Diffusion And Random Walks,
2011
Denison University
Diffusion And Random Walks, Lewis Ludwig, Annabel Edwards
Faculty Publications
No abstract provided.
Reactivity Studies Of Cyclopentadienyl Complexes Of Group 6 Metals With Arylsulfides, Organo P-S And P-Se Heterocycles And Arylthiolate Phosphine Ligands.,
2011
Universiti Malaya
Reactivity Studies Of Cyclopentadienyl Complexes Of Group 6 Metals With Arylsulfides, Organo P-S And P-Se Heterocycles And Arylthiolate Phosphine Ligands., Ooi Mei Lee
Student Works (2010-2019)
The reactivity of [CpM(CO)3]2 (M = Cr (1), Mo (3)) together with their congeners, [CpM(CO)2]2 (M = Cr (2), Mo (4)) towards alkyl sulfides such as bibenzyl di- and trisulfide, organophosphorus chalcogen heterocycles such as 2,4-bis(ptolylthio) 1,3-dithia-2,4-diphosphetane-2,4-disulfide (Davy’s reagent), 1,3,2,4- dithiadiphosphetane 2,4-diselenides (Woollins’ Reagent) and thioarylphosphines have been investigated. Reactions that occurred under mild conditions for 1 was found to proceed via the highly reactive monomer radical, CpCr(CO)3·. However, the reactions with 2 and 4 required more forcing conditions at elevated temperature. Forty metal complexes were synthesized and characterized in this work. All the products were elucidated via IR, 1H, …
Vibrationally Promoted Electron Emission At A Metal Surface: Electron Kinetic Energy Distributions,
2010
Chapman University
Vibrationally Promoted Electron Emission At A Metal Surface: Electron Kinetic Energy Distributions, Jerry L. Larue, Tim Schäfer, Daniel Matsiev, Luis Velarde, N. Hendrick Nahler, Daniel J. Auerbach, Alec M. Wodtke
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
We report the first direct measurement of the kinetic energy of exoelectrons produced by collisions of vibrationally excited molecules with a low work function metal surface exhibiting electron excitations of 64% (most probable) and 95% (maximum) of the initial vibrational energy. This remarkable efficiency for vibrational-to-electronic energy transfer is in good agreement with previous results suggesting the coupling of multiple vibrational quanta to a single electron.
Site-Specific Photocatalytic Splitting Of Methanol On Tio2(110),
2010
Dalian Institute of Chemical Physics
Site-Specific Photocatalytic Splitting Of Methanol On Tio2(110), Chuanyao Zhou, Zefeng Ren, Shijing Tan, Zhibo Ma, Xinchun Mao, Dongxu Dai, Hongjun Fan, Xueming Yang, Jerry L. Larue, Russell Cooper, Alec M. Wodtke, Zhou Wang, Zhenyu Li, Bing Wang, Jinlong Yang, Jianguo Hou
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Clean hydrogen production is highly desirable for future energy needs, making the understanding of molecular-level phenomena underlying photocatalytic hydrogen production both fundamentally and practically important. Water splitting on pure TiO2 is inefficient, however, adding sacrificial methanol could significantly enhance the photocatalyzed H2 production. Therefore, understanding the photochemistry of methanol on TiO2 at the molecular level could provide important insights to its photocatalytic activity. Here, we report the first clear evidence of photocatalyzed splitting of methanol on TiO2 derived from time-dependent two-photon photoemission (TD-2PPE) results in combination with scanning tunneling microscopy (STM). STM tip induced molecular manipulation …
A Surface Femtosecond Two-Photon Photoemission Spectrometer For Excited Electron Dynamics And Time-Dependent Photochemical Kinetics,
2010
Dalian Institute of Chemical Physics
A Surface Femtosecond Two-Photon Photoemission Spectrometer For Excited Electron Dynamics And Time-Dependent Photochemical Kinetics, Zefeng Ren, Chuanyao Zhou, Zhibo Ma, Chun-Lei Xhao, Xinchun Mao, Dongxu Dai, Jerry L. Larue, Russell Cooper, Alec M. Wodtke, Xueming Yang
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
A surface femtosecond two-photon photoemission (2PPE) spectrometer devoted to the study of ultrafast excited electron dynamics and photochemical kinetics on metal and metal oxide surfaces has been constructed. Low energy photoelectrons are measured using a hemispheri- cal electron energy analyzer with an imaging detector that allows us to detect the energy and the angular distributions of the photoelectrons simultaneously. A Mach-Zehnder interferom- eter was built for the time-resolved 2PPE (TR-2PPE) measurement to study ultrafast surface excited electron dynamics, which was demonstrated on the Cu(111) surface. A scheme for measuring time-dependent 2PPE (TD-2PPE) spectra has also been developed for studies of …
The Development Of An Effective Water-Soluble Receptor For Pyrene Derivative Dyes,
2010
Lynchburg College
The Development Of An Effective Water-Soluble Receptor For Pyrene Derivative Dyes, Ashley Longstreet
Undergraduate Theses and Capstone Projects
A receptor with enhanced water solubility was synthesized from an existing receptor to be used as a pyranine fluorescence quencher in endovesiculation detection assays. The existing receptor consisted of a cyclen core with four protruding arms containing an aryl nitro group at each end. Its poor water solubility limited the accuracy and precision of the endovesiculation assay because the low concentration of receptor did not match the concentration of pyranine. To increase the water solubility, ethoxy groups were attached to the ends of each arm by first selectively reducing the nitro group to an amine with NaBHU4, H2, and a …
Transition States In Ei Reactions,
2010
University of Nebraska-Lincoln
Transition States In Ei Reactions, Charles A. Kingsbury
Department of Chemistry: Faculty Publications
The pyrolysis of amine oxides, sulfoxides, selenoxides, and esters to form alkenes is believed to be a concerted reaction with a cyclic transition state. Phosphine oxides, sulfones, and nitro compounds are unreactive. This study seeks to identify reasons for the lack of reactivity of the latter. Transition states were located for all substrates progressing from RHF/3-21G* to the MP2/6-31+G(d,p) level (in certain cases). For sulfones and nitro compounds, two possible reasons for lack of reactivity were considered: (1) Atoms approaching one another in the transition state may be considered to participate in a local nO→σ*CH …
Process For Preparation Of Conducting Polymers,
2010
Lincoln, NE
Process For Preparation Of Conducting Polymers, Reuben D. Rieke
Department of Chemistry: Faculty Publications
Methods of preparing conducting polymers and the conductive polymers prepared therefrom are provided. The method includes a) combining a monomer-metal complex together with a manganese (II) halide to provide a monomer-manga nese complex, and b) combining the monomer-manganese complex together with a metal catalyst to provide the conductive polymer. Electronic devices can be made using the polymers prepared as described herein.
Self-Assembled Heteroleptic
Chiral Ligands, Asymmetric
Catalyst Systems And Methods,
2010
Lincoln, NE
Self-Assembled Heteroleptic Chiral Ligands, Asymmetric Catalyst Systems And Methods, James M. Takacs
Department of Chemistry: Faculty Publications
A method of synthesizing a heteroleptic, multiple metal containing metallocyclic catalyst, particularly Suited for asymmetric catalysis, comprising combining a plurality of plural functional group-containing, monodentate ligands of complementary chirality, said plural functional groups being tethered to each other by tethers in the presence of a scaffold structural metal Ms or derivative thereof, wherein at least one functional group on each ligand combines to ligate M to form a bidentate, Ms centered ligand scaffold containing the remaining functional groups and combining said bidentate ligand scaffold with a catalytic metal Mc or derivative thereof whereby the remaining functional groups combine …
Corrosion Of Steel
Shipwreck In The
Marine Environment:
Uss Arizona—Part 1,
2010
National Park Service
Corrosion Of Steel Shipwreck In The Marine Environment: Uss Arizona—Part 1, Donald L. Johnson, Brent M. Wilson, James D. Carr, Matthew A. Russell, Larry E. Murphy, David L. Conlin
Department of Chemistry: Faculty Publications
The USS Arizona has remained submerged in Pearl Harbor, Hawaii, since the Japanese attack on December 7, 1941. The ship presents a potential hazard from fuel oil still present in the ship’s hull. As an important factor in management decisions, the effect of corrosion after nearly 65 years is being studied to determine the integrity of the ship’s structure. Coupon samples from the hull revealed decreasing corrosion rates from ~1 to 3 mpy (0.03 to 0.08 mm/y) from just below the water surface to the mudline. This is about one-third of that expected in the absence of biofouling or concretion. …
The Antioxidant Properties Of Whey Permeate Treated Fresh-Cut Tomatoes,
2010
Technological University Dublin
The Antioxidant Properties Of Whey Permeate Treated Fresh-Cut Tomatoes, Lubna Ahmed, Ana Belen Martin-Diana, Daniel Rico, Catherine Barry-Ryan
Articles
The aim of this research was to analyse the effects of three types of cheese whey permeate treatment on the antioxidant properties of fresh-cut tomatoes. Tomatoes were treated with whey permeate concentrate (PC), delactosed permeate (DP) and delactosed concentrate (DC), stored at 4 C for 10 days and compared to samples treated with the industry standard, chlorine (120 ppm). Samples treated with DP retained significantly higher antioxidant activity (FRAP) and total phenols (TP), when compared with those treated with PC and DC. DP showed significantly higher results than chlorine for DPPH, FRAP and TP. In DPPH assay, all whey permeate-treated …
Tuning Σ-Holes: Charge Redistribution In The Heavy (Group 14) Analogues Of Simple And Mixed Halomethanes Can Impose Strong Propensities For Halogen Bonding,
2010
University of Richmond
Tuning Σ-Holes: Charge Redistribution In The Heavy (Group 14) Analogues Of Simple And Mixed Halomethanes Can Impose Strong Propensities For Halogen Bonding, Kelling J. Donald, Bernard K. Wittmaack, Chad Crigger
Chemistry Faculty Publications
Halogen bonding between halide sites (in substituted organic molecules or inorganic halides) and Lewis bases is a rapidly progressing area of exploration. Investigations of this phenomenon have improved our understanding of weak intermolecular interactions and suggested new possibilities in supramolecular chemistry and crystal engineering. The capacity for halogen bonding is investigated at the MP2(full) level of theory for 100 compounds, including all 80 MH4-nXn systems (M = C, Si, Ge, Sn, and Pb; X = F, Cl, Br, and I). The charge redistribution in these molecules and the (in)stability of the σ-hole at X as …
Supramolecular Self-Assembly Strategies Involving Water Soluble Calixarenes.,
2010
Universiti Malaya
Supramolecular Self-Assembly Strategies Involving Water Soluble Calixarenes., Irene Ling
Student Works (2010-2019)
Fundamental investigations of host-guest interactions on the supramolecular self-assembly involving water-soluble p-sulfonatocalix[4]arene, with a series of imidazolium-based cations and pyrrolidinium cation with variable alkyl chain lengths, which featured extensively in ionic liquids have been established. Combinatorial studies incorporating multiple components concerning p-sulfonatocalix[4]arene, imidazolium cations or pyrrolidinium cation, phosphonium cations and lanthanide ions have been developed, which yielded diverse solid state motifs with a common structural characteristic that the imidazolium or pyrrolidinium cation resides in the cavity of the calixarene. Shorter terminal alkyl chain of mono-imidazolium molecules, i.e. n-ethyl and n-butyl imidazoliums are confined in the „molecular capsule‟, being encapsulated by …
Improved Arene Fluorination Methodology For I(Iii) Salts,
2010
University of Nebraska-Lincoln
Improved Arene Fluorination Methodology For I(Iii) Salts, Bijia Wang, Linlin Qin, Kiel D. Neumann, Shriharsha Uppaluri, Ronald Cerny, Stephen G. Dimagno
Ronald Cerny Publications
The use of low polarity aromatic solvents (benzene or toluene) and/or the removal of inorganic salts results in dramatically improved yields of fluorinated arenes from diaryliodonium salts. This methodology is shown to “scale down” to the conditions used typically for radiotracer synthesis.
Corrosion Of Steel
Shipwrecks In The
Marine Environment:
Uss Arizona—Part 2,
2010
National Park Service
Corrosion Of Steel Shipwrecks In The Marine Environment: Uss Arizona—Part 2, Donald L. Johnson, Brent M. Wilson, James D. Carr, Matthew A. Russell, Larry E. Murphy, David L. Conlin
Department of Chemistry: Faculty Publications
This article is a continuation of Part 1 (October 2006 MP) on the USS Arizona hull. It discusses additional methods being investigated for use in determining corrosion rates with a minimal impact on the existing structure. Marine biofouling (concretion) has accumulated on the hull. Concretion samples have been studied using x-ray diffraction, environmental electron microscopy, and corrosion potential (Ecorr) to characterize the relationship between concretion and the steel substrate. The data presented in this study confirm the viability of concretion analysis as a minimum-impact procedure to estimate the corrosion rate of mild steel in seawater.
Corrosion Of
Civil War Era
Sub Marine
Explorer—Part 2,
2010
Submerged Resources Center, National Park Service
Corrosion Of Civil War Era Sub Marine Explorer—Part 2, Donald L. Johnson, James D. Carr, Brent M. Wilson, Larry E. Murphy, James P. Delgado
Department of Chemistry: Faculty Publications
The Sub Marine Explorer was designed and built by Julius H. Kroehl, who was born in Prussia in 1820. After migrating to the United States in 1838 and becoming a citizen, he served in the Union Navy (United States Navy during the Civil War) as an underwater demolitions expert. He left the Navy in 1863 and began designing a “sub-marine” that would facilitate Union forces’ mine removal and obstruction clearance. At the end of the Civil War, he became an engineer for the Pacific Pearl Co., an organization interested in using the craft to recover pearls from deep sea oyster …
Corrosion Of
Civil War Era
Sub Marine
Explorer—Part 1,
2010
Submerged Resources Center, National Park Service
Corrosion Of Civil War Era Sub Marine Explorer—Part 1, Donald L. Johnson, James D. Carr, Brent M. Wilson, Larry E. Murphy, James P. Delgado
Department of Chemistry: Faculty Publications
The Sub Marine Explorer is one of five submersibles (submarines) constructed prior to 1870 that have survived either in museums or as in situ archaeological sites around the world. Since 1869, the wreck of Explorer has emerged at low tide on the beach of Isla San Telmo, Archipiélago de las Perlas, Panama, located ~75 km southwest of Panama City in the Bay of Panama. In 2001, James Delgado visited the site. Locals described the wreck as a World War II-era Japanese midget submarine. Delgado consulted with Richard Wills, an expert on American Civil War submarines, and confirmed that the well-preserved …
Method For Monitoring The Stereoselectivity And Relative
Rate Of Organic Chemical Reactions,
2010
Lincoln, NE
Method For Monitoring The Stereoselectivity And Relative Rate Of Organic Chemical Reactions, David R. Berkowitz, Sangeeta Dey, Kannan R. Karukurichi, Weijun Shen
Department of Chemistry: Faculty Publications
A method for monitoring the stereoselectivity of at least one organic chemical reaction and the relative rate of at least one organic chemical reaction, wherein the reaction produces a product that can exist as at least two stereoisomers, is provided herein. Also disclosed are methods for identifying and preparing catalysts for the above reactions.
Shorter Still: Compressing C-C Single Bonds,
2010
University of Richmond
Shorter Still: Compressing C-C Single Bonds, Gerarso Martinez-Guajardo, Kelling J. Donald, Bernard K. Wittmaack, Miguel Angel Vazquez, Gabriel Merino
Chemistry Faculty Publications
How short can a C-C single bond get? The bonding in a set of molecules that are related structurally to previously synthesized or theoretically examined systems with short C-C bonds is investigated. According to calculations, a single C-C bond could be compressed to 1.313 A! To the best of our knowledge, this is the shortest single C-C bond reported to date. This shortening is a consequence of a change in the C-C-C bond angle, θ, to minimize strain in the cages and an effort to offset the tension in the surrounding bridges.
Copper Thin-Film Dissolution/Precipitation Kinetics In Organic Hf Containing Cleaning Solution,
2010
Portland State University
Copper Thin-Film Dissolution/Precipitation Kinetics In Organic Hf Containing Cleaning Solution, Nabil George Mistkawi, Makarem A. Hussein, Malgorzata Ziomek-Moroz, Shankar B. Rananavare
Chemistry Faculty Publications and Presentations
The corrosion behavior of electrochemically deposited copper thin films in deaerated and non-deaerated commercial cleaning solution containing HF has been investigated. Thin-film copper dissolution and reaction kinetics were investigated by monitoring Cu2+ , employing inductively coupled plasma–mass spectroscopy, and the oxidation states of copper on Si wafer surface, employing X-ray photoelectron spectroscopy. It was determined that the reaction kinetics is first order with respect to both HF and oxygen concentrations. A kinetic scheme involving reduction of oxygen and oxidation of Cu0 and Cu1+ is proposed, which is consistent with the experimentally determined reaction kinetic orders and the …
