Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Engineering (91)
- Materials Science and Engineering (50)
- Physics (36)
- Organic Chemistry (31)
- Materials Chemistry (22)
-
- Chemical Engineering (19)
- Computer Sciences (15)
- Physical Chemistry (15)
- Numerical Analysis and Scientific Computing (14)
- Inorganic Chemistry (13)
- Life Sciences (12)
- Mechanical Engineering (11)
- Biochemical and Biomolecular Engineering (9)
- Biomedical Engineering and Bioengineering (7)
- Electrical and Computer Engineering (7)
- Aerospace Engineering (6)
- Biochemistry, Biophysics, and Structural Biology (6)
- Biology (6)
- Petroleum Engineering (6)
- Computer Engineering (4)
- Nuclear (4)
- Polymer Chemistry (4)
- Analytical Chemistry (3)
- Civil and Environmental Engineering (3)
- Geological Engineering (3)
- Computational Chemistry (2)
- Dermatology (2)
- Earth Sciences (2)
- Keyword
-
- Iron (14)
- Enantiomer separation (13)
- Mössbauer Spectroscopy (12)
- Nuclear Magnetic Resonance (8)
- Quantum chemistry (8)
-
- Alzheimer's disease (7)
- Amino acids (7)
- Magnetic Moments (7)
- Polymers (7)
- Potential energy (7)
- Potential energy surfaces (7)
- Teicoplanin (7)
- Aerogels (6)
- Chemistry (6)
- Isotopes (6)
- Magnetism (6)
- Nanoparticles (6)
- Temperature Dependence (6)
- Article (5)
- Calculations (5)
- Chiral stationary phases, LC (5)
- Crystallography (5)
- Kinetics (5)
- Magnetic Susceptibility (5)
- Magnetization (5)
- Melanoma (5)
- Oxygen evolution reaction (5)
- Colloidal unimolecular polymer (CUP) (4)
- Crystal structure (4)
- Crystallization (4)
- Publication Year
Articles 361 - 390 of 939
Full-Text Articles in Chemistry
A 1-D Coordination Polymer Route To Catalytically Active Co@C Nanoparticles, Anand Pariyar, Siddharth Gopalakrishnan, Joseph Stansbery, Rajankumar L. Patel, Xinhua Liang, Nikolay Nikolaevich Gerasimchuk, Amitava Choudhury
A 1-D Coordination Polymer Route To Catalytically Active Co@C Nanoparticles, Anand Pariyar, Siddharth Gopalakrishnan, Joseph Stansbery, Rajankumar L. Patel, Xinhua Liang, Nikolay Nikolaevich Gerasimchuk, Amitava Choudhury
Chemistry Faculty Research & Creative Works
Pyrolysis of a 1-D polymeric cobalt(ii) coordination complex ([Co(BDC)(Mim)2]n, H2BDC = benzenedicarboxylic acid; Mim = N-methylimidazole) results in the formation of carbon embedded fcc cobalt nanoparticle composites, Co@C. The as-prepared Co@C shows an agglomerated secondary structure with a highly embedded carbon shell comprising of cobalt nanoparticles of 20-100 nm. These Co@C particles show excellent catalytic activity in the reduction of nitrophenol to aminophenol, studied as a model reaction, and evolves as a promising candidate for the gas phase reduction process.
The Ideal And Real Gas Heat Capacity Of Potassium Atoms At High Temperatures, Louis Biolsi, Michael Biolsi
The Ideal And Real Gas Heat Capacity Of Potassium Atoms At High Temperatures, Louis Biolsi, Michael Biolsi
Chemistry Faculty Research & Creative Works
The Ideal Gas Heat Capacity, Cp, of Potassium Atoms is Calculated to High Temperatures using Statistical Mechanics. Since There Are a Large Number of Electronic Energy Levels in the Partition Function (Boltzmann Sum) Below the First Ionization Potential, the Partition Function and Cp will become very large as the Temperature Increases Unless the Number of Energy Levels Contributing to the Partition Function is Constrained. Two Primary Categories of Arguments Are Used to Do This. First, at High Temperatures, the Increased Size of the Atoms Constrains the Sum (Bethe Method). Second, an Argument based on the Existence of Interacting …
In Crystallo Capture Of A Covalent Intermediate In The Udp-Galactopyranose Mutase Reaction, Ritcha Mehra-Chaudhary, Yumin Dai, Pablo Sobrado, John J. Tanner
In Crystallo Capture Of A Covalent Intermediate In The Udp-Galactopyranose Mutase Reaction, Ritcha Mehra-Chaudhary, Yumin Dai, Pablo Sobrado, John J. Tanner
Chemistry Faculty Research & Creative Works
UDP-galactopyranose mutase (UGM) plays an essential role in galactofuranose biosynthesis in pathogens by catalyzing the conversion of UDP-galactopyranose to UDP-galactofuranose. Here we report the first crystal structure of a covalent intermediate in the UGM reaction. The 2.3 Å resolution structure reveals UDP bound in the active site and galactopyranose linked to the FAD through a covalent bond between the anomeric C of galactopyranose and N5 of the FAD. The structure confirms the role of the flavin as nucleophile and supports the hypothesis that the proton destined for O5 of galactofuranose is shuttled from N5 of the FAD via O4 of …
Calculated Vibrational States Of Ozone Up To Dissociation, Steve Alexandre Ndengué, Richard Dawes, Xiaogang Wang, Tucker Carrington Jr., Zhigang Sun, Hua Guo
Calculated Vibrational States Of Ozone Up To Dissociation, Steve Alexandre Ndengué, Richard Dawes, Xiaogang Wang, Tucker Carrington Jr., Zhigang Sun, Hua Guo
Chemistry Faculty Research & Creative Works
A new accurate global potential energy surface for the ground electronic state of ozone [R. Dawes et al., J. Chem. Phys. 139, 201103 (2013)] was published fairly recently. The topography near dissociation differs significantly from previous surfaces, without spurious submerged reefs and corresponding van der Waals wells. This has enabled significantly improved descriptions of scattering processes, capturing the negative temperature dependence and large kinetic isotope effects in exchange reaction rates. The exchange reactivity was found to depend on the character of near-threshold resonances and their overlap with reactant and product wavefunctions, which in turn are sensitive to the potential. Here …
Metabolic Disorders, Drug Development, Drug Design And Biomarkers, Gjumrakch Aliev, Ramon Cacabelos, V. Prakash Reddy
Metabolic Disorders, Drug Development, Drug Design And Biomarkers, Gjumrakch Aliev, Ramon Cacabelos, V. Prakash Reddy
Chemistry Faculty Research & Creative Works
No abstract provided.
A Computational And Experimental Study Of Thieno[3,4-B]Thiophene As A Proaromatic Π-Bridge In Dye-Sensitized Solar Cells, Phillip Brogdon, Fabrizio Giordano, George A. Puneky, Amala Dass, Shaik M. Zakeeruddin, Mohammad Khaja Nazeeruddin, Michael Grätzel, Gregory S. Tschumper, Jared H. Delcamp
A Computational And Experimental Study Of Thieno[3,4-B]Thiophene As A Proaromatic Π-Bridge In Dye-Sensitized Solar Cells, Phillip Brogdon, Fabrizio Giordano, George A. Puneky, Amala Dass, Shaik M. Zakeeruddin, Mohammad Khaja Nazeeruddin, Michael Grätzel, Gregory S. Tschumper, Jared H. Delcamp
Chemistry Faculty Research & Creative Works
Four D-π-A dyes (D=donor, A=acceptor) based on a 3,4-thienothiophene π-bridge were synthesized for use in dye-sensitized solar cells (DSCs). The proaromatic building block 3,4-thienothiophene is incorporated to stabilize dye excited-state oxidation potentials. This lowering of the excited-state energy levels allows for deeper absorption into the NIR region with relatively low molecular weight dyes. The influence of proaromatic functionality is probed through a computational analysis of optimized bond lengths and nucleus independent chemical shifts (NICS) for both the ground- and excited- states. To avoid a necessary lowering of the TiO2 semiconductor conduction band (CB) to promote efficient dye-TiO2 electron …
Calculating Potential Energy Curves With Fixed-Node Diffusion Monte Carlo: Co And N₂, Andrew D. Powell, Richard Dawes
Calculating Potential Energy Curves With Fixed-Node Diffusion Monte Carlo: Co And N₂, Andrew D. Powell, Richard Dawes
Chemistry Faculty Research & Creative Works
This study reports on the prospect for the routine use of Quantum Monte Carlo (QMC) for the electronic structure problem, applying fixed-node Diffusion Monte Carlo (DMC) to generate highly accurate Born-Oppenheimer potential energy curves (PECs) for small molecular systems. The singlet ground electronic states of CO and N2 were used as test cases. The PECs obtained by DMC employing multiconfigurational trial wavefunctions were compared with those obtained by conventional high-accuracy electronic structure methods such as multireference configuration interaction and/or the best available empirical spectroscopic curves. The goal was to test whether a straightforward procedure using available QMC codes could …
Sub-Millisecond Response Time In A Photorefractive Composite Operating Under Cw Conditions, Jong-Sik Moon, Tyler E. Stevens, Todd C. Monson, Dale L. Huber, Sung-Ho Jin, Jin-Woo Oh, Jeffrey G. Winiarz
Sub-Millisecond Response Time In A Photorefractive Composite Operating Under Cw Conditions, Jong-Sik Moon, Tyler E. Stevens, Todd C. Monson, Dale L. Huber, Sung-Ho Jin, Jin-Woo Oh, Jeffrey G. Winiarz
Chemistry Faculty Research & Creative Works
Extensive study of photorefractive polymeric composites photosensitized with semiconductor nanocrystals has yielded data indicating that the inclusion of such nanocrystals enhances the charge-carrier mobility, and subsequently leads to a reduction in the photorefractive response time. Unfortunately, the included nanocrystals may also act as a source of deep traps, resulting in diminished diffraction efficiencies as well as reduced two beam coupling gain coefficients. Nonetheless, previous studies indicate that this problem is mitigated through the inclusion of semiconductor nanocrystals possessing a relatively narrow band-gap. Here, we fully exploit this property by doping PbS nanocrystals into a newly formulated photorefractive composite based on …
The Virtual Atomic And Molecular Data Centre (Vamdc) Consortium, Marie-Lise Dubernet, B. K. Antony, Ernesto Quintas-Sánchez, For Full List Of Authors, See Publisher's Website.
The Virtual Atomic And Molecular Data Centre (Vamdc) Consortium, Marie-Lise Dubernet, B. K. Antony, Ernesto Quintas-Sánchez, For Full List Of Authors, See Publisher's Website.
Chemistry Faculty Research & Creative Works
The Virtual Atomic and Molecular Data Centre (VAMDC) Consortium is a worldwide consortium which federates atomic and molecular databases through an e-science infrastructure and an organisation to support this activity. About 90% of the inter-connected databases handle data that are used for the interpretation of astronomical spectra and for modelling in many fields of astrophysics. Recently the VAMDC Consortium has connected databases from the radiation damage and the plasma communities, as well as promoting the publication of data from Indian institutes. This paper describes how the VAMDC Consortium is organised for the optimal distribution of atomic and molecular data for …
The Onset Of Electron-Induced Proton-Transfer In Hydrated Azabenzene Cluster Anions, Yi Wang, Xinxing Zhang, Svetlana Lyapustina, Michael M. Nilles, Shoujun Xu, Jacob D. Graham, Kit H. Bowen, John T. Kelly, Gregory S. Tschumper, Nathan I. Hammer
The Onset Of Electron-Induced Proton-Transfer In Hydrated Azabenzene Cluster Anions, Yi Wang, Xinxing Zhang, Svetlana Lyapustina, Michael M. Nilles, Shoujun Xu, Jacob D. Graham, Kit H. Bowen, John T. Kelly, Gregory S. Tschumper, Nathan I. Hammer
Chemistry Faculty Research & Creative Works
The prospect that protons from water may be transferred to N-heterocyclic molecules due to the presence of an excess electron is studied in hydrated azobenzene cluster anions using anion photoelectron spectroscopy and computational chemistry. In the case of s-triazine (C3H3N3), which has a positive adiabatic electron affinity, proton transfer is not energetically favored nor observed experimentally. Heterocyclic rings with only 1 or 2 nitrogen atoms have negative electron affinities, but the addition of solvating water molecules can yield stable negative ions. In the case of the diazines (C4H4N2: …
Method And Apparatus For Cancer Screening, Yinfa Ma, Stephen Gibbons
Method And Apparatus For Cancer Screening, Yinfa Ma, Stephen Gibbons
Chemistry Faculty Research & Creative Works
A method and apparatus for detection of pteridine levels in a biological sample using CE-LIF which is useful for early cancer screening involving fully oxidizing pteridine compounds in a sample such as a urine sample, subjecting to CE-LIF to assess compound concentration, and compare to expected levels in for healthy or cancer-bearing patients.
Assessing The Accuracy Of Some Popular Dft Methods For Computing Harmonic Vibrational Frequencies Of Water Clusters, J. Coleman Howard, Jordan D. Enyard, Gregory S. Tschumper
Assessing The Accuracy Of Some Popular Dft Methods For Computing Harmonic Vibrational Frequencies Of Water Clusters, J. Coleman Howard, Jordan D. Enyard, Gregory S. Tschumper
Chemistry Faculty Research & Creative Works
A wide range of density functional theory (DFT) methods (37 altogether), including pure, hybrid, range-separated hybrid, double-hybrid, and dispersion-corrected functionals, have been employed to compute the harmonic vibrational frequencies of eight small water clusters ranging in size from the dimer to four different isomers of the hexamer. These computed harmonic frequencies have been carefully compared to recently published benchmark values that are expected to be very close to the CCSD(T) complete basis set limit. Of the DFT methods examined here, ωB97 and ωB97X are the most consistently accurate, deviating from the reference values by less than 20 cm-1 on …
Functionalized Nanodiamond Reinforced Biopolymers, Gongyao Zhou, Peter I. Lelkes, Yury Gogotsi, Vadym Mochalin
Functionalized Nanodiamond Reinforced Biopolymers, Gongyao Zhou, Peter I. Lelkes, Yury Gogotsi, Vadym Mochalin
Chemistry Faculty Research & Creative Works
The present invention includes a composition for implantation in a patient, comprising surface-functionalized nanodiamonds and at least one biodegradable biocompatible polymer. The present invention also includes a surgical fixation device for use in a patient.
Biomaterial Compositions, Kathleen V. Kilway, Lynda F. Bonewald, Thomas P. Schuman
Biomaterial Compositions, Kathleen V. Kilway, Lynda F. Bonewald, Thomas P. Schuman
Chemistry Faculty Research & Creative Works
Biomaterial compositions comprising organosilicon monomers (such as silorane monomers) and chemical curing systems or dual chemical/light curing systems, in conjunction with optional tetraoxaspiro[5.5]undecanes (“TOSUs”) and/or fillers. The present invention is directed to biomaterial compositions, as well as methods for manufacturing the same, and methods of using the compositions. The biomaterial composition comprises one or more organosilicon monomers (such as a silorane) and a chemical curing system or dual chemicaVlight curing system for polymerizing the 10 monomer(s). The compositions may include one or more tetraoxaspiro[5.5]undecanes “TOSUs”) and/or fillers. Accelerators (such as photoacids), photosensitizers, and/or electron donors may also be included in …
An Electrodeposited Inhomogeneous Metal-Insulator-Semiconductor Junction For Efficient Photoelectrochemical Water Oxidation, James C. Hill, Alan T. Landers, Jay A. Switzer
An Electrodeposited Inhomogeneous Metal-Insulator-Semiconductor Junction For Efficient Photoelectrochemical Water Oxidation, James C. Hill, Alan T. Landers, Jay A. Switzer
Chemistry Faculty Research & Creative Works
The photoelectrochemical splitting of water into hydrogen and oxygen requires a semiconductor to absorb light and generate electron-hole pairs, and a catalyst to enhance the kinetics of electron transfer between the semiconductor and solution. A crucial question is how this catalyst affects the band bending in the semiconductor, and, therefore, the photovoltage of the cell. We introduce a simple and inexpensive electrodeposition method to produce an efficient n-Si/SiOx/Co/CoOOH photoanode for the photoelectrochemical oxidation of water to oxygen. The photoanode functions as a solid-state, metal-insulator-semiconductor photovoltaic cell with spatially non-uniform barrier heights in series with a low overpotential water-splitting electrochemical cell. …
Water Network-Mediated, Electron-Induced Proton Transfer In [C5h5n·(H2o)N]⁻ Clusters, Andrew F. Deblase, Conrad T. Wolke, Gary H. Weddle, Kaye A. Archer, Kenneth D. Jordan, John T. Kelly, Gregory S. Tschumper, Nathan I. Hammer, Mark A. Johnson
Water Network-Mediated, Electron-Induced Proton Transfer In [C5h5n·(H2o)N]⁻ Clusters, Andrew F. Deblase, Conrad T. Wolke, Gary H. Weddle, Kaye A. Archer, Kenneth D. Jordan, John T. Kelly, Gregory S. Tschumper, Nathan I. Hammer, Mark A. Johnson
Chemistry Faculty Research & Creative Works
The role of proton-assisted charge accommodation in electron capture by a heterocyclic electron scavenger is investigated through theoretical analysis of the vibrational spectra of cold, gas phase [Py·(H2O) n=3-5]- clusters. These radical anions are formed when an excess electron is attached to water clusters containing a single pyridine (Py) molecule in a supersonic jet ion source. Under these conditions, the cluster ion distribution starts promptly at n = 3, and the photoelectron spectra, combined with vibrational predissociation spectra of the Ar-tagged anions, establish that for n > 3, these species are best described as hydrated hydroxide ions …
Synergistic Effects Of Halogen Bond And Π-Π Interactions In Thiophene-Based Building Blocks, Jamey Wilson, Jon Steven Dal Williams, Chesney Petkovsek, Peyton Reves, Jonah W. Jurss, Nathan I. Hammer, Gregory S. Tschumper, Davita L. Watkins
Synergistic Effects Of Halogen Bond And Π-Π Interactions In Thiophene-Based Building Blocks, Jamey Wilson, Jon Steven Dal Williams, Chesney Petkovsek, Peyton Reves, Jonah W. Jurss, Nathan I. Hammer, Gregory S. Tschumper, Davita L. Watkins
Chemistry Faculty Research & Creative Works
Although recognized as a significant force in crystal engineering, halogen bonding (XB) has been scarcely investigated in "bottom-up" approaches towards organic electronics. We report, herein, the use of a thiophene-based building block, pyridyl-thiophene (Pyr-T), to achieve an assembly driven by XB and π-π stacking interactions with iodopentafluorobenzene (IPFB). Spectroscopic and thermal analysis of the co-crystal provide indirect evidence of the assembly. The combined effects of XB and π-π stacking are confirmed experimentally via X-ray crystallography. Density functional theory (DFT) computations support experimental observations. The results of the study speak to the use of halogen bond driven self-assembly in organic electronic …
Generalized Synthesis Of Eas [E = Fe, Co, Mn, Cr] Nanostructures And Investigating Their Morphology Evolution, Prachi Desai, Nikitaa Ashokan, Manashi Nath
Generalized Synthesis Of Eas [E = Fe, Co, Mn, Cr] Nanostructures And Investigating Their Morphology Evolution, Prachi Desai, Nikitaa Ashokan, Manashi Nath
Chemistry Faculty Research & Creative Works
This paper illustrates a novel route for the synthesis of nanostructured transition metal arsenides including those of FeAs, CoAs, MnAs, and CrAs through a generalized protocol. The key feature of the method is the use of one-step hot-injection and the clever use of a combination of precursors which are low-melting and highly reactive such as metal carbonyls and triphenylarsine in a solventless setup. This method also facilitates the formation of one-dimensional nanostructures as we move across the periodic table from CrAs to CoAs. The chemical basis of this reaction is simple redox chemistry between the transition metals, wherein the transition …
X-Ray Structure Of A Mammalian Stearoyl-Coa Desaturase, Yonghong Bai, Jason G. Mccoy, Elena J. Levin, Pablo Sobrado, Kanagalaghatta R. Rajashankar, Brian G. Fox, Ming Zhou
X-Ray Structure Of A Mammalian Stearoyl-Coa Desaturase, Yonghong Bai, Jason G. Mccoy, Elena J. Levin, Pablo Sobrado, Kanagalaghatta R. Rajashankar, Brian G. Fox, Ming Zhou
Chemistry Faculty Research & Creative Works
Stearoyl-CoA desaturase (SCD) is conserved in all eukaryotes and introduces the first double bond into saturated fatty acyl-CoAs. Because the monounsaturated products of SCD are key precursors of membrane phospholipids, cholesterol esters and triglycerides, SCD is pivotal in fatty acid metabolism. Humans have two SCD homologues (SCD1 and SCD5), while mice have four (SCD1-SCD4). SCD1-deficient mice do not become obese or diabetic when fed a high-fat diet because of improved lipid metabolic profiles and insulin sensitivity5,6. Thus, SCD1 is a pharmacological target in the treatment of obesity, diabetes and other metabolic diseases7. SCD1 is an integral …
Vibrational Energy Levels Of The Simplest Criegee Intermediate (Ch₂Oo) From Full-Dimensional Lanczos, Mctdh, And Multimode Calculations, Hua-Gen Yu, Steve Alexandre Ndengué, Jun Li, Richard Dawes, Hua Guo
Vibrational Energy Levels Of The Simplest Criegee Intermediate (Ch₂Oo) From Full-Dimensional Lanczos, Mctdh, And Multimode Calculations, Hua-Gen Yu, Steve Alexandre Ndengué, Jun Li, Richard Dawes, Hua Guo
Chemistry Faculty Research & Creative Works
Accurate vibrational energy levels of the simplest Criegee intermediate (CH2OO) were determined on a recently developed ab initio based nine-dimensional potential energy surface using three quantum mechanical methods. the first is the iterative Lanczos method using a conventional basis expansion with an exact Hamiltonian. the second and more efficient method is the multi-configurational time-dependent Hartree (MCTDH) method in which the potential energy surface is refit to conform to the sums-of-products requirement of MCTDH. Finally, the energy levels were computed with a vibrational self-consistent field/virtual configuration interaction method in MULTIMODE. the low-lying levels obtained from the three methods are …
New Potential Energy Surface For The Hcs⁺-He System And Inelastic Rate Coefficients, Marie-Lise Dubernet, Ernesto Quintas-Sánchez, Philip Tuckey
New Potential Energy Surface For The Hcs⁺-He System And Inelastic Rate Coefficients, Marie-Lise Dubernet, Ernesto Quintas-Sánchez, Philip Tuckey
Chemistry Faculty Research & Creative Works
A new high quality potential energy surface is calculated at a coupled-cluster single double triple level with an aug-cc-pV5Z basis set for the HCS+-He system. This potential energy surface is used in low energy quantum scattering calculations to provide a set of (de)-excitation cross sections and rate coefficients among the first 20 rotational levels of HCS+ by He in the range of temperature from 5 K to 100 K. The paper discusses the impact of the new ab initio potential energy surface on the cross sections at low energy and provides a comparison with the HCO+ …
Erratum: "H2 - Agcl: A Spectroscopic Study Of A Dihydrogen Complex" (Journal Of Chemical Physics 141:114306 (2014)), Garry S. Grubbs, Daniel A. Obenchain, Herbert M. Pickett, Stewart E. Novick
Erratum: "H2 - Agcl: A Spectroscopic Study Of A Dihydrogen Complex" (Journal Of Chemical Physics 141:114306 (2014)), Garry S. Grubbs, Daniel A. Obenchain, Herbert M. Pickett, Stewart E. Novick
Chemistry Faculty Research & Creative Works
No abstract provided.
Acoustic Attenuators Based On Porous Nanostructured Materials, Hongbing Lu, Ning Xiang, Nicholas Leventis, Chariklia Sotiriou-Leventis
Acoustic Attenuators Based On Porous Nanostructured Materials, Hongbing Lu, Ning Xiang, Nicholas Leventis, Chariklia Sotiriou-Leventis
Chemistry Faculty Research & Creative Works
The invention is directed to a porous, acoustic attenuating composition, wherein the composition comprises a nanostructured material and wherein the composition exhibits acoustic transmission loss ranging from 20 to 60 dB/cm thickness of the composition.
Towards A Global Model Of Spin-Orbit Coupling In The Halocarbenes, Silver Nyambo, Cyrus Karshenas, Scott A. Reid, Phalgun Lolur, Richard Dawes
Towards A Global Model Of Spin-Orbit Coupling In The Halocarbenes, Silver Nyambo, Cyrus Karshenas, Scott A. Reid, Phalgun Lolur, Richard Dawes
Chemistry Faculty Research & Creative Works
We report a global analysis of spin-orbit coupling in the mono-halocarbenes, CH(D)X, where X = Cl, Br, and I. These are model systems for examining carbene singlet-triplet energy gaps and spin-orbit coupling. Over the past decade, rich data sets collected using single vibronic level emission spectroscopy and stimulated emission pumping spectroscopy have yielded much information on the ground vibrational level structure and clearly demonstrated the presence of perturbations involving the low-lying triplet state. To model these interactions globally, we compare two approaches. First, we employ a diabatic treatment of the spin-orbit coupling, where the coupling matrix elements are written in …
An Unprecedented Nadph Domain Conformation In Lysine Monooxygenase Nbtg Provides Insights Into Uncoupling Of Oxygen Consumption From Substrate Hydroxylation, Claudia Binda, Reeder M. Robinson, Julia S. Martin Del Campo, Nicholas D. Keul, Pedro J. Rodriguez, Howard H. Robinson, Andrea Mattevi, Pablo Sobrado
An Unprecedented Nadph Domain Conformation In Lysine Monooxygenase Nbtg Provides Insights Into Uncoupling Of Oxygen Consumption From Substrate Hydroxylation, Claudia Binda, Reeder M. Robinson, Julia S. Martin Del Campo, Nicholas D. Keul, Pedro J. Rodriguez, Howard H. Robinson, Andrea Mattevi, Pablo Sobrado
Chemistry Faculty Research & Creative Works
N-Hydroxylating monooxygenases are involved in the biosynthesis of iron-chelating hydroxamate-containing siderophores that play a role in microbial virulence. These flavoenzymes catalyze the NADPH-and oxygen-dependent hydroxylation of amines such as those found on the side chains of lysine and ornithine. In this work we report the biochemical and structural characterization of Nocardia farcinica Lys monooxygenase (NbtG), which has similar biochemical properties to mycobacterial homologs. NbtG is also active on D-Lys, although it binds L-Lys with a higher affinity. Differently from the ornithine monooxygenases PvdA, SidA, and KtzI, NbtG can use both NADH and NADPH and is highly uncoupled, producing more superoxide …
Benchmark Structures And Harmonic Vibrational Frequencies Near The Ccsd(T) Complete Basis Set Limit For Small Water Clusters: (H2o)N = 2, 3, 4, 5, 6, J. Coleman Howard, Gregory S. Tschumper
Benchmark Structures And Harmonic Vibrational Frequencies Near The Ccsd(T) Complete Basis Set Limit For Small Water Clusters: (H2o)N = 2, 3, 4, 5, 6, J. Coleman Howard, Gregory S. Tschumper
Chemistry Faculty Research & Creative Works
A series of (H2O)n clusters ranging from the dimer to the hexamer have been characterized with the CCSD(T) and the 2-body: Many-body CCSD(T):MP2 methods near the complete basis set (CBS) limit to generate benchmark-quality optimized structures and harmonic vibrational frequencies for these important systems. Quadruple-ζ correlation-consistent basis sets that augment the O atoms with diffuse functions have been employed in the analytic computation of harmonic vibrational frequencies for the global minima of the dimer, trimer, tetramer, and pentamer as well as the ring, book, cage, and prism isomers of the hexamer. Prior calibration [J. Chem. Phys. 2013, …
Growth Of Ordered Nanostructure Arrays Including Nanotubes And Nanorods For High Efficiency Solar Cells, Wipula P. Liyanage, Manashi Nath
Growth Of Ordered Nanostructure Arrays Including Nanotubes And Nanorods For High Efficiency Solar Cells, Wipula P. Liyanage, Manashi Nath
Chemistry Faculty Research & Creative Works
A simple and straightforward approach has been described for the fabrication of CdTe nanotube and nanorod arrays with a high degree of precision through confined electrodeposition on lithographically patterned nanoelectrodes. This technique has the potential of growing these nanotube/nanowire arrays with extreme uniformity over a significantly large area. the desired nanoelectrode pattern was defined through electron beam lithography on indium tin oxide coated glass, and electrodeposition of the semiconducting material of interest (CdTe) on the nanoelecrodes produced the nanotubes/nanowires. It is interesting to note that the measured photocurrent density of nanotube device created by this protocol exceeds that obtained from …
Kinetic Isotope Effect Of The ¹⁶O+³⁶O₂ And ¹⁸O+³²O₂ Isotope Exchange Reactions: Dominant Role Of Reactive Resonances Revealed By An Accurate Time-Dependent Quantum Wavepacket Study, Zhigang Sun, Dequan Yu, Wenbo Xie, Jiayi Hou, Richard Dawes, Hua Guo
Kinetic Isotope Effect Of The ¹⁶O+³⁶O₂ And ¹⁸O+³²O₂ Isotope Exchange Reactions: Dominant Role Of Reactive Resonances Revealed By An Accurate Time-Dependent Quantum Wavepacket Study, Zhigang Sun, Dequan Yu, Wenbo Xie, Jiayi Hou, Richard Dawes, Hua Guo
Chemistry Faculty Research & Creative Works
The O + O2 isotope exchange reactions play an important role in determining the oxygen isotopic composition of a number of trace gases in the atmosphere, and their temperature dependence and kinetic isotope effects (KIEs) provide important constraints on our understanding of the origin and mechanism of these and other unusual oxygen KIEs important in the atmosphere. This work reports a quantum dynamics study of the title reactions on the newly constructed Dawes-Lolur-Li-Jiang-Guo (DLLJG) potential energy surface (PES). The thermal reaction rate coefficients of both the 18O + 32O2 and 16O + 36O2 reactions obtained using the …
Boyd Group Electronegativity Influence On The Parr Global Electrophilicity Of Vilsmeier Reagent-Derived Imidates: New Insights Toward Improving Mitsunobu Chemistry, Jeremy M. Carr, Gregory S. Tschumper, A. Paige Lathem
Boyd Group Electronegativity Influence On The Parr Global Electrophilicity Of Vilsmeier Reagent-Derived Imidates: New Insights Toward Improving Mitsunobu Chemistry, Jeremy M. Carr, Gregory S. Tschumper, A. Paige Lathem
Chemistry Faculty Research & Creative Works
Reactivities of 19 methylated imidate analogs were examined using B3LYP and M06-2X DFT methods. The resulting HOMO and LUMO energies of each optimized structure were used to calculate corresponding Parr global electrophilicity (ω) values. When the resulting quantities were compared against Boyd group electronegativity (XG) values, a clear correlation was observed, suggesting that electron-withdrawing effects influence the reactivity of imidates. These findings represent an important first step in developing a novel method toward improving traditional Mitsunobu functionalization reactions.
Indolizine-Based Donors As Organic Sensitizer Components For Dye-Sensitized Solar Cells, Aron J. Huckaba, Fabrizio Giordano, Louis E. Mcnamara, Katelyn M. Dreux, Nathan I. Hammer, Gregory S. Tschumper, Shaik M. Zakeeruddin, Michael Grätzel, Mohammad K. Nazeeruddin, Jared H. Delcamp
Indolizine-Based Donors As Organic Sensitizer Components For Dye-Sensitized Solar Cells, Aron J. Huckaba, Fabrizio Giordano, Louis E. Mcnamara, Katelyn M. Dreux, Nathan I. Hammer, Gregory S. Tschumper, Shaik M. Zakeeruddin, Michael Grätzel, Mohammad K. Nazeeruddin, Jared H. Delcamp
Chemistry Faculty Research & Creative Works
Strong electron-donating functionality is desirable for many organic donor-π-bridge-acceptor (D-π-A) dyes. Strategies for increasing the electron-donating strength of common nitrogen-based donors include planarization of nitrogen substituents and the use of low resonance-stabilized energy aromatic ring-substituted nitrogen atoms. Organic donor motifs based on the planar nitrogen containing heterocycle indolizine are synthesized and incorporated into dye-sensitized solar cell (DSC) sensitizers. Resonance active substitutions at several positions on indolizine in conjugation with the D-π-A π-system are examined computationally and experimentally. The indolizine-based donors are observed to contribute electron density with strengths greater than triarylamines and diarylamines, as evidenced by UV/Vis, IR absorptions, and …