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 181 - 210 of 1105
Full-Text Articles in Chemistry
Synthesis And Characterization Of Biomimetic Models Of Mononuclear Nonheme Iron Dioxygenases And Their Reactive Intermediates, Anne Alyse Fischer
Synthesis And Characterization Of Biomimetic Models Of Mononuclear Nonheme Iron Dioxygenases And Their Reactive Intermediates, Anne Alyse Fischer
Dissertations (1934 -)
Mononuclear non-heme iron dioxygenases (MNIDs) are a class of enzymes that catalyze a variety of reactions, from amino acid catabolism to bioremediation using molecular oxygen. This work focuses on three types of MNIDs: thiol dioxygenaes (TDOs), aminophenoldioxygenases (APDOs), and sulfoxide synthases (SOSs). TDOs, found in mammals, regulate the levels of cysteine along with other thiol-containing molecules, using molecular oxygen to convert them into their corresponding sulfinic acids. APDOs catalyze the oxidative ring cleavage in the biodegradation of nitroaromatics. SOSs are involved in the biosynthesis of large biologically relevant molecules in humans. Although this class of enzymes has gained more attention …
Nadph-Cytochrome P450 Oxidoreductase: Extraction Of The Full-Length Protein And Methyl-Trosy Nmr Of The Soluble Mutants, Sara Ali Jamal Arafeh
Nadph-Cytochrome P450 Oxidoreductase: Extraction Of The Full-Length Protein And Methyl-Trosy Nmr Of The Soluble Mutants, Sara Ali Jamal Arafeh
Master's Theses (2009 -)
NADPH-cytochrome p450 oxidoreductase (CYPOR) is a membrane-bound protein in living cells. CYPOR delivers electrons to cytochrome p450 proteins (CYPs) to catalyze metabolism of drugs and synthesis of steroids. Extraction and solubilization of CYPOR from the membrane is typically done with the TritonX-100 detergent. The amount of the solubilized protein by this detergent, however, remains relatively low to structurally analyze CYPOR with NMR spectroscopy. The goal of the first project in this thesis was to optimize the amount of the extracted CYPOR from the E. coli membrane using various detergents and additives. To this aim, non-ionic detergents with variable hydrophobicity (TritonX-100, …
Photoremovable Protecting Groups Based On Electrocyclization With Leaving Group Expulsion Via A Proposed Zwitterion, Gilbert Ndzeidze
Photoremovable Protecting Groups Based On Electrocyclization With Leaving Group Expulsion Via A Proposed Zwitterion, Gilbert Ndzeidze
Dissertations (1934 -)
The triplet excited state of thioxanthone produced by photolysis undergoes reversible triplet energy transfer with a trimethylene - linked benzothiophene-2-carboxanilide ring system. The ensuing electrocyclic ring closure of the anilide moiety produces a putative zwitterionic intermediate that is capable of expelling leaving groups (LG-) from the C-3 position of the benzothiophene ring. Stern-Volmer quenching studies with cyclohexadiene as quencher furnish the rate constants for the triplet excitation transfer in the forward and reverse directions, which can be expressed as an equilibrium constant K = 0.058. Overall, the rate of triplet excited state reaction becomes K x kr = 5.7 x …
Insight Into Solvent Coordination Of An Iron Porphyrin Hydroxylamine Complex From Spectroscopy And Dft Calculations, Md. Hafizur Rahman, Michael D. Ryan
Insight Into Solvent Coordination Of An Iron Porphyrin Hydroxylamine Complex From Spectroscopy And Dft Calculations, Md. Hafizur Rahman, Michael D. Ryan
Chemistry Faculty Research and Publications
The reduction of Fe(OEP)(NO) in the presence of substituted phenols leads to a three‐electron reduction to form Fe(OEP)(NH2OH), which has been characterized by visible spectroscopy and electron stoichiometry. In this work, we have further characterized this species using infrared and 1H NMR spectroscopy, along with DFT calculations. The infrared bands in the 3400–3600 cm–1 region, due to hydroxylamine, were significantly downshifted to the 2500–2700 cm–1 region when 4‐[D1]chlorophenol replaced the normal abundance acid. Using 1H NMR spectroscopy, the hydroxylamine and the meso‐protons were identified. From DFT calculations, the 1H NMR …
Synthetic Analogues Of The Snail Toxin 6-Bromo-2-Mercaptotryptamine Dimer (Brmt) Reveal That Lipid Bilayer Perturbation Does Not Underlie Its Modulation Of Voltage-Gated Potassium Channels, Chris Dockendorff, Disha M. Gandhi, Ian H. Kimball, Kenneth S. Eum, Radda Rusinova, Helgi I. Ingolfsson, Ruchi Kapoor, Thasin Peyear, Matthew W. Dodge, Stephen F. Martin, Richard W. Aldrich, Olaf S. Andersen, Jon T. Sack
Synthetic Analogues Of The Snail Toxin 6-Bromo-2-Mercaptotryptamine Dimer (Brmt) Reveal That Lipid Bilayer Perturbation Does Not Underlie Its Modulation Of Voltage-Gated Potassium Channels, Chris Dockendorff, Disha M. Gandhi, Ian H. Kimball, Kenneth S. Eum, Radda Rusinova, Helgi I. Ingolfsson, Ruchi Kapoor, Thasin Peyear, Matthew W. Dodge, Stephen F. Martin, Richard W. Aldrich, Olaf S. Andersen, Jon T. Sack
Chemistry Faculty Research and Publications
Drugs do not act solely by canonical ligand–receptor binding interactions. Amphiphilic drugs partition into membranes, thereby perturbing bulk lipid bilayer properties and possibly altering the function of membrane proteins. Distinguishing membrane perturbation from more direct protein–ligand interactions is an ongoing challenge in chemical biology. Herein, we present one strategy for doing so, using dimeric 6-bromo-2-mercaptotryptamine (BrMT) and synthetic analogues. BrMT is a chemically unstable marine snail toxin that has unique effects on voltage-gated K+ channel proteins, making it an attractive medicinal chemistry lead. BrMT is amphiphilic and perturbs lipid bilayers, raising the question of whether its action against K …
From Intramolecular (Circular) In An Isolated Molecule To Intermolecular Hole Delocalization In A Two‐Dimensional Solid‐State Assembly: The Case Of Pillarene, Maxim V. Ivanov, Denan Wang, Tushar S. Navale, Sergey V. Lindeman, Rajendra Rathore
From Intramolecular (Circular) In An Isolated Molecule To Intermolecular Hole Delocalization In A Two‐Dimensional Solid‐State Assembly: The Case Of Pillarene, Maxim V. Ivanov, Denan Wang, Tushar S. Navale, Sergey V. Lindeman, Rajendra Rathore
Chemistry Faculty Research and Publications
To achieve long‐range charge transport/separation and, in turn, bolster the efficiency of modern photovoltaic devices, new molecular scaffolds are needed that can self‐assemble in two‐dimensional (2D) arrays while maintaining both intra‐ and intermolecular electronic coupling. In an isolated molecule of pillarene, a single hole delocalizes intramolecularly via hopping amongst the circularly arrayed hydroquinone ether rings. The crystallization of pillarene cation radical produces a 2D self‐assembly with three intermolecular dimeric (sandwich‐like) contacts. Surprisingly, each pillarene in the crystal lattice bears a fractional formal charge of +1.5. This unusual stoichiometry of oxidized pillarene in crystals arises from effective charge distribution within the …
Nmr Resonance Assignments Of Rnase P Protein From Thermotoga Maritima, Danyun Zeng, Benjamin P. Brown, Markus W. Voehler, Sheng Cai, Nicholas J. Reiter
Nmr Resonance Assignments Of Rnase P Protein From Thermotoga Maritima, Danyun Zeng, Benjamin P. Brown, Markus W. Voehler, Sheng Cai, Nicholas J. Reiter
Chemistry Faculty Research and Publications
Ribonuclase P (RNase P) is an essential metallo-endonuclease that catalyzes 5′ precursor-tRNA (ptRNA) processing and exists as an RNA-based enzyme in bacteria, archaea, and eukaryotes. In bacteria, a large catalytic RNA and a small protein component assemble to recognize and accurately cleave ptRNA and tRNA-like molecular scaffolds. Substrate recognition of ptRNA by bacterial RNase P requires RNA-RNA shape complementarity, intermolecular base pairing, and a dynamic protein-ptRNA binding interface. To gain insight into the binding specificity and dynamics of the bacterial protein-ptRNA interface, we report the backbone and side chain 1H, 13C, and 15N resonance assignments of the …
Reaction Chemistry Of Silver(I) Trifluoromethanesulfonate Complexes Of Nitrogen-Confused C-Scorpionates, James R. Gardinier, Kristin J. Meise, Fathiya Jahan, Sergey V. Lindeman
Reaction Chemistry Of Silver(I) Trifluoromethanesulfonate Complexes Of Nitrogen-Confused C-Scorpionates, James R. Gardinier, Kristin J. Meise, Fathiya Jahan, Sergey V. Lindeman
Chemistry Faculty Research and Publications
Two new C-scorpionate ligands with a bis(3,5-dimethylpyrazol-1-yl)methyl group bound to the 3 position of either an N-tosyl (TsL*) or an N–H pyrazole (HL*) ring have been prepared. The silver(I) complexes of these new ligands and the two previously reported analogous ligands with unsubstituted bis(pyrazol-1-yl)methyl groups (TsL and HL) in both 1:1 and 2:1 ligand/metal ratios were investigated to explore the effects of ligand sterics on their physical and chemical properties. The structurally characterized derivatives of the type [Ag(L)2](OTf) are four-coordinate, where the confused pyrazolyl is not bound to the …
Elucidating Charge Separation Dynamics In A Hybrid Metal–Organic Framework Photocatalyst For Light-Driven H2 Evolution, Sizhuo Yang, Donghua Fan, Wenhui Hu, Brian Pattengale, Cunming Liu, Xiaoyi Zhang, Jier Huang
Elucidating Charge Separation Dynamics In A Hybrid Metal–Organic Framework Photocatalyst For Light-Driven H2 Evolution, Sizhuo Yang, Donghua Fan, Wenhui Hu, Brian Pattengale, Cunming Liu, Xiaoyi Zhang, Jier Huang
Chemistry Faculty Research and Publications
Metal–organic frameworks (MOFs) have emerged as novel scaffolds for artificial photosynthesis due to their unique capability in incorporating homogeneous photosensitizer and catalyst to their robust heterogeneous matrix. In this work, we report the charge separation dynamics between molecular Ru-photosensitizer and Pt-catalyst, both of which were successfully incorporated into a Zr-MOF that demonstrates excellent activity and stability for light-driven H2 generation from water. Using optical transient absorption (OTA) spectroscopy, we show that charge separation in this hybrid MOF occurs via electron transfer (ET) from Ru-photosensitizer to Pt-catalyst. Using Pt L3-edge X-ray transient absorption (XTA) spectroscopy, we observed the …
Par1 Agonists Stimulate Apc-Like Endothelial Cytoprotection And Confer Resistance To Thromboinflammatory Injury, Karen De Ceunynck, Christian G. Peters, Abhishek Jain, Sarah J. Higgins, Omozuanvbo Aisiku, Jennifer L. Fitch-Tewfik, Sharjeel A. Chaudhry, Chris Dockendorff, Samir M. Parikh, Donald E. Ingber, Robert Flaumenhaft
Par1 Agonists Stimulate Apc-Like Endothelial Cytoprotection And Confer Resistance To Thromboinflammatory Injury, Karen De Ceunynck, Christian G. Peters, Abhishek Jain, Sarah J. Higgins, Omozuanvbo Aisiku, Jennifer L. Fitch-Tewfik, Sharjeel A. Chaudhry, Chris Dockendorff, Samir M. Parikh, Donald E. Ingber, Robert Flaumenhaft
Chemistry Faculty Research and Publications
Stimulation of protease-activated receptor 1 (PAR1) on endothelium by activated protein C (APC) is protective in several animal models of disease, and APC has been used clinically in severe sepsis and wound healing. Clinical use of APC, however, is limited by its immunogenicity and its anticoagulant activity. We show that a class of small molecules termed “parmodulins” that act at the cytosolic face of PAR1 stimulates APC-like cytoprotective signaling in endothelium. Parmodulins block thrombin generation in response to inflammatory mediators and inhibit platelet accumulation on endothelium cultured under flow. Evaluation of the antithrombotic mechanism showed that parmodulins induce cytoprotective signaling …
Facile Synthesis, Structure, Biocompatibility And Antimicrobial Property Of Gold Nanoparticle Composites From Cellulose And Keratin, Chieu D. Tran, Franja Prosenc, Mladen Franko
Facile Synthesis, Structure, Biocompatibility And Antimicrobial Property Of Gold Nanoparticle Composites From Cellulose And Keratin, Chieu D. Tran, Franja Prosenc, Mladen Franko
Chemistry Faculty Research and Publications
A novel, one-pot method was developed to synthesize gold nanoparticle composite from cellulose (CEL), wool keratin (KER) and chloroauric acid. Two ionic liquids, butylmethylimmidazolium chloride and ethylmethylimmidazolium bis(trifluoromethylsulfonyl)imide were used to dissolve CEL, KER and HAuCl4. X-ray diffraction and X-ray photoelectron results show that Au3+ was completely reduced to Au0NPs with size of (5.5 ± 1) nm directly in the composite with NaBH4. Spectroscopy and imaging results indicate that CEL and KER remained chemically intact and were homogeneously distributed in the composites with Au0NPs. Encapsulating Au0NPs into [CEL+KER] composite …
Study Of Förster Resonance Energy Transfer To Lipid Domain Markers Ascertains Partitioning Of Semisynthetic Lipidated N-Ras In Lipid Raft Nanodomains, Anna K. Shishina, Elizaveta A. Kovrigina, Azamat R. Galiakhmetov, Rajendra Rathore, Evgenii L. Kovrigin
Study Of Förster Resonance Energy Transfer To Lipid Domain Markers Ascertains Partitioning Of Semisynthetic Lipidated N-Ras In Lipid Raft Nanodomains, Anna K. Shishina, Elizaveta A. Kovrigina, Azamat R. Galiakhmetov, Rajendra Rathore, Evgenii L. Kovrigin
Chemistry Faculty Research and Publications
Cellular membranes are heterogeneous planar lipid bilayers displaying lateral phase separation with the nanometer-scale liquid-ordered phase (also known as “lipid rafts”) surrounded by the liquid-disordered phase. Many membrane-associated proteins were found to permanently integrate into the lipid rafts, which is critical for their biological function. Isoforms H and N of Ras GTPase possess a unique ability to switch their lipid domain preference depending on the type of bound guanine nucleotide (GDP or GTP). This behavior, however, has never been demonstrated in vitro in model bilayers with recombinant proteins and therefore has been attributed to the action of binding of Ras …
Several Levels Of Theory For Description Of Isotope Effects In Ozone: Symmetry Effect And Mass Effect, Alexander Teplukhin, Dmitri Babikov
Several Levels Of Theory For Description Of Isotope Effects In Ozone: Symmetry Effect And Mass Effect, Alexander Teplukhin, Dmitri Babikov
Chemistry Faculty Research and Publications
The essential components of theory for the description of isotope effects in recombination reaction that forms ozone are presented, including the introduction of three reaction pathways for symmetric and asymmetric isotopomers, a brief review of relevant experimental data for singly- and doubly substituted isotopologues, the definitions of ζ-effect and η-effect, and the introduction of isotopic enrichment δ. Two levels of theory are developed to elucidate the role of molecular symmetry, atomic masses, vibrational zero-point energies, and rotational excitations in the recombination process. The issue of symmetry is not trivial, since the important factors, such as 1/2 and 2, appear in …
Strength Of Π-Stacking, From Neutral To Cation: Precision Measurement Of Binding Energies In An Isolated Π-Stacked Dimer, Damian Kokkin, Maxim V. Ivanov, John Loman, Jin-Zhe Cai, Rajendra Rathore, Scott A. Reid
Strength Of Π-Stacking, From Neutral To Cation: Precision Measurement Of Binding Energies In An Isolated Π-Stacked Dimer, Damian Kokkin, Maxim V. Ivanov, John Loman, Jin-Zhe Cai, Rajendra Rathore, Scott A. Reid
Chemistry Faculty Research and Publications
π-Stacking interactions are ubiquitious across chemistry and biochemistry, impacting areas from organic materials and photovoltaics to biochemistry and DNA. However, experimental data is lacking regarding the strength of π-stacking forces—an issue not settled even for the simplest model system, the isolated benzene dimer. Here, we use two-color appearance potential measurements to determine the binding energies of the isolated, π-stacked dimer of fluorene (C13H10) in ground, excited, and ionic states. Our measurements provide the first precise values for π-stacking interaction energies in these states, which are key benchmarks for theory. Indeed, theoretical predictions using ab initio and …
DicarbonYl{[(E,E)-(2,3,4,5-Η)-6-MethOxy-6-Oxo-2,4-HexaDienYl]TriPhenylPhosphoNium}(TriPhenylPhosphane-ΚP)Iron(1+) HexaFluoridoPhosphate, Yuzhi Ma, Sergey V. Lindeman, William A. Donaldson
DicarbonYl{[(E,E)-(2,3,4,5-Η)-6-MethOxy-6-Oxo-2,4-HexaDienYl]TriPhenylPhosphoNium}(TriPhenylPhosphane-ΚP)Iron(1+) HexaFluoridoPhosphate, Yuzhi Ma, Sergey V. Lindeman, William A. Donaldson
Chemistry Faculty Research and Publications
In the title compound, [Fe(C25H24O2P)(C18H15P)(CO)2]PF6, the Fe atom adopts a square-based pyramidal coordination geometry with the carbonyl groups and the two C=C bonds of the diene defining the basal sites and the phosphane ligand the apical position. The diene ligand has an E,E geometry, with the phosphonium fragment pointed away from the Fe atom. The crystal structure displays C—H⋯F and C—H⋯O hydrogen bonding. The PF6− anion is rotationally disordered over four orientations.
A–C Estrogens As Potent And Selective Estrogen Receptor-Beta Agonists (Serbas) To Enhance Memory Consolidation Under Low-Estrogen Conditions, Alicia M. Hanson, K. L. Iresha Sampathi Perera, Jaekyoon Kim, Rajesh K. Pandey, Noreena Sweeney, Xingyun Lu, Andrea Imhoff, Alexander Craig Mackinnon, Adam J. Wargolet, Rochelle M. Van Hart, Karyn M. Frick, William A. Donaldson, Daniel S. Sem
A–C Estrogens As Potent And Selective Estrogen Receptor-Beta Agonists (Serbas) To Enhance Memory Consolidation Under Low-Estrogen Conditions, Alicia M. Hanson, K. L. Iresha Sampathi Perera, Jaekyoon Kim, Rajesh K. Pandey, Noreena Sweeney, Xingyun Lu, Andrea Imhoff, Alexander Craig Mackinnon, Adam J. Wargolet, Rochelle M. Van Hart, Karyn M. Frick, William A. Donaldson, Daniel S. Sem
Chemistry Faculty Research and Publications
Estrogen receptor-beta (ERβ) is a drug target for memory consolidation in postmenopausal women. Herein is reported a series of potent and selective ERβ agonists (SERBAs) with in vivo efficacy that are A–C estrogens, lacking the B and D estrogen rings. The most potent and selective A–C estrogen is selective for activating ER relative to seven other nuclear hormone receptors, with a surprising 750-fold selectivity for the β over α isoform and with EC50s of 20–30 nM in cell-based and direct binding assays. Comparison of potency in different assays suggests that the ER isoform selectivity is related to the …
Recent Progress In The Synthesis Of Six-Membered Aminocyclitols (2008-2017), William A. Donaldson
Recent Progress In The Synthesis Of Six-Membered Aminocyclitols (2008-2017), William A. Donaldson
Chemistry Faculty Research and Publications
Aminocyclitols are of interest as glucosidase inhibitors, as probes for the study of pseudoglycosyltransferases, and as potential therapeutics for the treatment of Gaucher’s disease. The synthesis of these targets was reviewed in early 2008, and the aim of this review is to cover material relevant to the synthesis of aminocyclitols since that time. While not a focus of this review, biological evaluation of compounds will be presented where it is recorded in the literature.
Quantum Dynamics Of Isolated Molecules: General Discussion, Dmitri Babikov, David Benoit, Joel Bowman, Timothy Burd, David Clary, Robert Donovan, Ingo Fischer, Francesco Gianturco, Majdi Hochlaf, Susmita Kar, Adam Kirrander, Stephen Leone, Thomas Malcomson, Uwe Manthe, Anne B. Mccoy, Jens Petersen, Jeremy Richardson, Petr Slavíček, Thierry Stoecklin, Krzysztof Szalewicz, Ad Van Der Avoird, Roland Wester, Graham Worth, Anne Zehnacker-Rentien
Quantum Dynamics Of Isolated Molecules: General Discussion, Dmitri Babikov, David Benoit, Joel Bowman, Timothy Burd, David Clary, Robert Donovan, Ingo Fischer, Francesco Gianturco, Majdi Hochlaf, Susmita Kar, Adam Kirrander, Stephen Leone, Thomas Malcomson, Uwe Manthe, Anne B. Mccoy, Jens Petersen, Jeremy Richardson, Petr Slavíček, Thierry Stoecklin, Krzysztof Szalewicz, Ad Van Der Avoird, Roland Wester, Graham Worth, Anne Zehnacker-Rentien
Chemistry Faculty Research and Publications
No abstract provided.
Human P450 Cyp17a1: Control Of Substrate Preference By Asparagine 202, Michael C. Gregory, Piotr J. Mak, Yogan Khatri, James R. Kincaid, Stephen G. Sligar
Human P450 Cyp17a1: Control Of Substrate Preference By Asparagine 202, Michael C. Gregory, Piotr J. Mak, Yogan Khatri, James R. Kincaid, Stephen G. Sligar
Chemistry Faculty Research and Publications
CYP17A1 is a key steroidogenic enzyme known to conduct several distinct chemical transformations on multiple substrates. In its hydroxylase activity, this enzyme adds a hydroxyl group at the 17α position of both pregnenolone and progesterone at approximately equal rates. However, the subsequent 17,20 carbon–carbon scission reaction displays variable substrate specificity in the numerous CYP17A1 isozymes operating in vertebrates, manifesting as different Kd and kcat values when presented with 17α-hydroxypregnenlone (OHPREG) versus 17α-hydroxyprogesterone (OHPROG). Here we show that the identity of the residue at position 202 in human CYP17A1, thought to form a hydrogen bond with the A-ring alcohol …
Fhbc, A Hexa‐Peri‐Hexabenzocoronene–Fluorene Hybrid: A Platform For Highly Soluble, Easily Functionalizable Hbcs With An Expanded Graphitic Core, Tushar S. Navale, Maxim V. Ivanov, Mohammad M. Hossain, Rajendra Rathore
Fhbc, A Hexa‐Peri‐Hexabenzocoronene–Fluorene Hybrid: A Platform For Highly Soluble, Easily Functionalizable Hbcs With An Expanded Graphitic Core, Tushar S. Navale, Maxim V. Ivanov, Mohammad M. Hossain, Rajendra Rathore
Chemistry Faculty Research and Publications
Materials based upon hexa‐peri‐hexabenzocoronenes (HBCs) show significant promise in a variety of photovoltaic applications. There remains the need, however, for a soluble, versatile, HBC‐based platform, which can be tailored by incorporation of electroactive groups or groups that can prompt self‐assembly. The synthesis of a HBC–fluorene hybrid is presented that contains an expanded graphitic core that is highly soluble, resists aggregation, and can be readily functionalized at its vertices. This new HBC platform can be tailored to incorporate six electroactive groups at its vertices, as exemplified by a facile synthesis of a representative hexaaryl derivative of FHBC. Synthesis of …
Structural Evidence Of A Major Conformational Change Triggered By Substrate Binding In Dape Enzymes: Impact On The Catalytic Mechanism, Boguslaw P. Nocek, Cory Reidl, Anna Starus, Tahirah Heath, David L. Bienvenue, Jerzy Osipiuk, Robert Jedrzejczak, Andzrej Joachimiak, Daniel P. Becker, Richard C. Holz
Structural Evidence Of A Major Conformational Change Triggered By Substrate Binding In Dape Enzymes: Impact On The Catalytic Mechanism, Boguslaw P. Nocek, Cory Reidl, Anna Starus, Tahirah Heath, David L. Bienvenue, Jerzy Osipiuk, Robert Jedrzejczak, Andzrej Joachimiak, Daniel P. Becker, Richard C. Holz
Chemistry Faculty Research and Publications
The X-ray crystal structure of the dapE-encoded N-succinyl-l,l-diaminopimelic acid desuccinylase from Haemophilus influenzae (HiDapE) bound by the products of hydrolysis, succinic acid and l,l-DAP, was determined at 1.95 Å. Surprisingly, the structure bound to the products revealed that HiDapE undergoes a significant conformational change in which the catalytic domain rotates ∼50° and shifts ∼10.1 Å (as measured at the position of the Zn atoms) relative to the dimerization domain. This heretofore unobserved closed conformation revealed significant movements within the catalytic domain compared to that of wild-type HiDapE, which results in effectively closing off access to …
Unravelling The Correlation Of Electronic Structure And Carrier Dynamics In Cuins2 Nanoparticles, Wenhui Hu, John Ludwig, Brian Pattengale, Sizhuo Yang, Cunming Liu, Xiaobing Zuo, Xiaoyi Zhang, Jier Huang
Unravelling The Correlation Of Electronic Structure And Carrier Dynamics In Cuins2 Nanoparticles, Wenhui Hu, John Ludwig, Brian Pattengale, Sizhuo Yang, Cunming Liu, Xiaobing Zuo, Xiaoyi Zhang, Jier Huang
Chemistry Faculty Research and Publications
In this work, we report the direct correlation of photoinduced carrier dynamics and electronic structure of CuInS2 (CIS) nanoparticles (NPs) using the combination of multiple spectroscopic techniques including steady-state X-ray absorption spectroscopy (XAS), optical transient absorption (OTA), and X-ray transient (XTA) absorption spectroscopy. XAS results show that CIS NPs contain a large amount of surface Cu atoms with ≪four-coordination, which is more severe in CIS NPs with shorter nucleation times, indicating the presence of more Cu defect states in CIS NPs with smaller size particles. Using the combination of OTA and XTA spectroscopy, we show that electrons are trapped …
Unravelling The Correlation Of Electronic Structure And Carrier Dynamics In Cuins2 Nanoparticles, Wenhui Hu, John Ludwig, Brian Pattengale, Sizhuo Yang, Cunming Liu, Xiaobing Zuo, Xiaoyi Zhang, Jier Huang
Unravelling The Correlation Of Electronic Structure And Carrier Dynamics In Cuins2 Nanoparticles, Wenhui Hu, John Ludwig, Brian Pattengale, Sizhuo Yang, Cunming Liu, Xiaobing Zuo, Xiaoyi Zhang, Jier Huang
Chemistry Faculty Research and Publications
In this work, we report the direct correlation of photoinduced carrier dynamics and electronic structure of CuInS2 (CIS) nanoparticles (NPs) using the combination of multiple spectroscopic techniques including steady-state X-ray absorption spectroscopy (XAS), optical transient absorption (OTA), and X-ray transient (XTA) absorption spectroscopy. XAS results show that CIS NPs contain a large amount of surface Cu atoms with ≪four-coordination, which is more severe in CIS NPs with shorter nucleation times, indicating the presence of more Cu defect states in CIS NPs with smaller size particles. Using the combination of OTA and XTA spectroscopy, we show that electrons are trapped …
Mechanistic Probes Of Zeolitic Imidazolate Framework For Photocatalytic Application, Brian Pattengale, Sizhuo Yang, Sungsik Lee, Jier Huang
Mechanistic Probes Of Zeolitic Imidazolate Framework For Photocatalytic Application, Brian Pattengale, Sizhuo Yang, Sungsik Lee, Jier Huang
Chemistry Faculty Research and Publications
In this work, we report a zeolitic imidazolate framework (ZIF-67) with remarkable activity in the hydrogen evolution reaction (HER): 40 500 μmol H2/g of metal organic framework (MOF). This is, to the best of our knowledge, the highest activity achieved by any MOF system. This result necessitated assessment of the atomic-scale mechanistic function of ZIF-67 in HER, using advanced spectroscopy techniques, including time-resolved optical (OTA) and in situ X-ray-absorption (XAS) spectroscopy. Through the correlation of the OTA results with the catalytic performance, we demonstrated that the electron transfer (ET) pathway, rather than the energy transfer (ENT) pathway, between …
Catalytic Reduction Of Bisulfite By Myoglobin/Surfactant Films, Radalla Abdellatty, Md. Hafizur Rahman, Michael D. Ryan
Catalytic Reduction Of Bisulfite By Myoglobin/Surfactant Films, Radalla Abdellatty, Md. Hafizur Rahman, Michael D. Ryan
Chemistry Faculty Research and Publications
The voltammetry of bisulfite at a film formed with myoglobin was studied in aqueous solutions. A broad wave was observed for the reduction of bisulfite. Using controlled potential electrolysis, the reduction at potentials positive of the FeII/FeIwave formed dithionite exclusively. As the potential approached the region for the FeII/FeI reduction, bisulfite was reduced primarily to HS−. Even at the negative potentials, some dithionite was still formed, which could then be electrochemically reduced to thiosulfate. Analysis of the formation of HS−, dithionite and thiosulfate during the electrolysis was consistent with …
Spectroscopic And Computational Studies Of Reversible O2 Binding By A Cobalt Complex Of Relevance To Cysteine Dioxygenase, Anne A. Fischer, Sergey V. Lindeman, Adam T. Fiedler
Spectroscopic And Computational Studies Of Reversible O2 Binding By A Cobalt Complex Of Relevance To Cysteine Dioxygenase, Anne A. Fischer, Sergey V. Lindeman, Adam T. Fiedler
Chemistry Faculty Research and Publications
The substitution of non-native metal ions into metalloenzyme active sites is a common strategy for gaining insights into enzymatic structure and function. For some nonheme iron dioxygenases, replacement of the Fe(II) center with a redox-active, divalent transition metal (e.g., Mn, Co, Ni, Cu) gives rise to an enzyme with equal or greater activity than the wild-type enzyme. In this manuscript, we apply this metal-substitution approach to synthetic models of the enzyme cysteine dioxygenase (CDO). CDO is a nonheme iron dioxygenase that initiates the catabolism of L-cysteine by converting this amino acid to the corresponding sulfinic acid. Two mononuclear …
Spectral Characterization Of Cytochromes P450 Active Sites Using Nmr And Resonance Raman Spectroscopy, Remigio Usai
Spectral Characterization Of Cytochromes P450 Active Sites Using Nmr And Resonance Raman Spectroscopy, Remigio Usai
Dissertations (1934 -)
The Cytochrome P450 (P450s) has been the subject of intense research for over six decades. An efficient approach for isotopic labeling of the prosthetic group in heme proteins was exploited to produce an analogue of the soluble bacterial cytochrome P450cam (P450cam) that contains a 13C labeled-protoheme prosthetic group. HU227 strain of E. coli, which lacks the δ-aminolevulinic acid (δ-ALA) synthase gene, was employed in the heterologous expression of P450cam harboring a prosthetic group labeled with 13C at the Cm and Cα positions by growing cells in the presence of [5-13C] δ-ALA, which was synthesized in four steps from [2-13C] glycine. …
Spin Crossover Behavior Of N-Confused C-Scorpionate Complexes Of Iron(Ii) Trifluoromethanesulfonate, Kristin Joy Meise
Spin Crossover Behavior Of N-Confused C-Scorpionate Complexes Of Iron(Ii) Trifluoromethanesulfonate, Kristin Joy Meise
Master's Theses (2009 -)
An understanding of the molecular properties that influence highly-cooperative SCO behavior is critical in the development of new electronic materials. The purpose of this thesis work is to more fully examine whether hydrogen bonding interactions can be used to assemble iron(II) scorpionate complexes and whether this leads to abruptness in the SCO behavior. In this contribution, new N-confused C-scorpionate ligands are prepared with two ‘normal’ pz* groups ( = 3,5-dimethylpyrazol-1yl) and a ‘confused’ pyrazolyl with either an N-H, HL*, or an N-Tosyl (Tosyl = p-toluenesulfonyl), TsL*, bound to a central methine. These bulky ligands complement those previously described, HL and …
Ruthenium Catalyzed Deaminative Coupling Reaction Of Amines Via C-N Bond Activation, Pandula T. Kirinde Arachchige
Ruthenium Catalyzed Deaminative Coupling Reaction Of Amines Via C-N Bond Activation, Pandula T. Kirinde Arachchige
Master's Theses (2009 -)
C–N bond activation via transition-metal catalyst has attracted much attention during the past two decades. This strategy has become one of the most promising way to generate secondary amines, which are very important in a broad spectrum of applications in pharmaceutical industry, synthetic organic chemistry and material science. The secondary amines can be utilized as an important synthetic intermediate for further manipulations. The in-situ formed catalytic system generated from the tetranuclear Ru–H complex with 4-(1,1-dimethylethyl)-1,2-benzenediol ligand was found to be effective for the synthesis of secondary amines from the direct deaminative coupling of amines. The ruthenium catalyst was highly effective …
Nucleotide-Dependent Preferential Localization Of Ras In Model Membranes With Lipid Raft Nanodomains, Anna Shishina
Nucleotide-Dependent Preferential Localization Of Ras In Model Membranes With Lipid Raft Nanodomains, Anna Shishina
Dissertations (1934 -)
Membrane proteins constitute a third of all proteins in the cell and more than 50% of drug targets. However, the analysis of membrane proteins has many challenges owing to their partially hydrophobic surfaces, flexibility and lack of stability. One example of an essential membrane protein is Ras superfamily. Ras is a small monomeric GTPase involved in regulation of cell growth, proliferation and differentiation. Therefore, Ras and its effectors are among the most important targets for cancer therapy. A detailed knowledge of the processes occurring during signal propagation via Ras might help to elucidate the mechanisms of the involved signal cascades. …