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Articles 91 - 120 of 1105
Full-Text Articles in Chemistry
Scope And Mechanistic Studies Of Ruthenium Catalyzed C-N Bond Activation Reactions, Pandula Taepith Kirinde Arachchige
Scope And Mechanistic Studies Of Ruthenium Catalyzed C-N Bond Activation Reactions, Pandula Taepith Kirinde Arachchige
Dissertations (1934 -)
Primary aliphatic amines which are ubiquitous in natural products, traditionally considered as inert to substitution reactions. Recent studies clearly demonstrated that the aliphatic deaminative coupling chemistry can be used to make valuable scaffolds through C–N bond activation on transition metal complexes. The catalytic system generated in situ from the tetranuclear Ru–H complex with a catechol ligand (2-9/2-16) and independently synthesized ruthenium catecholate complex 2-11 was found to be effective for the direct deaminative coupling of primary amines. The catalytic system formed in-situ from the reaction of cationic Ru–H complex 2-10 with 3,4,5,6-tetrachloro-1,2-benzoquinone 2-12 was found to mediate a regioselective deaminative …
Hydrogen-Bonded Clusters: A Study Of The Elusive Anisole-Ammonia And Anisole-Water 1:1 Complexes, John Lawrence Loman
Hydrogen-Bonded Clusters: A Study Of The Elusive Anisole-Ammonia And Anisole-Water 1:1 Complexes, John Lawrence Loman
Master's Theses (2009 -)
The hydrogen bond is one of the most important and versatile interactions found in most subsets of chemistry and biology. This interaction is responsible for reactions and characteristic properties of the systems in thereof. This interaction is just one of several available non-covalent interactions that can occur and over the past several decades of molecular spectroscopy studies, the definition of the hydrogen bond has become broader compared to the “classic” definition. To accurately study the hydrogen-bonding in these systems can be quite challenging due to the size and complexity of the molecules involved, as well as the other interactions that …
Synthesis Of Composites From Cellulose, Chitosan, And Ciprofloxacin Hci Encapsulated In Sporopollenin Capsules, Mark Mitmoen
Synthesis Of Composites From Cellulose, Chitosan, And Ciprofloxacin Hci Encapsulated In Sporopollenin Capsules, Mark Mitmoen
Master's Theses (2009 -)
In order to be effective dressings for the treatment of infected wounds in the battlefield, it is essential that composite materials made from the biopolymers Cellulose and Chitosan contain broad-spectrum antibiotic drugs. These drugs must first be encapsulated into microcapsules in order to protect them from the manufacturing process, ensuring that they remain in a usable form in the final product. Here we demonstrate the successful encapsulation of Ciprofloxacin HCl into Sporopollenin Exine Capsules (SEC) to produce Cipro@SEC, followed by incorporation of Cipro@SEC into a polymer composite consisting of a mixture of Cellulose and Chitosan dissolved in 1-butylmethylimidazolium chloride, an …
Biochemical Analysis Of Dual T-Loop Rna Motifs That Perform Shape Recognition Of The Trna Elbow, John Aparicio Aguirre
Biochemical Analysis Of Dual T-Loop Rna Motifs That Perform Shape Recognition Of The Trna Elbow, John Aparicio Aguirre
Master's Theses (2009 -)
T-loops are highly abundant, structurally conserved five nucleotide motifs that facilitate long range intra- and intermolecular interactions and function to stabilize the tertiary fold of RNA. Interlocked or dual T-loop motifs provide additional thermodynamic stability and perform long-range docking of other RNA molecules. Dual T-loop RNA structures are present within the multi-turnover ribonuclease P-based ribozyme, the ribosome, and the bacterial tRNA-sensing riboswitch genetic element. In all three systems, a dual T-loop structure recognizes TYC/D-loop region of tRNA. Interestingly, sequence conservation at specific positions in the T-loops suggest a conserved interlocked RNA architecture. While X-ray crystallography provides insight into the putative …
Four Isotope-Labeled Recombination Pathways Of Ozone Formation, Dmitri Babikov, Elizaveta Grushnikova, Igor Gayday, Alexander Teplukhin
Four Isotope-Labeled Recombination Pathways Of Ozone Formation, Dmitri Babikov, Elizaveta Grushnikova, Igor Gayday, Alexander Teplukhin
Chemistry Faculty Research and Publications
A theoretical approach is developed for the description of all possible recombination pathways in the ozone forming reaction, without neglecting any process a priori, and without decoupling the individual pathways one from another. These pathways become physically distinct when a rare isotope of oxygen is introduced, such as 18O, which represents a sensitive probe of the ozone forming reaction. Each isotopologue of O3 contains two types of physically distinct entrance channels and two types of physically distinct product wells, creating four recombination pathways. Calculations are done for singly and doubly substituted isotopologues of ozone, eight rate coefficients …
Unraveling A Trifecta Of Weak Non-Covalent Interactions: The Dissociation Energy Of The Anisole-Ammonia 1:1 Complex, John L. Loman, James T. Makuvaza, Damian L. Kokkin, Scott A. Reid
Unraveling A Trifecta Of Weak Non-Covalent Interactions: The Dissociation Energy Of The Anisole-Ammonia 1:1 Complex, John L. Loman, James T. Makuvaza, Damian L. Kokkin, Scott A. Reid
Chemistry Faculty Research and Publications
The anisole-ammonia 1:1 complex is a challenge for both experiment and theory. Early studies supported a non-planar structure, involving a trifecta of weak non-covalent interactions: N-H/O, N-H/π, and C-H/N. The calculated structure and binding energy of the complex proved remarkably sensitive to the level of theory employed. Here, we report the first experimental measurement of the ground state dissociation energy of the complex, and derive an excited (S1) state dissociation energy that is in excellent agreement with the cutoff observed in the experimental excitation spectrum. Results are compared with previous predictions and new calculations based on benchmarked Density …
The Electronic Properties Of Ni(Pnn) Pincer Complexes Modulate Activity In Catalytic Hydrodehalogenation Reactions, Denan Wang, James R. Gardinier
The Electronic Properties Of Ni(Pnn) Pincer Complexes Modulate Activity In Catalytic Hydrodehalogenation Reactions, Denan Wang, James R. Gardinier
Chemistry Faculty Research and Publications
Three chloronickel(II) complexes of PNN‐ pincer ligands with pyrazolyl and diphenylphosphino donors appended to different arms of diarylamido anchors were prepared and fully characterized. The three derivatives (1‐OMe, 1‐Me, 1‐CF3) differ only by the identity of the para‐aryl substituent on the pyrazolyl arm with 1‐OMe being 310 mV easier to oxidize than 1‐CF3. All three complexes are competent catalysts for hydrodehalogenation reactions of 1‐bromooctane and a variety of aryl halides in dimethylacetamide using NaBH4 as both base and hydride source. Comparative studies using diverse substrates showed that catalytic activity correlates with electron donor properties; …
Iron(Iii)-Bipyridine Incorporated Metal–Organic Frameworks For Photocatalytic Reduction Of Co2 With Improved Performance, Yuan-Ping Wei, Sizhuo Yang, Peng Wang, Jin-Han Guo, Jier Huang, Wei-Yin Sun
Iron(Iii)-Bipyridine Incorporated Metal–Organic Frameworks For Photocatalytic Reduction Of Co2 With Improved Performance, Yuan-Ping Wei, Sizhuo Yang, Peng Wang, Jin-Han Guo, Jier Huang, Wei-Yin Sun
Chemistry Faculty Research and Publications
Metal–organic frameworks (MOFs) represent an emerging class of platforms to assemble single site photocatalysts for artificial photosynthesis. In this work, we report a new CO2 reduction photocatalyst (UiO-68-Fe-bpy) based on a robust Zr(IV)-MOF platform with incorporated Fe(bpy)Cl3 (bpy refers to the 4′-methyl-[2,2′-bipyridine] moiety) via amine–aldehyde condensation. We show that this hybrid catalyst can reduce CO2 to form CO under visible light illumination with excellent selectivity and enhanced activity with respect to its parent MOF and corresponding homogeneous counterpart. Using steady state and transient absorption (TA) spectroscopy, we show that the enhanced photocatalytic activity of UiO-68-Fe-bpy is attributed …
P450 Cyp17a1 Variant With A Disordered Proton Shuttle Assembly Retains Peroxo-Mediated Lyase Efficiency, Yilin Liu, Ilia G. Denisov, Yelena V. Grinkova, Stephen G. Silgar, James R. Kincaid
P450 Cyp17a1 Variant With A Disordered Proton Shuttle Assembly Retains Peroxo-Mediated Lyase Efficiency, Yilin Liu, Ilia G. Denisov, Yelena V. Grinkova, Stephen G. Silgar, James R. Kincaid
Chemistry Faculty Research and Publications
Human cytochrome P450 CYP17A1 first catalyzes hydroxylation at the C17 position of either pregnenolone (PREG) or progesterone (PROG), and a subsequent C17−C20 bond scission to produce dehydroepiandrosterone (DHEA) or androstenedione (AD). In the T306A mutant, replacement of the Threonine 306 alcohol functionality, essential for efficient proton delivery in the hydroxylase reaction, has only a small effect on the lyase activity. In this work, resonance Raman spectroscopy is employed to provide crucial structural insight, confirming that this mutant, with its disordered proton shuttle, fails to generate essential hydroxylase pathway intermediates, accounting for the loss in hydroxylase efficiency. Significantly, …
Probing The Magnetic Anisotropy Of Co(Ii) Complexes Featuring Redox-Active Ligands, Praveen Kumar, Daniel J. Santa Lucia, Kinga Kaniewska-Laskowska, Sergey V. Lindeman, Andrew Ozarowski, J. Krzystek, Mykhaylo Ozerov, Joshua Telser, John F. Berry, Adam T. Fiedler
Probing The Magnetic Anisotropy Of Co(Ii) Complexes Featuring Redox-Active Ligands, Praveen Kumar, Daniel J. Santa Lucia, Kinga Kaniewska-Laskowska, Sergey V. Lindeman, Andrew Ozarowski, J. Krzystek, Mykhaylo Ozerov, Joshua Telser, John F. Berry, Adam T. Fiedler
Chemistry Faculty Research and Publications
Coordination complexes that possess large magnetic anisotropy (otherwise known as zero-field splitting, ZFS) have possible applications in the field of magnetic materials, including single molecule magnets (SMMs). Previous studies have explored the role of coordination number and geometry in controlling the magnetic anisotropy and SMM behavior of high-spin (S = 3/2) Co(II) complexes. Building upon these efforts, the present work examines the impact of ligand oxidation state and structural distortions on the spin states and ZFS parameters of pentacoordinate Co(II) complexes. The five complexes included in this study (1–5) have the general formula, [Co(TpPh2 …
Copper-Catalyzed Formal Transfer Hydrogenation/Deuteration Of Aryl Alkynes, Samantha E. Sloane, Albert Reyes, Zoua Pa Vang, Lingzi Li, Kiera T. Behlow, Joseph R. Clark
Copper-Catalyzed Formal Transfer Hydrogenation/Deuteration Of Aryl Alkynes, Samantha E. Sloane, Albert Reyes, Zoua Pa Vang, Lingzi Li, Kiera T. Behlow, Joseph R. Clark
Chemistry Faculty Research and Publications
A copper-catalyzed reduction of alkynes to alkanes and deuterated alkanes is described under transfer hydrogenation and transfer deuteration conditions. Commercially available alcohols and silanes are used interchangeably with their deuterated analogues as the hydrogen or deuterium sources. Transfer deuteration of terminal and internal aryl alkynes occurs with high levels of deuterium incorporation. Alkyne-containing complex natural product analogues undergo transfer hydrogenation and transfer deuteration selectively, in high yield. Mechanistic experiments support the reaction occurring through a cis-alkene intermediate and demonstrate the possibility for a regioselective alkyne transfer hydrodeuteration reaction.
Ion Pairing Versus Solvation Of Dinitrobenzene Anions In Room-Temperature Ionic Liquids (Rtils): Vibrational Signatures Of Rtil–Substrate Interactions, Abderrahman Atifi, Piotr J. Mak, Michael D. Ryan
Ion Pairing Versus Solvation Of Dinitrobenzene Anions In Room-Temperature Ionic Liquids (Rtils): Vibrational Signatures Of Rtil–Substrate Interactions, Abderrahman Atifi, Piotr J. Mak, Michael D. Ryan
Chemistry Faculty Research and Publications
The mechanism of solvation of ions by ionic liquids is more complex than solvation in most molecular solvents as the ionic liquid itself provides the counter ion. Solvation and ion pairing of anionic substrates in room-temperature ionic liquids (RTILs) were investigated using resonance Raman spectroscopy and DFT calculations. The purpose of this study was to differentiate between the formation of discrete cation/anion structures and a double-layer cloud of counter ions without specific atomic interactions between the ionic species. In acetonitrile/RTIL mixtures, the radical anion and dianion of dinitrobenzene (DNB) are stabilized by RTILs through solvation and ion pairing. The formation …
Solving Complex Eigenvalue Problems On A Quantum Annealer With Applications To Quantum Scattering Resonances, Alexander Teplukhin, Brian K. Kendrick, Dmitri Babikov
Solving Complex Eigenvalue Problems On A Quantum Annealer With Applications To Quantum Scattering Resonances, Alexander Teplukhin, Brian K. Kendrick, Dmitri Babikov
Chemistry Faculty Research and Publications
Quantum computing is a new and rapidly evolving paradigm for solving chemistry problems. In previous work, we developed the Quantum Annealer Eigensolver (QAE) and applied it to the calculation of the vibrational spectrum of a molecule on the D-Wave quantum annealer. However, the original QAE methodology was applicable to real symmetric matrices only. For many physics and chemistry problems, the diagonalization of complex matrices is required. For example, the calculation of quantum scattering resonances can be formulated as a complex eigenvalue problem where the real part of the eigenvalue is the resonance energy and the imaginary part is proportional to …
Unravelling A Long-Lived Ligand-To-Metal Cluster Charge Transfer State In Ce–Tcpp Metal Organic Frameworks, Sizhou Yang, Wenhui Hu, James Nayakuchena, Christian Fiankor, Cunming Liu, Eli Diego Kinigstein, Jian Zhang, Xiaoyi Zhang, Jier Huang
Unravelling A Long-Lived Ligand-To-Metal Cluster Charge Transfer State In Ce–Tcpp Metal Organic Frameworks, Sizhou Yang, Wenhui Hu, James Nayakuchena, Christian Fiankor, Cunming Liu, Eli Diego Kinigstein, Jian Zhang, Xiaoyi Zhang, Jier Huang
Chemistry Faculty Research and Publications
Metal organic frameworks (MOFs) have emerged as promising photocatalytic materials for solar energy conversion. However, a fundamental understanding of light harvesting and charge separation (CS) dynamics in MOFs remains underexplored, yet they are key factors that determine the efficiency of photocatalysis. Herein, we report the design and CS dynamics of the Ce–TCPP MOF using ultrafast spectroscopic methods.
Distance Dependent Energy Transfer Dynamics From A Molecular Donor To A Zeolitic Imidazolate Framework Acceptor, Wenhui Hu, Fan Yang, Nick Pietraszak, Jing Gu, Jier Huang
Distance Dependent Energy Transfer Dynamics From A Molecular Donor To A Zeolitic Imidazolate Framework Acceptor, Wenhui Hu, Fan Yang, Nick Pietraszak, Jing Gu, Jier Huang
Chemistry Faculty Research and Publications
Zeolitic Imidazolate frameworks (ZIFs) have been demonstrated as promising light harvesting and photocatalytic materials for solar energy conversion. To facilitate their application in photocatalysis, it is essential to develop a fundamental understanding of their light absorption properties and energy transfer dynamics. In this work, we report distance-dependent energy transfer dynamics from a molecular photosensitizer (RuN3) to ZIF-67, where the distance between RuN3 and ZIF-67 is finely tuned by depositing an ultrathin Al2O3 layer on the ZIF-67 surface using an atomic layer deposition (ALD) method. We show that energy transfer time decreases with increasing distance between RuN3 and …
Solving The Conundrum: Widespread Proteins Annotated For Urea Metabolism In Bacteria Are Carboxyguanidine Deiminases Mediating Nitrogen Assimilation From Guanidine, Nicholas O. Schneider, Lambros J. Tassoulas, Danyun Zeng, Amanda J. Laseke, Nicholas J. Reiter, Lawrence P. Wackett, Martin St. Maurice
Solving The Conundrum: Widespread Proteins Annotated For Urea Metabolism In Bacteria Are Carboxyguanidine Deiminases Mediating Nitrogen Assimilation From Guanidine, Nicholas O. Schneider, Lambros J. Tassoulas, Danyun Zeng, Amanda J. Laseke, Nicholas J. Reiter, Lawrence P. Wackett, Martin St. Maurice
Chemistry Faculty Research and Publications
Free guanidine is increasingly recognized as a relevant molecule in biological systems. Recently, it was reported that urea carboxylase acts preferentially on guanidine, and consequently, it was considered to participate directly in guanidine biodegradation. Urea carboxylase combines with allophanate hydrolase to comprise the activity of urea amidolyase, an enzyme predominantly found in bacteria and fungi that catalyzes the carboxylation and subsequent hydrolysis of urea to ammonia and carbon dioxide. Here, we demonstrate that urea carboxylase and allophanate hydrolase from Pseudomonas syringae are insufficient to catalyze the decomposition of guanidine. Rather, guanidine is decomposed to ammonia through the combined activities of …
Computationally-Guided Investigation Of Dual Amine/Pi Lewis Acid Catalysts For Direct Additions Of Aldehydes And Ketones To Unactivated Alkenes And Alkynes, Eric Greve, Jacob D. Porter, Chris Dockendorff
Computationally-Guided Investigation Of Dual Amine/Pi Lewis Acid Catalysts For Direct Additions Of Aldehydes And Ketones To Unactivated Alkenes And Alkynes, Eric Greve, Jacob D. Porter, Chris Dockendorff
Chemistry Faculty Research and Publications
Dual amine/pi Lewis acid catalyst systems have been reported for intramolecular direct additions of aldehydes/ketones to unactivated alkynes and occasionally alkenes, but related intermolecular reactions are rare and not presently of significant synthetic utility, likely due to undesired coordination of enamine intermediates to the metal catalyst. We reasoned that bulky metal ligands and bulky amine catalysts could minimize catalyst poisoning and could facilitate certain examples of direct intermolecular additions of aldehydes/ketones to alkenes/alkynes. Density Functional Theory (DFT) calculations were performed that suggested that pyridine-2,6-bis(oxazoline) (PyBOX)-Pt(II) catalysts for alkene/alkyne activation could be combined with MacMillan's imidazolidinone organocatalyst for aldehyde/ketone activation to …
1. Dft-Guided Discovery Of Hybrid Catalysts For C-C Bond Formation; 2. Synthesis Of A Reported Pdi Inhibitor, Eric Greve
1. Dft-Guided Discovery Of Hybrid Catalysts For C-C Bond Formation; 2. Synthesis Of A Reported Pdi Inhibitor, Eric Greve
Dissertations (1934 -)
1. Dual amine/pi Lewis acid catalyst systems have been reported for intramolecular direct additions of aldehydes/ketones to unactivated alkynes and occasionally alkenes, but related intermolecular reactions are rare. We reasoned that bulky metal ligands and bulky amine catalysts could minimize catalyst poisoning and could facilitate certain examples of direct intermolecular additions of unactivated aldehydes/ketones to alkenes/alkynes. Density Functional Theory (DFT) ground state calculations on putative catalytic intermediates for alkyne versus organocatalyst complexation to the -acid, and also the key carbon-carbon bond formation were used to prioritize ligand/organocatalyst combinations. Our calculations suggested that PyBOX-Pt(II) catalysts for alkene/alkyne activation could be combined …
Synthesis And Evaluation Of Small Molecule Inhibitors Of Pyruvate Carboxylase, Daniel John Burkett
Synthesis And Evaluation Of Small Molecule Inhibitors Of Pyruvate Carboxylase, Daniel John Burkett
Master's Theses (2009 -)
Through structure-based drug design (SBDD), a series of small molecules have been synthesized and evaluated for inhibitory activity against the pyruvate carboxylase (PC) enzyme via two biological assays. The -hydroxycinnamic acid scaffold was identified as the most privileged scaffold for inhibition of PC. Analogues of phenylpyruvic acid were generated and evaluated, leading to the discovery of inhibitors with single digit micromolar (M) IC50 values. The most potent inhibitors identified were evaluated for inhibitory activity against other metalloproteins, and 2-hydroxy-3-(quinolone-2-yl)propenoic acid did not significantly inhibit human carbonic anhydrase II, matrix metalloproteinase-2, malate dehydrogenase, or lactate dehydrogenase. The small molecules presented in …
Resonance Raman Spectroscopic Studies Of Peroxo And Hydroperoxo Intermediates In Lauric Acid (La)-Bound Cytochrome P450 119, Remigio Usai, Daniel Kaluka, Piotr J. Mak, Yilin Liu, James R. Kincaid
Resonance Raman Spectroscopic Studies Of Peroxo And Hydroperoxo Intermediates In Lauric Acid (La)-Bound Cytochrome P450 119, Remigio Usai, Daniel Kaluka, Piotr J. Mak, Yilin Liu, James R. Kincaid
Chemistry Faculty Research and Publications
Cytochromes P450 bind and cleave dioxygen to generate a potent intermediate compound I, capable of hydroxylating inert hydrocarbon substrates. Cytochrome P450 119, a bacterial cytochrome P450 that serves as a good model system for the study of the intermediate states in the P450 catalytic cycle. CYP119 is found in high temperature and sulfur rich environments. Though the natural substrate and redox partner are still unknown, a potential application of such thermophilic P450s is utilizing them as biocatalysts in biotechnological industry; e.g., the synthesis of organic compounds otherwise requiring hostile environments like extremes of pH or temperature. In the present work …
Mqct: User-Ready Program For Calculations Of Inelastic Scattering Of Two Molecules, Alexander Semenov, Bikramaditya Mandal, Dmitri Babikov
Mqct: User-Ready Program For Calculations Of Inelastic Scattering Of Two Molecules, Alexander Semenov, Bikramaditya Mandal, Dmitri Babikov
Chemistry Faculty Research and Publications
A program named MQCT is developed for calculations of rotationally and vibrationally inelastic scattering of molecules using the mixed quantum/classical theory approach. Calculations of collisions between two general asymmetric top rotors are now possible, which is a feature unavailable in other existing codes. Vibrational states of diatomic molecules can also be included in the basis set expansion, to carry out calculations of ro-vibrational excitation and quenching. Minimal input for the code assumes several defaults and is very simple, easy to set-up and run by non-experts. Multiple options, available for expert calculations, are listed in the Supplemental Information. The code is …
Probing Cooperativity In C–H⋯N And C–H⋯Π Interactions: Dissociation Energies Of Aniline⋯(Ch4)N (N = 1, 2) Van Der Waals Complexes From Resonant Ionization And Velocity Mapped Ion Imaging Measurements, James Makuvaza, John L. Loman, Damian L. Kokkin, Scott A. Reid
Probing Cooperativity In C–H⋯N And C–H⋯Π Interactions: Dissociation Energies Of Aniline⋯(Ch4)N (N = 1, 2) Van Der Waals Complexes From Resonant Ionization And Velocity Mapped Ion Imaging Measurements, James Makuvaza, John L. Loman, Damian L. Kokkin, Scott A. Reid
Chemistry Faculty Research and Publications
Recent studies of the weakly bound anisole⋯CH4 complex found a dual mode of binding, featuring both C/H⋯π and C/H⋯O noncovalent interactions. In this work, we examine the dissociation energies of related aniline⋯(CH4)n (n = 1, 2) van der Waals clusters, where both C/H⋯π and C/H⋯N 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), we derive the dissociation energies of both complexes in the ground (S0), excited (S1), and cation radical (D …
Silver(I) And Copper(I) Complexes Of Semi‐Bulky Nitrogen‐Confused C‐Scorpionates, Denan Wang, Fathiya Jahan, Kristin J. Meise, Sergey V. Lindeman, James R. Gardinier
Silver(I) And Copper(I) Complexes Of Semi‐Bulky Nitrogen‐Confused C‐Scorpionates, Denan Wang, Fathiya Jahan, Kristin J. Meise, Sergey V. Lindeman, James R. Gardinier
Chemistry Faculty Research and Publications
Two new sterically demanding nitrogen‐confused C‐scorpionate ligands with a bis(3,5‐diisopropylpyrazol‐1‐yl)methyl group bound to the 3‐ position of a normal pyrazole (HLiPr2) or an N‐toluenesulfonyl pyrazole (TsLiPr2) have been prepared. Reactions between the ligands (xLiPr2) and silver trifluoromethanesulfonate, AgOTf, gave four new compounds of the types [Ag(xLiPr2)](OTf) (x = Ts, 1a; x = H, 2a) or [Ag(xLiPr2)2](OTf) (x = Ts, 1b; x = H, 2b) depending on the initial metal:ligand ratio. Similarly, the reactions with [Cu(CH3CN)4](PF6 …
Electron Ratchets: State Of The Field And Future Challenges, Bryan Lau, Ofer Kedem
Electron Ratchets: State Of The Field And Future Challenges, Bryan Lau, Ofer Kedem
Chemistry Faculty Research and Publications
Electron ratchets are non-equilibrium electronic devices that break inversion symmetry to produce currents from non-directional and random perturbations, without an applied net bias. They are characterized by strong parameter dependence, where small changes in operating conditions lead to large changes in the magnitude and even direction of the resulting current. This high sensitivity makes electron ratchets attractive research subjects, but leads to formidable challenges in their deeper study, and particularly to their useful application. This perspective reviews the progress that was made in the field starting from the first experimental electron ratchets in the late 1990s, and how the field …
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 …
Hybrid Metal/Covalent Organic Frameworks For Solar Fuel Conversion, Sizhuo Yang
Hybrid Metal/Covalent Organic Frameworks For Solar Fuel Conversion, Sizhuo Yang
Dissertations (1934 -)
Due to the harsh environment issues such as air pollution and global warming and global energy crisis raised by using fossil fuels, it is urgent to find an alternative sustainable energy source. How to utilize solar energy-the most clean and abundant energy source on earth is challenging. Convert solar energy to clean fuel energy like H2 or hydrocarbons is ideal energy conversion strategy. Thus, design new materials for hydrogen generation or CO2 reduction have attract researcher’s attention.The present study focuses on two types of materials of interest, the first of which is Metal Organic Frameworks (MOFs), including enhancing the …
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 …
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 …
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 …