Chemistry Commons^™

Recent Progress In The Mechanistic Understanding Of Formic Acid Oxidation On Pt Electrode, Jie Xu, Dao-Chuan Jiang, Dong Mei, Zheng-Da He, Yan-Xia Chen

Journal of Electrochemistry

This article reviews the recent progress in understanding of the mechanisms for formic acid oxidation on Pt electrode. There are two pathways for formic acid oxidation on Pt electrode: (1) Indirect Pathway through which HCOOH is oxidized to CO₂ through CO_ad intermediate. This pathway contributes only 1% of the total current; (2) Direct Pathway where HCOOH is oxidized directly to CO₂. The results from IR Spectroscopy, single-crystal electrochemistry and DFT calculation all support that the bridge-bonded formate is neither the intermediate of direct pathway nor the precursor for CO_ad formation in indirect pathway. Possible mechanism …

Preparation Of Pt-Tio2/Graphene Composites With High Catalytic Activity Towards Methanol Oxidation And Oxygen Reduction Reaction, Li Qi, Ying Yin, Wen-Guang Tu, Bing-Bing Wu, Zhao-Sheng Wang, Jian-Guo Liu, Jun Gu, Zhi-Gang Zou

Journal of Electrochemistry

A series of graphene-supported TiO₂ nanoparticles (TiO₂/G) with different TiO₂ contents were prepared by a facile hydrothermal method, and then the Pt-TiO₂/G catalysts were successfully prepared by reducing Pt-precursor with microwave technique. Compared with Pt-G catalysts, the catalytic performance toward oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR) of Pt-TiO₂/G catalysts was improved due to the addition of TiO₂. However, the excessive TiO₂ would lead to a poor catalytic performance of Pt-TiO₂/G catalysts because of the low electrical conductivity of TiO₂.

Silyl Triflate-Accelerated Additions Of Catalytically Generated Zinc Acetylides To N-Phenyl Nitrones, C. Wade Downey, Erin N. Maxwell, Danielle N. Confair

Chemistry Faculty Publications

Terminal alkynes readily form zinc acetylides in the presence of iPr₂NEt and 20 mol% ZnBr₂, then attack N-phenyl nitrones activated by trimethylsilyl trifluoromethanesulfonate. Deprotection with aqueous acid yields the N-hydroxyl propargylamine. Yields are generally high for nitrones derived from aromatic aldehydes. Control experiments suggest that the silyl triflate has a significant accelerating effect upon the reaction.

Relay Cross Metathesis Reactions Of Vinylphosphonates, Raj Malla, Jeremy Ridenour, Christopher Spilling

Chemistry & Biochemistry Faculty Works

Dimethyl (β-substituted) vinylphosphonates do not readily undergo cross metathesis reactions with Grubbs catalyst and terminal alkenes. However, the corresponding mono- or diallyl vinylphosphonate esters undergo facile cross metathesis reactions. The improved reactivity is attributed to a relay step in the cross metathesis reaction mechanism.

Low Voltage Electrowetting Device And Method For Making Same, Yuguang Cai, Xiaoning Zhang

Chemistry Faculty Patents

An electrowetting device includes a substrate having a first face, a charged adhesion layer immobilized on the first face of the substrate and a dielectric layer bound to the charged adhesion layer. An unbound ionic liquid phase contacts the dielectric layer.

Facile Synthesis Of 1-Alkoxy-1h-Benzo- And 7-Azabenzotriazoles From Peptide Coupling Agents, Mechanistic Studies, And Synthetic Applications, Mahesh K. Lakshman, Manish K. Singh, Mukesh Kumar, Raghu Ram Chamala, Vijayender R. Yedulla, Domenick Wagner, Evan Leung, Lijia Yang, Asha Matin, Sadia Ahmad

Publications and Research

(1H-Benzo[d][1,2,3]triazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate (BOP), 1H-benzo[d][1,2,3]triazol-1-yl 4-methylbenzenesulfonate (Bt-OTs), and 3H-[1,2,3]triazolo[4,5-b]pyridine-3-yl 4-methylbenzenesulfonate (At-OTs) are classically utilized in peptide synthesis for amide-bond formation. However, a previously undescribed reaction of these compounds with alcohols in the presence of a base, leads to 1-alkoxy-1H-benzo- (Bt-OR) and 7-azabenzotriazoles (At-OR). Although BOP undergoes reactions with alcohols to furnish 1-alkoxy-1H-benzotriazoles, Bt-OTs proved to be superior. Both, primary and secondary alcohols undergo reaction under generally mild reaction conditions. Correspondingly, 1-alkoxy-1H-7-azabenzotriazoles were synthesized from At-OTs. Mechanistically, there are three pathways by which these peptide-coupling agents can react with alcohols. From 31P{1H}, [18O]-labeling, and other chemical experiments, phosphonium and tosylate derivatives of …

Simple, Label-Free And Non-Instrumented Analyte Quantitation By Flow Distance Measurement In Microfluidic Devices, Debolina Chatterjee

Theses and Dissertations

Rapid determination of the concentrations of molecules related to diseases can provide timely information for treatment options. However, most biomarker quantitation methods require costly and complex equipment. On the other hand, point-of-care systems have less complex instrumentation needs than laboratory-based equipment, but often provide less information; for example, biomarker presence or absence instead of concentration. A complete analysis setup addressing key limitations of both laboratory-based and portable systems is highly desirable. I developed microfluidic devices with visual inspection readout of a target’s concentration from microliter volumes of solution flowed into a microchannel. Microchannels are formed within polydimethylsiloxane (PDMS), and the …

Characterization Of Fall Leaves As A Source Of Cellulosic Ethanol, Justin Burum

Journal of Undergraduate Research at Minnesota State University, Mankato

Ethanol is becoming increasingly popular as a fossil fuel additive or substitute. However, current production of ethanol from corn impacts food prices and appears to have an overall low net yield. New sources need to be identified and new processes developed for ethanol production. Cellulosic ethanol is one such new source. Plant material contains a large amount of cellulose and other polysaccharides which are potential feed stocks for ethanol production. The purpose of this experiment was to characterize the polysaccharide, lignin, and ash content of fall leaves to estimate their potential for ethanol production. A slight modification of the NREL …

N-Methylimidazole Promotes The Reaction Of Homophthalic Anhydride With Imines, J. Liu, Z. Wang, A. Levin, T. J. Emge, Paul R. Rablen, D. M. Floyd, S. Knapp

Chemistry & Biochemistry Faculty Works

The addition of N-methylimidazole (NMI) to the reaction of homophthalic anhydride with imines such as pyridine-3-carboxaldehyde-N-trifluoroethylimine (9) reduces the amount of elimination byproduct and improves the yield of the formal cycloadduct, tetrahydroisoquinolonic carboxylate 10. Carboxanilides of such compounds are of interest as potential antimalarial agents. A mechanism that rationalizes the role of NMI is proposed, and a gram-scale procedure for the synthesis and resolution of 10 is also described.

Effect Of Sweeteners On The Renin-Angiotensin System In Rats, Jacob Ball

Journal of Undergraduate Research at Minnesota State University, Mankato

Normal abundant dietary sugars such as fructose and sucrose can contribute to hypertension and other health issues. To avoid these health complications, many individuals use artificial sweeteners. An equivalent intake of some artificial sweeteners also can lead to hypertension. However, Stevia, a sweetener that is isolated from a Paraguayan plant, was shown in relevant literature to decrease blood pressure in both rat specimens and humans. The general purpose of this research project was to study the effect of Stevia, saccharin, and sucrose on the expression of two key components of the renin-angiotensin- aldosterone system (RAAS): prorenin receptor (PRR) and angiotensin …

Synthesis And Biological Evaluation Of N-Heterocycles For Activity On Monoamine Transporters And Exploration Of Iridium Chemistry For Synthesis Of Medicinally Important Molecules, Tushar D. Apsunde

LSU New Orleans Theses and Dissertations

The focus of these studies was directed towards the synthesis of novel N-heterocyclic compounds and pharmacological evaluation of these compounds for activity at monoamine transporters. A series of novel piperidine and pyrrolidine analogues were prepared from commercially available starting material with a three and four step synthetic method, respectively. A variety of substituents on the aromatic ring were incorporated to achieve a diverse library of compounds. The preliminary binding studies of piperidine molecules showed strong affinity towards serotonin transporters and moderate affinity towards dopamine transporters. The focus of further studies was directed towards utilization of iridium catalysis for the development …

Determining Kinetics For Simulated Sunlight-Exposed Oil Compounds, Dustin D. Kountz

LSU New Orleans Theses and Dissertations

Understanding of the fate of oil in the environment is of utmost importance; however, accurate, predictive models are still in very early stages. To aid in the development of these models, photodegradation of selected polycyclic aromatic hydrocarbons (PAHs) in an n-alkane hydrocarbon matrix was followed for individual PAHs and mixtures of PAHs similar to that found in the Deepwater Horizon spill. Tetracene in tetradecane photodegraded quickest of all observed PAHs, with a loss of 99% after only one hour of irradiation. Binary mixtures of PAHs showed different degradation amounts, including changes in PAH kinetics. These results suggest that the …

Synthesis And Applications Of Mutimodal Hybrid Albumin Nanoparticles For Chemotherapeutic Drug Delivery And Phototherml Therapy Platforms, Donna V. Peralta

LSU New Orleans Theses and Dissertations

Progress has been made in using human serum albumin nanoparticles (HSAPs) as carrier systems for targeted treatment of cancer. Human serum albumin (HSA), the most abundant human blood protein, can form HSAPs via a desolvation and crosslinking method, with the size of the HSAPs having crucial importance for drug loading and in vivo performance. Gold nanoparticles have also gained medicinal attention due to their ability to absorb near-infrared (NIR) light. These relatively non-toxic particles offer combinational therapy via imaging and photothermal therapy (PPTT) capabilities.

A desolvation and crosslinking approach was employed to encapsulate gold nanoparticles (AuNPs), hollow gold nanoshells (AuNSs), …

Mechanisms And Transients Involved In The Solar Conversion Of Petroleum Films In Aquatic Systems, Phoebe Z. Ray

LSU New Orleans Theses and Dissertations

The behavior of Deepwater Horizon crude oil and other sources of oil were investigated when exposed to sunlight in aquatic systems under environmentally relevant conditions. This research decoupled the abiotic and biotic weathering modifications of oil by focusing solely on the photochemical transformations of oil in aquatic systems. Photochemical rates and mechanisms were measured through the determination of reactive transients. Total hydroxyl radical formation was studied using high benzoic acid concentrations and varying exposure time. Titanium dioxide (TiO₂) nanomaterials were added to the system in an effort to determine if the photocatalyst would enhance oil photodegradation. Photochemical production …

Publisher’S Note: “Derivative Couplings Between Tddft Excited States Obtained By Direct Differentiation In The Tamm-Dancoff Approximation” [J. Chem. Phys. 141, 024114 (2014)], Qi Ou, Shervin Fatehi, Ethan Alguire, Yihan Shao, Joseph Subotnik

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

No abstract provided.

Biopolymeric Hydrogels Functionalized With Tobacco Mosaic Virus For In Vitro Three Dimensional Culture And Differentiation Of Stem Cells And In Vivo Tissue Regeneration, Jittima Amie Luckanagul

Theses and Dissertations

Plant viruses have been highlighted among material research due to their well-defined structures in nanoscale, mono-dispersity, stability, and chemical functionalities. Each of the thousands coated protein subunits on a viral nanoparticle can be homogenously modified, chemically, and genetically with a functional ligand leading to a high-density and spatial distribution of ligands on each particle (multivalency). Many reports from our group have clearly shown that virus coated substrates induced the acceleration of bone marrow stromal cells differentiation into bone cells. We hypothesized that this phenomenon could rely on the multivalency that the viral nanoparticle has to offer. Moving to a more …

Synthesis, Characterization And Optical Properties Of Conjugated Boronate-Linked Materials And Their Applications In Optical Sensing Of Lewis Bases, Min Cai

Theses and Dissertations

Organoboron compounds, with Lewis acidic boron centers, have been emerged as an important class of materials, especially in the area of chemical sensors. Herein, boranes and boronate esters in the sensing perspective were overviewed in Chapter 1. Examples of synthesis and sensing applications of boron-containing conjugated polymers were highlighted.

Boronate ester formation provides the advantages of facile synthesis, tunable optical properties, enhanced stability and planar geometry. Thus, boronate esters, especially dioxaboroles, were proposed to use as alternatives of boranes to design better sensors for Lewis bases. Based on the previous investigation of fluorenyl bis- and poly- dioxaboroles by our group, …

Novel Monomers And Solution Polymerization Methods For Polybenzimidazole Polymers, Jason Hoffman

Theses and Dissertations

The goal of this work was to identify and study various monomers and polymerization methods for polybenzimidazole polymers. Beginning with the solution polymerization of polybenzimidazole via a bisulfite adduct monomer, Chapter 2 describes the efforts to optimize and scale up this process. Chapter 3 then covers an alternative method to prepare polybenzimidazole in solution by using an orthoester monomer. Finally, in Chapter 4, the research to incorporate an adamantane moiety into the backbone of polybenzimidazole is described.

Polyol Induced Extraction (Pie) Of Water From Organic Solvents, Mithilesh Deshpande

Seton Hall University Dissertations and Theses (ETDs)

Acetonitrile (ACN) is used in huge quantities for Reversed Phase High Performance Liquid Chromatography (RP-HPLC) experiments. For most of the part, these results in waste that is only contaminated with large amounts of water, buffer and trace organic impurities. It would seem worthwhile to purify the ACN from water using a mass separating agent (MSA). In a quest for an MSA, our investigation reveals polyols as a new class of MSAs. It is observed that when a polyol such as glycerol, sorbitol, erythritol, xylitol, Isomalt® or maltitol is added to a mixture of ACN-water, the ACN separates out of the …

Extending The Limits Of Solid Phase Microextraction, Shilpi Chopra

Seton Hall University Dissertations and Theses (ETDs)

Solid phase microextraction (SPME) is a solventless extraction technique that combines sample preparation and sample introduction into a gas chromatograph into a single step. For the past 20 years, solid-phase micro-extraction (SPME) has been used in numerous fields such as: food analysis, including juices, alcohols fruits and vegetables for volatiles, aroma, caffeine, fatty esters, environmental applications including volatile organic contaminants, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, phenols, pesticides, steroids, herbicides, acid/neutral/base compounds, and organometallic compounds from water, air, soil, sludge, and sediment samples and in biomedical analysis.

This work demonstrates the extension of the limitations of SPME with respect to extraction …

Carboxylate Selective Lanthanide Imprinted Polymer Sensors For Sensor Array, Yang Xu

Theses and Dissertations

A europium-based molecularly imprinted polymer (MIP) was developed and characterized, which combined the highly luminescent properties of europium and the recognition properties of molecularly imprinted polymers. The europium-based MIPs were used as selective sensors for different types of carboxylates. The ultimate goal of this work was to develop a europium-based sensor array to differentiate carboxylates anions. The polymer was synthesized by using a europium–salen complex as the monomer and ethylene glycol dimethacrylate (EGDMA) as the crosslinker. First, a europium containing non-imprinted polymer (NIP) and a series of europium containing MIPs imprinted with acetate, benzoate and phenylacetate were synthesized by free …

Insights Into The Evolutional Adaptations And Functional Switching Mechanism In Dual Function Hemoglobin/Dehaloperoxidase (Dhp) And Modeling Of Cytochrome P450 Active Site With H93g Myoglobin Cavity Mutant, Shengfang Sun

Theses and Dissertations

The coelomic hemoglobin, dehaloperoxidase (DHP), from the sea worm Amphitrite ornata, is a dual function oxygen-binding heme protein that also possesses a significant peroxidase activity. As evolved from an ancient oxygen carrier globin, several structural adaptations have enabled DHP to evolutionally gain significantly enhanced peroxidase capability for self-protection while only minimally compromising its primary function as an O2 carrier. To elucidate these adaptations, the peroxidase activities and O2 affinities of several DHP and sperm whale myoglobin (Mb) mutants have been prepared. Several heme environmental structural factors that regulate the dual functions of DHP have been found, providing insight into how …

Synthesis And Characterization Of Polymer Nanomaterials Using Controlled Radical Polymerization, Lei Wang

Theses and Dissertations

This research focuses on creating and investigating polymer/organic bound interfaces on nanoparticles with advanced architectures to tailor the properties of polymer nanocomposites for various applications. Reversible addition-fragmentation chain transfer (RAFT) polymerization and a toolbox of surface functionalization from the simple to the advanced were developed to prepare the polymer nanomaterials.

In the first part (Chapter 2), a variety of RAFT agents (xanthate, dithiocarbamate and trithiocarbonate) were used to mediate the polymerizations of several classes of free radical polymerizable monomers. These monomers consist of styrene, methyl acrylate, methyl methacrylate, vinyl acetate and isoprene, which have different activities and require different classes …

Mechanistic Investigation Of A Silylation-Based Kinetic Resolution Using Linear Free Energy Relationships And Its Application To Substrate Expansion And Polymer Supported Kinetic Resolutions, Ravish K. Akhani

Theses and Dissertations

This dissertation represents our preliminary mechanistic investigations on the silylation-based kinetic resolution of secondary alcohols, and how we use that knowledge for further expansion of this methodology. Chapter 2 describes how we came up with a preliminary mechanism of our silylation-based methodology using a linear free energy relationship and a rate study. In this chapter, several para substituted triphenylsilyl chlorides were prepared that varied electronically and sterically in order to understand the substituent effects on the rate and the selectivity of the reaction. Selectivity factors and initial rates were experimentally determined for the kinetic resolution reactions with the newly designed …

Investigation Into The Synthesis And Characterization Of Poly(Dioxaborolane)S, Shakena Daniel

Theses and Dissertations

Boronate esters have evolved from being primarily used as sensors to being the integral linkage in complex materials such as macrocycles, covalent organic frameworks, and linear polymers. Poly(boronate)s, linear polymers that are linked via a boronate ester, have not been extensively researched. In 2005, the Lavigne group published the first manuscript on poly(dioxaborolane)s, i.e., six-membered, nonconjugated polyboronates. The behavior of the materials in solution was studied extensively, but little is known about the solid state properties of the material other than they form brittle films.

Poly(dioxaborolane)s are generated in high yield through a facile step-growth polymerization, but the reaction parameters, …

Design, Synthesis, Characterization, And Evaluation Of Surface Modified Boronate Ester Covalent Organic Frameworks, Matthew W. Di Carmine

Theses and Dissertations

Covalent Organic Frameworks (COFs) were first reported in 2005 and are analogous to Metal Organic Frameworks (MOFs), with proposed applications in separation, storage and sequestration. Since COFs are comprised of lighter elements they are considered more advantageous for weight-sensitive applications. However, COFs are susceptible to degradation by weak nucleophiles such as water (i.e. hydrolysis). The Lavigne group has focused on developing structure-property relationships for COFs. It was previously demonstrated that the porosity of the COFs could be tailored by incorporating small alkyl chains on one monomer. Inclusion of these alkylated monomers into COF materials effectively increased the COF hydrophobicity resulting …

New Methods And Strategies For Orthogonal Oligosaccharide Synthesis, Scott James Hasty

Dissertations

Although scientists have been able to isolate certain classes of naturally occurring carbohydrates, the overall availability of pure natural isolates remains inadequate. As a result, chemical synthesis has been employed to access complex carbohydrates. Unfortunately, traditional oligosaccharide synthesis often requires laborious protecting-group manipulations that results in lower yields. Expeditious strategies effectively shorten the task of oligosaccharide assembly by minimizing the need for protecting-group manipulations between glycosylation steps, or even purification of the intermediates. Additionally, prediction of the stereoselective outcome of the coupling reaction between two sugar units is a major obstacle facing carbohydrate chemists. It is well known that 1,2-trans …

Surgical Adhesive From Mussel Mimetic Polymer, Jenna Desousa, Cori Jenkins, Jonathan Wilker

The Summer Undergraduate Research Fellowship (SURF) Symposium

Injuries involving damaged tissues are currently repaired through an invasive technique involving the use of screws, plates and sutures as support, which can damage these tissues. The biomedical field currently lacks an adhesive that can replace harmful implants. A surgical adhesive can provide a quick and easy alternative, which will minimize the risk of damaging healthy tissue in surgery. Inspiration for such materials can be found by looking at marine mussels as they are able to stick to nearly any surface, even in wet environments. Marine mussels affix themselves to different surfaces using adhesive plaques consisting of various proteins. Polymer …

Using Stable Isotopes To Quantify Nitrogen Fates In Container Plants, Sam Raimann, Greg Michalski, Michael V. Mickelbart

The Summer Undergraduate Research Fellowship (SURF) Symposium

Currently, in the agriculture field, it is not yet known the accurate amount of Nitrogen in fertilizer that plants take up. This statistic, known as the Nitrogen Use Efficiency is currently known to be within the 30-50% range (Lea-Cox and Ross, 2001). This is very important figure to know and it is a figure that can be improved, and therefore much time, energy, and resources can be saved. This research project will use concepts involving stable isotopes to examine red maple plant material and the soilless media that the plants were grown in. Three different isotope-labelled fertilizer treatments will be …

Evaluating Contaminants Of Emerging Concern In Commercial Biosolid-Based Fertilizers, John Hemmerling, Michael L. Mashtare, Linda S. Lee

The Summer Undergraduate Research Fellowship (SURF) Symposium

The production and popularity of commercially available biosolid-based fertilizers are increasing because of their economic, environmental, and plant nutrition benefits, particularly in urban and suburban areas. Because biosolid-based fertilizers are derived from waste water treatment plant residuals, we hypothesized that there is the potential for micropollutants to persist in these products. Their presence would be of particular concern due to their potential impact on human and ecological health and risk of bioaccumulation. This study involves quantifying contaminants of emerging concern in three biosolid-based fertilizers, and 2 non-biosolid-based fertilizers, a composted animal manure and an organic compost. Our extraction method employed …