Physical Chemistry Commons^™

Co2 Reduction Under Periodic Illumination Of Zns, Ruixin Zhou, Marcelo I. Guzman

Chemistry Faculty Publications

The photoreduction of CO₂ to formate (HCOO^–) in sphalerite (ZnS) aqueous suspensions is systematically studied in the presence of Na₂S hole scavenger. A series of cut-on filters at λ_cut-on ≥ 280, 295, 305, 320, and 400 nm are used to measure the reaction rate of formate production. The dependence of the measured reaction rates on λ_cut-on indicates that a wavelength of λ = 345 nm is associated with the actual bandgap of the semiconductor nanocrystallites suspended in water. The results from apparent quantum yield measurements during periodic illumination experiments suggest that (1) valence-band …

A Small Molecule That Binds And Inhibits The Etv1 Transcription Factor Oncoprotein, Marius C. Pop, Nicolas Stransky, Colin W. Garvie, Jean-Philippe Theurillat, Emily C. Hartman, Timothy A. Lewis, Cheng Zhong, Elizabeth K. Culyba, Fallon Lin, Douglas S. Daniels, Raymond Pagliarini, Lucienne Ronco, Angela N. Koehler, Levi A. Garraway

Chemistry Faculty Publications

Members of the ETS transcription factor family have been implicated in several cancers, where they are often dysregulated by genomic derangement. ETS variant 1 (ETV1) is an ETS factor gene that undergoes chromosomal translocation in prostate cancers and Ewing's sarcomas, amplification in melanomas, and lineage dysregulation in gastrointestinal stromal tumors. Pharmacologic perturbation of ETV1 would be appealing in these cancers; however, oncogenic transcription factors are often deemed “undruggable” by conventional methods. Here, we used small-molecule microarray (SMM) screens to identify and characterize drug-like compounds that modulate the biological function of ETV1. We identified the 1,3,5-triazine small molecule BRD32048 as a …

Science Classics, Mark Masthay

Chemistry Faculty Publications

An essay on the impact of the works in the Imprints and Impressions: Milestones in Human Progress, an exhibition of rare books from the collection of Stuart Rose. Exhibition was held Sept. 29-Nov. 9, 2014, at the University of Dayton.

Phosphate Esters, Thiophosphate Esters And Metal Thiophosphates As Lubricant Additives, David W. Johnson, John E. Hils

Chemistry Faculty Publications

Phosphate esters, thiophosphate esters and metal thiophosphates have been used as lubricant additives for over 50 years. While their use has been extensive, a detailed knowledge of how they work has been a much more recent development. In this paper, the use of phosphate esters and thiophosphate esters as anti-wear or extreme pressure additives is reviewed with an emphasis on their mechanism of action. The review includes the use of alkyl phosphates, triaryl phosphates and metal containing thiophosphate esters. The mechanisms of these materials interacting with a range of iron and steel based bearing material are examined.

Conversion Of Iodide To Hypoiodous Acid And Iodine In Aqueous Microdroplets Exposed To Ozone, Elizabeth A. Pillar, Marcelo I. Guzman, Jose M. Rodriguez

Chemistry Faculty Publications

Halides are incorporated into aerosol sea spray, where they start the catalytic destruction of ozone (O₃) over the oceans and affect the global troposphere. Two intriguing environmental problems undergoing continuous research are (1) to understand how reactive gas phase molecular halogens are directly produced from inorganic halides exposed to O₃ and (2) to constrain the environmental factors that control this interfacial process. This paper presents a laboratory study of the reaction of O₃ at variable iodide (I^–) concentration (0.010–100 μM) for solutions aerosolized at 25 °C, which reveal remarkable differences in the reaction intermediates …

Structure, Theoretical Studies And Coupling Reactions Of Some New Cyclic Boronic Esters, Andrew Kuttler, Sravanthi Durganala, Albert Fratini, Alexander Morgan, Vladimir Benin

Chemistry Faculty Publications

The present report describes the X-ray structural and theoretical studies of some new pinacolboronate esters, and it also outlines the use of the target structures in Suzuki coupling reactions to produce new aromatic or heteroaromatic esters and amides. X-ray structural analysis of the studied compounds revealed that the pinacolborane ring's position with respect to the benzene ring varies, depending on the particular environment. An ortho-positioned carboxylic ester (methyl ester) causes a nearly perpendicular orientation of the pinacolborane unit with respect to the benzene ring, whereas an ortho-positioned amide (N,N-dimethylamide) causes the pinacolborane unit to orient itself nearly coplanar. A plausible …

Characterization By Nmr Of Reactants And Products Of Hydrofluoroether Isomers, Cf3(Cf2)3och3 And (Cf3)2c(F)Cf2och3, Reacting With Isopropyl Alcohol, Howard Knachel, Vladimir Benin, William E. Moddeman, Janine C. Birkbeck, Thomas A. Kestner, Tayna L. Young

Chemistry Faculty Publications

The 3M Company product Novec™ 71IPA DL, a mixture of methoxyperfluorobutane, methoxyperfluoroisobutane and 4.5 wt.% isopropyl alcohol, has been found to be very stable at ambient temperature, producing fluoride at the rate of ~1 ppm/year. Our earlier kinetic and theoretical studies have identified the reaction mechanism. This paper identifies the ¹H and ¹⁹F NMR chemical shifts, multiplicities, and coupling constants of reactants and the major products that result from aging the mixture in sealed Pyrex NMR tubes for periods up to 1.8 years at temperatures from 26 °C to 102 °C. Chemical shifts and coupling constants of fluorine …

Interaction Between Lubricants Containing Phosphate Ester Additives And Stainless Steels, David W. Johnson, Matthew Bachus, John E. Hils

Chemistry Faculty Publications

One way to improve fuel efficiency in today’s jet aircraft engines is to create an environment for higher operating temperatures and speeds. New and improved lubricants and bearing materials must be developed to remain stable in these elevated operating temperatures. Three lubricants, with varying amounts of tricresyl phosphate added as an anti-wear/extreme pressure additive were tested on two different stainless steels at varying temperatures ranging from 300 °C to 350 °C in vacuum. Significant decomposition of the lubricant base-stocks and the phosphate ester additive did occur in most of the trials resulting in the formation of carboxylic acids and phenols. …

Patent: Dual Function Proteins For Treating Metabolic Disorders, Brian R. Boettcher, Shari L. Caplan, Susan E. Cellitti, Douglas S. Daniels, Norio Hamamatsu, Bernhard Hubert Geierstanger, Stuart Licht, Andreas Loew, Stephen Craig Weldon

Chemistry Faculty Publications

The present invention relates to new proteins comprising fibroblast growth factor 2 1 (FGF21 ) and other metabolic regulators known to improve metabolic profiles in subjects to whom they are administered.

Patent: Fusion Proteins For Treating Metabolic Disorders, Brian R. Boettcher, Shari L. Caplan, Douglas S. Daniels, Norio Hamamatsu, Stuart Licht, Stephen Craig Weldon

Chemistry Faculty Publications

The invention relates to the identification of fusion proteins comprising polypeptide and protein variants of fibroblast growth factor 21 (FGF21) with improved pharmaceutical properties. Also disclosed are methods for treating FGF21 associated disorders, including metabolic conditions.

Metastable Nanostructured Metallized Fluoropolymer Composites For Energetics, Hannah A. Miller, Bradley S. Kusel, Seth T. Danielson, James W. Neat, Eryn K. Avjian, Scott N. Pierson, Stephen M. Budy, David W. Ball, Scott T. Iacono, Sharon C. Kettwich

Chemistry Faculty Publications

Fluoropolymers have long served as potent oxidizers for metal-based pyrolant designs for the preparation of energetic materials. Commercial perfluoropolyethers (PFPEs), specifically known as Fomblins®, are well-known to undergo accelerated thermal degradation in the presence of native metals and Lewis acids producing energetically favorable metal fluoride species. This study employs the use of PFPEs to coat nano-aluminum (n-Al) and under optimized stoichiometric formulations, harness optimized energy output. The PFPEs serve as ideal oxidizers of n-Al because they are non-volatile, viscous liquids that coat the particles thereby maximizing surface interactions. The n-Al/PFPE blended combination is required to interface with an epoxy-based matrix …

Preparation Of Phosphonoterephthalic Acids Via Palladium-Catalyzed Coupling Of Aromatic Iodoesters, Nathaniel Ivan, Vladimir Benin, Alexander Morgan

Chemistry Faculty Publications

The current article reports in detail the preparation of two phosphonoterephthalic acids: 2-phosphonoterephthalic acid (1) and 2,5-diphosphonoterephthalic acid (2). Efficient, scalable syntheses have been developed for both compounds based on Pd-catalyzed coupling reactions of iodinated terephthalate esters. Phosphonoterephthalic acids are potentially useful as flame-retardant additives or as monomers for the construction of acid-pendant polymer chains.

Reaction Between Polyol-Esters And Phosphate Esters In The Presence Of Metal Carbides, David W. Johnson, Carolyn Iacullo, John E. Hils

Chemistry Faculty Publications

The reaction of metal carbides with polyol esters found in aerospace lubricants and phosphate esters commonly used as additives was investigated. Carbides were of particular interest since modern materials under consideration at high temperature bearings have surfaces that are primarily metal carbides. Vanadium and chromium carbide were found to react with the ester and phosphate ester by a transesterification reaction, producing an alkyl phosphate which is less stable than the aromatic phosphate esters. In the process, the metal carbide is converted to the metal phosphate and metal polyphosphate, evidenced by the infrared and Raman spectra of the solid residue and …

Organics In Environmental Ices: Sources, Chemistry, And Impacts, V. F. Mcneill, A. M. Grannas, J. P. D. Abbatt, M. Ammann, P. Ariya, T. Bartels-Rausch, F. Domine, D. J. Donaldson, Marcelo I. Guzman, D. Heger, T. F. Kahan, P. Klán, S. Masclin, C. Toubin, D. Voisin

Chemistry Faculty Publications

The physical, chemical, and biological processes involving organics in ice in the environment impact a number of atmospheric and biogeochemical cycles. Organic material in snow or ice may be biological in origin, deposited from aerosols or atmospheric gases, or formed chemically in situ. In this manuscript, we review the current state of knowledge regarding the sources, properties, and chemistry of organic materials in environmental ices. Several outstanding questions remain to be resolved and fundamental data gathered before an accurate model of transformations and transport of organic species in the cryosphere will be possible. For example, more information is needed regarding …

Reactions Of Methyl Perfluoroalkyl Ethers With Isopropyl Alcohol: Experimental And Theoretical Studies, Howard Knachel, Vladimir Benin, Chadwick Barklay, Janine C. Birkbeck, Billy D. Faubion, William E. Moddeman

Chemistry Faculty Publications

The reaction of an isomeric mixture of the methyl perfluoroalkyl ether, C4F9OCH3 (Novec-7100), in the presence of isopropyl alcohol (IPA) and/or water has been studied by measuring the rate of product formation using an ion-selective electrode (ISE) for fluoride ion, Karl Fisher coulometric titrations for water, and 1H and 19F NMR spectroscopy for product identification and rate studies. The results showed the methyl perfluoroalkyl ether to be very stable with products forming at the rate of ∼1 ppm per year at a laboratory temperature of 20 °C. Measurements over the temperature range of 6° to 100 °C were made on …

Concentration Effects And Ion Properties Controlling The Fractionation Of Halides During Aerosol Formation, Marcelo I. Guzman, Richa R. Athalye, Jose M. Rodriguez

Chemistry Faculty Publications

During the aerosolization process at the sea surface, halides are incorporated into aerosol droplets, where they may play an important role in tropospheric ozone chemistry. Although this process may significantly contribute to the formation of reactive gas phase molecular halogens, little is known about the environmental factors that control how halides selectively accumulate at the air-water interface. In this study, the production of sea spray aerosol is simulated using electrospray ionization (ESI) of 100 nM equimolar solutions of NaCl, NaBr, NaI, NaNO(2), NaNO(3), NaClO(4), and NaIO(4). The microdroplets generated are analyzed by mass spectrometry to study the comparative enrichment of …

Maxwell's Equations, Part Vii, David W. Ball

Chemistry Faculty Publications

This is the seventh (and perhaps last) installment of a series of columns on Maxwell’s equations of electrodynamics. In previous columns (available at Spectroscopy’s website, www.spectroscopyonline.com/The+Baseline+Column), we have covered history, the background of the first three equations, and the mathematics underlying them. Here we will present the fourth equation, and after reaching it we’ll see how light is described in terms of these four mathematical expressions.

Patent: Methods Of Treating Fgf21-Associated Disorders, Brian R. Boettcher, Shari L. Caplan, Douglas S. Daniels, Bernhard Hubert Geierstanger, Norio Hamamatsu, Stuart Licht, Andreas Loew, Stephen Craig Weldon

Chemistry Faculty Publications

The invention relates to the identification of new polypeptide and protein variants of fibroblast growth factor 21 (FGF21) that have improved pharmaceutical properties. Also disclosed are methods for treating FGF21-associated disorders, includ ing metabolic conditions.

Introducing Nob-Nobs: Nitrogen-Oxygen-Boron Cycles With Potential High-Energy Properties, Aloysus K. Lawong, David W. Ball

Chemistry Faculty Publications

As a follow-up on a study of a family of boron-oxygen-nitrogen compounds composed of two datively bonded B–O–N backbones, we investigate a similar series of compounds that have similar fragments but are covalently bonded. B3LYP/6-31G(d,p) quantum mechanical calculations have been performed to determine the minimum-energy geometries, vibrational frequencies, and thermochemical properties of the parent compound and a series of nitro-substituted derivatives. Our results indicate that some of the derivatives have at least appropriate thermodynamics for possible high-energy materials, in some cases being favorable over similar dimeric compounds with coordinate covalent B–N bonds

Bon-Bons: Cyclic Molecules With A Boron-Oxygen-Nitrogen Backbone. Computational Studies Of Their Thermodynamic Properties, Aloysus K. Lawong, David W. Ball

Chemistry Faculty Publications

Although they were first reported in 1963, molecules with a boron-oxygen-nitrogen dimeric backbone do not seem to have been investigated seriously in terms of thermodynamic properties. Here we report on the calculated structures and properties, including thermodynamics, of several so-called “BON-BON” molecules. With the popularity of nitrogen-containing substituents on new high-energy materials, nitro-substituted BON-BONs were a focus of our investigation. A total of 42 BON-BON molecules were evaluated, and thermochemical analysis shows a decrease in the specific enthalpy of combustion or decomposition with increasing NO₂ content, consistent with other systems.

Water Diffusion In And Out Of The Β-Barrel Of Gfp And The Fast Maturing Fluorescent Protein, Turbogfp, Marc Zimmer, Binsen Li, Ramza Shahid, Paola Peshkepija

Chemistry Faculty Publications

The chromophore of fluorescent proteins is formed by an internal cyclization of the tripeptide 65SYG67 fragment and a subsequent oxidation. The oxidation is slow – the kinetics of this step is presumably improved in fast maturing GFPs. Water molecules can aid in the chromophore formation. We have used 50ns molecular dynamics simulations of the mature and immature forms of avGFP and TurboGFP to examine the diffusion of water molecules in-and-out of the protein β-barrel. Most crystal structures of GFPs have well-structured waters within hydrogen-bonding distance of Glu222 and Arg96. It has been proposed that they have an important role in …

Maxwell's Equations, Part V, David W. Ball

Chemistry Faculty Publications

This is the fifth installment in a series devoted to explaining Maxwell’s equations, the four mathematical statements upon which the classical theory of electromagnetic fields – and light – is based. Previous installments can be found on Spectroscopy’s website (whose URL can be found throughout these issues). Maxwell’s equations are expressed in the language of vector calculus, so a significant part of some previous columns have been devoted to explaining vector calculus, not spectroscopy. For better or worse, that’s par for the course, and it’s my job to explain it well – I trust readers will let me know if …

Synthesis And Flame Retardant Testing Of New Boronated And Phosphonated Aromatic Compounds, Vladimir Benin, Sravanthi Durganala, Alexander Morgan

Chemistry Faculty Publications

The present report describes the preparation and use of some dimethyl terephthalate derivatives in transition metal-catalyzed coupling reactions to produce new reactive flame retardants. Dimethyl iodoterephthalate and dimethyl 2,5-diiodoterephthalate were successfully employed in the preparation of phosphonic and boronic esters and acids. The latter were tested for heat release with a microcombustion calorimeter (ASTM D7309) to determine the potential for heat release reduction of these flame retardant molecules. The results showed that the addition of boronic or phosphonic acids greatly lowered the heat release, due to a condensed phase (char formation) mechanism. Adding ester groups to the boronic acids or …

Maxwell's Equations, Part Iv, David W. Ball

Chemistry Faculty Publications

In this column, we continue our explanation of Maxwell’s equations, the seminal classical explanation of electricity and magnetism (and, ultimately, light). For those of you new to the series, consider finding the last few appearances of this column to get caught up. Alternately, you should be able to find past columns on our website, www.spectroscopymag.com and look for “The Baseline” link. Words of warning: for my own reasons, the figures are being numbered sequentially through this series of columns, which is why the first figure in this column is numbered 26. Also, we’re going to get a bit mathematical. Unfortunately …

The Tetrafluoroborate Salt Of 4-Methoxybenzyl N-2-(Dimethylamino)Ethyl-N-Nitrosocarbamate: Synthesis, Crystal Structure And Dft Calculations, Helene Hedian, Vladimir Benin

Chemistry Faculty Publications

The tetrafluoroborate salt of 4-methoxybenzyl N-2-(dimethylamino)ethyl-N-nitrosocarbamate was prepared in two steps, via the corresponding carbamate. Its crystal structure is monoclinic, space group P21/c. The unit cell dimensions are: a = 19.499(8) Å, b = 5.877(3) Å, c = 15.757(7) Å, α = 90°, β = 110.019(7)°, γ = 90°, V = 1696.5(12) Å3, Z = 4. The structure exhibits an unexpected, pseudo-gauche conformation with respect to the C2–C3 bond, due to a stabilizing hydrogen bond between the carbonyl oxygen (O1) and the hydrogen atom at the trialkylammonium center (H3n), with a distance between them of …

Application Of Raman Spectroscopy To Lubricants, Lubricated Surfaces And Lubrication Phenomena, David W. Johnson

Chemistry Faculty Publications

Recent advances in lasers and detector technologies and the development of low-cost instruments and fiber-optic probes have brought about an explosion in the lubrication systems being studied by Raman spectroscopy. This article provides examples of the use of Raman spectroscopy in the study of lubrication phenomena, including the characterization of liquid lubricants, lubricant additives, and solid lubricants; the study of vapor-phase lubrication; and the use of coated nanoparticles as lubricants.

Maxwell's Equations, Part Ii, David W. Ball

Chemistry Faculty Publications

This is the second part of a multi-part production on Maxwell’s equations of electromagnetism. The ultimate goal is a definitive explanation of these four equations; readers will be left to judge how definitive it is. A note: for certain reasons, figures are being numbered sequentially throughout this series, which is why the first figure in this column is numbered 8. I hope this does not cause confusion. Another note: this is going to get a bit mathematical. It can’t be helped: models of the physical universe, like Newton’s second law F = ma, are based in math. So are Maxwell’s …

Maxwell's Equations, Part I: History, David W. Ball

Chemistry Faculty Publications

Maxwell’s equations for electromagnetism are the fundamental understanding of how light behaves. There are various versions, depending on whether there is vacuum, a charge present, matter present, the system is relativistic or quantum, or are written in terms of differential or integral calculus. Here, I inaugurate a multi-part series on a discussion of each of Maxwell’s equations. The goal is for this series to become the definitive explanation of these rules (I know, a heady goal!). I trust readers will let me know if I succeed. In this first installment, we will discuss a little bit of historical development as …

A Sodium Salt Of The Dimer Of Boronoterephthalic Acid Anhydride, Scott Simmons, Albert Fratini, Vladimir Benin

Chemistry Faculty Publications

The title compound, sodium bis­(6-carb­oxy-1-hy­droxy-3-oxo-1,3-dihydro-2,1-benzoxaborol-1-yl)oxidanium, Na+·C16H15B2O13-, was prepared in two steps from 2-bromo-p-xylene. Its crystal structure was determined at 140 K and has triclinic (P) symmetry. The compound presents a unique structural motif, including two units of the cyclic anhydride of boronoterephthalic acid, joined by a protonated, and thereby trivalent, oxonium center. Association in the crystal is realized by complementary hydrogen bonding of the carboxyl groups, as well as by coordination of the sodium cations to the oxygen centers on the five-membered rings.

Theoretical Investigation Of A Reported Antibiotic From The 'Miracle Tree' Moringa Oleifera, Michael Horwath, Vladimir Benin

Chemistry Faculty Publications

Moringa oleifera, sometimes called the “Miracle Tree,” has received international attention for its potential to improve health in impoverished tropical areas. In addition to high vitamin content in the leaves and pods, the tree contains compounds with antioxidant and antibacterial properties. This study focused on the theoretical investigation of the suggested structure of one antibacterial compound, “pterygospermin,” whose existence was proposed after some studies of the roots of M. oleifera. The structure of pterygospermin was first proposed by a research group working in the 1950s, but later studies have not found evidence of this compound and have instead …