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Articles 121 - 150 of 690
Full-Text Articles in Chemistry
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 …
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 …
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 …