Open Access. Powered by Scholars. Published by Universities.®

Chemistry Commons

Open Access. Powered by Scholars. Published by Universities.®

21,354 Full-Text Articles 31,177 Authors 3,813,508 Downloads 244 Institutions

All Articles in Chemistry

Faceted Search

21,354 full-text articles. Page 2 of 544.

Immobilization Of Gold Nanoparticles On Nitrided Carbon Fiber Ultramicroelectrodes By Direct Reduction, George Affadu-Danful 2018 East Tennessee State University

Immobilization Of Gold Nanoparticles On Nitrided Carbon Fiber Ultramicroelectrodes By Direct Reduction, George Affadu-Danful

Electronic Theses and Dissertations

Due to enhanced properties such as large surface area-to-volume ratio, metal nanoparticles are often employed as catalysts for various applications. However, most studies involving nanoparticle catalysts have been conducted on collections of particles rather than single nanoparticles. Results obtained for ensemble systems can be difficult to interpret due to variations in particle loading and interparticle distance, which are often challenging to control and characterize. In this study, two immobilization strategies for incorporating gold nanoparticles (AuNPs) on carbon fiber ultramicroelectrodes (UMEs) were compared with the goal of extending these techniques to nanoelectrodes for studies of single AuNPs. Both layer-by-layer deposition of ...


Comparing Laser Assisted Pulling And Chemical Vapor Deposition Methods In The Fabrication Of Carbon Ultramicro- And Nanoelectrodes, Theophilus Neequaye 2018 East Tennessee State University

Comparing Laser Assisted Pulling And Chemical Vapor Deposition Methods In The Fabrication Of Carbon Ultramicro- And Nanoelectrodes, Theophilus Neequaye

Electronic Theses and Dissertations

Ultramicroelectrodes (UMEs) (limiting dimensions <~25 μm) and nanoelectrodes (<~100 nm) exhibit enhanced electrochemical properties compared to macroscopic electrodes. Their small sizes and enhanced properties make them well-suited for various interesting and important applications such as measuring redox-active species in nonaqueous solvents, studying intermediates of fast electrochemical reactions, and investigating electrochemical and electrocatalytic properties of single nanoparticles. While UMEs are commercially available, nanoelectrode fabrication is still largely confined to research labs. Various methods for constructing nanoelectrodes have been reported and continue to be developed, but most require considerable expertise, and comparisons between different fabrication processes are lacking. In this work, a comparison of laser-assisted pulling and chemical vapor deposition (CVD) methods of electrode fabrication is made with the aim of optimizing production of carbon nanoelectrodes for single nanoparticle electrochemical measurements. By examining effects of pulling parameters, post-pulling treatments, and CVD processing, electrodes as small as ~50 nm were successfully produced.


Investigations Into Factors Affecting The Wpd-Loop In The Protein Tyrosine Phosphatases Yoph And Ptp1b, Gwendolyn Moise 2018 Utah State University

Investigations Into Factors Affecting The Wpd-Loop In The Protein Tyrosine Phosphatases Yoph And Ptp1b, Gwendolyn Moise

All Graduate Theses and Dissertations

The research in this dissertation documents connections between the primary amino acid sequence of proteins, the dynamics of proteins, and their catalytic function. This research project studied two proteins called protein-tyrosine phosphatases (PTPs): the human enzyme PTP1B, and the bacterial enzyme YopH. PTP1B is a human enzyme that down regulates the insulin receptor on the outer cellular membrane, and causes the insulin receptor to be less responsive to insulin. A deeper knowledge of how PTP1B is different from other human PTPs might be useful in designing drugs to increase insulin sensitivity in diabetics. Yersinia Pestis is the bacteria that caused ...


Safe Use Of Hydrogen Peroxide In The Organic Lab, Patrick Dussault 2018 University of Nebraska-Lincoln

Safe Use Of Hydrogen Peroxide In The Organic Lab, Patrick Dussault

Organic Peroxides: Safety Issues

The article describes good practices for use of hydrogen peroxide (H2O2) in an organic lab setting. Major headings include:

Leading references; Toxicity; Physical properties; Chemical properties; Stability and incompatibilities; Confinement/pressure; and, References to accidents involving H2O2.


Alkene Ozonolysis In The Academic Lab, Patrick Dussault 2018 University of Nebraska-Lincoln

Alkene Ozonolysis In The Academic Lab, Patrick Dussault

Organic Peroxides: Safety Issues

The following information is offered as a guide based upon our experience with application of ozone for organic oxidations and hydroperoxide synthesis. Please send suggestions, requests, or corrections to pdussault1@unl.edu.

Introduction and leading references

Overview of ozonolysis: Mechanism, Substrate reactivity, Typical reaction conditions, Reaction monitoring, Reaction work-ups

Safety Issues

Acknowledgements:

------------

The following provides a brief introduction to the application of ozonolysis within academic labs. Ozonolysis remains among the most frequently used of methods for oxidative cleavage of alkenes. While best known as a means by which to introduce aldehydes and ketones, ozonolysis can also be used to generate ...


Synthesis And Characterization Of Zinc(Ii) Dipyrrin Photosensitizers, Norah Alqahtani 2018 East Tennessee State University

Synthesis And Characterization Of Zinc(Ii) Dipyrrin Photosensitizers, Norah Alqahtani

Electronic Theses and Dissertations

Photocatalytic carbon dioxide reduction transforms CO2 to useful chemicals and fuels, reducing CO2 emissions and making fossil fuels more renewable. Due to a lack of earthabundant sensitizers, we want to design new earth-abundant sensitizers to go with the many known carbon dioxide reduction catalysts. Zn(II) dipyrrin complexes strongly absorb visible light, but their excited state properties have not been widely studied. To investigate their photophysical properties, two Zn dipyrrin complexes, with and without heavy atoms, were synthesized and characterized by NMR and mass spectrometry. The photophysical properties of the two complexes were measured in polar and non-polar solvents, particularly ...


Chemical Strategies For Drug Development Of Fucose-Truncated Ipomoeassin F Analogues, Melissa Hirsch 2018 University of Arkansas, Fayetteville

Chemical Strategies For Drug Development Of Fucose-Truncated Ipomoeassin F Analogues, Melissa Hirsch

Theses and Dissertations

Natural product synthesis has many applications in the field of chemical biology, due to

the protein binding affinity to the complex three-dimensional structure. However, synthetic and

structure-activity relationship studies concerning certain drug targets are scarce. For example,

members of the ipomoeassin family have exhibited anti-cancer properties, but cost-effective

optimization of these compounds has not yet been extensively studied. Ipomoeassin F, a natural

glycoresin isolated from the leaves of the Ipomoea squamosa plant in the Suriname rainforest, has

shown high cytotoxicity, with IC50 values measured at the low nanomolar range. Two studies by

Postema and Fuerstner have outlined synthesis pathways for ...


Hydrocarbon Reaction Experiment [Chemistry], Kevin Mark 2018 CUNY La Guardia Community College

Hydrocarbon Reaction Experiment [Chemistry], Kevin Mark

Open Educational Resources

The Foundations of Chemistry SCC 110 course is required for LaGuardia’s Health Sciences students interested in the Nursing, Dietetic Technician and Veterinary Technician programs. This course has been designated for the Inquiry and Problem Solving competency as well the Digital Communication ability. SCC 110 students will use SCC 110 lecture material and information in the SCC 110 lab manual to perform an electrophilic addition. Students will be able to correlate the organic theory concepts with the experiment by making physical observations (e.g., color changes) when carrying out the lab procedures. The student findings will be synthesized and expressed ...


Hydrolysis Of Cellulose And Biomass Using Blue Molybdenum, Farouk Awudu 2018 East Tennessee State University

Hydrolysis Of Cellulose And Biomass Using Blue Molybdenum, Farouk Awudu

Electronic Theses and Dissertations

Hydrolysis of cellulosic biomass is an important and ongoing subject of research due to generating precursors for biofuel synthesis. This work involves hydrolysis of microcrystalline cellulose and Arundo donax to glucose. Methods for acid hydrolysis include the use of sulfuric acid, phosphomolybdic acid, blue molybdenum using low concentrations at 40-100 °C. For comparison purposes, enzymatic hydrolysis was also carried out using cellulase. Products were quantified by measuring total organic carbon and reducible sugars using dinitrosalicylic acid. Use of phosphomolybdic acid, blue molybdenum and sulfuric acid even at 6.0 M did not increase the amount of glucose compared to using ...


3d-Printed Fluidic Devices And Incorporated Graphite Electrodes For Electrochemical Immunoassay Of Biomarker Proteins, Abdulhameed Alabdulwaheed 2018 East Tennessee State University

3d-Printed Fluidic Devices And Incorporated Graphite Electrodes For Electrochemical Immunoassay Of Biomarker Proteins, Abdulhameed Alabdulwaheed

Electronic Theses and Dissertations

Biomarkers are measurable indicators of health status or disease state that can be used for diagnosis and may help guide patient treatment strategies. Enzyme-linked immunosorbent assays (ELISA) and other many clinical techniques currently used for measuring biomarker proteins lack sensitivity, demand high analysis cost, are often not well-suited for measuring multiple biomarkers in a single sample, and require long analysis times. Here, we demonstrate simple, low-cost 3D-printed flow-through devices with integrated electrodes modified with gold nanoparticles (AuNPs) for electrochemical immunoassays of S100B, a biomarker protein related to conditions like skin cancer and brain injuries. Flow-through devices are fabricated from photocurable-resin ...


Novel Relative Spontaneous Ignition Temperature Determination Using Carbon Dioxide Onset With Sta/Ir, Antonio David Trevino 2018 Stephen F. Austin State University

Novel Relative Spontaneous Ignition Temperature Determination Using Carbon Dioxide Onset With Sta/Ir, Antonio David Trevino

Electronic Theses and Dissertations

Simultaneous thermal analysis, coupled with infrared spectroscopy (STA/IR), was utilized to monitor the evolution of gaseous products during the thermal degradation of samples from Triadica sebifera (Chinese tallow), Ligustrum sinense (Chinese privet), and Ilex vomitoria (yaupon) plants. Identification of carbon dioxide was successful with a spectral match of 90.2 percent and further used in the determination of relative spontaneous ignition temperature, or RSIT. The RSIT value during the growing season for Chinese tallow, Chinese tallow stem, Chinese privet, and Yaupon were 208.4°C, 250.3°C, 210.1°C, and 232.3°C respectively. During the dormant ...


1,1´-Diethyl-2,2´,3,3´,4,4´,5,5´-Octamethylferrocenium Tetracyanoethylenide, [Fe(C5etme4)2]+[Tcne]–, A Charge-Transfer Salt Magnetic Solid With A Novel Structural Motif, T. David Harris, Michael Castellani, Arnold L. Rheingold, William M. Reiff, Gordon T. Yee 2018 Marshall University

1,1´-Diethyl-2,2´,3,3´,4,4´,5,5´-Octamethylferrocenium Tetracyanoethylenide, [Fe(C5etme4)2]+[Tcne]–, A Charge-Transfer Salt Magnetic Solid With A Novel Structural Motif, T. David Harris, Michael Castellani, Arnold L. Rheingold, William M. Reiff, Gordon T. Yee

Michael P. Castellani

1,1′-Diethyl-2,2′,3,3′,4,4′,5,5′-octamethylferrocene has been utilized as a one-electron donor in the synthesis of a tetracyanoethylene charge-transfer salt, [Fe(C5EtMe4)2]+[TCNE]. Structural characterization shows that it adopts an arrangement of anions and cations completely different from the usual π stacking seen in analogous decamethylferrocenium compounds. The TCNE radical sits along side of the ferrocene, nearly perpendicular to the planes of the C5 rings. The nearly square geometry of the TCNE anion creates disorder over two orientations. [Fe(C5EtMe4)2]+[TCNE] is a simple paramagnet ...


1 Halogen Oxidation Reactions Of (C5ph5)Cr(Co)3 And Lewis Base Addition To [(C5ph5)Cr(Μ-X)X]2: Electrochemical, Magnetic, And Raman Spectroscopic Characterization Of [(C5ph5)Crx2]2 And (C5ph5)Crx2(Thf) (X = Cl, Br, I). X-Ray Crystal Structure Of [(C5ph5)Cr(Μ-Cl)Cl]2, Marc A. Hutton, James C. Durham, Robert W. Grady, Brett E. Harris, Carter S. Jarrell, J. Matthew Mooney, Michael Castellani, Arnold L. Rheingold, Ulrich Kölle, Brenda J. Korte, Roger D. Sommer, Gordon T. Yee, J. Matthew Boggess, Roman S. Czernuszewicz 2018 Marshall University

1 Halogen Oxidation Reactions Of (C5ph5)Cr(Co)3 And Lewis Base Addition To [(C5ph5)Cr(Μ-X)X]2: Electrochemical, Magnetic, And Raman Spectroscopic Characterization Of [(C5ph5)Crx2]2 And (C5ph5)Crx2(Thf) (X = Cl, Br, I). X-Ray Crystal Structure Of [(C5ph5)Cr(Μ-Cl)Cl]2, Marc A. Hutton, James C. Durham, Robert W. Grady, Brett E. Harris, Carter S. Jarrell, J. Matthew Mooney, Michael Castellani, Arnold L. Rheingold, Ulrich Kölle, Brenda J. Korte, Roger D. Sommer, Gordon T. Yee, J. Matthew Boggess, Roman S. Czernuszewicz

Michael P. Castellani

The 17-electron complex (C5Ph5)Cr(CO)3 reacts with halogens (C6H5I•Cl2, Br2, and I2) in C6H6 to yield the dimeric oxidation products [(C5Ph5)Cr(m-X)X]2 as thermally stable solids. Reactions with other chlorinating agents similarly yield [(C5Ph5)CrCl2]2. An X-ray crystal structure of [(C5Ph5)Cr(m-Cl)Cl]2 was obtained. The magnetic properties of the Cl2 bridged dimer have been determined and modeled using the usual isotropic hamiltonian which yields J/k = –30 K. Low-temperature (77 K) Raman spectra of solid [(C5Ph5)CrX2]2 (X = Cl, I) allow assignments to be made for the metal-ring ...


Working With Organic Peroxides In The Academic Lab, Patrick Dussault 2018 University of Nebraska-Lincoln

Working With Organic Peroxides In The Academic Lab, Patrick Dussault

Organic Peroxides: Safety Issues

ABSTRACT: The following is a brief introduction to peroxide safety from the viewpoint of a synthetic chemist. Major topics include: classes of organic peroxides; peroxide reactivity; hazard identification and minimization; reaction monitoring; and, hazards associated with auto-oxidation of peroxidizable solvents.

KEYWORDS: peroxide, hydroperoxide, hydroperoxyacetal, ozonide, perester, dihydroperoxide, monoperoxyacetal, active oxygen, peroxide strips, TLC indicator, self-accelerating decomposition, radical, exothermicity, transition metals.

CONTENTS: 1. Literature resources 2. Major classes of peroxides 3. Basis for peroxide reactivity 4. Determining reactivity and minimizing hazards a. Steps to take before an experiment b. Minimizing hazard during reactions c. Monitoring reactions d. Working with isolated peroxides ...


Ultrafast And Nonlinear Spectroscopy Of Nanomaterials, Rami Anthony Khoury 2018 Louisiana State University and Agricultural and Mechanical College

Ultrafast And Nonlinear Spectroscopy Of Nanomaterials, Rami Anthony Khoury

LSU Doctoral Dissertations

Ultrafast and nonlinear spectroscopies are implemented in the investigation of excited-state dynamics and structural properties of materials and nanomaterials. In the first study, the excited-state dynamics of size-dependent colloidal TiO2-Au nanocomposites are investigated using ultrafast transient absorption spectroscopy. The dynamics corresponding to the plasmon depletion band are characterized by electron-phonon and phonon-phonon coupling lifetimes that are observed to be independent of the gold nanocluster shell thickness. The excited-state dynamics corresponding to the interband transition of gold is also spectrally overlapped with the interfacial electron transfer lifetime, which is shown to decrease as the nanocluster shell thickness increases. In ...


The Fate Of Arsenic In Noah’S Flood, Aaron R. Hutchison, Campbell F. Bortel 2018 Cedarville University

The Fate Of Arsenic In Noah’S Flood, Aaron R. Hutchison, Campbell F. Bortel

Aaron R. Hutchison, Ph.D.

One potential consequence of Noah’s Flood would be the mobilization of toxic elements such as arsenic (As), a group 15 metalloid with a significant solubility and redox chemistry in water and a high toxicity to human beings. This paper discusses the likely chemistry of arsenic during the Flood. The Flood would have released arsenic through hydrothermal activity, volcanic eruptions, and weathering of crustal rock. Arsenic in hydrothermal fluid would likely be rapidly precipitated by sulfides. Likewise, much of the arsenic in volcanoes would actually be deposited sub-surface as sulfides. In the presence of oxygen-rich waters, these sulfide minerals can ...


The Fate Of Arsenic In Noah’S Flood, Aaron R. Hutchison, Campbell F. Bortel 2018 Cedarville University

The Fate Of Arsenic In Noah’S Flood, Aaron R. Hutchison, Campbell F. Bortel

The Proceedings of the International Conference on Creationism

One potential consequence of Noah’s Flood would be the mobilization of toxic elements such as arsenic (As), a group 15 metalloid with a significant solubility and redox chemistry in water and a high toxicity to human beings. This paper discusses the likely chemistry of arsenic during the Flood. The Flood would have released arsenic through hydrothermal activity, volcanic eruptions, and weathering of crustal rock. Arsenic in hydrothermal fluid would likely be rapidly precipitated by sulfides. Likewise, much of the arsenic in volcanoes would actually be deposited sub-surface as sulfides. In the presence of oxygen-rich waters, these sulfide minerals can ...


Hiv-1 Integrase-Targeted Short Peptides Derived From A Viral Protein R Sequence, Xue Zhi Zhao, Mathieu Métifiot, Evgeny Kiselev, Jacques Kessl, Kasthuraiah Maddali, Christophe Marchand, Mamuka Kvaratskhelia, Yves Pommier, Terrence R. Burke Jr. 2018 Center of Cancer Research

Hiv-1 Integrase-Targeted Short Peptides Derived From A Viral Protein R Sequence, Xue Zhi Zhao, Mathieu Métifiot, Evgeny Kiselev, Jacques Kessl, Kasthuraiah Maddali, Christophe Marchand, Mamuka Kvaratskhelia, Yves Pommier, Terrence R. Burke Jr.

Faculty Publications

HIV-1 integrase (IN) inhibitors represent a new class of highly effective anti-AIDS therapeutics. Current FDA-approved IN strand transfer inhibitors (INSTIs) share a common mechanism of action that involves chelation of catalytic divalent metal ions. However, the emergence of IN mutants having reduced sensitivity to these inhibitors underlies efforts to derive agents that antagonize IN function by alternate mechanisms. Integrase along with the 96-residue multifunctional accessory protein, viral protein R (Vpr), are both components of the HIV-1 pre-integration complex (PIC). Coordinated interactions within the PIC are important for viral replication. Herein, we report a 7-mer peptide based on the shortened Vpr ...


Unraveling Substituent Effects On The Glass Transition Temperatures Of Biorenewable Polyesters, Xiaopeng Yu, Junteng Jia, Shu Xu, Ka Un Lao, Maria J. Sanford, Ramesh K. Ramakrishnan, Sergei I. Nazarenko, Thomas R. Hoye, Geoffrey W. Coates, Robert A. DiStasio Jr. 2018 Cornell University

Unraveling Substituent Effects On The Glass Transition Temperatures Of Biorenewable Polyesters, Xiaopeng Yu, Junteng Jia, Shu Xu, Ka Un Lao, Maria J. Sanford, Ramesh K. Ramakrishnan, Sergei I. Nazarenko, Thomas R. Hoye, Geoffrey W. Coates, Robert A. Distasio Jr.

Faculty Publications

Converting biomass-based feedstocks into polymers not only reduces our reliance on fossil fuels, but also furnishes multiple opportunities to design biorenewable polymers with targeted properties and functionalities. Here we report a series of high glass transition temperature (Tg up to 184 °C) polyesters derived from sugar-based furan derivatives as well as a joint experimental and theoretical study of substituent effects on their thermal properties. Surprisingly, we find that polymers with moderate steric hindrance exhibit the highest Tg values. Through a detailed Ramachandran-type analysis of the rotational flexibility of the polymer backbone, we find that additional steric hindrance does ...


The Commutator Of The Runge Lenz Vector With Other Operators Of The H-Atoms Physics Using Maxima, Carl W. David 2018 University of Connecticut

The Commutator Of The Runge Lenz Vector With Other Operators Of The H-Atoms Physics Using Maxima, Carl W. David

Chemistry Education Materials

Commutators of components of the Runge-Lenz vector and constants of the motion and ladder operators for the H-atom problem are evaluated using brute force calculus and Maxima.


Digital Commons powered by bepress