Chemistry Commons^™

Role Of Iron In The Mechanism Of Asbestos-Induced Apoptosis In Human Lung And Pleural Target Cells, Aleksander Baldys

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Occupational exposure to asbestos has been associated with increased incidence of pulmonary interstitial fibrosis, mesothelioma of the pleura, and bronchogenic carcinoma. Although the mechanism by which asbestos causes cancer remains unknown, iron associated with asbestos is thought to play a role in the pathogenic effects of fibers.

The aim of this research was to examine and compare the asbestos-induced signaling phenomena in relevant human lung and pleural target cells, and to determine the role of iron from asbestos fibers in these events. Exposure of human airway epithelial (A549) cells, human pleural mesothelial (MET5A) cells, and normal human small airway epithelial …

Comparison Between Hydrogen And Dihydrogen Bonds Among H3bnh3, H2bnh2, And Nh3, T. Kar, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Several possible binary complexes among ammonia-borane, aminoborane, and ammonia, via hydrogen and/or dihydrogen bonds, have been investigated to understand the effect of different hybridization. Møller–Plesset second-order perturbation theory with aug-cc-pVDZ basis set was used. The interaction energy is corrected for basis set superposition error, and the Morokuma–Kitaura method was employed to decompose the total interaction energy. Like H₃BNH₃, the sp² hybridized H₂BNH₂ also participates in H- and dihydrogen bond formation. However, such bonds are weaker than their sp³ analogs. The contractions of BN bonds are associated with blueshift in …

Electronic Structure And Bonding In Unligated And Ligated Feii Porphyrins, M.-S. Liao, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The electronic structure and bonding in a series of unligated and ligated Fe^II porphyrins (FeP) are investigated by density functional theory (DFT). All the unligated four-coordinate iron porphyrins have a ³A_2g ground state that arises from the (d_xy)²(d_z²)²(d_π)² configuration. The calculations confirm experimental results on Fe tetraphenylporphine but do not support the resonance Raman assignment of Fe octaethylporphine as ³E_g, nor the early assignment of Fe octamethyltetrabenzporphine as ⁵B_2g. For the six-coordinate Fe–P( …

Electronic Structure And Bonding In Metal Porphyrins, Metal=Fe, Co, Ni, Cu, Zn, M.-S. Liao, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

A systematic theoretical study of the electronic structure and bonding in metal meso-tetraphenyl porphines MTPP, M=Fe, Co, Ni, Cu, Zn has been carried out using a density functional theory method. The calculations provide a clear elucidation of the ground states for the MTPPs and for a series of [MTPP]^x ions (x = 2+, 1+, 1−, 2−, 3−, 4−), which aids in understanding a number of observed electronic properties. The calculation supports the experimental assignment of unligated FeTPP as ³A_2g, which arises from the configuration (d_xy)²(d_{z …}

PkA Determination Of Enzyme Bound Coenzyme M With Epoxyalkane: Com Transferase, Matthew Stephen Mciff

Undergraduate Honors Capstone Projects

Epoxide metabolism in the aerobic bacterium Xanthobacter strain Py2 proceeds by a coenzyme M (2-mercaptoethanesulfonic acid), NADPH, and NAD⁺ dependent carboxylation reaction that form beta keto acids as products. Epoxide carboxylase, the enzyme catalyzing this reaction, was resolved into four protein components that are required for functional reconstitiution of epoxide carboxylase activity. Component I, the first step in epoxide carboxylation, catalyzes the conversion of R and S-epoxypropane into Rand S-hydroxypropyl-coenzyme M respectively. This reaction consists of an epoxide ring opening, nucleophilic addition of coenzyme M, and oxygen reduction. Coenzyme M, a compound previously found only in the methanogenic Archaea, …

Electronic Structure And Bonding In Metal Phthalocyanines, Metal=Fe, Co, Ni, Cu, Zn, Mg, M.-S. Liao, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Electronic structure and bonding in metal phthalocyanines (Metal=Fe, Co, Ni, Cu, Zn, Mg) is investigated in detail using a density functional method. The metal atoms are strongly bound to the phthalocyanine ring in each case, by as much as 10 eV. The calculated orbital energy levels and relative total energies of these D_4h structures indicate that Fe and Co phthalocyanines have ³A_2g and ²E_g ground states, respectively, but that these states are changed upon interaction with strong-field axial ligands. The valence electronic structures of Fe and Co phthalocyanines differ significantly from those of …

Rotational Structure Of Extremely Floppy Van Der Waals Complexes: Adiabatic Separation Of Angular And Radial Motion, P. Daniel Ward

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The adiabatic or Born-Oppenheimer approximation is often used in molecular calculations to simplify the solution to the Schrödinger equation. The basis of the approximation is the large difference in the relative motions of the nuclei and electrons in the molecule—the electrons are able to respond almost instantly to the movements of the nuclei. Thus, the nuclei may be regarded as being fixed in a certain position and the Schrödinger equation can then be solved using the potential obtained by solving the electronic problem at fixed nuclear configuration.

A similar argument can be used to decouple the angular and radial motions …

Studies On The Roles Of Atp In Nitrogenase Catalysis, Wei Wu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nitrogenase is the enzyme that catalyzes the reduction of nitrogen to ammonia in a reaction requiring MgATP hydrolysis. Two component proteins of nitrogenase are the iron protein (Fe protein) and the molybdenum-iron protein (MoFe protein).

Nitrogenase contains two nucleotide binding sites. During catalysis, the Fe protein binds two MgATP first. The conformational changes induced upon MgATP binding allow the Fe protein to associate with the MoFe protein. After the formation of the Fe protein-MoFe protein complex, a single electron is transferred from the Fe protein to the MoFe protein, an event that is coupled to MgATP hydrolysis in the Fe …

The Role Of Iron And Reactive Oxygen Species In Particulate Air Pollution-Dependent Biochemical And Biological Activities, Kevin Richard Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Particulate air pollution is known to exacerbate respiratory diseases, such as asthma and chronic obstructive pulmonary disease, in humans. It has been proposed that transition meta ls from inhaled particles may play a role in this exacerbation by generating radical species leading to damage in the lungs.

The aim of this research was to determine the role that iron from particulate air pollution played in the generation of reactive oxygen species and subsequently the induction of inflammatory mediators in cells in culture. The production of reactive oxygen species by particulate air pollution was found to be dependent on the mobilization …

Comparison Of Methods For Calculating The Properties Of Intramolecular Hydrogen Bonds. Excited State Proton Transfer, T. Kar, Steve Scheiner, M. Cuma

Chemistry and Biochemistry Faculty Publications

A series of molecules related to malonaldehyde, containing an intramolecular H-bond, are used as the testbed for a variety of levels of ab initio calculation. Of particular interest are the excitation energies of the first set of valence excited states, nπ^∗ and ππ^∗, both singlet and triplet, as well as the energetics of proton transfer in each state. Taking coupled cluster results as a point of reference, configuration interaction-singles–second-order Møller–Plesset (CIS–MP2) excitation energies are too large, as are CIS to a lesser extent, although these approaches successfully reproduce the order of the various states. The …

Plant-Availability Fractionation Of Nickel For Bioremediation, Jason Henrie

Undergraduate Honors Capstone Projects

The bioremediation of contaminated soils or the biomining of waste tillings has been explored through the use of hyperaccumulating plants such as S. polygaloides which is a nickel hyperaccumulator. However, it is important to discover which soils are well-suited for this type of process by determining the plant-availability of the nickel. By extracting the nickel sequentially with increasing severity it is possible to determine the chemical distribution, or fractionation, of nickel in a soil. One fraction is already suspected to be plant-available and correlates very well with the results of a previous plant-availability study. A calcareous Millville silt loam which …

Site-Directed Mutagenesis Of The Nitrogenase Fe-Protein From Azotobacter Vinelandii, Talmage L. Shill

Undergraduate Honors Capstone Projects

Nitrogen fixation is the chemical reaction of dinitrogen (N₂) being reduced to ammonia (NH₃). This reaction occurs naturally by nitrogen fixing microorganisms which contain the enzyme nitrogenase. The overall reaction is written below.

Determination Of Intracellular Glutathione Concentration Using Monobromobimane, Ryan R. Owens

Undergraduate Honors Capstone Projects

Asbestos is a general term for a group of fibrous silicates. Diseases such as asbestosis, bronchogenic carcinoma, and mesothelioma have been linked to asbestos exposure (1,2). The 1 two classes of asbestos, serpentine and amphibole, are distinguished by differences in structure and chemical composition (3). The amphibole crocidolite contains 27% iron while the serpentine chrysotile contains only 2-3% iron. The higher iron content of crocidolite is proposed to be a contributing factor for a much higher incidence of cancer with crocidolite exposure compared with chrysotile exposure ( 4). Iron mobilized intracellularly from asbestos fibers may participate in the formation of …

Thermal Decomposition Of Cp*Re(Co)(No)No2, Kale Allen Swainston

Undergraduate Honors Capstone Projects

The focus of this work is to examine the thermal reactivity of the Cp*Re(CO)(NO)NO₂ complex. Upon heating with a flame, the orange crystals decompose very rapidly, with a darkening of color and gas production. To investigate this reaction, the decomposition was carefully controlled by heating with N2 gas, and in heated solution. The products obtained from the heated solution were purified using column chromatography, yielding two new interesting compounds, believed to be Cp*ReNO dimers with bridging oxygens.

Synthesis And Protection Of Nitrogen Containing Heterocycles, Timothy I. Elwell

Undergraduate Honors Capstone Projects

The pyrrolo[2,3-d] pyrimidine ring systems are present in a variety of antibacterial/anticancer compounds. A scarcity of natural sources has made necessary the need for researchers to find more efficient methodologies to synthesize such compounds.1 The Edstrom research group is currently exploring new routes to these compounds, varying the protecting groups and the precursors used to make them.

Thermodynamics And Kinetics Of Small Molecule Binding To [Cyclopentadienyl-Ru-No] And [Rh-Co] Electrophilic Centers, Anna Svetlanova

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This work is concentrated on the thermodynamic and kinetic aspects of water, alcohols, alkyl halides, ethers, and lactones bound and activated by the electrophilic [Cp'Ru(N0)]⁺² and [Cp’Ru (NO)(CH₃)] + centers (Cp' = cyclopentadienyl group). Counterions in these systems include OSO₂CF₃- (OTf`) and [(3, 5-(CF₃)₂C₆H₃)₄B]- ([BAr₄']-). The displacement of OTf- in Cp'Ru(N0) (0Tf)2 by H20 in dichloromethane is exothermic but entropically unfavorable due to the required reorganization of the solvent cage around released triflate ions. Thermodynamic parameters are also determined for OTf …

Characterization Of Ground And Excited Electronic State Deprotonation Energies Of Systems Containing Double Bonds Using Natural Bond Orbital Analysis, J. K. Badenhoop, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Natural bond orbital analysis is applied to the ground and excited states of a set of neutral, cationic, and anionic doubly bonded species H_nC=XH_n (X=C, N, O) isoelectronic with ethylene. The character of the excitation is correlated with calculated charge shifts and geometry changes upon relaxation. For these planar molecules, depopulation of the π bond or population of the π∗ antibond causes an out‐of‐plane twist or pyramidalization upon relaxation correlated to the amount of charge shift. These nonplanar distortions generally lower the energy more than changes in bond lengths and angles. Population of a σ_XH^{∗ …}

Iron-Dithiothreitol Dependent Production Of 8-Hydroxy-2'-Deoxyguanosine In Dna, David Allan Cook

Undergraduate Honors Capstone Projects

Oxidative damage to DNA in a metal-thiol system was studied. Calf thymus DNA was incubated in an iron(IIl)-dithiothreitol system prepared in various buffers. Damage was measured by monitoring the production of 8-hydroxy-2'-deoxyguanosine. DNA oxidation was proportional to the concentration of dithiothreitol (DTT) in HEPES and tris(hydroxymethyl)aminomethane (Tris) buffers while it was only roughly related to DTT concentration in sodium chloride. Incubation in potassium phosphate buffer produced no damage. The results indicate that hydroxyl radicals may be generated by the iron-OTT system in HEPES, Tris, and sodium chloride, while in the phosphate buffer an iron phosphate complex may be formed which …

Investigation Of New Methods For The Synthesis Of Pyrrolidines And The Generation Of Novel Heterocumulenes, Travis R. Taylor

Undergraduate Honors Capstone Projects

The following paper is a summary of the research completed from March to August of 1990. This research project proceeded through the guidance of Dr. Eric Edstrom incorporating a senior thesis in conjunction with the Honors Program.

Effect Of Iron Binding On The Ability Of Crocidolite To Cause Dna Single-Strand Breaks, Jeanne Ann Hardy

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Fibrous carcinogens, such as crocidolite asbestos, are known to catalyze many of the same reactions as iron, namely O₂ consumption, generation of reduced oxygen species, and damage to DNA, such as strand breaks, and modifications of bases. Upon inhalation, fibers are also known to become coated with an iron-rich material. The mechanism by which this iron is bound to fibers in the lung is not known, and the effect of this additional iron on the reactivity of the fibers is also not well understood. The studies described here were undertaken to elucidate the abilities of crocidolite asbestos, in its …

The Pharmacodynamics And Toxicodynamics Of Inotropic Drugs In Calves With Natural And Artificial Hearts, Scott D. Everett

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Inotropic support for the failing myocardium as the therapy for congestive heart failure (CHF) is intended to achieve an increase in cardiac output via positive responses in myocardial contractility and vasodilation. A novel approach to differentiate these two responses is the use of an animal with an implanted total artificial heart (TAH). Three inotropic drugs, dobutamine, enoximone, and pimobendan, were tested in eight animals with their natural heart intact and five animals implanted with a TAH. Baseline values of the TAH and natural heart (NH) were compared to determine their hemodynamic similarities. Each of the three drugs was given randomly …

Ab Initio Study Of He(1s)+Cl2(X 1Σg,3Πu) Potential Energy Surfaces, G. Chalasinski, M. Gutowski, M. M. Szczesniak, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The potential energy surface of the ground state He+Cl₂(¹Σ_g) is calculated by using the perturbation theory of intermolecular forces and supermolecular Møller–Plesset perturbation theory approach. The potential energy surface of the first excited triplet He+Cl₂(³Π_u) was evaluated using the supermolecular unrestricted Møller–Plesset perturbation theory approach. In the ground state two stable isomers are found which correspond to the linear He–Cl–Cl structure (a primary minimum, D_e=45.1 cm⁻¹, R_e=4.25 Å) and to the T‐shaped structure with He perpendicular to the molecular axis (a secondary …

Theoretical Study Of Hydrogen Bonding And Proton Transfer In The Ground And Lowest Excited Singlet States Of Tropolone, M. V. Vener, Steve Scheiner, N. D. Sokolov

Chemistry and Biochemistry Faculty Publications

Theoretical models of hydrogen bonding and proton transfer in the ground (S₀) and lowest excited ππ∗ singlet (S₁) states of tropolone are developed in terms of the localized OH...O fragment model and ab initio three‐dimensional potential energy surfaces (PESs). The PESs for proton transfer in the S₀ and S₁ states are calculated using ab initio SCF and CIS methods, respectively, with a 6–31G basis set which includes polarization functions on the atoms involved in the internal H bond. The Schrödinger equation for nuclear vibrations is solved numerically using adiabatic separation of the …

Proton‐Donor Properties Of Water And Ammonia In Van Der Waals Complexes. Be–H2o And Be–Nh3, G. Chalasinski, M. M. Szczesniak, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The potential energy surfaces (PES) of Be–H₂O and Be–NH₃ are studied with particular attention to characterization of proton‐donor properties of water and ammonia. Calculations were performed by means of both supermolecular and intermolecular Møller Plesset perturbation theory. The Be–H₂O PES reveals two van der Waals minima: the C_2v minimum (D_e=176 cm⁻¹, R_e=6.5 bohr), and the H‐bonded minimum (D_e=161 cm⁻¹, R_e=7.5 bohr), separated by a barrier of 43 cm⁻¹ at the T‐shaped configuration. The Be–NH₃ PES reveals only …

New Syntheses Of Diaryl Ethers, Tyrosinols, B-Hydroxytyrosinols, L,L-Isodityrosinol And L,L-Isodityrosine-Derived Agents Via The Diels-Alder Reaction, Xianqi Feng

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Syntheses of diaryl ethers were approached by use of a Diels-Alder reaction employing a new type of diene attached with an aryloxy group. Thus, 2-methyl-3-phenoxybutadiene (90b ), 2- methoxy-3-phenoxybutadiene (92b) and (4S)-3-(t- butyloxycarbony1)-2 ,2-dimethyl-4-( 4-(3-methoxy-1,3 -butadienyl-2- oxy )phenylmethyl]oxazolidine (93b) were synthesized in ~65% yields by methylenation of the carbonyl function in the corresponding 2- substituted acrylate aryl ester using Tebbe's reagent. The 1,3- bis[(trimethylsilyl)oxy ]-2-phenoxybutadiene (105) was made from 1-phenoxy-2-propanone (101) by a sequence of formylation and enolsilylation. Methyl propiolate (107) and dimethyl acetylenedicarboxylate (113) were heated at reflux with diene 9 0 b and 92b in toluene to provide …

Mobilization Of Iron Enhances The Iron-Dependent Biochemical Reactivity Of Asbestos In Vitro And Contributes To The Cytotoxicity Of Asbestos In Cultured Cells, Loren Glen Lund

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Asbestos related research began approximately 60 years ago, yet, the mechanism(s) by which asbestos exerts its biological effects is not well understood. The hypothesis upon which this dissertation is based is that mobilization of iron from asbestos enhances the iron-dependent biochemical reactivity of asbestos in vitro and contributes to asbestos-dependent cytotoxicity. The specific aims for this hypothesis were, 1) to determine whether iron was responsible for the biochemical reactivity of asbestos in vitro and asbestos-induced cytotoxicity in cultured cells, and 2) to determine whether mobilization of iron from asbestos enhanced the reactions catalyzed by asbestos in vitro and contributes to …

Calculation Of Barriers To Proton Transfer Using Variations Of Multiconfiguration Self‐Consistent‐Field Methods. Ii. Configuration Interaction, K. Luth, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Various means are tested of including additional electron correlation into multiconfiguration self‐consistent‐field (MCSCF) methods for computing proton transfer potentials in HF₂⁻, H₇N₂⁺, H₃O₂⁻, and H₅O₂⁺. Configuration interaction allowing single excitations (CIS) and configuration interaction with single + double excitations (CISD) calculations are performed following MCSCF expansion of the wave function using various different MCSCF reference wave functions. The CISD results are excellent, being fairly independent of choice of reference space although it is important that the occupied orbitals be balanced between the …

Calculation Of Barriers To Proton Transfer Using Multiconfiguration Self‐Consistent‐Field Methods. I. Effects Of Localization, K. Luth, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The usefulness of multiconfiguration self‐consistent‐field (MCSCF) calculations in computing correlated proton transfer potentials is investigated for the systems HF₂⁻, H₇N₂⁺, H₃O₂⁻, and H₅O₂⁺. In deciding whether to include particular molecular orbitals, it is important to consider the balance of electron density between the donor and acceptor groups and the interactions that are incorporated in the orbitals. Only orbitals which have the proper symmetry to interact with the transferring hydrogen need be included in the MCSCF active space. Reasonable transfer barriers are obtained …

Proton–Donor Properties Of Water And Ammonia In Van Der Waals Complexes With Rare‐Gas Atoms. Kr–H2o And Kr–Nh3, G. Chalasinski, M. M. Szczesniak, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The perturbation theory of intermolecular forces in conjunction with the supermolecular Møller–Plesset perturbation theory is applied to the analysis of the potential‐energy surfaces of Kr–H₂O and Kr–NH₃ complexes. The valleylike minimum region on the potential‐energy surface of Kr–H₂O ranges from the coplanar geometry with the C₂ axis of H₂O nearly perpendicular to the O–Kr axis (T structure) to the H‐bond structure in which Kr faces the H atom of H₂O. Compared to the previously studied Ar–H₂O [J. Chem. Phys. 94, 2807 (1991)] the minimum has more …

Theoretical Vibrational Study Of Fx...Nh3 (X=H, D, Li) Complexes, Y. Bouteiller, Z. Latajka, H. Ratajczak, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

This paper presents the first ab initio attempt to construct the stretching fundamentals ν_FX and ν_F...N (X=H, D, Li) in the FX...NH₃ complexes taking into account the mechanical anharmonicity. A potential‐energy surface V(r_FX,R_F...N) grid was generated at the self‐consistent‐field and second‐order Møller–Plesset levels. The coefficients fitting the potential‐energy surface up to the fourth order have been used to compute the ν_FX and ν_F...N stretching modes. The vibrational problem is solved by means of a variational treatment which includes the effects of mechanical …