Chemistry Commons^™

Activation Of Tri(2-Furyl)Phosphine At A Dirhenium Centre: Formation Of Phosphido-Bridged Dirhenium Complexes, Shishir Ghosh, Mansura Khatun, Daniel T. Haworth, Sergey V. Lindeman, Tasneem Siddiquee, Dennis W. Bennett, Graeme Hogarth, Ebbe Nordlander, Shariff E. Kabir

Chemistry Faculty Research and Publications

Reaction of tri(2-furyl)phosphine (PFu₃) with [Re₂(CO)_10−n(NCMe)_n] (n = 1, 2) at 40 °C gave the substituted complexes [Re₂(CO)_10−n(PFu₃)_n] (1 and 2), the phosphines occupying axial position in all cases. Heating [Re₂(CO)₁₀] and PFu₃ in refluxing xylene also gives 1 and 2 together with four phosphido-bridged complexes; [Re₂(CO)_8−n(PFu₃)_n(μ-PFu₂)(μ-H)] (n = 0, 1, 2) (3–5) and [Re₂(CO)_{6 …}

Distance Dependence Of Electron Transfer Kinetics For Azurin Protein Adsorbed To Monolayer Protected Nanoparticle Film Assemblies, Morgan Lynn Vargo, Chris P. Gulka, John K. Gerig, Christopher M. Manieri, Jonathan D. Dattelbaum, Carolyn B. Marks, Nathaniel T. Lawrence, Matthew L. Trawick, Michael C. Leopold

Chemistry Faculty Publications

The distance dependence and kinetics of the heterogeneous electron transfer (ET) reaction for the redox protein azurin adsorbed to an electrode modified with a gold nanoparticle film are investigated using cyclic voltammetry. The nanoparticle films are comprised of nonaqueous nanoparticles, known as monolayer-protected clusters (MPCs), which are covalently networked with dithiol linkers. The MPC film assembly serves as an alternative adsorption platform to the traditional alkanethiolate self-assembled monolayer (SAM) modified electrodes that are commonly employed to study the ET kinetics of immobilized redox proteins, a strategy known as protein monolayer electrochemistry. Voltammetric analysis of the ET kinetics for azurin adsorbed …

Mitigating Co2 Production In Coal-To-Liquids Process, Robert Walty

UNLV Renewable Energy Symposium

The 3rd Annual Renewable Energy Symposium took place on the UNLV campus August 11 & 12. The event focused on renewable energy production in Nevada, the US Southwest, and renewable research projects nationwide. The event was a great success with over 200 individuals in attendance.

Hydrogen In Non-Crystalline Materials: From Solar Cells To Hydrogen Storage, Anatolii Shkrebtii

UNLV Renewable Energy Symposium

The 3rd Annual Renewable Energy Symposium took place on the UNLV campus August 11 & 12. The event focused on renewable energy production in Nevada, the US Southwest, and renewable research projects nationwide. The event was a great success with over 200 individuals in attendance.

Hydrogen R&D At Sandia National Labs, Lennie Klebanoff

UNLV Renewable Energy Symposium

The 3rd Annual Renewable Energy Symposium took place on the UNLV campus August 11 & 12. The event focused on renewable energy production in Nevada, the US Southwest, and renewable research projects nationwide. The event was a great success with over 200 individuals in attendance.

Development Of Biocompatible Polymer Monoliths For The Analysis Of Proteins And Peptides, Yun Li

Theses and Dissertations

Biocompatibility is an important issue for the development of chromatographic stationary phases for the analysis of biomolecules (including proteins and peptides). A biocompatible stationary phase material is a material that resists nonspecific adsorption of biomolecules and does not interact with them in a way that would alter or destroy their structures or biochemical functions. The monolithic column format is a good alternative to typical spherical particle packed columns for capillary liquid chromatography of biomacromolecules. Several novel anion-exchange polymer monoliths for the analysis of proteins were synthesized for improved biocompatibility. Two novel polymeric monoliths were prepared in a single step by …

Current Projects At The Unlv Center For Energy Research, Robert F. Boehm

UNLV Renewable Energy Symposium

The 3rd Annual Renewable Energy Symposium took place on the UNLV campus August 11 & 12. The event focused on renewable energy production in Nevada, the US Southwest, and renewable research projects nationwide. The event was a great success with over 200 individuals in attendance.

Real-Time Virus Analysis Via Image Charge Detection Surface Induced Dissociation Tandem Mass Spectrometry, Seth T. Call

Theses and Dissertations

This thesis reports on the development of a novel mass spectrometer combining image charge detection with surface induced dissociation for real-time analysis of intact viruses. Protonated viruses produced using electrospray are accelerated and subsequently impact on a solid surface. Capsid peptides released during the impact are analyzed using time-of-flight mass spectrometry. Image charge detection is used to measure the mass and charge states of structurally intact, electrosprayed viruses prior to impact. Since virus capsids are composed of loosely-bound proteins, collision of viruses with surfaces at moderate impact energies could release intact proteins. The masses and numbers of different protein types …

Mesoporosity And Functional Group Dependent Endocytosis And Cytotoxicity Of Silica Nanomaterials, Zhimin Tao, Jerry Goodisman, Tewodros Asefa, Bonnie B. Toms

Chemistry - All Scholarship

We report different mesoporosity-dependent and functional group-dependent cytotoxicity and endocytosis of various silica nanomaterials on suspended and adherent cells. This dependency further varied with incubation time and particle dosage, and appeared to be associated with the particles’ endocytotic efficiency and their chemical and physical properties. We studied two common mesoporous nanomaterials (MSNs), MCM-41 and SBA-15, and one type of solid-cored silica microsphere, paralleled by their quaternary amine functionalized counterparts. Compared to SBA-15, MCM-41 has a larger surface area but smaller pore size, whereas SMS exhibits low surface area and poor porosity. In Jurkat cells, SBA-15 and MCM- 41 exhibited different …

Mesoporosity And Functional Group Dependent Endocytosis And Cytotoxicity Of Silica Nanomaterials, Zhimin Tao, Bonnie B. Toms, Jerry Goodisman, Tewodros Asefa

Chemistry - All Scholarship

We report different mesoporosity-dependent and functional group-dependent cytotoxicity and endocytosis of various silica nanomaterials on suspended and adherent cells. This dependency further varied with incubation time and particle dosage, and appeared to be associated with the particles' endocytotic efficiency and their chemical and physical properties. We studied two common mesoporous nanomaterials (MSNs), MCM-41 and SBA-15, and one type of solid-cored silica microsphere, paralleled by their quaternary amine functionalized counterparts. Compared to SBA-15, MCM-41 has a larger surface area but smaller pore size, whereas SMS exhibits low surface area and poor porosity. In Jurkat cells, SBA-15 and MCM-41 exhibited different cytotoxicity …

Design And Characterization Of A Human Exposure Chamber And Inversion Episodes In Salt Lake City, Utah In January/February Of 2009, Roman Yuri Kuprov

Theses and Dissertations

Research on health effects of particulate matter (PM) has been a very active area in the last two decades. One plausible mechanism by which exposure to PM affects human health includes modification of autonomic endothelium function. Decreased endothelium activity causes heightened risks of cardiovascular disease. A human exposure chamber designed to conduct experiments to quantify diminished function of endothelium from short term exposure to PM is described. The chamber consists of two stages for containment and pre-treatment of PM and exposure of human subjects. Concentrations of CO, CO2, NO, NO2, O3, and PM2.5, are monitored and controlled in the exposure …

Undergraduate Research Opportunities Program, University Of Nevada Las Vegas, College Of Sciences

Undergraduate Research Opportunities Program (UROP)

No abstract provided.

The Study Of Variations In The Properties Of Biodiesel On Addition Of Antioxidants, Hiranmayee Kandala

Masters Theses & Specialist Projects

This research studies variations in biodiesel upon addition of different concentrations of antioxidant and petrodiesel additives. Oxidation onset temperature, oxidation induction time, oxidative stability, thermal stability, crystallization onset temperature and moisture retention properties of the biodiesel, with and without antioxidants have been studied. Antioxidants like BHT, BHA, PrG, Vit E and Vit C were added to the biodiesel during the study. These samples were analyzed using the PDSC, TGA, DSC and TGA-SA instrumentation.

The results of this research show an improvement in the OOT, OIT and Oxidative stability of biodiesel with the addition of antioxidants and by blending the biodiesel …

Increased Control Over Gold Colloid Adsorption On Substrates For Colloid Displacement Lithography, Vara Prasad Reddy Sakampally

Masters Theses & Specialist Projects

Colloid displacement lithography is proving to be very effective in the designing of nanometer scale electronic devices. Precise control of the structure of matter at the nanometer scale has brought a revolutionary change in science and technology. The use of these nanometer scale devices ranges from the diagnosis of various diseases to cell repair to ultra strong materials. This research focused on optimizing the conditions for gold colloid particle adsorption for colloid displacement lithography, an expansion on gold colloid particle manipulation techniques using a scanned probe microscope. The system consists of a scrupulously cleaned glass surface that is coated with …

Synthesis And Characterization Of Bis-Phosphine Complexes With Transition Metals, Alicia L. Mcdaniel

Masters Theses & Specialist Projects

Extractants and extraction methodologies play a vital role in many industrial processes, from the concentration of precious metals from ores to the separation of longlived nuclei from radioactive waste as well as the removal of heavy metals from soils and water for remediation. The vast majority of extractants rely on the use of nitrogen, oxygen, sulfur or selenium as Lewis base donor atoms to form coordination complexes with the metal ions of interest. These extractants often make use of the chelate effect and/or the macrocyclic effect in order to form stable complexes. Some of the best known types of chelate …

Rephasing Ion Packets In The Orbitrap Mass Analyzer To Improve Resolution And Peak Shape, Richard H. Perry, Qizhi Hu, Gary A. Salazar, R. Graham Cooks, Robert J. Noll

Chemistry and Physics Faculty Articles

A method is described to improve resolution and peak shape in the Orbitrap under certain experimental conditions. In these experiments, an asymmetric anharmonic axial potential was first produced in the Orbitrap by detuning the voltage on the compensator electrode, which results in broad and multiply split mass spectral peaks. An AC waveform applied to the outer electrode, 180° out of phase with ion axial motion and resonant with the frequency of ion axial motion, caused ions of a given m/z to be de-excited to the equator (z = 0) and then immediately re-excited. This process, termed “rephasing,” leaves the …

Pinpointing The Extent Of Electronic Delocalization In The Re(I)-To-Tetrazine Charge-Separated Excited State Using Time-Resolved Infrared Spectroscopy, Guifeng Li, Kumar Parimal, Shubham Vyas, Christopher M. Hadad, Amar H. Flood, Ksenija D. Glusac

Chemistry Faculty Publications

Femtosecond mid-IR transient absorption spectroscopy (TRIR) and time-dependent density functional theory (TD-DFT) calculations on Re(CO)(3)Cl(Me(2)BPTZ) [Me(2)BPTZ = 3,6-bis(5-methyl-2-pyridine)-1,2,4,5-tetrazine] are used to demonstrate that the lowest excited state of the complex is a triplet metal-to-ligand charge-transfer ((3)MLCT) state with a lifetime of 225 ps. The short excited-state lifetime is explained by the energy-gap taw. Vibrational cooling of the (3)MLCT state shows up as early-time dynamics (3.6 ps). The structural changes in the excited state are deduced from the frequency shifts in the TRIR vibrational bands. The vibrational frequencies of the CO groups increase upon excitation as a result of decreased back-bonding …

Spiroadamantyl 1,2,4-Trioxolane, 1,2,4-Trioxane, And 1,2,4-Trioxepane Pairs: Relationship Between Peroxide Bond Iron(Ii) Reactivity, Heme Alkylation Efficiency, And Antimalarial Activity, Xiaofang Wang, Darren J. Creek, Charles E. Schiaffo, Yuxiang Dong, Jacques Chollet, Christian Scheurer, Segio Wittlin, Susan A. Charman, Patrick Dussault, James K. Wood, Jonathan L. Vennerstrom

Patrick Dussault Publications

These data suggest that iron(II) reactivity for a set of homologous spiroadamantyl 1,2,4-trioxolane, 1,2,4-trioxane, and 1,2,4-trioxepane peroxide heterocycles is a necessary, but insufficient, property of animalarial peroxides. Heme alkylation efficiency appears to give a more accurate prediction of antimalarial activity than FeSO₄-mediated reaction rates, suggesting that antimalarial activity is not merely dependent on peroxide bond cleavage, but also on the ability of reactive intermediates to alkylate heme or other proximal targets.

Isu Chem-Letter, Fall 2009, Illinois State University, Department Of Chemistry

Chem Letter

Newsletter of the Illinois State University Department of Chemistry

Synthesis And Characterization Of Some Rhenium Complexes, Joseph Brian Scott

Masters Theses & Specialist Projects

Plastics or polymers are thought to behave oppositely from metals. Ideally, polymers behave as insulators while metals conduct electricity. Shirakawa and coworkers discovered conductive polymers in 1977.1 These conductor polymers have been extensively studied, discovering that charge transfer oxidative doping of polyacteylene could increase its conductivity by 12 orders of magnitude. Polyacetylene, although showing promise as an organic conductor, because it is highly air-sensitive and oxidizes when exposed to molecular oxygen, therefore making this an unattractive use for commercial products. Attention has been focused on heterocylic aromatic polymers such as polythiophene and polypyrrole, in efforts to produce conductive polymers that …

Continued Development Of An Empirical Function For Predicting And Rationalizing Protein–Protein Binding Affinities, Joseph Audie

Chemistry & Physics Faculty Publications

Here we summarize recent work on the continued development of our fast and simple empirical equation for predicting and structurally rationalizing protein–protein and protein–peptide binding affinities. Our empirical expression consists of six regression-weighted physical descriptors and derives from two key simplifying assumptions: (1) the assumption of rigid-body association and (2) the assumption that all contributions not explicitly considered in the equation make a net contribution to binding of ≈0 kcal. Within the strict framework of rigid-body association, we tested relative binding affinity predictions using our empirical equation against the corresponding experimental binding free energy data for 197 interface alanine mutants. …

Classification And Energetics Of The Base-Phosphate Interactions In Rna, Craig L. Zirbel, Judit E. Šponer, Jiri Šponer, Jesse Stombaugh, Neocles B. Leontis

Chemistry Faculty Publications

Structured RNA molecules form complex 3D architectures stabilized by multiple interactions involving the nucleotide base, sugar and phosphate moieties. A significant percentage of the bases in structured RNA molecules in the Protein Data Bank (PDB) hydrogen-bond with phosphates of other nucleotides. By extracting and superimposing base-phosphate (BPh) interactions from a reduced-redundancy subset of 3D structures from the PDB, we identified recurrent phosphate-binding sites on the RNA bases. Quantum chemical calculations were carried out on model systems representing each BPh interaction. The calculations show that the centers of each cluster obtained from the structure superpositions correspond to energy minima on the …

Spiroadamantyl 1,2,4-Trioxolane, 1,2,4-Trioxane, And 1,2,4-Trioxepane Pairs: Relationship Between Peroxide Bond Iron(Ii) Reactivity, Heme Alkylation Efficiency, And Antimalarial Activity, Xiaofang Wang, Darren J. Creek, Yuxiang Dong, Jacques Chollet, Christian Scheurer, Sergio Wittlin, Susan A. Charman, Patrick H. Dussault, James K. Wood, Jonathan L. Vennerstrom

Chemistry Faculty Publications

These data suggest that iron(II) reactivity for a set of homologous spiroadamantyl 1,2,4-trioxolane, 1,2,4-trioxane, and 1,2,4-trioxepane peroxide heterocycles is a necessary, but insufficient, property of animalarial peroxides. Heme alkylation efficiency appears to give a more accurate prediction of antimalarial activity than FeSO4-mediated reaction rates, suggesting that antimalarial activity is not merely dependent on peroxide bond cleavage, but also on the ability of reactive intermediates to alkylate heme or other proximal targets.

Factors Affecting Redox Magnetohydrodynamics For Flow In Small Volumes, Matthew D. Gerner

Graduate Theses and Dissertations

Lab-on-a-chip technologies offer the possibility of developing analytical devices that are low-cost, portable, disposable, fast, and operable by non-technical personnel. Such devices require automated methods to manipulate ultra-small volumes (picoliters) of samples and solution, including pumping, stirring, and positioning. Current methods for ultra-small volume microfluidics have limitations that restrict their use including high voltage requirements, disadvantageous flow profiles or rates, and relatively complicated fabrication due to mechanical parts. Redox magnetohydrodyanmics (RMHD) that utilizes permanent magnets for portability shows promise as a micropump with ease of switching flow direction, no moving parts, compatibility with both aqueous and non-aqueous solutions, low voltages …

Synthesis And Characterization Of Magnetic Solids Containing Periodic Arrays Of Transition Metal Oxide Nanostructures, Wendy Queen

All Dissertations

The ultimate goal of the research presented in this dissertation was to explore new systems containing low–dimensional magnetic nanostructures in hopes of finding new extended solids exhibiting novel magnetic properties due to the confined magnetic lattices. The scope of this research is threefold: 1) to explore new solids containing low–dimensional magnetic nanostructures in the A–M–X–O system, where A is an alkali or alkalinendash;earth metal cation, M is a first–row transition metal cation, and X is P, As, or V, 2) to characterize these new materials and, through chemical substitution, fine tune (and optimize) magnetic and electronic properties of solids that …

Synthesis Of Complex Fluorides For Optical Applications, Seth Stepleton

All Dissertations

Large single crystals of alkali metal fluorides are desirable for many reasons. Fluoride laser crystals have a wide transmission range and on account of their low phonon energies, many efficient laser emissions have been obtained from 285 nm to 4.34 µm.1,2 Inorganic fluoride single crystals feature large bandgaps, very wide optical transmittance ranges from vacuum-ultraviolet (VUV) to mid-IR wavelength regions, lower refractive indices than those of oxides, and typically lower phonon energies (which drastically reduce multiphonon relaxation rates of rare earth ions).3
The main goal of this work was to investigate the hydrothermal synthesis of alkali metal fluorides. Melt techniques …

Effects Of Adding An Enhanced Material Instructional Model To A Collaborative Grouping Instructional Strategy In A College Preparatory Chemistry Course, Chinyere Fidelia Shaw-Nnajiofor

Theses and Dissertations - UTB/UTPA

This research study investigated comparable academic achievement outcomes between an experimental group (EG) and a control group (CG) in a college preparatory chemistry course using a mixture of instructional pedagogies. The subjects comprised native and non-native English speakers, often identified as Limited English Proficiency (LEP) students. The study found no statistically significant difference between the pre-test scores of EG and CG students and a significant difference between the post-test scores of students in the experimental group compared to those of the control group. No significant difference was observed when comparing the test scores of the post-tests of the LEP-EG students …

Phenomenological Investigation Of The Effectiveness Of A Cooperative Problem-Based Laboratory And A Metacognitive Problem-Solving Exercise, Todd Gatlin

All Theses

Problem-solving has been described by many as the most important goal of chemistry teaching and learning. Solving real problems requires not only cognitive abilities but also a regulation of those abilities-metacognition. In fact, metacognition is recognized as having considerable impact on problem-solving success and learning. Recent research focused on the development of interventions designed to enhance the use of metacognition. The main objective of this study was to determine 'how' and 'why' two interventions were effective in increasing students' metacognitive use, and problem-solving abilities. Therefore, this study represents the qualitative portion of a sequential explanatory mixed-methods study; Qualitative evidence was …

Synthesis Of Polymers Featuring Novel Diphosphines, Eleanor Tennyson

All Theses

This report details the synthesis of functionalized platinum-based metallopolymers featuring m-terphenyl-scaffolded and light-harvesting phosphine ligands. Substituents placed on both the phosphine and pendant alkynyl units can enhance the optical activity of the metallopolymers depending on their inherent properties. The presence of the platinum metal atom can be exploited to increase conductivity of the molecule and promises to be a unique and valuable modification for polymers to be used in light emitting diodes and photovoltaics. Light-harvesting phosphines prepared in the course of the metallopolymer development have also been used to prepare luminescent polyelectrolytes that prove valuable for well-defined composite film formation …

Hydrothermal Crystal Growth Of Tetravalent And Pentavalent Metal Oxides, James Mann

All Dissertations

Over the past two hundred years synthetic growth of crystals has become vital to the technological advancement of our society. A variety of crystal growth techniques have been developed during this time, with each having its own nuances. These differences have enabled the growth of a wide spectrum of crystalline materials that can be used for many applications which include solid state lasers, semiconductors, and communication devices. Despite these techniques there are entire classes of materials which have thus far proved quite difficult to prepare as single crystals. In particular, crystal growth of the tetravalent and pentavalent metal oxides has …