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Articles 121 - 150 of 1110
Full-Text Articles in Chemistry
Theoretical And Experimental Investigation Of Non-Covalent Interactions In S-Nitrosothiols And Thio-Carboxylic Acids, Niloufar Hendinejad
Theoretical And Experimental Investigation Of Non-Covalent Interactions In S-Nitrosothiols And Thio-Carboxylic Acids, Niloufar Hendinejad
Dissertations (1934 -)
S-Nitrosothiols (RSNOs) are ubiquitous biomolecules whose chemistry is tightly controlled in unknown. In this work, we demonstrate, using high-level ab initio and DFT calculations, the ability of RSNOs to participate in intermolecular interactions with electron pair donors/Lewis bases (LBs) via a σ-hole, a region of positive electrostatic potential on the molecular surface at the extension of the N–S bond. Analysis of the nature of the intermolecular interactions in σ-hole bound RSNO-LB complexes shows the dominant role of electrostatic and dispersion interactions. Importantly, σ-hole binding is able to modulate the properties of RSNOs by changing the balance between two chemically opposite …
Catalytic Carbon–Carbon Bond Activation Of Saturated And Unsaturated Carbonyl Compounds Via Chelate-Assisted Coupling Reaction With Indoles, Nuwan Asanka Pannilawithana, Chae S. Yi
Catalytic Carbon–Carbon Bond Activation Of Saturated And Unsaturated Carbonyl Compounds Via Chelate-Assisted Coupling Reaction With Indoles, Nuwan Asanka Pannilawithana, Chae S. Yi
Chemistry Faculty Research and Publications
The chelate assistance strategy was devised to promote a highly regioselective catalytic C–C bond activation reaction of saturated and unsaturated carbonyl compounds. The cationic Ru–H complex 1 was found to be an effective catalyst for mediating the coupling reaction of 1,2-disubstituted indoles with α,β-unsaturated aldehydes and ketones, in which the regioselective Cα–Cβ activation of the carbonyl substrates has been achieved in forming the 3-alkylindole products. The analogous coupling reaction of indoles with saturated aldehydes and ketones directly led to the Cα–Cβ cleavage of the carbonyl substrates in forming the 3-alkylindole products. The coupling reaction …
Photophysical Properties And Excited State Dynamics Of Porous Organic Materials, Korlan Duisenova
Photophysical Properties And Excited State Dynamics Of Porous Organic Materials, Korlan Duisenova
Master's Theses (2009 -)
Charge transfer complexes are charge separated states that are formed at donor - acceptor interfaces and play significant role in charge photogeneration. One of the main criteria for efficient charge transfer is suppression of charge recombination process. Previous experiments show that one of the most effective ways to inhibit recombination is an introduction of bridge molecules between donor and acceptor or increase the number of electron donating and withdrawing groups. These solutions are inspired by photosynthetic reaction centers where charge transfer occurs over long distances. Covalent Organic Frameworks (COFs) are advanced porous crystalline materials that can be constructed of multiple …
Modified Synthesis Of The Peptidomimetic Natriuretic Peptide Receptor-C Antagonist M372049, Jacob Porter, Sergey V. Lindeman, Chris Dockendorff
Modified Synthesis Of The Peptidomimetic Natriuretic Peptide Receptor-C Antagonist M372049, Jacob Porter, Sergey V. Lindeman, Chris Dockendorff
Chemistry Faculty Research and Publications
The Natriuretic Peptide Receptors (NPRs) regulate vascular sodium levels and have been of significant interest for the potential treatment of hypertension and related cardiovascular complications. The peptidomimetic antagonist M372049 is a valuable probe for the study of NPR-C signaling, unfortunately it is presently not commercially available. Described is a detailed protocol for its synthesis that does not require specialized apparatus and builds upon a prior patent from Veale and colleagues. Key steps include a base-mediated lactam formation and a solid-supported peptide synthetic sequence. An X-ray crystal structure of a key lactam intermediate was obtained to confirm the structure and relative …
Restructuring A General College Chemistry Sequence Using The Acs Anchoring Concepts Content Map, Scott A. Reid
Restructuring A General College Chemistry Sequence Using The Acs Anchoring Concepts Content Map, Scott A. Reid
Chemistry Faculty Research and Publications
Many STEM (science, technology, engineering, and mathematics) disciplines require a two-semester sequence of introductory college chemistry, which are thus critical gateway courses to a variety of majors. Recognizing the benefit to educators of a structure of content learning across the chemistry curriculum, in 2012, the American Chemical Society (ACS) developed the Anchoring Concepts Content Map, or ACCM. The development and subsequent revision of the general chemistry ACCM inspired the restructuring of our first-year chemistry sequence. Thus our CHEM 1001 and 1002 courses, taught in an atoms-first framework, were reorganized into a set of nine modules, each intentionally linked to one …
Tuning Internal Strain In Metal–Organic Frameworks Via Vapor Phase Infiltration For Co2 Reduction, Fan Yang, Wenhui Hu, Chongqing Yang, Margaret Patrick, Andrew L. Cooksy, Jian Zhang, Jeffery A. Aguiar, Chengcheng Fang, Yinghua Zhou, Ying Shirley Meng, Jier Huang, Jing Gu
Tuning Internal Strain In Metal–Organic Frameworks Via Vapor Phase Infiltration For Co2 Reduction, Fan Yang, Wenhui Hu, Chongqing Yang, Margaret Patrick, Andrew L. Cooksy, Jian Zhang, Jeffery A. Aguiar, Chengcheng Fang, Yinghua Zhou, Ying Shirley Meng, Jier Huang, Jing Gu
Chemistry Faculty Research and Publications
A gas-phase approach to form Zn coordination sites on metal–organic frameworks (MOFs) by vapor-phase infiltration (VPI) was developed. Compared to Zn sites synthesized by the solution-phase method, VPI samples revealed approximately 2.8 % internal strain. Faradaic efficiency towards conversion of CO2 to CO was enhanced by up to a factor of four, and the initial potential was positively shifted by 200–300 mV. Using element-specific X-ray absorption spectroscopy, the local coordination environment of the Zn center was determined to have square-pyramidal geometry with four Zn−N bonds in the equatorial plane and one Zn-OH2 bond in the axial plane. The …
Infrared Spectroelectrochemistry Of Iron-Nitrosyl Triarylcorroles. Implications For Ligand Noninnocence, Md. Hafizur Rahman, Michael D. Ryan, Hugo Vazquez-Lima, Abraham Alemayehu, Abhik Ghosh
Infrared Spectroelectrochemistry Of Iron-Nitrosyl Triarylcorroles. Implications For Ligand Noninnocence, Md. Hafizur Rahman, Michael D. Ryan, Hugo Vazquez-Lima, Abraham Alemayehu, Abhik Ghosh
Chemistry Faculty Research and Publications
Recent DFT calculations have suggested that iron nitrosyl triarylcorrole complexes have substantial {FeNO}7–corrole•2– character. With this formulation, reduction of Fe(C)(NO) complexes, where C = triarylcorrole, should be centered on the corrole macrocycle rather than on the {FeNO}7 moiety. To verify this proposition, visible and infrared spectroelectrochemical studies of Fe(C)(NO) were carried out and the results were interpreted using DFT (B3LYP/STO-TZP) calculations. The first reduction of Fe(C)(NO) led to significant changes in the Soret and Q-band regions of the visible spectrum as well as to a significant downshift in the νNO and changes in the corrole …
Unraveling The Intermediate Species Of Co3O4 Hollow Spheres For Co2 Photoreduction By In Situ X-Ray Absorption Spectroscopy, Peilei He, Sizhou Yang, Wenhui Hu, Sungsik Lee, Jier Huang
Unraveling The Intermediate Species Of Co3O4 Hollow Spheres For Co2 Photoreduction By In Situ X-Ray Absorption Spectroscopy, Peilei He, Sizhou Yang, Wenhui Hu, Sungsik Lee, Jier Huang
Chemistry Faculty Research and Publications
Nanostructured hollow materials have emerged as a promising class of materials for energy conversion and storage. In this work, we report a Co3O4 hollow sphere nanostructure that can serve as a CO2 reduction catalyst to form CO with high selectivity upon visible-light illumination in the presence of a [Ru(bpy)3]2+ molecular photosensitizer. Using in situ X-ray absorption spectroscopy, we not only showed that the Co center in the Co3O4 hollow sphere is the active site for CO2 reduction but also identified a key intermediate species, that is, a reduced Co …
Influence Of The Coriolis Effect On The Properties Of Scattering Resonances In Symmetric And Asymmetric Isotopomers Of Ozone, Igor Gayday, Elizaveta Grushnikova, Dmitri Babikov
Influence Of The Coriolis Effect On The Properties Of Scattering Resonances In Symmetric And Asymmetric Isotopomers Of Ozone, Igor Gayday, Elizaveta Grushnikova, Dmitri Babikov
Chemistry Faculty Research and Publications
Scattering resonances above dissociation threshold are computed for four isotopically substituted ozone species: 16O18O16O, 16O16O18O, 18O16O18O and 16O18O18O, using a variational method with accurate treatment of the rotation–vibration coupling terms (Coriolis effect) for all values of the total angular momentum J from 0 to 4. To make these calculations numerically affordable, a new approach was developed which employs one vibrational basis set optimized for a typical rotational excitation (J,Λ), to run coupled rotation–vibration calculations at several …
Route Exploration And Synthesis Of The Reported Pyridone-Based Pdi Inhibitor Stk076545, Eric Greve, Sergey V. Lindeman, Christina Scartelli, Lin Lin, Robert Flaumenhaft, Chris Dockendorff
Route Exploration And Synthesis Of The Reported Pyridone-Based Pdi Inhibitor Stk076545, Eric Greve, Sergey V. Lindeman, Christina Scartelli, Lin Lin, Robert Flaumenhaft, Chris Dockendorff
Chemistry Faculty Research and Publications
The enzyme protein disulfide isomerase (PDI) is essential for the correct folding of proteins and the activation of certain cell surface receptors, and is a promising target for the treatment of cancer and thrombotic conditions. A previous high-throughput screen identified the commercial compound STK076545 as a promising PDI inhibitor. To confirm its activity and support further biological studies, a resynthesis was pursued of the reported β-keto-amide with an N-alkylated pyridone at the α-position. Numerous conventional approaches were complicated by undesired fragmentations or rearrangements. However, a successful 5-step synthetic route was achieved using an aldol reaction with an α-pyridone allyl …
Nonheme Iron–Thiolate Complexes As Structural Models Of Sulfoxide Synthase Active Sites, Danushka M. Ekanayake, Anne A. Fischer, Maya E. Elwood, Alexandra M. Guzek, Sergey V. Lindeman, Cordina V. Popescu, Adam T. Fiedler
Nonheme Iron–Thiolate Complexes As Structural Models Of Sulfoxide Synthase Active Sites, Danushka M. Ekanayake, Anne A. Fischer, Maya E. Elwood, Alexandra M. Guzek, Sergey V. Lindeman, Cordina V. Popescu, Adam T. Fiedler
Chemistry Faculty Research and Publications
Two mononuclear iron(II)–thiolate complexes have been prepared that represent structural models of the nonheme iron enzymes EgtB and OvoA, which catalyze the O2-dependent formation of carbon–sulfur bonds in the biosynthesis of thiohistidine compounds. The series of Fe(II) complexes reported here feature tripodal N4 chelates (LA and LB) that contain both pyridyl and imidazolyl donors (LA = (1H-imidazol-4-yl)-N,N-bis((pyridin-2-yl)methyl)methanamine; LB = N,N-bis((1-methylimidazol-2-yl)methyl)-2-pyridylmethylamine). Further coordination with monodentate aromatic or aliphatic thiolate ligands yielded the five-coordinate, high-spin Fe(II) complexes [FeII(LA)(SMes)]BPh …
Voltammetry And Spectroelectrochemistry Of Tcnq In Acetonitrile/Rtil Mixtures, Abderrahman Atifi, Michael D. Ryan
Voltammetry And Spectroelectrochemistry Of Tcnq In Acetonitrile/Rtil Mixtures, Abderrahman Atifi, Michael D. Ryan
Chemistry Faculty Research and Publications
Understanding the solvation and ion-pairing interactions of anionic substrates in room-temperature ionic liquids (RTIL) is key for the electrochemical applications of these new classes of solvents. In this work, cyclic voltammetry and visible and infrared spectroelectrochemistry of tetracyanoquinodimethane (TCNQ) was examined in molecular (acetonitrile) and RTIL solvents, as well as mixtures of these solvents. The overall results were consistent with the formation of RTIL/acetonitrile nanodomains. The voltammetry indicated that the first electrogenerated product, TCNQ−, was not incorporated into the RTIL nanodomain, while the second electrogenerated product, TCNQ2−, was strongly attracted to the RTIL nanodomain. The visible …
Enhanced Light Harvesting Ability In Zeolitic Imidazolate Frameworks Through Energy Transfer From Cds Nanowires, Yixuan Zhou, Wenhui Hu, Sizhuo Yang, Jier Huang
Enhanced Light Harvesting Ability In Zeolitic Imidazolate Frameworks Through Energy Transfer From Cds Nanowires, Yixuan Zhou, Wenhui Hu, Sizhuo Yang, Jier Huang
Chemistry Faculty Research and Publications
Zeolitic imidazolate frameworks (ZIFs) represent a novel class of porous crystalline materials that have demonstrated potential as light harvesting materials for solar energy conversion. In order to facilitate their application in solar energy conversion, it is necessary to expand their absorption further into the realm of the solar spectrum. In this work, we report the incorporation of semiconductor cadmium sulfide nanowires (CdS NWs) into ZIF-67 (CdS@ZIF-67), where a broader region of the solar spectrum can be absorbed by CdS NWs and relayed to ZIF-67 through an energy transfer (EnT) process. Using steady-state emission and time resolved emission and absorption spectroscopy, …
Adiabatic Trajectory Approximation Within The Framework Of Mixed Quantum/Classical Theory, Bikramaditya Mandal, Alexander Semenov, Dmitri Babikov
Adiabatic Trajectory Approximation Within The Framework Of Mixed Quantum/Classical Theory, Bikramaditya Mandal, Alexander Semenov, Dmitri Babikov
Chemistry Faculty Research and Publications
A hierarchy of approximate methods is proposed for solving the equations of motion within a framework of the mixed quantum/classical theory (MQCT) of inelastic molecular collisions. Of particular interest is a limiting case: the method in which the classical-like equations of motion for the translational degrees of freedom (scattering) are decoupled from the quantum-like equations for time evolution of the internal molecular states (rotational and vibrational). In practice, trajectories are pre-computed during the first step of calculations with driving forces determined solely by the potential energy surface of the entrance channel, which is an adiabatic trajectory approximation. Quantum state-to-state transition …
Dynamic Evolution And Reversibility Of Single-Atom Ni(Ii) Active Site In 1t-Mos2 Electrocatalysts For Hydrogen Evolution, Brian Pattengale, Yichao Huang, Xingxu Yan, Sizhou Yang, Sabrina Younan, Wenhui Hu, Zhida Li, Sungsik Lee, Xiaoping Pan, Jing Gu, Jier Huang
Dynamic Evolution And Reversibility Of Single-Atom Ni(Ii) Active Site In 1t-Mos2 Electrocatalysts For Hydrogen Evolution, Brian Pattengale, Yichao Huang, Xingxu Yan, Sizhou Yang, Sabrina Younan, Wenhui Hu, Zhida Li, Sungsik Lee, Xiaoping Pan, Jing Gu, Jier Huang
Chemistry Faculty Research and Publications
1T-MoS2 and single-atom modified analogues represent a highly promising class of low-cost catalysts for hydrogen evolution reaction (HER). However, the role of single atoms, either as active species or promoters, remains vague despite its essentiality toward more efficient HER. In this work, we report the unambiguous identification of Ni single atom as key active sites in the basal plane of 1T-MoS2 (Ni@1T-MoS2) that result in efficient HER performance. The intermediate structure of this Ni active site under catalytic conditions was captured by in situ X-ray absorption spectroscopy, where a reversible metallic Ni species (Ni0) …
Composition Effect On The Carrier Dynamics And Catalytic Performance Of Cuins2/Zns Quantum Dots For Light Driven Hydrogen Generation, Wenhui Hu, Sizhuo Yang, Jier Huang
Composition Effect On The Carrier Dynamics And Catalytic Performance Of Cuins2/Zns Quantum Dots For Light Driven Hydrogen Generation, Wenhui Hu, Sizhuo Yang, Jier Huang
Chemistry Faculty Research and Publications
Water soluble CuInS2/ZnS quantum dots (QDs) represent one of the most promising single component photocatalysts for the hydrogen evolution reaction (HER). In this work, we report the effect of cation composition in CuInS2/ZnS QDs on the carrier relaxation and charge separation dynamics as well as their photocatalytic performance for the HER. With decreasing Cu to In ratio (increasing Cu deficiency), we observed slightly faster electron trapping and carrier recombination but significantly improved photocatalytic activity for the HER. This can be attributed to the enhanced electron transfer (ET) from the sacrificial donor to CuInS2/ZnS QDs …
Spectroscopic And Computational Comparisons Of Thiolate-Ligated Ferric Nonheme Complexes To Cysteine Dioxygenase: Second-Sphere Effects On Substrate (Analogue) Positioning, Anne A. Fischer, Joshua R. Miller, Richard J. Jodts, Danushka M. Ekanayake, Sergey V. Lindeman, Thomas C. Brunold, Adam T. Fiedler
Spectroscopic And Computational Comparisons Of Thiolate-Ligated Ferric Nonheme Complexes To Cysteine Dioxygenase: Second-Sphere Effects On Substrate (Analogue) Positioning, Anne A. Fischer, Joshua R. Miller, Richard J. Jodts, Danushka M. Ekanayake, Sergey V. Lindeman, Thomas C. Brunold, Adam T. Fiedler
Chemistry Faculty Research and Publications
Parallel spectroscopic and computational studies of iron(III) cysteine dioxygenase (CDO) and synthetic models are presented. The synthetic complexes utilize the ligand tris(4,5-diphenyl-1-methylimidazol-2-yl)phosphine (Ph2TIP), which mimics the facial three-histidine triad of CDO and other thiol dioxygenases. In addition to the previously reported [FeII(CysOEt)(Ph2TIP)]BPh4 (1; CysOEt is the ethyl ester of anionic l-cysteine), the formation and crystallographic characterization of [FeII(2-MTS)(Ph2TIP)]BPh4 (2) is reported, where the methyl 2-thiosalicylate anion (2-MTS) resembles the substrate of 3-mercaptopropionate dioxygenase (MDO). One-electron chemical oxidation of 1 and 2 yields ferric species …
Hybrid Catalysis For The Direct Addition Of Unactivated Aldehydes And Ketones To Alkenes And Alkynes, Jacob Porter
Hybrid Catalysis For The Direct Addition Of Unactivated Aldehydes And Ketones To Alkenes And Alkynes, Jacob Porter
Dissertations (1934 -)
Reactions for the alpha functionalization of carbonyl compounds are important for the synthesis of complex organic materials such as pharmaceuticals, agrochemicals, and natural products. Current methodology used to perform these reactions is inefficient in that pre-activated coupling partners or sensitive catalysts are usually required. Described herein is the study and development of bifunctional and dual catalytic systems for carbon-carbon bond formation via the direct addition of unactivated carbonyl compounds to unactivated alkenes/alkynes. A dual catalyst system is one which utilizes two distinct catalysts to simultaneously activate separate reactants, and in a bifunctional catalyst the two catalytic components are present separately …
Proton Transfer Versus Hydrogen Bonding In A Reduced Iron Porphyrin Nitrosyl Complex, Md. Hafizur Rahman, Yilin Liu, Michael D. Ryan
Proton Transfer Versus Hydrogen Bonding In A Reduced Iron Porphyrin Nitrosyl Complex, Md. Hafizur Rahman, Yilin Liu, Michael D. Ryan
Chemistry Faculty Research and Publications
The 1H NMR spectra of Fe(OEP)(HNO), which was formed from Fe(OEP)(NO)− in the presence of 3,5-dichlorophenol, were studied as a function of temperature. The chemical shift of the HNO proton showed a unique behavior which could be explained based on the equilibrium between the protonated complex, Fe(OEP)(HNO), and the hydrogen-bonded complex, Fe(OEP)(NO)−···HOPh. This equilibrium was consistent with UV/visible spectroscopy and the voltammetric data. UV/visible stopped-flow experiments showed that the hydrogen-bonded complex, which was formed when weak acids such as phenol were added, and the Fe(OEP)(HNO) complex were quite similar. In addition to the HNO proton resonance, …
Empirical Mappings Of The Frequency Response Of An Electron Ratchet To The Characteristics Of The Polymer Transport Layer, Mohamad S. Kodaimati, Ofer Kedem, George C. Schatz, Emily A. Weiss
Empirical Mappings Of The Frequency Response Of An Electron Ratchet To The Characteristics Of The Polymer Transport Layer, Mohamad S. Kodaimati, Ofer Kedem, George C. Schatz, Emily A. Weiss
Chemistry Faculty Research and Publications
Flashing electron ratchets oscillate a periodic asymmetric potential to rectify nondirectional forces and thereby produce directional transport of electrons with zero source-drain bias. The relationship between the oscillation frequency of the potential and the ratchet (short-circuit) current reflects microscopic mechanisms of charge transport within the device. This paper describes experimental mappings of the “optimal frequency(ies)” of the ratchet fpeak—the oscillation frequencies that produce the largest ratchet current—to the carrier concentration, nh, and to the linear field effect transistor mobility, μh, for a poly(3-hexylthiophene-2,5-diyl) (P3HT) transport layer. Measurements on multiple devices, multiple P3HT films per …
The Parmodulin Nrd-21 Is An Allosteric Inhibitor Of Par1 Gq Signaling With Improved Anti-Inflammatory Activity And Stability, Disha M. Gandhi, Ricardo Rosas Jr., Eric Greve, Kaitlin Kentala, N'Guessan D.-R, Diby, Vladyslava A. Snyder, Allison Stephans, Teresa H.W. Yeung, Saravanan Subramaniam, Elliot Dimilo, Khia E. Kurtenbach, Leggy A. Arnold, Hartmut Weiler, Chris Dockendorff
The Parmodulin Nrd-21 Is An Allosteric Inhibitor Of Par1 Gq Signaling With Improved Anti-Inflammatory Activity And Stability, Disha M. Gandhi, Ricardo Rosas Jr., Eric Greve, Kaitlin Kentala, N'Guessan D.-R, Diby, Vladyslava A. Snyder, Allison Stephans, Teresa H.W. Yeung, Saravanan Subramaniam, Elliot Dimilo, Khia E. Kurtenbach, Leggy A. Arnold, Hartmut Weiler, Chris Dockendorff
Chemistry Faculty Research and Publications
Novel analogs of the allosteric, biased PAR1 ligand ML161 (parmodulin 2, PM2) were prepared in order to identify potential anti-thrombotic and anti-inflammatory compounds of the parmodulin class with improved properties. Investigations of structure-activity relationships of the western portion of the 1,3-diaminobenzene scaffold were performed using an intracellular calcium mobilization assay with endothelial cells, and several heterocycles were identified that inhibited PAR1 at sub-micromolar concentrations. The oxazole NRD-21 was profiled in additional detail, and it was confirmed to act as a selective, reversible, negative allosteric modulator of PAR1. In addition to inhibiting human platelet aggregation, it showed superior anti-inflammatory activity to …
Evaluation Of Α-Hydroxycinnamic Acids As Pyruvate Carboxylase Inhibitors, Daniel J. Burkett, Brittney N. Wyatt, Mallory Mews, Anson Bautista, Ryan Engel, Chris Dockendorff, William A. Donaldson, Martin St. Maurice
Evaluation Of Α-Hydroxycinnamic Acids As Pyruvate Carboxylase Inhibitors, Daniel J. Burkett, Brittney N. Wyatt, Mallory Mews, Anson Bautista, Ryan Engel, Chris Dockendorff, William A. Donaldson, Martin St. Maurice
Chemistry Faculty Research and Publications
Through a structure-based drug design project (SBDD), potent small molecule inhibitors of pyruvate carboxylase (PC) have been discovered. A series of α-keto acids (7) and α-hydroxycinnamic acids (8) were prepared and evaluated for inhibition of PC in two assays. The two most potent inhibitors were 3,3′-(1,4-phenylene)bis[2-hydroxy-2-propenoic acid] (8u) and 2-hydroxy-3-(quinoline-2-yl)propenoic acid (8v) with IC50 values of 3.0 ± 1.0 μM and 4.3 ± 1.5 μM respectively. Compound 8v is a competitive inhibitor with respect to pyruvate (Ki = 0.74 μM) and a mixed-type inhibitor with respect to ATP, indicating …
Β-Fluorofentanyls Are Ph-Sensitive Mu Opioid Receptor Agonists, Ricardo Rosas Jr., Xi-Ping Huang, Bryan L. Roth, Chris Dockendorff
Β-Fluorofentanyls Are Ph-Sensitive Mu Opioid Receptor Agonists, Ricardo Rosas Jr., Xi-Ping Huang, Bryan L. Roth, Chris Dockendorff
Chemistry Faculty Research and Publications
The concept recently postulated by Stein and co-workers (Science2017, 355, 966) that mu opioid receptor (MOR) agonists possessing amines with attenuated basicity show pH-dependent activity and can selectively act at damaged, low pH tissues has been additionally supported by in vitro studies reported here. We synthesized and tested analogs of fentanyl possessing one or two fluorine atoms at the beta position of the phenethylamine side chain, with additional fluorines optionally added to the benzene ring of the side chain. These compounds were synthesized in 1 to 3 steps from commercial building blocks. The novel bis-fluorinated analog …
Improving Performance Of The Smd Solvation Model: Bondi Radii Improve Predicted Aqueous Solvation Free Energies Of Ions And PkA Values Of Thiols, Saber Mirzaei, Maxim Vadimovich Ivanov, Qadir K. Timerghazin
Improving Performance Of The Smd Solvation Model: Bondi Radii Improve Predicted Aqueous Solvation Free Energies Of Ions And PkA Values Of Thiols, Saber Mirzaei, Maxim Vadimovich Ivanov, Qadir K. Timerghazin
Chemistry Faculty Research and Publications
Calculation of the solvation free energy of ionic molecules is the principal source of errors in the quantum chemical evaluation of pKa values using implicit polarizable continuum solvent models. One of the important parameters affecting the performance of these models is the choice of atomic radii. Here, we assess the performance of the solvation model based on density (SMD) implicit solvation model employing SMD default radii (SMD) and Bondi radii (SMD-B), a set of empirical atomic radii developed based on the crystallographic data. For a set of 112 ions (60 anions and 52 cations), the SMD-B model showed …
Calculation Of Molecular Vibrational Spectra On A Quantum Annealer, Alexander Teplukhin, Brian K. Kendrick, Dmitri Babikov
Calculation Of Molecular Vibrational Spectra On A Quantum Annealer, Alexander Teplukhin, Brian K. Kendrick, Dmitri Babikov
Chemistry Faculty Research and Publications
Until recently molecular energy calculations using quantum computing hardware have been limited to gate-based quantum computers. In this paper, a new methodology is presented to calculate the vibrational spectrum of a molecule on a quantum annealer. The key idea of the method is a mapping of the ground state variational problem onto an Ising or quadratic unconstrained binary optimization (QUBO) problem by expressing the expansion coefficients using spins or qubits. The algorithm is general and represents a new revolutionary approach for solving the real symmetric eigenvalue problem on a quantum annealer. The method is applied to two chemically important molecules: …
Selective Excited-State Dynamics In A Unique Set Of Rationally Designed Ni Porphyrins, Brian Pattengale, Qiuhua Liu, Wenhui Hu, Sizhuo Yang, Peilei He, Sir Lawrence Tender, Yingqi Wang, Xiaoyi Zhang, Zaichun Zhou, Jian Zhang, Jier Huang
Selective Excited-State Dynamics In A Unique Set Of Rationally Designed Ni Porphyrins, Brian Pattengale, Qiuhua Liu, Wenhui Hu, Sizhuo Yang, Peilei He, Sir Lawrence Tender, Yingqi Wang, Xiaoyi Zhang, Zaichun Zhou, Jian Zhang, Jier Huang
Chemistry Faculty Research and Publications
In this work, we report the design and photophysical properties of a unique class of Ni porphyrins, in which the tert-butyl benzene substituents at the meso positions of the macrocycle were tethered by ethers with alkyl linkers. This not only results in the permanently locked ruf distortion of the macrocycle but also enables the engineering of the degree of distortion through varying the length of alkyl linkers, which addressed the complication of uncertainty in the specific structural distortions that has long plagued the porphyrin photophysical community. Using advanced time-resolved optical and X-ray absorption spectroscopy, we observed tunability in the …
Synthesis And Reactivity Of Silver Complexes Of Nitrogen Confused Scorpionate Ligands, Fathiya Jahan
Synthesis And Reactivity Of Silver Complexes Of Nitrogen Confused Scorpionate Ligands, Fathiya Jahan
Master's Theses (2009 -)
Scorpionate ligands are one of the most crucial nitrogen donor ligands in coordination chemistry. The scorpionate ligands have served as excellent ligand scaffolds for investigating iron(II) spin crossover chemistry. In this study, the complex, [Fe(HL*)2](OTf)2, 1, where HL* = bis(3,5-dimethylpyrazol-1-yl)(3-1H-pyrazole)methane was prepared which exhibited multiple solid-state structures and solvates. Six crystalline forms of 1 were prepared by controlling the crystallization conditions. Thus, when reagents are combined in CH3CN, an equilibrium mixture of cis- and trans- is established that favors the latter below 310K. Among the six crystal forms, trans-1, trans-1.CH3CN, cis-1 and co-1 undergo SCO below 250K while trans-1.xCH3CN (x=2,4) …
The Alpha-Activator Complex, Cellular Maturation, And Catalytic Mechanism Of Iron-Type Nitrile Hydratase, Wasantha Lankathilaka Karunagala Pathiranage
The Alpha-Activator Complex, Cellular Maturation, And Catalytic Mechanism Of Iron-Type Nitrile Hydratase, Wasantha Lankathilaka Karunagala Pathiranage
Dissertations (1934 -)
In industry, chemicals are typically synthesized through catalytically accelerated chemical processes. The use of biocatalysts is an increasingly important trend in achieving environmentally friendly chemical production processes. Nitrile Hydratases (NHases) are well-known biocatalysts that are used by several manufacturers such as Mitsubishi Rayon Corporation and Lonza for the conversion of acrylonitrile to acrylamide and 3-cyanopyridine to nicotinamide, respectively. Amides, in general, are used in polymer preparation, adhesive manufacturing, and the paper industry. Refrigeration is needed in the enzymatic hydration process on the industrial scale to maintain a low reaction temperature to stabilize the NHase enzyme. The use of whole cells …
Structure And Mechanisms Of Metalloenzymes For Incorporation Of Water Across Cn And C-Cl Bonds, Xinhang Yang
Structure And Mechanisms Of Metalloenzymes For Incorporation Of Water Across Cn And C-Cl Bonds, Xinhang Yang
Dissertations (1934 -)
Metalloenzymes are widely involved in water incorporation across CN and C-Cl bonds.1 In this research, the structure and mechanisms of two novel metalloenzymes that incorporate water across CN and C-Cl bonds were examined by biophysical approaches, computational modeling, and crystallographic methods.In the research of water incorporation across CN bonds, a novel eukaryotic nitrile hydratase (NHase, EC 4.2.1.84) from Monosiga brevicollis (MbNHase) was characterized, and the functional role of a (His)17 section and an insert region in the MbNHase, were examined by gene modifications. Each of these MbNHase enzymes provided an 22 heterotetramer, identical to that observed for prokaryotic NHases …
Investigation Of The Active Site Maturation And Catalytic Mechanism Of Nitrile Hydratases (Nhase, E.C.4.2.1.84), Irene Anyango Ogutu
Investigation Of The Active Site Maturation And Catalytic Mechanism Of Nitrile Hydratases (Nhase, E.C.4.2.1.84), Irene Anyango Ogutu
Dissertations (1934 -)
Nitrile hydratase (NHase, E.C.4.2.1.84) is a metalloenzyme that catalyzes the hydration of nitriles into their corresponding amide under ambient conditions. NHase enzymes contain either a non-heme Fe3+ ion or a non-corrin Co3+ ion in their active site. NHase enzymes have industrial applications as biocatalysts in the large-scale production of acrylamide and nicotinamide, though it’s catalytic and biochemical properties are not fully understood. This research project provides insight into the active site maturation process and catalytic mechanism of NHase using peptide model complexes, site-directed mutagenesis and synthesis of deuterated proteins.Insight into the sequential maturation of the NHase active site has been …