MOR). Copper nanomaterials (Cu NM) with specific surface facets can tailor their catalytic activity. Understanding reagents responsible for Cu NM growth is important for morphology-controlled synthesis of the nanostructures. This research studies the halide influence on Cu NM growth and morphology in an oil-based synthesis. The morphology of the Cu NM varies with the halide type (i.e., Cl-, Br-, I-), and the halide concentration. Additionally, the type of Cu precursor also influenced the morphology of …

Electrochemical Time Of Flight For Rapid And Direct Measurement Of Diffusion Coefficients, Jonathan C. Moldenhauer

Graduate Theses and Dissertations

The determination of diffusion coefficients is of fundamental importance to the understanding of electrochemistry and sensors. Developing a method by which diffusion coefficients of Red/ox active analytes can be determined quickly and elegantly, would be a great advancement over presently accepted methods. This dissertation reports the reviving electrochemical time of flight (ETOF), and developing a method that allows for empirical determination of diffusion coefficients from a single measurement. ETOF is a generate and detect experiment where the time an electrochemically generated species takes to transit a known distance is measured and related to the diffusion coefficient of the species. The …

Ultraviolet And Infrared Spectroscopy Of Synthetic Foldamers, Aib Homopeptides, And Solvated 1,2-Diphenylethane In The Gas Phase, Joseph R. Gord

Open Access Dissertations

The work presented here implements a supersonic jet expansion source to funnel the population of model peptides and solvated-bichromophore clusters into their low lying structural minima and to collisionally cool these minima to their respective zero-point vibrational levels. Single-conformation ultraviolet and infrared spectroscopy techniques are then used to probe these systems and investigate their electronic properties and uncover their intrinsic conformational preferences in the gas phase.

Model β/γ-peptides known as synthetic foldamers and aminoisobutyric acid (Aib) homopeptides incorporate structural constraints that are designed/known to impose particular structural motifs. Here the ability of a β/γ-dipeptide to replicate the backbone length of …

Advances In Raman Hyperspectral Compressive Detection Instrumentation For Fast Label Free Classification, Quantitation And Imaging, Bharat R. Makani

Open Access Dissertations

Multiple prototypes of hyperspectral compressive detection (CD) Raman spectrometers have previously been constructed in the Ben-Amotz lab and have proven to be useful for fast, label-free chemical identification, quantitation and imaging. The CD spectrometer consists of a volume holographic grating (VHG) that linearly disperses the Raman photons into its component wavelengths and all wavelengths are focused onto a digital micromirror devise (DMD). The DMD is an optical modulator that consists of an array of programmable 10μm mirrors that can reflect photons in either +12° or -12° to the incoming light. The DMD is tilted such that the +12° photons go …

Single-Conformation Spectroscopy Of Hydrogen Bonding Networks: Solvation, Synthetic Foldamers, And Neurodegenerative Diseases, Patrick S. Walsh

Open Access Dissertations

The hydrogen bond is one of the most important interactions in natural processes ranging from protein folding to chemical reactions. Two complementary methodologies are applied to understanding this important interaction: top-down and bottom-up. Top-down methods use large molecules, such as proteins, revealing secondary structure information. Bottom-up experiments are performed on small molecules, utilizing high-resolution spectroscopy to reveal underlying quantum mechanical effects. The complexity gap is formed between these two experimental regimes; between large and small molecules; between bulk and individual solvent molecules; between classical mechanics calculations and quantum chemical calculations. This dissertation will focus on the application of gas phase, …

Mutlifunctional Platforms For Gene And Drug Delivery For Cancer Therapy, Jeffery J. Ambrose Jr.

Doctoral Dissertations

The National Cancer Institute and the American Cancer Society estimate that 1.6 million new cancer incidences and over half a million cancer related deaths occur annually [1][2]. Cancer the second most common cause of death in the United States [1], [2]. Although the causes of cancer can vary depending on cell type, all or almost all instances of cancer arise from a mutation or from an abnormal activation of the cellular genes that control cell growth and mitosis [3].

Treatment of a given cancer type depends on the subtype, stage and progression of the cancer. Varieties of cancer therapy include …

Influence Of Shelling Temperature And Time On The Optical And Structural Properties Of Cuins2/Zns Quantum Dots, Colette Robinson

Graduate Theses and Dissertations

CIS/ZnS core/shell QDs are an important class of nanomaterials for optoelectronic, photovoltaic and photoluminescence applications. They consist of lower toxicity materials than the prototypical II-VI Cd-based QDs and show long fluorescence lifetimes, which generates prospective in biological imaging applications. It is vital to develop reproducible synthetic methods for this new class of nanomaterials in order to maintain small sizes with high QYs. CIS core QDs have been shelled with ZnS at various temperatures from 90-210°C for reaction times ranging from 20-140 minutes to examine the role of thermodynamics and kinetics on the shell growth. Using HR-TEM and ICP-MS, it was …

Photochemistry Of A Series Of Weakly Coupled Dinuclear Ruthenium(Ii) Complexes, Latisha Michelle Puckett

Graduate Theses and Dissertations

An improved synthetic method was developed for symmetric ruthenium(II) polypyridine complexes with the form L2Ru(diphen)RuL2. The scope of the reaction was investigated in regards to the ligands, bridging ligands, and starting materials. Several ligands were successful in the synthesis, including 2,2’-bipyridine (bpy), 4,4’-dimethyl-2,2’-dipyridyl (dmb), 1,10-phenanthroline (phen), 4,7-diphenyl-1,10-phenanthroline (dpphen), and 3,4,7,8-tetramethyl-1,10-phenanthroline (tmphen). Ligands that did not react to form symmetric dimeric complexes were 2,2’-bipyrazine, bpz, and 2,2’-bipyrimidine, bpm.

Dpp, 2,3-bis(2-pyridyl)-pyrazine, effectively replaced diphen as the bridging ligand to produce (phen)2Ru(dpp)Ru(phen)24+. However, replacing the [Ru(CO)2Cl2]n with Ru(DMSO)4Cl2 did not prove successful. The newly developed synthesis was also applied to the synthesis of …

Fret Study Of Ligand Binding And Exchange Kinetics On The Surface Of Cdse/Zns Quantum Dots, Randee Jean Mcbride

Graduate Theses and Dissertations

Quantum dots are a valuable tool in many research applications and commercial development. Their applications are far reaching and as such have become a topic of great interest. One of their greatest assets is the ability to utilize them as water soluble fluorescent labels. Rendering the nanocrystals water soluble can be accomplished in several ways, but one very popular method is by capping them with water-soluble multi-functional organic ligands. However, these ligands, when attached to the quantum dot surface, are labile and can be exchanged which can be problematic when using the quantum dots in research applications. This projects investigates …

Fundamental Studies Of Magnetoconvective Forces And Density Gradients In A Microfluidic Environment, Adam James Kreidermacher

Graduate Theses and Dissertations

Magnetoconvection is a promising phenomenon for developing new electrochemical-based microfluidic flow devices with unique capabilities, such as easily switching flow direction and adjusting flow speeds and flow patterns as well as avoiding bubble formation. In order to develop these devices it is necessary to study the underlying forces. Four contributions toward fluid flow were considered. The first and foremost is the magnetohydrodynamic force, which is the magnetic component of the Lorentz force and governed by the right hand rule. It generates the majority of the convention, and is the most well-known. The second is the gravitational force, which causes convection …

Surface Modification Of Noble Metal Nanostructures Toward Biomedical Applications, Samir V. Jenkins

Graduate Theses and Dissertations

Noble metal nanostructures have seen a steady increase in biomedical application over the last several decades; new diagnostic and therapeutic modalities are under intense investigation. Many of these applications are possible because of post-synthetic modifications to the particle surface. These modifications take a variety of forms and can significantly affect the pharmacokinetics of these particles. In this work, various surface modifications were investigated. Particle agglomeration, which occurs when particle surfaces remain in contact, can significantly affect the toxicity and efficacy of a nanomedicine. Darkfield microscopy and single-particle ICP-MS were developed as complementary methods to detect agglomeration in blood, with the …

Inertial Force-Driven Synthesis Of Near-Infrared Plasmonic Nanosphere Composites: Physicochemical Characterizations, Joseph Noel Batta-Mpouma

Graduate Theses and Dissertations

Near-infrared (NIR) responsive nanoparticles (NPs) like gold nanorods (GNRs) are important in biomedical fields because of their transparency for biological tissues. Although GNRs are sought after as contrast agents for theranostics in cancer studies, capping ligands like cetyltrimethylammonium bromide (CTAB) for the GNR synthesis are toxic for biological tissues. The need for an alternative to toxic GNRs is of interest to alleviate the problem.

This work aimed to optimize the synthesis of NIR responsive nanosphere composites (NSCs) by inertial force (g-force) using colloidal gold NPs as model, elucidate the mechanism for the NSC formation, and study their detailed physicochemical characteristics. …

Resonant Two-Photon Ionization Studies Of Non Covalent Interactions In Halo Aromatic Clusters And Spin-Orbit Coupling Modeling In Mono-Halocarbenes, Silver Nyambo

Dissertations (1934 -)

Non-covalent interactions in halobenzenes (PhX) (X=F, Cl, Br) and phenylamine (C₆ H₅ NH₂ ) have been studied here using resonance two-photon ionization (R2PI) spectroscopy combined with a linear TOF-mass spectrometer. Their interaction with polar molecules in form of ammonia (NH ₃ ) and trifluorohalomethanes (CF₃ X) has also been studied. DFT and TD-DFT calculations using M06-2X functionals were carried out on different cluster conformations to compliment experimental results. A general trend of broadness in homogenous dimers (PhX)₂ , has been attributed to mainly the presence of multiple cluster isomers and Frank-Condon activity in the low …

Gas-Phase Ion/Ion Reactions Of Biomolecules: An Examination Of Carboxylate Reactivity And Arginine Based Non-Covalent Complexes, Nathan Zachary Barefoot

Open Access Theses

The advent of Electrospray Ionization with the ability to generate multiply charges ions has contributed significantly to the study of gas-phase ion/ion reactions. With the tools available in mass spectrometry it has been shown that these reactions are effective at transforming one type of gaseous ion into another through a series of reactions. This work examines some of these reactions and their application to field of proteomics specifically focusing on the amino acids of arginine and lysine. NHS reagents have been shown to react to both of these molecules with in the gas-phase under different conditions but have relies on …

Investigation Of Isotope Effects Of Ozone As A Function Of Temperature, Daniel J. Mcmahon

Open Access Theses

Ozone is an important oxidizer in the atmosphere and plays a crucial role as a cleanser, removing various compounds such NOx and SOx. It also is intriguing to those that study stable isotopes as it has a unique signature found in no other oxygen containing molecule. Ozone is observed to fractionate mass independently, which means it does not follow the typical δ 17 O /δ18 O = 0.52 ratio expected for molecules enriched with 17 O and 18 O. The magnitude of ozone's mass independent enrichment has been studied in laboratory experiments and atmospheric observations but its explanation is still …

Monodentate, Bidentate And Photocrosslinkable Thiol Ligands For Improving Aqueous Biocompatible Quantum Dots, Hiroko Takeuchi

Graduate Theses and Dissertations

Water-soluble Quantum Dots (QDs) are highly sensitive fluorescent probes that are often used to study biological species. One of the most common ways to render QDs water-soluble for such applications is to apply hydrophilic thiolated ligands to the QD surface. However, these ligands are labile and can be easily exchanged on the QD surface, which can severely limit their application. As one way to overcome this limitation while maintaining a small colloidal size of QDs, we developed a method to stabilize hydrophilic thiolated ligands on the surface of QDs through the formation of a crosslinked shell using a photocrosslinking approach. …

Construction And Demonstration Of A Tandem Mass Spectrometer Based Instrument For Cold Ion Spectroscopy, James Gerhardt Redwine

Open Access Dissertations

A new instrument incorporating ion trap based tandem mass spectrometry and cold ion UV and UV-IR double resonance spectroscopy has been developed at Purdue University for the study of gas phase, biologically relevant ions. The instrument incorporates multiple quadrupole linear ion trap mass analyzers to prepare and isolate the precursor ions as well as to analyze the resultant photofragments. A 22-pole ion trap cooled to 5 K via a closed cycle helium cryostat is used to cool the ions for spectroscopic interrogation. Results show the vibrational and rotational temperature of a wide assortment of ions to be 12±2 K.

The …

Gas-Phase Covalent And Non-Covalent Ion/Ion Chemistry Of Biological Macromolecules, John Robert Stutzman

Open Access Dissertations

Gas-phase ion/ion chemistry involves the interaction of oppositely charged ions inside of the mass spectrometer. During this gas-phase chemistry, particle transfer (i.e., proton and electron) or synthesis can occur at rapid reaction rates. Particle transfer represents a mature area of ion/ion chemistry, while selective covalent modification represents a fairly new area of gas-phase chemistry. Gas-phase covalent chemistry is based on traditional solution phase organic chemistry.

The work demonstrated in this dissertation greatly involves gas-phase covalent and non-covalent Schiff base chemistry on peptide and protein ions. The reagent dianion, 4-formyl 1,3-benzene disulfonic acid, has been used to covalently modify unprotonated primary …

Spectroscopic Characterization Of The Water-Oxidation Intermediates In The Ru-Based Catalysts For Artificial Photosynthesis, Dooshaye Moonshiram

Open Access Dissertations

Utilization of sunlight requires solar capture, light-to-energy conversion and storage. One effective way to store energy is to convert it into chemical energy by fuel-forming reactions, such as water splitting into hydrogen and oxygen. Ruthenium complexes are among few molecular-defined catalysts capable of water splitting. Insight into the mechanism of their action will help to design future robust and economically feasible catalysts for light-to-energy conversion. Mechanistic insights about the design of such catalysts can be acquired through spectroscopic analysis of short-lived intermediates of catalytic water oxidation. Development of time-resolved approaches through stopped flow UV-Vis Spectroscopy to follow the catalysis of …

Fabrication Of Tungsten Tips Suitable For Scanning Probe Microscopy By Electrochemical Etching Methods, Gobind Basnet

Graduate Theses and Dissertations

The fabrication of metal tips is becoming an interesting field for scientists who are working in spectroscopy measurements. A significant amount of work has already been done in the tips fabrication process. Metal tips used to analyze the surface of materials play a key role in the scanning tunneling microscope (STM) technique. It's remarkable quality that it is used to study the surface of material at the atomic level.

There are various methods used in the tips fabrication process. Of diverse methods, three different electrochemical etching methods: submerged method, single lamella drop-off method, and double lamella drop-off method are commonly …

Modeling Chemical Reactions In Aqueous Solutions, Osman Uner

Graduate Theses and Dissertations

The energy barriers for SN2 ligand exchange reactions between the chloride anion and para-substituted benzyl chlorides were investigated both in water solution and in the gas phase by using quantum chemical simulations at the DFT and Hartree-Fock levels. The question addressed was the effect of the solvent (water) and of the substituent on the barrier height. The para substitutient groups included NH2, OH, OCH3, CH3, C(CH3)3, H, F, Cl, Br, I, CF3, CN, NO2, and SO3- . The calculations in aqueous solution were carried out with the recently developed Ultrafast Monte Carlo method using the TIP3P explicit water model. The …

Optimization Of Sample Preparation In Matrix-Assisted Laser Desorption/Ionization (Maldi) Mass Spectrometry Of Macromolecules, Evgenia Akhmetova

Graduate Theses and Dissertations

New method for the matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) and Fourier transform mass spectrometry (MALDI-FTMS) analysis of low molecular weight polyvinyl acetate (PVAc) was developed and then applied to the characterization of commercially available chewing gum. The optimization of MALDI analysis of PVAc was achieved by investigating the influence of sample preparation variables such as the choice of solvent and choice of matrix-analyte ratio. It was demonstrated that the use of ethyl acetate as a solvent and 2,5-Dihydroxybenzoic acid as a matrix yielded the highest signal intensity for the pure polymer sample. The application of TOF technique did not …

Semiconductor Nanocrystals: From Quantum Dots To Quantum Disks, Zheng Li

Graduate Theses and Dissertations

The bottom-up colloidal synthesis opened up the possibility of finely tuning and tailoring the semiconductor nanocrystals. Numerous recipes were developed for the preparation of colloidal semiconductor nanocrystals, especially the traditional quantum dots. However, due to the lack of thorough understanding to those systems, the synthesis chemistry is still on the empirical level. CdS quantum dots synthesis in non-coordinating solvent were taken as a model system to investigate its molecular mechanism and formation process, ODE was identified as the reducing agent for the preparation of CdS nanocrystals, non-injection and low-temperature synthesis methods developed. In this model system, we not only proved …

Synthesis, Modification, And Characterization Of Spherical Sba-15 Ordered Mesoporous Silica And Evaluation In High Performance Liquid Chromatography, Alexander P. Giaquinto

Seton Hall University Dissertations and Theses (ETDs)

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Adsorbents With Chemically Bonded Saccharide Surfaces: Synthesis And Application For Stereoisomer Separation And The Synthesis Of Chiral Porous Silicas Using Templates Chiral Surfactant, Edwin Vega

Seton Hall University Dissertations and Theses (ETDs)

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Symmetry-Based Techniques For Qualitative Understanding Of Rovibrational Effects In Spherical-Top Molecular Spectra And Dynamics, Justin Chadwick Mitchell

Graduate Theses and Dissertations

Using light to probe the structure of matter is as natural as opening our eyes. Modern physics and chemistry have turned this art into a rich science, measuring the delicate interactions possible at the molecular level.

Perhaps the most commonly used tool in computational spectroscopy is that of matrix diagonalization. While this is invaluable for calculating everything from molecular structure and energy levels to dipole moments and dynamics, the process of numerical diagonalization is an opaque one. This work applies symmetry and semi-classical techniques to elucidate numerical spectral analysis for high-symmetry molecules.

Semi-classical techniques, such as the Potential Energy Surfaces, …

Hydrophobic Silicas With Well-Defined Chemistry And Geometry: Synthesis, Adsorption, And Interfacial Properties, Francis Bernardoni

Seton Hall University Dissertations and Theses (ETDs)

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Molecular Dynamics Simulations Of Human Quadruplexes In K+ Solution And The Role Of The Carboxyl Terminus Of Bacteriorhodopsin In Protein Stability, Farah Rezae

Seton Hall University Dissertations and Theses (ETDs)

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Electronic Spectroscopy And Dissociation Dynamics Of Gasphase Transition Metal Containing Cations And Dications, Kanchana Manori Perera

Doctoral Dissertations 1896 - February 2014

Studies of gas-phase ionic clusters have become an integral component in understanding microsolvation and catalysis by transition metal cations. Further interest in this field is due to the possibility of bridging the gap between the condensed and gas phases by developing our understanding of clusters and the possibility that small clusters can have unique chemical and catalytic properties. Most gas phase studies have focused on singly charged ions. Electrospray allows for the production of multiply charged ions solvated by a few solvent molecules. Understanding smaller reactive species such as metal centered clusters with well-defined, gas phase conditions also allows for …

The Effect Of Adsorbent Geometry And Surface Chemistry On Hplc Retention, Zhaoxia Liu

Seton Hall University Dissertations and Theses (ETDs)

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