Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Organic Chemistry (57)
- Analytical Chemistry (23)
- Materials Chemistry (22)
- Physical Chemistry (22)
- Inorganic Chemistry (16)
-
- Medicinal-Pharmaceutical Chemistry (8)
- Other Chemistry (8)
- Environmental Chemistry (7)
- Physics (7)
- Life Sciences (6)
- Engineering (4)
- Electrical and Computer Engineering (3)
- Biochemistry (2)
- Biochemistry, Biophysics, and Structural Biology (2)
- Biological and Chemical Physics (2)
- Biology (2)
- Medicine and Health Sciences (2)
- Radiochemistry (2)
- Analytical, Diagnostic and Therapeutic Techniques and Equipment (1)
- Bioimaging and Biomedical Optics (1)
- Biomedical Engineering and Bioengineering (1)
- Chemical Engineering (1)
- Earth Sciences (1)
- Electrical and Electronics (1)
- Electronic Devices and Semiconductor Manufacturing (1)
- Equipment and Supplies (1)
- Geochemistry (1)
- Geology (1)
- Keyword
-
- Nanocomposites (43)
- Polystyrene (25)
- Fire retardancy (22)
- Cone calorimetry (13)
- Spectroelectrochemistry (13)
-
- Cobalt (10)
- Iron (10)
- Kinetics (10)
- NMR (10)
- Poly(methyl methacrylate) (10)
- Thermal stability (10)
- Inelastic scattering (9)
- Ligands (9)
- Electrochemistry (8)
- Nanocomposite (8)
- Thermal degradation (8)
- Catalysis (7)
- Fire Retardancy (7)
- Ionic liquid (7)
- X-ray structures (7)
- Cellulose (6)
- Cross-linking (6)
- Crystal structure (6)
- Cyclic voltammetry (6)
- Cytochrome P450 (6)
- Layered double hydroxide (6)
- Layered double hydroxides (6)
- Molecular data (6)
- Oxidation (6)
- Ozone (6)
- Publication Year
- Publication
- Publication Type
- File Type
Articles 151 - 180 of 1105
Full-Text Articles in Chemistry
Synthesis Of Simplified Azasordarin Analogs As Potential Antifungal Agents, Yibiao Wu, Chris Dockendorff
Synthesis Of Simplified Azasordarin Analogs As Potential Antifungal Agents, Yibiao Wu, Chris Dockendorff
Chemistry Faculty Research and Publications
A new series of simplified azasordarin analogs was synthesized using as key steps a Diels–Alder reaction to generate a highly substituted bicyclo[2.2.1]heptane core, followed by a subsequent nitrile alkylation. Several additional strategies were investigated for the generation of the key tertiary nitrile or aldehyde thought to be required for inhibition at the fungal protein eukaryotic elongation factor 2. This new series also features a morpholino glycone previously reported in semisynthetic sordarin derivatives with broad spectrum antifungal activity. Despite a lack of activity against Candida albicans for these early de novo analogs, the synthetic route reported here permits more comprehensive modifications …
Cooperative Transport In A Multi-Particle, Multi-Dimensional Flashing Ratchet, Ofer Kedem, Emily A. Weiss
Cooperative Transport In A Multi-Particle, Multi-Dimensional Flashing Ratchet, Ofer Kedem, Emily A. Weiss
Chemistry Faculty Research and Publications
Random and undirected forces are rectified in biological and synthetic systems using ratcheting mechanisms, which employ periodic asymmetric potentials and nonequilibrium conditions to produce useful transport. The density of motors or transported particles is known to strongly affect the nature and efficacy of transport in biological systems, as well as in synthetic ratchets and active swimmer systems. While experimental ratchet implementations typically employ potentials varying in two dimensions (2D), the role of the density of interacting particles in such a system has not been modeled. Prompted by experimental observations and building upon previous simulations, this paper describes the ratcheting process …
The Ratio Of The Number Of States In Asymmetric And Symmetric Ozone Molecules Deviates From The Statistical Value Of 2, Igor Gayday, Alexander Teplukhin, Dmitri Babikov
The Ratio Of The Number Of States In Asymmetric And Symmetric Ozone Molecules Deviates From The Statistical Value Of 2, Igor Gayday, Alexander Teplukhin, Dmitri Babikov
Chemistry Faculty Research and Publications
Accurate calculations of vibrational states in singly and doubly substituted ozone molecules are carried out, up to dissociation threshold. Analysis of these spectra reveals noticeable deviations from the statistical factor of 2 for the ratio between the number of states in asymmetric and symmetric ozone molecules. It is found that, for the lower energy parts of spectra, the ratio is less than 2 in the singly substituted ozone molecules, but it is more than 2 in the doubly substituted ozone molecules. However, the upper parts of spectra, just below dissociation thresholds, exhibit a different behavior. In this energy range, the …
C–H/Π And C–H–O Interactions In Concert: A Study Of The Anisole–Methane Complex Using Resonant Ionization And Velocity Mapped Ion Imaging, James Makuvaza, Damian Kokkin, John Loman, Scott A. Reid
C–H/Π And C–H–O Interactions In Concert: A Study Of The Anisole–Methane Complex Using Resonant Ionization And Velocity Mapped Ion Imaging, James Makuvaza, Damian Kokkin, John Loman, Scott A. Reid
Chemistry Faculty Research and Publications
Noncovalent forces such as hydrogen bonding, halogen bonding, π–π stacking, and C–H/π and C–H/O interactions hold the key to such chemical processes as protein folding, molecular self-assembly, and drug–substrate interactions. Invaluable insight into the nature and strength of these forces continues to come from the study of isolated molecular clusters. In this work, we report on a study of the isolated anisole–methane complex, where both C–H/π and C–H/O interactions are possible, using a combination of theory and experiments that include mass-selected two-color resonant two-photon ionization spectroscopy, two-color appearance potential (2CAP) measurements, and velocity mapped ion imaging (VMI). Using 2CAP and …
Proton-Coupled Reduction Of An Iron Nitrosyl Porphyrin In The Protic Ionic Liquid Nanodomain, Abderrahman Atifi, Piotr J. Mak, Michael D. Ryan
Proton-Coupled Reduction Of An Iron Nitrosyl Porphyrin In The Protic Ionic Liquid Nanodomain, Abderrahman Atifi, Piotr J. Mak, Michael D. Ryan
Chemistry Faculty Research and Publications
The one-electron reduction of many molecules becomes much more favorable if combined with proton transfers or strong hydrogen bonding. Protic room temperature ionic liquids (RTILs), which can form nanodomains in solutions with molecular solvents (MS), can provide an efficient avenue for this process. In this work, we report on the voltammetry, UV/visible and resonance Raman spectroelectrochemistryof Fe(TPP)(NO) in the presence of aprotic/protic ammonium-based ionic liquids. While aprotic RTILs did shift the reduction to more positive potentials, similar shifts could be observed at much lower concentrations of diethylmethylammonium triflate (HAmOTf, a protic ionic liquid). Deconvolution of the rotating ring-disk electrode (RRDE) …
Design And Evaluation Of Heterobivalent Par1–Par2 Ligands As Antagonists Of Calcium Mobilization, Mark W. Majewski, Disha M. Gandhi, Ricardo Rosas Jr., Revathi Kodall, Leggy A. Arnold, Chris Dockendorff
Design And Evaluation Of Heterobivalent Par1–Par2 Ligands As Antagonists Of Calcium Mobilization, Mark W. Majewski, Disha M. Gandhi, Ricardo Rosas Jr., Revathi Kodall, Leggy A. Arnold, Chris Dockendorff
Chemistry Faculty Research and Publications
A novel class of bivalent ligands targeting putative protease-activated receptor (PAR) heteromers has been prepared based upon reported antagonists for the subtypes PAR1 and PAR2. Modified versions of the PAR1 antagonist RWJ-58259 containing alkyne adapters were connected via cycloaddition reactions to azide-capped polyethylene glycol (PEG) spacers attached to imidazopyridazine-based PAR2 antagonists. Initial studies of the PAR1–PAR2 antagonists indicated that they inhibited G alpha q-mediated calcium mobilization in endothelial and cancer cells driven by both PAR1 and PAR2 agonists. Compounds of this novel class hold promise for the prevention of restenosis, cancer cell metastasis, and other proliferative disorders.
Investigation Of Solvation And Solvent Coordination Effects In Iron Porphyrin Nitrosyls By Infrared Spectroelectrochemistry And Dft Calculations, Md. Hafizur Rahman, Michael D. Ryan
Investigation Of Solvation And Solvent Coordination Effects In Iron Porphyrin Nitrosyls By Infrared Spectroelectrochemistry And Dft Calculations, Md. Hafizur Rahman, Michael D. Ryan
Chemistry Faculty Research and Publications
Visible and infrared spectroelectrochemistry of Fe(OEPone)(NO) (H2OEPone = octaethylporphinone) were examined in methylene chloride and THF. The visible spectra of Fe(OEPone)(NO) were similar in both solvents. Unlike other ferrous porphyrin nitrosyls, a six-coordinate complex was formed with THF as a ligand. This led to two nitrosyl bands in the infrared spectrum. The absorbance of these bands depended on the concentration of THF in the solution. Solvation and coordination effects on the carbonyl and nitrosyl bands were observed for both the nitrosyl and reduced-nitrosyl complexes. DFT calculations were carried out to interpret the spectral changes.
Unveiling Charge-Separation Dynamics In Cds/Metal–Organic Framework Composites For Enhanced Photocatalysis, Hai-Qun Xu, Sizhuo Yang, Xing Ma, Jier Huang, Hai-Long Wang
Unveiling Charge-Separation Dynamics In Cds/Metal–Organic Framework Composites For Enhanced Photocatalysis, Hai-Qun Xu, Sizhuo Yang, Xing Ma, Jier Huang, Hai-Long Wang
Chemistry Faculty Research and Publications
Photocatalytic water splitting for H2 production becomes one of the most favorable pathways for solar energy utilization, while the charge-separation dynamics in composite photocatalysts is largely elusive. In the present work, CdS-decorated metal–organic framework (MOF) composites, namely, CdS/UiO-66, have been synthesized and exhibit high H2 production activity from photocatalytic water splitting, far surpassing the MOF and CdS counterparts, under visible light irradiation. Transient absorption (TA) spectroscopy has been adopted in this report to unveil the charge-separation dynamics in CdS/UiO-66 composites, a key process that dictates their function in photocatalysis. We show that, in addition to the preferable formation …
Erratum: “Several Levels Of Theory For Description Of Isotope Effects In Ozone: Effect Of Resonance Lifetimes And Channel Couplings”, Alexander Teplukhin, Igor Gayday, Dmitri Babikov
Erratum: “Several Levels Of Theory For Description Of Isotope Effects In Ozone: Effect Of Resonance Lifetimes And Channel Couplings”, Alexander Teplukhin, Igor Gayday, Dmitri Babikov
Chemistry Faculty Research and Publications
No abstract provided.
Reactive Pathways In The Bromobenzene-Ammonia Dimer Cation Radical: Evidence For A Roaming Halogen Radical, Silver Nyambo, Brandon Uhler, Lloyd Godfrey Muzangwa, Maxim Vadimovich Ivanov, Bradley K. Welch, Richard Dawes, Scott A. Reid
Reactive Pathways In The Bromobenzene-Ammonia Dimer Cation Radical: Evidence For A Roaming Halogen Radical, Silver Nyambo, Brandon Uhler, Lloyd Godfrey Muzangwa, Maxim Vadimovich Ivanov, Bradley K. Welch, Richard Dawes, Scott A. Reid
Chemistry Faculty Research and Publications
Photoinitiated reactions in van der Waals complexes provide a means to examine reactive pathways from well-defined initial geometries. In recent work, we re-examined reactive pathways following resonant two-photon ionization (R2PI) of the chlorobenzene-ammonia (PhCl⋯NH3) dimer. The dimer cation radical reacts primarily via Cl atom loss, and additional channels corresponding to HCl and H atom loss were identified. The structure of the reactive complex was confirmed as an in-plane σ-type, and computational studies of the dimer cation radical potential energy landscape revealed two nearly isoenergetic arenium ion intermediates (or Wheland intermediates). The intermediate produced from ipso addition was not …
Several Levels Of Theory For Description Of Isotope Effects In Ozone: Effect Of Resonance Lifetimes And Channel Couplings, Alexander Teplukhin, Dmitri Babikov, Igor Gayday
Several Levels Of Theory For Description Of Isotope Effects In Ozone: Effect Of Resonance Lifetimes And Channel Couplings, Alexander Teplukhin, Dmitri Babikov, Igor Gayday
Chemistry Faculty Research and Publications
In this paper, two levels of theory are developed to determine the role of scattering resonances in the process of ozone formation. At the lower theory level, we compute resonance lifetimes in the simplest possible way, by neglecting all couplings between the diabatic vibrational channels in the problem. This permits to determine the effect of “shape” resonances, trapped behind the centrifugal barrier and populated by quantum tunneling. At the next level of theory, we include couplings between the vibrational channels, which permits to determine the role of Feshbach resonances and interaction of different reaction pathways on the global PES of …
Multielectron Redox Chemistry Of Transition Metal Complexes Supported By A Non‐Innocent N3p2 Ligand: Synthesis, Characterization, And Catalytic Properties, Denan Wang, Danushka M. Ekanayake, Sergey V. Lindeman, Cláudio N. Verani, Adam T. Fiedler
Multielectron Redox Chemistry Of Transition Metal Complexes Supported By A Non‐Innocent N3p2 Ligand: Synthesis, Characterization, And Catalytic Properties, Denan Wang, Danushka M. Ekanayake, Sergey V. Lindeman, Cláudio N. Verani, Adam T. Fiedler
Chemistry Faculty Research and Publications
A new redox‐active, diarylamido‐based ligand (LN3P2) capable of κ5‐N,N,N,P,P chelation has been used to prepare a series of complexes with the general formula [MII(LN3P2)]X, where M = Fe (1; X = OTf), Co (2; X = ClO4), or Ni (3; X = ClO4). The diarylamido core of monoanionic LN3P2 is derived from bis(2‐amino‐4‐methylphenyl)amine, which undergoes condensation with two equivalents of 2‐(diphenylphosphanyl)benzaldehyde to provide chelating arms with both arylphosphine and imine donors. X‐ray structural, magnetic, …
Dft-Assisted Design And Evaluation Of Bifunctional Amine/Pyridine-Oxazoline Metal Catalysts For Additions Of Ketones To Unactivated Alkenes And Alkynes, Eric Greve, Jacob D. Porter, Chris Dockendorff
Dft-Assisted Design And Evaluation Of Bifunctional Amine/Pyridine-Oxazoline Metal Catalysts For Additions Of Ketones To Unactivated Alkenes And Alkynes, Eric Greve, Jacob D. Porter, Chris Dockendorff
Chemistry Faculty Research and Publications
Bifunctional catalyst systems for the direct addition of ketones to unactivated alkenes/alkynes were designed and modeled by density functional theory (DFT). The designed catalysts possess bidentate ligands suitable for binding of pi-acidic group 10 metals capable of activating alkenes/alkynes, and a tethered organocatalyst amine to activate the ketone via formation of a nucleophilic enamine intermediate. The structures of the designed catalysts before and after C–C bond formation were optimized using DFT, and reaction steps involving group 10 metals were predicted to be significantly exergonic. A novel oxazoline precatalyst with a tethered amine separated by a meta-substituted benzene spacer was synthesized …
Π-Π Stacking Vs. C–H/Π Interaction: Excimer Formation And Charge Resonance Stabilization In Van Der Waals Clusters Of 9,9′-Dimethylfluorene, Damian Kokkin, Maxim Vadimovich Ivanov, John Loman, Sheng Cai, Brandon Uhler, Neil Reilly, Rajendra Rathore, Scott A. Reid
Π-Π Stacking Vs. C–H/Π Interaction: Excimer Formation And Charge Resonance Stabilization In Van Der Waals Clusters Of 9,9′-Dimethylfluorene, Damian Kokkin, Maxim Vadimovich Ivanov, John Loman, Sheng Cai, Brandon Uhler, Neil Reilly, Rajendra Rathore, Scott A. Reid
Chemistry Faculty Research and Publications
Studies of exciton and hole stabilization in multichromophoric systems underpin our understanding of electron transfer and transport in materials and biomolecules. The simplest model systems are dimeric, and recently we compared the gas-phase spectroscopy and dynamics of van der Waals dimers of fluorene, 9-methylfluorene (MF), and 9,9′-dimethylfluorene (F1) to assess how sterically controlled facial encumbrance modulates the dynamics of excimer formation and charge resonance stabilization (CRS). Dimers of fluorene and MF show only excimer emission upon electronic excitation, and significant CRS as evidenced in a reduced ionization potential for the dimer relative the monomer. By contrast, the dimer of F1 …
A Synthetic Model Of The Nonheme Iron–Superoxo Intermediate Of Cysteine Dioxygenase, Anne A. Fischer, Sergey V. Lindeman, Adam T. Fiedler
A Synthetic Model Of The Nonheme Iron–Superoxo Intermediate Of Cysteine Dioxygenase, Anne A. Fischer, Sergey V. Lindeman, Adam T. Fiedler
Chemistry Faculty Research and Publications
A nonheme Fe(II) complex (1) that models substrate-bound cysteine dioxygenase (CDO) reacts with O2 at −80 °C to yield a purple intermediate (2). Analysis with spectroscopic and computational methods determined that 2 features a thiolate-ligated Fe(III) center bound to a superoxide radical, mimicking the putative structure of a key CDO intermediate.
Dft-Assisted Design And Evaluation Of Bifunctional Copper(I) Catalysts For The Direct Intermolecular Addition Of Aldehydes And Ketones To Alkynes, Jacob D. Porter, Eric Greve, Abdulmohsen Alsafran, Adam R. Benoit, Sergey V. Lindeman, Chris Dockendorff
Dft-Assisted Design And Evaluation Of Bifunctional Copper(I) Catalysts For The Direct Intermolecular Addition Of Aldehydes And Ketones To Alkynes, Jacob D. Porter, Eric Greve, Abdulmohsen Alsafran, Adam R. Benoit, Sergey V. Lindeman, Chris Dockendorff
Chemistry Faculty Research and Publications
Bifunctional catalysts containing discrete metal pi-acid and amine sites were designed and investigated for the direct intermolecular addition of aldehydes and ketones to unactivated alkynes. Copper(I)-based catalysts were prioritized based on intramolecular (Conia-ene type) reactions, and complexes were designed with tridentate ligands and potentially hemilabile heterocyclic spacers. The structures of the designed catalysts were computed using density functional theory (DFT), and the relative energies of putative catalytic intermediates were estimated and used to prioritize catalyst designs. Novel bifunctional precatalysts containing a thiazole spacer were synthesized via a 9-step sequence and combined with transition metals before screening for the direct addition …
Synthesis And Evaluation Of 4-Cycloheptylphenols As Selective Estrogen Receptor-Β Agonists (Serbas), K. L. Iresha Sampathi Perera, Alicia M. Hanson, Sergey V. Lindeman, Andrea Imhoff, Xingyun Lu, Daniel S. Sem, William A. Donaldson
Synthesis And Evaluation Of 4-Cycloheptylphenols As Selective Estrogen Receptor-Β Agonists (Serbas), K. L. Iresha Sampathi Perera, Alicia M. Hanson, Sergey V. Lindeman, Andrea Imhoff, Xingyun Lu, Daniel S. Sem, William A. Donaldson
Chemistry Faculty Research and Publications
A short and efficient route to 4-(4-hydroxyphenyl)cycloheptanemethanol was developed, which resulted in the preparation of a mixture of 4 stereoisomers. The stereoisomers were separated by preparative HPLC, and two of the stereoisomers identified by X-ray crystallography. The stereoisomers, as well as a small family of 4-cycloheptylphenol derivatives, were evaluated as estrogen receptor-beta agonists. The lead compound, 4-(4-hydroxyphenyl)cycloheptanemethanol was selective for activating ER relative to seven other nuclear hormone receptors, with 300-fold selectivity for the β over α isoform and with EC50 of 30–50 nM in cell-based and direct binding assays.
Synthesis Of A Novel Bicyclic Scaffold Inspired By The Antifungal Natural Product Sordarin, Yibiao Wu, Chris Dockendorff
Synthesis Of A Novel Bicyclic Scaffold Inspired By The Antifungal Natural Product Sordarin, Yibiao Wu, Chris Dockendorff
Chemistry Faculty Research and Publications
A simplified bicyclic scaffold inspired by the antifungal natural product sordarin was designed and synthesized which maintains the carboxylic acid/aldehyde (or nitrile) pharmacophore. Docking studies with the target for sordarin, the fungal protein eukaryotic elongation factor 2 (eEF2), suggested that the novel scaffolds may bind productively. A densely functionalized chiral cyclopentadiene was constructed in 8 steps and utilized in a Diels-Alder reaction with acrylonitrile. The resulting [2.2.1] cycloheptene was transformed into a scaffold possessing vicinal carboxylic acid and nitrile groups, with orientations predicted to provide high affinity for eEF2. The synthetic approach disclosed here sets the stage for a renewed …
Vertical Vs. Adiabatic Ionization Energies In Solution And Gas-Phase: Probing Ionization-Induced Reorganization In Conformationally-Mobile Bichromophoric Actuators Using Photoelectron Spectroscopy, Electrochemistry And Theory, Maxim Vadimovich Ivanov, Denan Wang, Depeng Zhang, Rajendra Rathore, Scott A. Reid
Vertical Vs. Adiabatic Ionization Energies In Solution And Gas-Phase: Probing Ionization-Induced Reorganization In Conformationally-Mobile Bichromophoric Actuators Using Photoelectron Spectroscopy, Electrochemistry And Theory, Maxim Vadimovich Ivanov, Denan Wang, Depeng Zhang, Rajendra Rathore, Scott A. Reid
Chemistry Faculty Research and Publications
Ionization-induced structural and conformational reorganization in various π-stacked dimers and covalently linked bichromophores is relevant to many processes in biological systems and functional materials. In this work, we examine the role of structural, conformational, and solvent reorganization in a set of conformationally mobile bichromophoric donors, using a combination of gas-phase photoelectron spectroscopy, solution-phase electrochemistry, and density functional theory (DFT) calculations. Photoelectron spectral analysis yields both adiabatic and vertical ionization energies (AIE/VIE), which are compared with measured (adiabatic) solution-phase oxidation potentials (Eox). Importantly, we find a strong correlation of Eox with AIE, but not VIE, reflecting variations …
Spreading Electron Density Thin: Increasing The Chromophore Size In Polyaromatic Wires Decreases Interchromophoric Electronic Coupling, Mohammad Mosharraf Hossain, Maxim Vadimovich Ivanov, Denan Wang, Scott A. Reid, Rajendra Rathore
Spreading Electron Density Thin: Increasing The Chromophore Size In Polyaromatic Wires Decreases Interchromophoric Electronic Coupling, Mohammad Mosharraf Hossain, Maxim Vadimovich Ivanov, Denan Wang, Scott A. Reid, Rajendra Rathore
Chemistry Faculty Research and Publications
The development of novel polychromophoric materials using extended polycyclic aromatic hydrocarbons as a single large chromophore holds promise for long-range charge-transfer applications in photovoltaic devices and molecular electronics. However, it is not well-understood how the interchromophoric electronic coupling varies with the chromophore size in linearly connected molecular wires. Here, we show with the aid of electrochemistry, electronic spectroscopy, density functional theory calculations, and theoretical modeling that as the number of aromatic moieties in a single chromophore increases, the interchromophoric electronic coupling decreases and may reach negligible values if the chromophore is sufficiently large. The origin of this initially surprising result …
Molecular Actuators In Action: Electron-Transfer-Induced Conformation Transformation In Cofacially Arrayed Polyfluorenes, Denan Wang, Marat R. Talipov, Maxim Vadimovich Ivanov, Saber Mirzaei, Sergey V. Lindeman, Sheng Cai, Rajendra Rathore, Scott A. Reid
Molecular Actuators In Action: Electron-Transfer-Induced Conformation Transformation In Cofacially Arrayed Polyfluorenes, Denan Wang, Marat R. Talipov, Maxim Vadimovich Ivanov, Saber Mirzaei, Sergey V. Lindeman, Sheng Cai, Rajendra Rathore, Scott A. Reid
Chemistry Faculty Research and Publications
There is much current interest in the design of molecular actuators, which undergo reversible, controlled motion in response to an external stimulus (light, heat, oxidation, etc.). Here we describe the design and synthesis of a series of cofacially arrayed polyfluorenes (MeFnHm) with varied end-capping groups, which undergo redox-controlled electromechanical actuation. Such cofacially arrayed polyfluorenes are a model molecular scaffold to investigate fundamental processes of charge and energy transfer across a π-stacked assembly, and we show with the aid of NMR and optical spectroscopies, X-ray crystallography and DFT calculations that in the neutral state the …
Design, Synthesis And Study Of Redox And Optoelectronic Properties Of Aromatic Oxidants And Polycyclic Aromatic Hydrocarbons, Mohammad Mosharraf Hossain
Design, Synthesis And Study Of Redox And Optoelectronic Properties Of Aromatic Oxidants And Polycyclic Aromatic Hydrocarbons, Mohammad Mosharraf Hossain
Dissertations (1934 -)
Organic materials play a significant role for the next generation photovoltaic devices that convert solar energy into usable forms of energy. In this regard, polycyclic aromatic hydrocarbons (PAHs) are fundamental tools in the developing area of molecular electronics and photovoltaics as they show excellent optical/electronic properties and are well-suited for applications in such developing areas as flexible display devices, field effect transistors and solar cell panels. Design and synthesis of novel materials for photovoltaics applications would require the proper understanding the mechanism of charge transport and identification of the structural features necessary in a particular molecular wire or PAH. To …
Photochemical Expulsion Of Leaving Groups From A Naphthothiophene-2-Carboxamide Linked To A Chromophore, Lingzi Li
Dissertations (1934 -)
Two bichromophoric systems were synthesized which have thioxanthone as the chromophore that absorbs the incident light and a naphthothiophene-2-carboxanilide, which serves as a triplet excited state energy acceptor. Upon excitation the triplet excited state of the thioxanthone is populated via intersystem crossing, which is efficient with isc = 0.68. Based on the relative energies of the triplet excited states of thioxanthone (ET = 65 kcal mol-1) and naphthothiophene (ET = 51 kcal mol-1), the subsequent triplet excited state energy transfer to generate the triplet excited state of the naphthothiophene-2-carboxamide should be a very rapid process that is 14 kcal mol1 …
The Photodynamic And Structural Analyses Of Advanced Materials For Solar Fuel Conversion, Brian Pattengale
The Photodynamic And Structural Analyses Of Advanced Materials For Solar Fuel Conversion, Brian Pattengale
Dissertations (1934 -)
Mitigating the current and future climate and pollution issues that have been brought on by the combustion of fossil fuels is of utmost importance and will rely on, in part, the availability of renewable fuel sources. Of the possible sources of energy, solar is abundant, but must be harnessed efficiently and stored as a solar fuel to overcome the current storage issues that limit photovoltaic cells. One such fuel, H2(g), represents a carbon-neutral source of energy if it can be efficiently liberated from water via the water splitting reaction. Thus, much attention is focused on designing materials to perform the …
Game Of Frontier Orbitals: A View On The Rational Design Of Novel Charge-Transfer Materials, Maxim Vadimovich Ivanov, Scott A. Reid, Rajendra Rathore
Game Of Frontier Orbitals: A View On The Rational Design Of Novel Charge-Transfer Materials, Maxim Vadimovich Ivanov, Scott A. Reid, Rajendra Rathore
Chemistry Faculty Research and Publications
Since the first application of frontier molecular orbitals (FMOs) to rationalize stereospecificity of pericyclic reactions, FMOs have remained at the forefront of chemical theory. Yet, the practical application of FMOs in the rational design and synthesis of novel charge transfer materials remains under-appreciated. In this Perspective, we demonstrate that molecular orbital theory is a powerful and universal tool capable of rationalizing the observed redox/optoelectronic properties of various aromatic hydrocarbons in the context of their application as charge-transfer materials. Importantly, the inspection of FMOs can provide instantaneous insight into the interchromophoric electronic coupling and polaron delocalization in polychromophoric assemblies, and therefore …
Characterization Of Protease-Activated Receptor (Par) Ligands: Parmodulins Are Reversible Allosteric Inhibitors Of Par1-Driven Calcium Mobilization In Endothelial Cells, Disha M. Gandhi, Mark W. Majewski, Ricardo Rosas Jr., Kaitlin Kentala, Trevor J. Foster, Eric Greve, Chris Dockendorff
Characterization Of Protease-Activated Receptor (Par) Ligands: Parmodulins Are Reversible Allosteric Inhibitors Of Par1-Driven Calcium Mobilization In Endothelial Cells, Disha M. Gandhi, Mark W. Majewski, Ricardo Rosas Jr., Kaitlin Kentala, Trevor J. Foster, Eric Greve, Chris Dockendorff
Chemistry Faculty Research and Publications
Several classes of ligands for Protease-Activated Receptors (PARs) have shown impressive anti-inflammatory and cytoprotective activities, including PAR2 antagonists and the PAR1-targeting parmodulins. In order to support medicinal chemistry studies with hundreds of compounds and to perform detailed mode-of-action studies, it became important to develop a reliable PAR assay that is operational with endothelial cells, which mediate the cytoprotective effects of interest. We report a detailed protocol for an intracellular calcium mobilization assay with adherent endothelial cells in multiwell plates that was used to study a number of known and new PAR1 and PAR2 ligands, including an alkynylated version of the …
The Role Of Torsional Dynamics On Hole And Exciton Stabilization In Π‐Stacked Assemblies: Design Of Rigid Torsionomers Of A Cofacial Bifluorene, Denan Wang, Maxim Vadimovich Ivanov, Damian Kokkin, John Loman, Jin-Zhe Cai, Scott A. Reid, Rajendra Rathore
The Role Of Torsional Dynamics On Hole And Exciton Stabilization In Π‐Stacked Assemblies: Design Of Rigid Torsionomers Of A Cofacial Bifluorene, Denan Wang, Maxim Vadimovich Ivanov, Damian Kokkin, John Loman, Jin-Zhe Cai, Scott A. Reid, Rajendra Rathore
Chemistry Faculty Research and Publications
Exciton and charge delocalization across π‐stacked assemblies is of importance in biological systems and functional polymeric materials. To examine the requirements for exciton and hole stabilization, cofacial bifluorene (F2) torsionomers were designed, synthesized, and characterized: unhindered (model) MeF2, sterically hindered tBuF2, and cyclophane‐like CF2, where fluorenes are locked in a perfect sandwich orientation via two methylene linkers. This set of bichromophores with varied torsional rigidity and orbital overlap shows that exciton stabilization requires a perfect sandwich‐like arrangement, as seen by strong excimeric‐like emission only in CF2 and MeF2. …
Photoinduced Interfacial Charge Separation Dynamics In Zeolitic Imidazolate Framework, Brian Pattengale, Jier Huang
Photoinduced Interfacial Charge Separation Dynamics In Zeolitic Imidazolate Framework, Brian Pattengale, Jier Huang
Chemistry Faculty Research and Publications
Owing to their porous structure and tunable framework, zeolitic imidazolate frameworks (ZIFs) have garnered considerable attention as promising photocatalytic materials. However, little is known regarding their photophysical properties. In this work, we report the photoinduced charge separation dynamics in a ZIF-67 thin film through interfacial electron transfer (ET) to methylene blue (MB+) via ultrafast transient absorption spectroscopy. We show that the ET process occurs through two distinct pathways, including an ultrafast (<200 fs) process from the [CoII(mim)2] units located on the surface of ZIF-67 film that are directly in contact with MB+ and a relatively slower ET process …
Practical Spectrophotometric Assay For The Dape-Encoded N-Succinyl-L,L-Diaminopimelic Acid Desuccinylase, A Potential Antibiotic Target, Tahirah K. Heath, Marlon R. Lutz Jr., Cory Reidl, Estefany R. Guzman, Claire A. Herbert, Boguslaw P. Nocek, Richard C. Holz, Kenneth W. Olsen, Miguel A. Ballicora, Daniel P. Becker
Practical Spectrophotometric Assay For The Dape-Encoded N-Succinyl-L,L-Diaminopimelic Acid Desuccinylase, A Potential Antibiotic Target, Tahirah K. Heath, Marlon R. Lutz Jr., Cory Reidl, Estefany R. Guzman, Claire A. Herbert, Boguslaw P. Nocek, Richard C. Holz, Kenneth W. Olsen, Miguel A. Ballicora, Daniel P. Becker
Chemistry Faculty Research and Publications
A new enzymatic assay for the bacterial enzyme succinyl-diaminopimelate desuccinylase (DapE, E.C. 3.5.1.18) is described. This assay employs N6-methyl-N2-succinyl-L,L-diaminopimelic acid (N6-methyl-L,L-SDAP) as the substrate with ninhydrin used to detect cleavage of the amide bond of the modified substrate, wherein N6-methylation enables selective detection of the primary amine enzymatic product. Molecular modeling supported preparation of the mono-N6-methylated-L,L-SDAP as an alternate substrate for the assay, given binding in the active site of DapE predicted to be comparable to the endogenous substrate. The alternate substrate for the assay, N6 …
Synthesis Of Symmetric And Unsymmetric Secondary Amines From The Ligand-Promoted Ruthenium-Catalyzed Deaminative Coupling Reaction Of Primary Amines, Pandula T. Kirinde Arachchige, Hanbin Lee, Chae S. Yi
Synthesis Of Symmetric And Unsymmetric Secondary Amines From The Ligand-Promoted Ruthenium-Catalyzed Deaminative Coupling Reaction Of Primary Amines, Pandula T. Kirinde Arachchige, Hanbin Lee, Chae S. Yi
Chemistry Faculty Research and Publications
The catalytic system generated in situ from the tetranuclear Ru–H complex with a catechol ligand (1/L1) was found to be effective for the direct deaminative coupling of two primary amines to form secondary amines. The catalyst 1/L1 was highly chemoselective for promoting the coupling of two different primary amines to afford unsymmetric secondary amines. The analogous coupling of aniline with primary amines formed aryl-substituted secondary amines. The treatment of aniline-d7 with 4-methoxybenzylamine led to the coupling product with significant deuterium incorporation on CH2 (18% D). The most pronounced carbon isotope effect …