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Articles 1 - 27 of 27
Full-Text Articles in Physical Sciences and Mathematics
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 …
Characterization Of Metal Binding Sites Within The Protein Only Rnase P, Ganga Nilmini Kumari Wijesinghe Mudiyanselage
Characterization Of Metal Binding Sites Within The Protein Only Rnase P, Ganga Nilmini Kumari Wijesinghe Mudiyanselage
Master's Theses (2009 -)
Transfer RNA (tRNA) maturation is an essential step that occurs after transcription and prior to the translation. In all domains of life, an RNA-based ribonuclease (RNase) P catalyzes the cleavage of the phosphodiester bond at the 5′ end of precursor tRNA. However, not all organelles utilize the RNA-based version of RNase P. A recent discovery altering the paradigm of RNase P has revealed that chloroplast organelles, parasitic trypanosomes, and the compact human mitochondrial (mt) genome rely solely on a protein-only 5′ tRNA processing enzyme. Structural and biochemical studies of the RNA-based and protein-based plant RNase P systems suggest that these …
Selective Isomer Formation And Crystallization-Directed Magnetic Behavior In Nitrogen-Confused C-Scorpionate Complexes Of Fe(O3Scf3)2, James R. Gardinier, Kristin J. Meise, Fathiya Jahan, Denan Wang, Sergey V. Lindeman
Selective Isomer Formation And Crystallization-Directed Magnetic Behavior In Nitrogen-Confused C-Scorpionate Complexes Of Fe(O3Scf3)2, James R. Gardinier, Kristin J. Meise, Fathiya Jahan, Denan Wang, Sergey V. Lindeman
Chemistry Faculty Research and Publications
The complex [Fe(HL*)2](OTf)2, 1, where HL* = bis(3,5-dimethylpyrazol-1-yl)(3-1H-pyrazole)methane, was prepared in order to compare its magnetic properties with those of the analogous parent complex, [Fe(HL)2](OTf)2, that lacks methyl groups on pyrazolyl rings and that undergoes spin crossover (SCO) from the low spin (LS) to the high spin (HS) form above room temperature. It was anticipated that this new semibulky derivative should favor the HS state and undergo SCO at a lower temperature range. During this study, six crystalline forms of 1 were prepared by …
Synthesis And Structural Analysis Of Macrocyclic Arenes: Experimental And Computational Insights, Saber Mirzaei
Synthesis And Structural Analysis Of Macrocyclic Arenes: Experimental And Computational Insights, Saber Mirzaei
Master's Theses (2009 -)
Synthesis, properties and applications of macrocyclic molecules have been one ofthe interesting branches of organic chemistry during the past century. Several classes ofmacrocyclic molecules, based on their repeating unit and connectivity pattern, have beendiscovered. Macrocyclic arenes, cyclo[n]veratrylenes, calix[n]arenes and pillar[n]arenes,were among the most interesting and studied molecules. The major difference betweenthese molecules is the methylene-bridged connectivity pattern. In the present thesis, Iattempted to synthesize these molecules using novel approach which has been developedin our group and performing some structural analysis using experimental andcomputational techniques.The first synthesized and investigated molecule is the …
Design And Synthesis Of Simplified Analogs Of The Natural Product Sordarin As Potential Antifungal Agents, Yibiao Wu
Dissertations (1934 -)
Invasive fungal infection is a life-threatening illness that causes high mortality, and is especially common among patients with compromised immune systems. However, currently there are only three major classes of clinically useful drugs capable of treating such infections. In addition, due to the fact that drug resistance has become a serious issue especially among patients who suffer from chronic infections, it is urgent to identify new drug candidates, particular those of new classes. The discovery of the natural product sordarin and its novel mechanism of action of inhibiting fungal protein synthesis via the fungal eukaryotic elongation factor 2 (eEF2) led …
Charge-Transfer Or Excimeric State? Exploring The Nature Of The Excited State In Cofacially Arrayed Polyfluorene Derivatives, Ainur Abzhanova, Lena V. Ivanova, Denan Wang, Tushar S. Navale, Sameh H. Abdelwahed, Maxim Vadimovich Ivanov, Sergey V. Lindeman, Rajendra Rathore, Scott A. Reid
Charge-Transfer Or Excimeric State? Exploring The Nature Of The Excited State In Cofacially Arrayed Polyfluorene Derivatives, Ainur Abzhanova, Lena V. Ivanova, Denan Wang, Tushar S. Navale, Sameh H. Abdelwahed, Maxim Vadimovich Ivanov, Sergey V. Lindeman, Rajendra Rathore, Scott A. Reid
Chemistry Faculty Research and Publications
It is well known that upon electronic excitation various π-stacked dimers readily exhibit excimer formation, facilitated by a perfect sandwich-like arrangement between the chromophores. However, it is unclear whether such a dimer is also capable of electron transfer upon excitation, if a strong electron-donating group is covalently attached. In this work, we probe the nature of the excited state in a series of cofacially arrayed polyfluorene derivatives with electron-rich aromatic donor attached via a methylene linker. Our studies show that in all cases excimer formation is energetically favorable, and promotion of a charge-transfer state in such systems is possible but …
Synthesis Of Simplified Azasordarin Analogs As Potential Antifungal Agents, Yibiao Wu, Chris Dockendorff
Synthesis Of Simplified Azasordarin Analogs As Potential Antifungal Agents, Yibiao Wu, Chris Dockendorff
Chemistry Faculty Research and Publications
A new series of simplified azasordarin analogs was synthesized using as key steps a Diels–Alder reaction to generate a highly substituted bicyclo[2.2.1]heptane core, followed by a subsequent nitrile alkylation. Several additional strategies were investigated for the generation of the key tertiary nitrile or aldehyde thought to be required for inhibition at the fungal protein eukaryotic elongation factor 2. This new series also features a morpholino glycone previously reported in semisynthetic sordarin derivatives with broad spectrum antifungal activity. Despite a lack of activity against Candida albicans for these early de novo analogs, the synthetic route reported here permits more comprehensive modifications …
Cooperative Transport In A Multi-Particle, Multi-Dimensional Flashing Ratchet, Ofer Kedem, Emily A. Weiss
Cooperative Transport In A Multi-Particle, Multi-Dimensional Flashing Ratchet, Ofer Kedem, Emily A. Weiss
Chemistry Faculty Research and Publications
Random and undirected forces are rectified in biological and synthetic systems using ratcheting mechanisms, which employ periodic asymmetric potentials and nonequilibrium conditions to produce useful transport. The density of motors or transported particles is known to strongly affect the nature and efficacy of transport in biological systems, as well as in synthetic ratchets and active swimmer systems. While experimental ratchet implementations typically employ potentials varying in two dimensions (2D), the role of the density of interacting particles in such a system has not been modeled. Prompted by experimental observations and building upon previous simulations, this paper describes the ratcheting process …
The Ratio Of The Number Of States In Asymmetric And Symmetric Ozone Molecules Deviates From The Statistical Value Of 2, Igor Gayday, Alexander Teplukhin, Dmitri Babikov
The Ratio Of The Number Of States In Asymmetric And Symmetric Ozone Molecules Deviates From The Statistical Value Of 2, Igor Gayday, Alexander Teplukhin, Dmitri Babikov
Chemistry Faculty Research and Publications
Accurate calculations of vibrational states in singly and doubly substituted ozone molecules are carried out, up to dissociation threshold. Analysis of these spectra reveals noticeable deviations from the statistical factor of 2 for the ratio between the number of states in asymmetric and symmetric ozone molecules. It is found that, for the lower energy parts of spectra, the ratio is less than 2 in the singly substituted ozone molecules, but it is more than 2 in the doubly substituted ozone molecules. However, the upper parts of spectra, just below dissociation thresholds, exhibit a different behavior. In this energy range, the …
C–H/Π And C–H–O Interactions In Concert: A Study Of The Anisole–Methane Complex Using Resonant Ionization And Velocity Mapped Ion Imaging, James Makuvaza, Damian Kokkin, John Loman, Scott A. Reid
C–H/Π And C–H–O Interactions In Concert: A Study Of The Anisole–Methane Complex Using Resonant Ionization And Velocity Mapped Ion Imaging, James Makuvaza, Damian Kokkin, John Loman, Scott A. Reid
Chemistry Faculty Research and Publications
Noncovalent forces such as hydrogen bonding, halogen bonding, π–π stacking, and C–H/π and C–H/O interactions hold the key to such chemical processes as protein folding, molecular self-assembly, and drug–substrate interactions. Invaluable insight into the nature and strength of these forces continues to come from the study of isolated molecular clusters. In this work, we report on a study of the isolated anisole–methane complex, where both C–H/π and C–H/O interactions are possible, using a combination of theory and experiments that include mass-selected two-color resonant two-photon ionization spectroscopy, two-color appearance potential (2CAP) measurements, and velocity mapped ion imaging (VMI). Using 2CAP and …
Proton-Coupled Reduction Of An Iron Nitrosyl Porphyrin In The Protic Ionic Liquid Nanodomain, Abderrahman Atifi, Piotr J. Mak, Michael D. Ryan
Proton-Coupled Reduction Of An Iron Nitrosyl Porphyrin In The Protic Ionic Liquid Nanodomain, Abderrahman Atifi, Piotr J. Mak, Michael D. Ryan
Chemistry Faculty Research and Publications
The one-electron reduction of many molecules becomes much more favorable if combined with proton transfers or strong hydrogen bonding. Protic room temperature ionic liquids (RTILs), which can form nanodomains in solutions with molecular solvents (MS), can provide an efficient avenue for this process. In this work, we report on the voltammetry, UV/visible and resonance Raman spectroelectrochemistryof Fe(TPP)(NO) in the presence of aprotic/protic ammonium-based ionic liquids. While aprotic RTILs did shift the reduction to more positive potentials, similar shifts could be observed at much lower concentrations of diethylmethylammonium triflate (HAmOTf, a protic ionic liquid). Deconvolution of the rotating ring-disk electrode (RRDE) …
Design And Evaluation Of Heterobivalent Par1–Par2 Ligands As Antagonists Of Calcium Mobilization, Mark W. Majewski, Disha M. Gandhi, Ricardo Rosas Jr., Revathi Kodall, Leggy A. Arnold, Chris Dockendorff
Design And Evaluation Of Heterobivalent Par1–Par2 Ligands As Antagonists Of Calcium Mobilization, Mark W. Majewski, Disha M. Gandhi, Ricardo Rosas Jr., Revathi Kodall, Leggy A. Arnold, Chris Dockendorff
Chemistry Faculty Research and Publications
A novel class of bivalent ligands targeting putative protease-activated receptor (PAR) heteromers has been prepared based upon reported antagonists for the subtypes PAR1 and PAR2. Modified versions of the PAR1 antagonist RWJ-58259 containing alkyne adapters were connected via cycloaddition reactions to azide-capped polyethylene glycol (PEG) spacers attached to imidazopyridazine-based PAR2 antagonists. Initial studies of the PAR1–PAR2 antagonists indicated that they inhibited G alpha q-mediated calcium mobilization in endothelial and cancer cells driven by both PAR1 and PAR2 agonists. Compounds of this novel class hold promise for the prevention of restenosis, cancer cell metastasis, and other proliferative disorders.
Investigation Of Solvation And Solvent Coordination Effects In Iron Porphyrin Nitrosyls By Infrared Spectroelectrochemistry And Dft Calculations, Md. Hafizur Rahman, Michael D. Ryan
Investigation Of Solvation And Solvent Coordination Effects In Iron Porphyrin Nitrosyls By Infrared Spectroelectrochemistry And Dft Calculations, Md. Hafizur Rahman, Michael D. Ryan
Chemistry Faculty Research and Publications
Visible and infrared spectroelectrochemistry of Fe(OEPone)(NO) (H2OEPone = octaethylporphinone) were examined in methylene chloride and THF. The visible spectra of Fe(OEPone)(NO) were similar in both solvents. Unlike other ferrous porphyrin nitrosyls, a six-coordinate complex was formed with THF as a ligand. This led to two nitrosyl bands in the infrared spectrum. The absorbance of these bands depended on the concentration of THF in the solution. Solvation and coordination effects on the carbonyl and nitrosyl bands were observed for both the nitrosyl and reduced-nitrosyl complexes. DFT calculations were carried out to interpret the spectral changes.