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Nuclear Magnetic Resonance Studies Of Imidazolium-Based Ionic Liquids And Garnet-Type Li7la3zr2o12, Shen Lai 2018 The Graduate Center, City University of New York

Nuclear Magnetic Resonance Studies Of Imidazolium-Based Ionic Liquids And Garnet-Type Li7la3zr2o12, Shen Lai

All Dissertations, Theses, and Capstone Projects

Advancements in electrochemical energy storage materials are critical in the development and utilization of renewable energy technologies. These advancements involve obtaining a better understanding of electrochemical mechanisms and properties through scientific research towards an improved energy storage technology. Nuclear magnetic resonance (NMR), is a sensitive and selective method to probe particle dynamics (magnetic relaxation, diffusometry, etc.) and material structures (spectroscopy) down to the atomic level. In this work, several NMR techniques are employed to study imidazolium-based ionic liquids and garnet-type inorganic materials. These are being studied due to their potential use as safer alternatives to organic solvent-based electrolytes in lithium-ion ...


A Stereospecific Pd-Catalyzed Suzuki Cross-Coupling Reaction And A Statistical Study Of The Ligand's Role In Stereoselection, Shibin Zhao 2018 The Graduate Center, City University of New York

A Stereospecific Pd-Catalyzed Suzuki Cross-Coupling Reaction And A Statistical Study Of The Ligand's Role In Stereoselection, Shibin Zhao

All Dissertations, Theses, and Capstone Projects

The development of palladium-catalyzed carbon-carbon cross-coupling reactions has profoundly influenced the manner through which we approach the synthesis of complex organic molecules. Among established cross-coupling reactions, which include Kumada, Negishi, and Stille reactions, the Suzuki cross-coupling reaction exhibits particularly wide functional group compatibility, while employing non-toxic, air-stable organoboron nucleophiles. Conventional studies of Pd-catalyzed Suzuki cross-coupling reactions have focused on C(sp2)-C(sp2) cross-coupling reactions, which result in the formation of planar products. Conceptually, the use of C(sp3) (secondary) nucleophiles would enable the reliable manipulation of organic molecules in three dimensions. However, this process has not ...


Synthesis And Evaluation Of Densely-Functionalized Troponoids, Danielle R. Hirsch 2018 The Graduate Center, City University of New York

Synthesis And Evaluation Of Densely-Functionalized Troponoids, Danielle R. Hirsch

All Dissertations, Theses, and Capstone Projects

Herein, we document our efforts to expand the scope of troponoid synthetic methodology towards densely-substituted scaffolds. This body of work has focused primarily on an oxidopyrylium cycloaddition/ring-opening strategy for the synthesis and biochemical evaluation of troponoids for assistance in a variety of medicinal chemistry studies. In Chapter 1, we outline the use of this synthetic strategy in the profiling of a library of synthetic αHTs against an aminoglycoside antibiotic resistance enzyme known as aminoglycoside-2’’-O-nucleotidyltransferase [ANT(2’’)-Ia]. Enzymatic mechanistic insights have been gleaned from an assessment of troponoid/antibiotic synergistic potential. In particular, two synthetic constructs were identified ...


Crystal Structure Of A Homoleptic Zinc(Ii) Complex Based On Bis­(3,5-Diiso­Propyl­Pyrazol-1-Yl)Acetate, Josiah G. Elsberg, Nicholas G. Spiropulos, Adam C. Colson, Eric C. Brown 2018 Boise State University

Crystal Structure Of A Homoleptic Zinc(Ii) Complex Based On Bis­(3,5-Diiso­Propyl­Pyrazol-1-Yl)Acetate, Josiah G. Elsberg, Nicholas G. Spiropulos, Adam C. Colson, Eric C. Brown

Chemistry Faculty Publications and Presentations

Deprotonation of the methyl­ene group in bis­(3,5-diiso­propyl­pyrazol-1-yl)methane with nBuLi and reaction with carbon dioxide yields lithium bis­(3,5-diiso­propyl­pyrazol-1-yl)acetate (1). Treatment of 1 with ZnCl2 results in the com­pound bis­[bis­(3,5-diiso­propyl­pyrazol-1-yl)acetato]­zinc(II), [Zn(C20H31N4O2)2] (2), whose structure has monoclinic (P21/c) symmetry. The ZnII ion resides on an inversion center and is coordinated by two bis­(3,5-diiso­propyl­pyrazol-1-yl)acetate (bdippza) ligands. Each ligand facially coordinates the zinc center via ...


Atomically Dispersed Pd On Nanodiamond/Graphene Hybrid For Selective Hydrogenation Of Acetylene, Fei Huang, Yuchen Deng, Yunlei Chen, Xiangbin Cai, Mia Peng, Zhimin Jia, Pengju Ren, Dequan Xiao, Xiaodong Wen, Ning Wang, Hongyang Liu, Ding Ma 2018 Chinese Academy of Sciences

Atomically Dispersed Pd On Nanodiamond/Graphene Hybrid For Selective Hydrogenation Of Acetylene, Fei Huang, Yuchen Deng, Yunlei Chen, Xiangbin Cai, Mia Peng, Zhimin Jia, Pengju Ren, Dequan Xiao, Xiaodong Wen, Ning Wang, Hongyang Liu, Ding Ma

Chemistry and Chemical Engineering Faculty Publications

An atomically dispersed palladium (Pd) catalyst supported onto a defective nanodiamond-graphene (ND@G) is reported here for selective hydrogenation of acetylene in the presence of abundant ethylene. The catalyst exhibits remarkable performance for the selective conversion of acetylene to ethylene: high conversion (100%), ethylene selectivity (90%), and good stability (i.e., steady for at least 30 hours). The unique struc-ture of the catalyst (i.e., atomically dispersion of Pd atoms on graphene through Pd-C bond anchoring) ensure the facile desorption of ethylene against the over-hydrogenation of ethylene to undesired ethane, which is the key for the outstanding selectivity of the ...


Rational Design Of Superhydrophilic/Superoleophobic Surfaces For Oil-Water Separation Via Thiol-Acrylate Photopolymerization, Li Xiong, Wei Guo, Benjamin M. Alameda, Reese Sloan, William D. Walker, Derek L. Patton 2018 University of Southern Mississippi

Rational Design Of Superhydrophilic/Superoleophobic Surfaces For Oil-Water Separation Via Thiol-Acrylate Photopolymerization, Li Xiong, Wei Guo, Benjamin M. Alameda, Reese Sloan, William D. Walker, Derek L. Patton

Faculty Publications

We report a simple, rapid, and scalable strategy to fabricate surfaces exhibiting in-air superoleophobic/superhydrophilic wetting via sequential spray deposition and photopolymerization of nanoparticle-laden thiol–acrylate resins comprising both hydrophilic and oleophobic chemical constituents. The combination of spray deposition with nanoparticles provides hierarchical surface morphologies with both micro- and nanoscale roughness. Mapping the wetting behavior as a function of resin composition using high- and low-surface-tension liquid probes enabled facile identification of coatings that exhibit a range of wetting behavior, including superhydrophilic/superoleophilic, superhydrophobic/superoleophobic, and in-air superhydrophilic/superoleophobic wetting. In-air superhydrophilic/superoleophobic wetting was realized by a dynamic rearrangement of ...


Exploring The Chemistry Of Asymmetric Phosphines & Phosphinidene Sulfides, Taylor E. Pritchard 2018 The University of Western Ontario

Exploring The Chemistry Of Asymmetric Phosphines & Phosphinidene Sulfides, Taylor E. Pritchard

Electronic Thesis and Dissertation Repository

The field of low-coordinate main group chemistry has seen huge development in the last 30 years, with novel compounds that demonstrate unique structures and reactivity. Isolation of these species has relied on thoughtfully designed substituents normally containing substructure steric bulk. The area of phosphinidene chalcogenide isolation and transfer remains poorly understood by comparison. In this context, the major focus of thesis was on the development of a room-temperature method for the transfer of RP=S moieties with and without sterically demanding substituents. The preparation and complete characterization of new asymmetric phosphines with m-terphenyl ligands was also reported. In Chapter ...


Stylolites Cathodoluminescence Under Cross Polarized Light, Katherine Dvorak 2018 Western Michigan University

Stylolites Cathodoluminescence Under Cross Polarized Light, Katherine Dvorak

The Hilltop Review

Devil's Gate limestone under cathodoluminescence. Bright yellow and orange areas are calcite and the bright blue indicates trace minerals along the solution seam. Trace minerals left in the seam are heavy metals and other silicate minerals.


High-Dimensional Isotope Relationships, Yuyang He 2018 Louisiana State University

High-Dimensional Isotope Relationships, Yuyang He

LSU Doctoral Dissertations

High-dimensional isotope relationships describes the relationships of two or more element or position-specific (PS) elements in the same molecule or ion. It provides us more powerful tools to study reaction mechanisms and dynamics. Chapter 1 is about dual or multiple stable isotope relationship on δ-δ (or δ'-δ') space. While temporal data sampled from a closed-system can be treated by a Rayleigh Distillation Model (RDM), spatial data should be treated by a Reaction-Transport Model (RTM). Here we compare the results of a closed-system RDM to a RTM for systems with diffusional mass transfer by simulating the trajectories on nitrate's ...


Modulating Viscoelasticity, Stiffness, And Degradation Of Synthetic Cellular Niches Via Stoichiometric Tuning Of Covalent Versus Dynamic Noncovalent Cross-Linking, Yu Tan, Henry Huang, David C. Ayers, Jie Song 2018 University of Massachusetts Medical School

Modulating Viscoelasticity, Stiffness, And Degradation Of Synthetic Cellular Niches Via Stoichiometric Tuning Of Covalent Versus Dynamic Noncovalent Cross-Linking, Yu Tan, Henry Huang, David C. Ayers, Jie Song

Open Access Articles

Viscoelasticity, stiffness, and degradation of tissue matrices regulate cell behavior, yet predictive synergistic tuning of these properties in synthetic cellular niches remains elusive. We hypothesize that reversible physical cross-linking can be quantitatively introduced to synthetic hydrogels to accelerate stress relaxation and enhance network stiffness, while strategic placement of isolated labile linkages near cross-linking sites can predict hydrogel degradation, both of which are essential for creating adaptive cellular niches. To test these hypotheses, chondrocytes were encapsulated in hydrogels formed by biorthogonal covalent and noncovalent physical cross-linking of a pair of hydrophilic building blocks. The stiffer and more viscoelastic hydrogels with DBCO-DBCO ...


Pre- And Post-Research Group Selection: Evolving Roles For Chemistry Librarians, Sarah Jeong, Kiyomi D. Deards 2018 Wake Forest University

Pre- And Post-Research Group Selection: Evolving Roles For Chemistry Librarians, Sarah Jeong, Kiyomi D. Deards

Library Conference Presentations and Speeches

Librarian consultations with research groups, flipped classroom exercises, active learning, and Just-In-Time instruction sessions are increasing at public and private doctoral granting universities at a time when many library staffs are shrinking. As the needs and points of contact with graduate students evolve it will be critical for the depth of knowledge and resources of chemistry librarians to be understood and shared both in-person and on-demand online. This presentation will outline the strategies used to meet the evolving needs of chemistry graduate students as they move from pre-research group selection into established research groups.


Determination Of Polar Solvents By Static Headspace Extraction – Gas Chromatography (She-Gc), Michael Sithersingh 2018 Seton Hall University

Determination Of Polar Solvents By Static Headspace Extraction – Gas Chromatography (She-Gc), Michael Sithersingh

Seton Hall University Dissertations and Theses (ETDs)

ABSTRACT

The term “headspace” is defined as the vapor that forms above or around a liquid or solid sample in a closed container. Usually, the vapor is above the liquid or solid at the top of the container, hence the term headspace. Headspace sampling is a method for separating volatile materials that may be extracted from a more solid sample matrix and then analyzed using gas chromatography. Headspace extraction refers to the collection and analysis of the vapor phase in the container. The Static Headspace Extraction – Gas Chromatography (SHE-GC) technique has been used since the early days of Gas Chromatography ...


Building On Nature: Spectroscopic Studies Of Photosynthesis-Inspired Pigments, Fused Light Harvesting Proteins, And Bacterial Reaction Center Mutants, Kaitlyn Faries 2018 Washington University in St. Louis

Building On Nature: Spectroscopic Studies Of Photosynthesis-Inspired Pigments, Fused Light Harvesting Proteins, And Bacterial Reaction Center Mutants, Kaitlyn Faries

Arts & Sciences Electronic Theses and Dissertations

Photosynthesis is the dominant form of solar energy conversion on the planet, making it critical to understand the fundamentals of the process in order to effectively mimic and improve upon it for human energy needs. The initial stages of photosynthesis include light harvesting and chemical conversion of that harvested energy via electron transport, with both of these stages relying on pigments (or chromophores) such as chlorophyll and specific protein architectures for the processes. In this work, the fundamental underpinnings of photosynthetic light harvesting and electron transport are explored via spectroscopy of various photosynthetic systems with altered natural pigments and proteins ...


Spin Alignment Generated In Inelastic Nuclear Reactions, Daniel Hoff 2018 Washington University in St. Louis

Spin Alignment Generated In Inelastic Nuclear Reactions, Daniel Hoff

Arts & Sciences Electronic Theses and Dissertations

The spin alignment of inelastically excited 7Li projectiles, when the target remains in its ground state, was determined through angular-correlation measurements between the breakup fragments of 7Li_ (_ + t). It was found that 7Li_ is largely aligned along the beam axis (longitudinal) in this type of inelastic reaction, regardless of the target. This longitudinal alignment is well described by DWBA calculations, which can be explained by an angular-momentum-excitation-energy mismatch condition. These calculations also explain the longitudinal spin alignment of excited nuclei in several other systems, showing the phenomenon is more general. The experiment involving 7Li was performed at the Texas ...


An Nmr Study Of Co2 Dynamics And Structural Characterization Of Porous Materials, Robert M. Marti 2018 Washington University in St. Louis

An Nmr Study Of Co2 Dynamics And Structural Characterization Of Porous Materials, Robert M. Marti

Arts & Sciences Electronic Theses and Dissertations

Nuclear magnetic resonance (NMR) has proven to be a versatile and powerful analytical tool to study many areas of interest to the scientific community, such as molecular dynamics and structural characterization. In this dissertation, NMR was used as a probe for CO2 dynamics in metal-organic frameworks. Variable temperature (VT) NMR was used to determine molecular dynamics of CO2, going as low as 8 K. In the fast motion regime, where the CO2 hopping rate is fast compared to the NMR experiment time, 13CO2 inside of Mg-MOF-74 still exhibits a chemical shift anisotropy (CSA) powder pattern. However, there is a certain ...


The Development Of Metal Complexes As Components Of Fluorescent And Nuclear Imaging Probes, William Turnbull 2018 The University of Western Ontario

The Development Of Metal Complexes As Components Of Fluorescent And Nuclear Imaging Probes, William Turnbull

Electronic Thesis and Dissertation Repository

The advent of molecular imaging as a discipline has drastically improved our ability to understand the biochemical and cellular events that drive life, death and disease. This thesis will document the discovery of new metal chelators for Re/99mTc, new methods of incorporating these metals into peptide structures, as well as new fluorescent compounds. These novel methods and compounds may be used in the development of molecular imaging probes for single photon emission computed tomography (SPECT) and optical imaging techniques, with applications for differentiating cancerous tissue from benign and healthy.

Chapter 2 discusses the development of a dual modality ...


Materials Characterization By Dynamic Nuclear Polarization Enhanced Solid-State Nmr Spectroscopy, Aaron Rossini 2018 Iowa State University and Ames Laboratory

Materials Characterization By Dynamic Nuclear Polarization Enhanced Solid-State Nmr Spectroscopy, Aaron Rossini

Chemistry Publications

High-resolution solid-state NMR spectroscopy is a powerful tool for the study of organic and inorganic materials because it can directly probe the symmetry and structure at nuclear sites, the connectivity/bonding of atoms and precisely measure inter-atomic distances. However, NMR spectroscopy is hampered by intrinsically poor sensitivity, consequently, the application of NMR spectroscopy to many solid materials is often infeasible. High-field dynamic nuclear polarization (DNP) has emerged as a technique to routinely enhance the sensitivity of solid-state NMR experiments by one to three orders of magnitude. This perspective gives a general overview of how DNP enables advanced solid-state NMR experiments ...


Expanding The I-Ii-V Phase Space: Soft Synthesis Of Polytypic Ternary And Binary Zinc Antimonides, Miles A. White, Katelyn J. Baumler, Yunhua Chen, Amrit Venkatesh, Alan M. Medina-Gonzalez, Aaron Rossini, Julia Zaikina, Emory Chan, Javier Vela 2018 Iowa State University

Expanding The I-Ii-V Phase Space: Soft Synthesis Of Polytypic Ternary And Binary Zinc Antimonides, Miles A. White, Katelyn J. Baumler, Yunhua Chen, Amrit Venkatesh, Alan M. Medina-Gonzalez, Aaron Rossini, Julia Zaikina, Emory Chan, Javier Vela

Chemistry Publications

Soft chemistry methods offer the possibility of synthesizing metastable and kinetic products that are unobtainable through thermodynamically-controlled, high-temperature reactions. A recent solution-phase exploration of Li-Zn-Sb phase space revealed a previously unknown cubic half-Heusler MgAgAs-type LiZnSb polytype. Interestingly, this new cubic phase was calculated to be the most thermodynamically stable, despite prior literature reporting only two other ternary phases (the hexagonal half-Heusler LiGaGe-type LiZnSb, and the full-Heusler Li2ZnSb). This surprising discovery, coupled with the intriguing optoelectronic and transport properties of many antimony containing Zintl phases, required a thorough exploration of syn-thetic parameters. Here, we systematically study the effects that different precursor ...


Theoretical Study Of Structure And Reactions Of Metalated Oximes And Oxime Ethers, Rainer Glaser, Andrew J. Streitwieser 2018 Missouri University of Science and Technology

Theoretical Study Of Structure And Reactions Of Metalated Oximes And Oxime Ethers, Rainer Glaser, Andrew J. Streitwieser

Rainer Glaser

The potential energy surfaces of acetaldoxime carbanion and its ion pairs formed with lithium and sodium cations ions have been explored with ab initio methods to model and study the regiochemistry of metalated oxime ethers. Planar structures of the carbanions produced by deprotonating acetaldoxime are minima on the potential energy surface. The syn-isomer is 2.6 Kcal/mole more stable than the anti. This difference is not a manifestation of cyclic conjugation but more likely is a result of electrostatic effects. Two chiral and almost isoenergetic minima have been located for the ion pairs formed by either of the isomeric ...


The Carriers Of The Interstellar Unidentified Infrared Emission Features: Constraints From The Interstellar C-H Stretching Features At 3.2-3.5 Μm, Xuejuan Yang, Rainer Glaser, Aigen Li, Jianxin Zhong 2018 Missouri University of Science and Technology

The Carriers Of The Interstellar Unidentified Infrared Emission Features: Constraints From The Interstellar C-H Stretching Features At 3.2-3.5 Μm, Xuejuan Yang, Rainer Glaser, Aigen Li, Jianxin Zhong

Rainer Glaser

The unidentified infrared emission (UIE) features at 3.3, 6.2, 7.7, 8.6, and 11.3 μm, commonly attributed to polycyclic aromatic hydrocarbon (PAH) molecules, have recently been ascribed to mixed aromatic/aliphatic organic nanoparticles. More recently, an upper limit of <9% was placed on the aliphatic fraction (i.e., the fraction of carbon atoms in aliphatic form) of the UIE carriers based on the observed intensities of the 3.4 μm and 3.3 μm emission features by attributing them to aliphatic and aromatic C-H stretching modes, respectively, and assuming A 3.4/A 3.3 ≈ 0.68 derived from a small set of aliphatic and aromatic compounds, where A 3.4 and A 3.3 are, respectively, the band strengths of the 3.4 μm aliphatic and 3.3 μm aromatic C-H bonds. To improve the estimate of the aliphatic fraction of the UIE carriers, here ...


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