Chemistry Commons^™

Development And Study Of Small Database For The Activation Of Nitrous Oxide Towards Formation Of Iron(Iv)-Oxo Species, Tobias Barthalomew Robertson

Masters Theses

Nitrous oxide (N₂O) can undergo an oxygen atom transfer (OAT) reaction resulting in inert nitrogen gas (N₂O) while transferring an oxygen atom to a molecular complex or material. This process is of catalytic importance since this OAT reaction can be leveraged to form iron(IV)-oxo sites, which are known to be catalytic intermediates. Here, an investigation of the ligand field effects on primarily iron(II) complexes for the formation of iron(IV)-oxo sites with nitrous oxide as the oxidant is reported. An initial database of sixty-four molecular complexes with ligand environments varying in field strength and coordination geometry was …

Applying Intensity-Based Methods To Disentangle Microwave Spectra Of Complex Mixtures: Analysis Of Weakly Bound Clusters Of 1,1-Difluoroethylene/Co2, Hannah Fino

Masters Theses

Microwave spectroscopy is used to study the solvent-solute interactions between molecules of CO₂ and fluoroethylenes by analyzing the formation of weakly-bound clusters in a gaseous mixture. One of the challenges to analyzing microwave spectra obtained for these weakly-bound species is that spectra for individual clusters are mixed together in an original complex spectrum. This prompts development of automated techniques that could separate complex data into subsets of related data to be more easily analyzed.

The techniques developed in this work are founded on intensity-based analyses, following the work of Dr. Robert Field on Extended Cross Correlation (XCC). The XCC …

Dissolved Organic Carbon And The Potential Role To Stream Acidity In The Great Smoky Mountains National Park, Jason R. Brown

Masters Theses

A substantial societal shift towards environmental awareness has focused research efforts on the impacts of pollution on natural landscapes. Improvements to pollutant regulations and technology have resulted in sizeable reductions of atmospheric deposition of anthropogenic acids, especially nitrates and sulfates, which has altered the role of these ions in the environment. As such, understandings of environmental chemistry dynamics have required regular updating.

Through the National Park Service Vital Signs monitoring program, increases in precipitation pH observed in Great Smoky Mountains National Park (GRSM) has been attributed to the reduction of inorganic acid concentrations. Unfortunately, these improvements have not been uniformly …

Developing A Basket-Shaped Host Molecule Based On P-Tert-Butylcalix[4]Arene Featuring Urea Groups For Encapsulating Volatile Guest Molecules, Lokugama Widanelage Vidula Priyadarshana

Masters Theses

Molecular baskets are a group of synthetic host molecules which are designed to govern the inclusion of small guest molecules. The basic structural features of basket-shaped host molecules are a cavity for holding a much smaller guest molecule and tunable gates for keeping the guest molecule inside. These types of gates can be tuned by changing temperature, concentration, pH, etc. In this research group's previous study, a molecular basket of cal ix[ 4]arene with carboxylic acid groups was synthesized by functionalizing calix[4]arene's phenol hydroxyl groups with benzyl bromide building blocks. In the study detailed here, 1 , l '-((5-(bromomethyl)-1,3-phenylene)bis(methylene))bis(3-isopropylurea) was …

In Situ Ph Determination Based On The Nmr Analysis Of ¹H-Nmr Signal Intensities And ¹⁹F-Nmr Chemical Shifts, Ming Huang

Masters Theses

"The pH of an NMR sample can be measured directly by NMR experiments of signal intensities, chemical shifts, or relaxation time constants that depend on the pH. The ¹H NMR peak intensities of the pH indicator phenolphthalein change as it changes from the OH-depleted form to the OH-rich form in the range of pH = 11.1 to 12.7. Because this range is rather small, another NMR technique was utilized based on ¹⁹F chemical shifts. The shift of F^- in an aqueous solution of NaF changes in the alkaline range between pH = 11.0 and 14.0 and even …

Three Body Interactions Of Rare Gas Solids Calculated Within The Einstein Model, Dan D'Andrea

Masters Theses

Three body interactions can become important in solids at higher pressures and densities as the molecules can come into close contact. At low temperatures, accurate studies of three body interactions in solids require averaging the three-body terms over the molecules' zero point motions. An efficient, but approximate, averaging approach is based on a polynomial approximation of the three-body term. The polynomial approximation can be developed as a function of the symmetry coordinates of a triangle displaced from its average geometry and also as a function of the Cartesian zero point displacements from each atom’s average position. The polynomial approximation approach …

Cd Transport In Eutectic Licl-Kcl And Contamination Of Zr Metal And Thermal Dehydration Of Bulk Licl-Kcl, Nicholas Azoy Earle

Masters Theses

Researchers at Idaho National Labs have noted unexpectedly high Cd content in empty cladding hulls after processing in the Mark-IV ER. It has been theorized that Cd metal is transporting from the LCC pool through the eutectic LiCl-KCl salt bath to the anode baskets containing the empty hull where it is retained as a Zr-Cd intermetallic. This study sought to replicate the Cd contamination in a dry Ar glovebox using small-scale analogue of the Mark-IV ER salt-Cd metal system.

Anhydrous eutectic LiCl-KCl was an essential regent in this research and experiments were conducted to investigate the feasibility of dehydrating nominally …

Correlating Morphology To Performance In Conjugated Polymer Nanocomposite Thin Films, Siddharth Pradhan

Masters Theses

The morphology and performance of thin films that consist of conjugated polymers and nanoparticles are investigated in this thesis. In the first system, the morphology of the nanocomposite that consists of low band gap alternating copolymers with a methano-fullerene are determined by neutron scattering and correlated to their photovoltaic performance as polymer solar cells. These results show that the conjugated alternating copolymers have high miscibility relative to other conjugated polymers. The analysis of the scattering data shows that the morphology of the conjugated polymer-fullerene bulk heterojunction can be described as the formation of aggregates on two length scales. Important parameters …

Catalytic Methane Dissociative Chemisorption Over Pt(111): Surface Coverage Effects And Reaction Path Description, Inara Colon-Diaz

Masters Theses

Density functional theory calculations were performed to study the dissociative chemisorption of methane over Pt(111) with the idea of finding the minimum energy path for the reaction and its dependence on surface coverage. Two approaches were used to evaluate this problem; first, we used different sizes of supercells (2x2, 3x3, 4x4) in order to decrease surface coverage in the absence of pre-adsorbed H and CH₃ fragments to calculate the energy barriers of dissociation. The second approach uses a 4x4 unit cell and surface coverage is simulated by adding pre-absorbed H and CH₃ fragments. Results for both approaches show …

Theoretical And Spectroscopic Analysis Of Ch...Π Interactions Of Fluorinated Aromatic Systems, Anuradha Gayathri Akmeemana

Masters Theses

CH...π interactions are non-covalent interactions which occur in organic compounds that are important in biological and chemical sciences in many ways. Microwave spectroscopy is an important technique that can be used to detect CH...π interactions in the gas phase molecules. Previously microwave spectroscopic studies of complexes containing CH...π interactions, benzene...HCCH (Ulrich, N.W.; Seifert, N.A.; Dorris, R.E.; Peebles, R.A.; Pate, B.H.; Peebles, S.A., Phys. Chem. Chem. Phys. 2014, 16, 8886-8894) and fluorobenzene...HCCH (Ulrich, N.W.; Songer, T.S.; Peebles, R.A.; Peebles, S.A.; Seifert, N.A.; Perez, C.; Pate, B.H. Phys. Chem. Chem. Phys., 2013, 15, 18148-18154) were done at Eastern Illinois University and the …

Computational And Experimental Studies Of Non-Covalent Interactions: Characterization Of Ch...Π Interactions And Structure Of 1,1-Difluoroethylene...Carbon Dioxide, Ashley M. Anderton

Masters Theses

Weakly bound CH/π interactions, due to the abundance of C-H bonds and π systems that exist in larger organic molecules, are an important driving force in the construction of biomacromolecules, supramolecular assemblies and crystal packing of organic compounds. To assist in the characterization of CH/π interactions, a density functional theory (DFT) study has been conducted to determine a quick and cheap method for accurate determination of the binding energy and rotational constants for CH/π interactions. Seven complexes were used in this study: five benzene-HY complexes (where Y= C≡CH, Cl, F, Br and C≡N) and two fluorobenzene-HY complexes (where Y= C≡CH …

Time Dependent Density-Functional Theory - Linear Response, Bryan Edman Sundahl

Masters Theses

The formal derivation of the linear response of time-dependent density-functional theory as shown by E. K. U. Gross is presented. The transformation of formal theory to the working linear response equations in the form of Casida's eigenvalue equation is demonstrated, and the results are applied to small monatomic, diatomic and triatomic systems. The application of different operators to the perturbed density is discussed, with the most attention being given to the dynamic polarizabilities. The dynamic polarizabilities and excitation spectra for N₂ [nitrogen gas] are then analyzed. The first excitation energy is noted to be in line with Koopmans' theorem. …

Hindered Rotation Of Dihydrogen On Synthesized Metal Oxides, George Houston Rouvelas

Masters Theses

A MATLAB program was written to calculate the hindered rotational energies of the hydrogen and deuterium molecules interacting with an anisotropic potential, which may be thought of as a potential energy surface of a metal oxide substrate. It was found that an increase in the hindering potential of the rotation about the azimuthal angle lifted the degeneracy of the j = 1,mj [magnetic quantum number] = plus or minus 1 states. A better understanding of how the rotational states of these systems change as a function of the hindering potential can help to explain features in rotational inelastic neutron scattering …

Exploring Phenyl Embrace Interactions In Trityloxy And Tritylamino Aromatic Compounds, Premnath Basa

Masters Theses

The area of supramolecular chemistry seeks to understand the organization of molecular structures and the interactions that hold such assemblies together by non-covalent interactions such as electrostatic, hydrogen bonding, π-π stacking interactions, and hydrophobic or solvatophobic effects. One such example that comes under supramolecular chemistry is the phenyl embrace interaction. These interactions occur due to the cooperative participation of at least three or more neighboring phenyl groups arranged as an interlocking propeller configuration to give complementary edge-to-face or offset face-to-face interactions. In order to understand the effect of functional groups on the tendencies of organic compounds to form phenyl embrace …

Examination Of 4he Droplets And Droplets Containing Impurities At Zero Kelvin Using A Density Functional Approach, Ellen Brown

Masters Theses

Abstract

Detailed in this manuscript is a methodology to model ground state properties of ⁴He droplets at zero pressure and zero Kelvin using a density functional theory of liquid helium. The density functional approach examined here consists of two noted functionals from the literature and corresponding mean field definitions. A mean field and trial density are defined for each system and optimized to self-consistency using a matrix diagonalization technique. Initial calculations of planar slabs are performed and demonstrate reasonable agreement with experiment and with prior studies using density functional theory. Quantum properties of droplets and droplets containing atomic dopants …

A Time Resolved Laser Spectroscopy Study Of Resonance Energy Transfer Between Tb(Iii) And An Organic Dye: 6-Hydroxy-5-[(2-Methoxy-5-Methyl-4-Sulfophenyl)Azo]-2-Naphthalenesulfonic Acid Disodium Salt, Ronald Wesley Tennis

Masters Theses

Intermolecular energy transfer is a process of crucial importance to photochemistry and photophysics. Complexed lanthanide ions are well suited as energy transfer donors because they display dependable absorption and luminescence qualities with narrow rare-earthion emission in addition to relatively long excited-state lifetimes.

This project used a pulsed nitrogen laser and high speed digital techniques to study energy transfer dynamics between excited state Tb(acac)₃ and an ionic organic dye called Red 40. Luminescence decay profiles of excited terbium atoms in the presence of the quencher were measured in both high and low viscosity solvents. The effects of solvent viscosity and …

Thermodynamics Of Ion Association In Aqueous Fluoride Solutions. Determination Of Stability Constants For (Naf), (Mgf)+ And (Caf)+ Ion Pairs, Waldo Zamorano-Santander

Masters Theses

Stoichiometric ion-association constants were determined at several ionic strengths for (NaF) over the temperature range 15-40°C and for (MgF)⁺ and (CaF)⁺ over the temperature range 25-45°C using fluoride ion selective electrode measurements.

Thermodynamic association constants, K°, were obtained through extrapolation of the stoichiometric values to infinite dilution. Values of K° for (NaF) are 1.70, 2.16 and 2.54 at 15, 25 and 40°C, respectively. The K° values for (MgF)⁺ are 73.4, 88.0 and 98.2, and for (CaF)⁺ are 13.7, 17.5 and 21.9 at 25, 35 and 45°C., respectively.

The stoichiometric association constants for (NaF) can be reproduced …

The Intermolecular Force Field Of Acetylene-Hcl: The Normal Coordinate And Centrifugal Distortion Analysis Of Two Weakly Bound Rigid Rods, Rebecca S. Lee

Masters Theses

In order to determine the intermolecular force field of C₂H₂⋅⋅HCl, a normal coordinate analysis appropriate for two weakly bound rigid rods is developed. An exact centrifugal distortion analysis is then carried out on the microwave spectrum of this "T''-shaped hydrogen-bonded π complex. The distortion constants and published matrix-isolated vibrational frequencies are employed in the normal coordinate analysis to obtain the intermolecular force field and refinements in the structural parameters. The following van der Waals force field is found to reproduce the existing spectroscopic constants of C₂H₂⋅⋅H³⁵Cl … . This study …

A Laser Interferometric Study Of Electric Field Effects On Methane-Oxygen Flame Plasmas, Mark D. Prairie

Masters Theses

A laser interferometer is developed to study the refractive index field, aerodynamic structure, and three dimensional temperature profile of a methane-oxygen flame system under the influence of D.C. electric fields. A combined graphical-numerical method is used to transform the observed interference patterns into radial temperature distributions. The results indicate that the electric field exerts a marked influence on the flame stability, geometry, and charged particle flow. Experimental evidence shows that these effects are most apparent under fuel rich conditions. It is suggested an electric field may change the concentration gradients of reacting species, leading to an altered course of fuel …

Spectroscopic Studies Of Pre-Mixed Hydrocarbon Flame Plasmas, Tsao-Chin C. Huang

Masters Theses

This thesis contains two different studies.

Chapter 1, "Infrared Emission Spectrum of the Hydroxyl Radical.", is in collaboration with Dr. Giles L. Henderson and Mr. Chun-Sheng Ko. This chapter has been submitted and accepted for publication by the Journal of Chemical Education.

In this chapter, we describe a rather novel physical chemistry experiment in which ab initio potential parameters for the OH radical are compared with those obtained from the ir emission spectrum of an oxy-acetylene welding torch.

Chapter 2, "A Preliminary Spectroscopic Study of Field-Induced Ion Movements in Flame Gases.", describes the effects of longitudinal electric fields on CH …

Synthesis And Reactivity Of Some Fe(0) And Ru(0) Compounds, Michael E. Hawkins

Masters Theses

The catalytic activity of the compounds used in this study, Ru[P(C₆H₅)₃]₄ (η²-CH₃CN)⋅CH₃CN, Ru(CO)[P(C₆H₅)₃]₃CH₃CN, Ru(CO)₂[P(C₆H₅)₃]₃, Fe(CO)₂[P(C₆H₅)₃]₃ was compared using the isomerization of allylbenzene to β-methylstyrene as the test reaction. The measured decreasing order of reactivity for these complexes is: Ru(CO)[P(C₆H₅)₃]₃CH₃CN > Ru[P(C₆H₅)₃]₄ (η …

A Numerical Method For The Solution Of The Schrödinger Equation By A Trial Wavefunction Improvement Formula, Chun-Sheng Ko

Masters Theses

A numerical method and corresponding computer algorithm for solving the one-dimensional radial Schrödinger equation to any desired accuracy is developed. The method uses a finite difference scheme in which an initial trial wavefunction is digitalized over a lattice covering the region of integration. The values of a rough solution are then altered at each lattice point by a simple improvement formula decreasing the value of the variational energy until the desired minimum is reached. The accuracy of these solutions depends only on the grid size. This method is characterized and tested with a harmonic oscillator potential. Practical evaluations and applications …

Computer Investigation Of The Variation Of Conductivity With Concentration, Larry Macpeers Shadwick

Masters Theses

Computer programs were developed tor the conductance equations of R. M. Fuoss and L. Onsager as well as for the conductance equations of T. J. Murphy and E. G. D. Cohen. These programs were used to calculate values from selected conductance measurements. The resulting values were compared with values produced by other computer programs using the equations of Fuoss and Onsager as well as the equations of E. Pitts. The comparisons demonstrated the equations of Murphy and Cohen to be the equal of or superior to the other equations for the majority of cases. The equations of Pitta were superior …

The Conductance Of Some Polyvalent Electrolytes, Jack Lee Worthington

Masters Theses

A new compound, 1,3,5-triphenylbenzene-4' ,4",4"'-trisulfonic acid, was synthesized by treating triphenylbenzene in 1,2-dichloroethane with chlorosulfonic acid. The reaction appears to be quantitative. Conductance measurements were then made on the sodium, potassium, and lanthanum salts of this new acid and of 1,3,5-benzenetrisulfonic acid.

The choice of these acids was based on two factors: 1) the desire to prepare a 3-3 symmetrical unassociated electrolyte which would allow the determination of a more reliable equivalent ionic conductance value for La³⁺ and 2) an interest in using the Murphy-Cohen equation to determine solute parameters such as association constants if association is present.

Conductance …

The Mechanism Of The Reaction Of Lead(Iv) Acetate, Thallium(Iii) Acetate And Mercury(Ii) Acetate With Ketones, Su Hsiung Tsung

Masters Theses

No abstract provided.

The Conductance Of Some Non-Rigid Bolaform Electrolytes, William Terry Schmidt

Masters Theses

Bolaform electrolytes are those which contain two or more charges separated by an inert framework. These are intermediate in structure between simple electrolytes and polyelectrolytes. Since these are similar to both synthetic and biological electrolytes, this investigation has been undertaken to determine some of their properties in solution.

The sodium and magnesium salts of ethane, propane, butane, pentane, hexane and decane α,ω-disulfonates were prepared. Each acid was prepared by refluxing the α,ω-dibromide of the desired salt with sodium sulfite. The sodium and magnesium salts were prepared by ion-exchange techniques.

The conductance of each salt was determined in methanol utilizing the …

Equilibrium And Kinetic Study Of The Substitution Reactions Of Pentacarbonylaminetungsten (O) With Triphenylphosphine, William O. Bailey

Masters Theses

A kinetic and equilibrium study of the reaction of triphenylphosphine (PPh₃) with pentacarbonylaminetungsten (O) [(CO)₅WNH₂C₆H₅] has been reported previously. Equilibrium constants for the reaction (CO)₅WNH₂C₆H₅ + PPh₃ = (CO)₅W[P(C₆H₅)₃] + C₆H₅NH₂ in toluene were reported to be 17.1, 49.2 and 65.7 respectively. In addition, the entropy change (ΔS) for the reaction was found to be 86±5 cal mol^-1 deg^-1.

In this study the above reaction was …

The Vapor-Liquid And Liquid-Liquid Phase Equilibria For The Partially Miscible System Methanol-Cyclohexane, Richard A. Christman

Masters Theses

By use of techniques of previous workers for determining liquid-liquid equilibrium and through the use of a circulation still, the complete phase diagram for the partially miscible system, methanol-cyclohexane, was determined. Tile accuracy of earlier liquid-liquid phase data was not improved upon although it was closely approximated. The critical solution temperature was found to be 46.4 degrees C., which is within the range of temperatures reported in earlier measurements.

Activity coefficients of methanol and cyclohexane were calculated from the phase boundaries of the boiling point diagram determined in the present investigation. These activity coefficients were in agreement with the Gibbs-Duhem …