Cu-Promoted C-H Bond Hydroxylation Inspired By Cu-Dependent Metalloenzymes, 2021 Southern Methodist University
Cu-Promoted C-H Bond Hydroxylation Inspired By Cu-Dependent Metalloenzymes, Rachel Trammell
Chemistry Theses and Dissertations
From 2003 to 2015, Schӧnecker and Baran proposed a dinuclear Cu/O2 species in their mechanistic proposal for the hydroxylation of sp3 C-H bonds within their systems (proposed based on yields). Inspired from the site selectivity of this methodology and poor analysis of the mechanism, the first project was inspired to re-examine the sp3 C-H bond hydroxylation by Schrӧnecker and Baran and perform an intensive investigation into understanding how Cu/O2 interact which led us to propose a new mechanism based on the evidence collected (i.e., LCuII-hydroperoxide species that undergoes homolytic O-O bond ...
Suzuki Coupling Catalyzed By (8-(Dimesitylboryl)Quinoline)Palladium(0) Species: A Theoretical Analysis, 2021 University of South Dakota
Suzuki Coupling Catalyzed By (8-(Dimesitylboryl)Quinoline)Palladium(0) Species: A Theoretical Analysis, Haley S. Rust
The Suzuki reaction is a catalyzed cross-coupling reaction which is of upmost importance in the formation of carbon-carbon (C-C) bonds in modern organic synthesis. Recently a new catalyst including an 8-(dimesitylboryl)quinoline for the coupling of aryl halides with phenylboronic acids was synthetized. We synthesized ligand that includes a frustrated Lewis pair, (quinolin-8-yl)dimesitylborane (DMBQ), complexed it with group X metals (nickel (Ni), palladium (Pd), and platinum (Pt)), and studied the process of oxidative addition with carbon-fluorine (C-F) bonds and activation towards Suzuki coupling. Mayer bond analysis and electron localization function maps showed a bond between the boron center ...
Investigating The Role Of Charge Separation In Triplet State Formation In Zinc Dipyrrin Photosensitizers, 2021 East Tennessee State University
Investigating The Role Of Charge Separation In Triplet State Formation In Zinc Dipyrrin Photosensitizers, Irene Y. Dzaye
Electronic Theses and Dissertations
About 85% of the world’s energy is derived from non-renewable sources—coal, petroleum, and natural gas. Solar photocatalysis is one way to potentially generate cheap renewable fuels by harnessing energy from the sun using a photosensitizer and converting it into chemical energy. The efficiency of a photosensitizer depends on its capacity to form a prolonged triplet excited state. Zinc dipyrrin complexes have the potential to be efficient sensitizers for reductive photochemistry, but their ability to form long-lived triplet excited states still needs extensive research. The overall aim of this research is to probe the role charge separation plays in ...
Synthesis Of A Zinc Dipyrrin Complex For Photocatalytic Reduction Of Co2, 2021 East Tennessee State University
Synthesis Of A Zinc Dipyrrin Complex For Photocatalytic Reduction Of Co2, Sylvia Meredith
Undergraduate Honors Theses
Zinc dipyrrin complexes have the potential to act as cheap, effective photosensitizers. Synthesizing and studying different types could lead to more efficient solar energy harvesting processes, especially the production of solar fuel. Here, two attempts to synthesize 1,3,7,9-tetraphenyl-5-mesityldipyrromethene are reported and discussed. According to 1H NMR, the first synthesis attempt was not successful. The second synthesis attempt was not purified effectively, so 1H NMR produced inconclusive results. Further purification strategies or alternate synthesis methods are required.
Periodic Tabletalks: The Elements Never Go Out Of Style, 2021 Iowa State University
Periodic Tabletalks: The Elements Never Go Out Of Style, Javier Vela, Emily A. Weiss
With the cancelation of the Spring ACS National meeting in 2020—and subsequent in-person meetings—because of the COVID-19 pandemic, the Division of Inorganic Chemistry (DIC) sought new ways to connect with its membership and continue to showcase the fantastic research carried out by inorganic chemists. The DIC executive committee thus initiated monthly Zoom webinars with two speakers each, typically one junior investigator and one more-established researcher, selected with input from each of the DIC subdivisions: Bioinorganic, Coordination, Solid-State, Organometallic, Nanoscience, and Sustainable Energy & Environment.
Visible Light Generation And Mechanistic Investigation Of High-Valent Metal-Oxo Species Supported By Different Ligands, 2021 Western Kentucky University
Visible Light Generation And Mechanistic Investigation Of High-Valent Metal-Oxo Species Supported By Different Ligands, Seth Ellis Klaine
Masters Theses & Specialist Projects
Numerous transition metal catalysts have been designed as biomimetic model compounds for the active site of metalloenzymes found throughout Nature, most notably cytochrome P450 monooxygenases that carry out the oxidative transformations of organic substrates with near-perfect chemo-, regio-, and stereo-selectivity. The primary active oxidants in catalytic and enzymatic cycles are fleeting high-valent metal-oxo intermediates where the oxo ligand can transfer to an organic substrate in a process known as oxygen atom transfer (OAT).
In the present work, porphyrin-manganese(III), salen-chromium(III), and salenmanganese( III) derivatives were successfully synthesized and spectroscopically characterized using 1H NMR and UV-Vis spectroscopies. A facile photochemical ...
Synthesis And Catalytic Oxidation Of Organic Substrates By Light-Harvesting Metalloporphyrins, 2021 Western Kentucky University
Synthesis And Catalytic Oxidation Of Organic Substrates By Light-Harvesting Metalloporphyrins, Christian Alcantar
Masters Theses & Specialist Projects
note: Some notation in this abstract may not appear exactly as formatted in the thesis.
In this work, ruthenium, iron, and manganese light-harvesting metalloporphyrins have been successfully synthesized to serve as biomimetic models of the active site of Cytochrome P450 for the development of a green and efficient oxidation catalyst. The covalent introduction of light-harvesting boron-dipyrrin (BODIPY) fluorophores on the porphyrin macrocycle allows for the absorption of a broader range of visible light in addition to that captured by the porphyrin aromatic system alone. It is expected that this core-antenna system will increase the absorbed light energy and transfer it ...
Interactions Of Organic Fluorophores With Plasmonic Surface Lattice Resonances, 2021 The Graduate Center, City University of New York
Interactions Of Organic Fluorophores With Plasmonic Surface Lattice Resonances, Robert J. Collison
Dissertations, Theses, and Capstone Projects
It is common knowledge that metals, alloys and pure elements alike, are lustrous and reflective, the more so when a metal surface is flat, polished, and free from oxidation and surface fouling. However, some metals reflect visible light, in the 380 nm to 740 nm range of wavelengths, much more strongly than others. In particular, some metals reflect wavelengths in certain portions of the ultraviolet (UV), visible, and near-infrared (NIR) regime, let us say 200 nm to 2000 nm, while absorbing light strongly in other segments of this range. There are several factors that account for this difference between various ...
The Rational Synthesis Of Lanthanum Manganite Nanomaterials For Magnetic Refrigeration Applications, 2021 Virginia Commonwealth University
The Rational Synthesis Of Lanthanum Manganite Nanomaterials For Magnetic Refrigeration Applications, Caitlin Hunt
Theses and Dissertations
Refrigeration systems for the cooling of commercial and residential buildings are a major drain on energy resources and source of greenhouse gas emissions. Magnetic refrigeration, which employs the magnetocaloric effect, has the potential to mitigate the energy drain and greenhouse gas emissions for air conditioning. In order to commercialize magnetic refrigerators, a material with a high magnetic entropy change, ΔS, near room temperature which is simple and inexpensive to create is needed.1 Current options for this solid refrigerant are either expensive, difficult to synthesize, or have a ΔS or Tc (the Curie Temperature, where ΔS is maximized) below ...
Continuing The Metalation And Ring Closure Of Biliazine, 2021 The University of Akron
Continuing The Metalation And Ring Closure Of Biliazine, Joshua Villers
Williams Honors College, Honors Research Projects
Continuing previous research conducted by Dr. Ziegler and his Graduate Students in which different metals were selected to metalate the compound Biliazine as well as finding metals that could be used to close the ring system in Biliazine.
Lithium Nickel Borides: Evolution Of [Nib] Layers Driven By Li Pressure, 2021 Iowa State University
Lithium Nickel Borides: Evolution Of [Nib] Layers Driven By Li Pressure, Volodymyr Gvozdetskyi, Yang Sun, Xin Zhao, Gourab Bhaskar, Scott L. Carnahan, Colin P. Harmer, Feng Zhang, Raquel A. Ribeiro, Paul C. Canfield, Aaron J. Rossini, Cai-Zhuang Wang, Kai-Ming Ho, Julia V. Zaikina
Here we show the effect of Li chemical pressure on the structure of layered polymorphs with LiNiB composition: RT-LiNiB (room temperature polymorph) and HT-LiNiB (high temperature polymorph), resulting in stabilization of the novel RT-Li1+xNiB (x ∼ 0.17) and HT-Li1+yNiB (y ∼ 0.06) phases. Depending on the synthesis temperature and initial Li content, precisely controlled via hydride route synthesis, [NiB] layers undergo structural deformations, allowing for extra Li atoms to be accommodated between the layers. In situ variable temperature synchrotron and time-dependent laboratory powder X-ray diffraction studies suggest Li step-wise deintercalation processes: RT-Li1+xNiB → RT-LiNiB (high temp.) → LiNi3B1.8 ...
Fluorinated Phthalonitriles And Phthalocyanines: Synthesis And Spectroscopic Properties, 2020 Seton Hall University
Fluorinated Phthalonitriles And Phthalocyanines: Synthesis And Spectroscopic Properties, Marius Pelmus
Seton Hall University Dissertations and Theses (ETDs)
Since their discovery at the beginning of the 20th century, phthalocyanines (Pc) have come a long way; today they are replacing the porphyrins (natural products) in most of their applications. The functionalization of the organic macrocycle, the use of different metals, and the change of the axial ligands resulted in Pc applications in a wide range of fields, ranging from photochemistry, paints, catalysis, to fuel cells and cosmetic products.
In Dr. Gorun’s group was developed a series of electron-deficient Pcs that benefit from a Teflon-like chemical shield, meant also to break the π-π interactions, namely the F64 ...
Integration And Optimization Of A 3d Printed Continuous Flow Reactor In An Inorganic Complexation Reaction, 2020 State University of New York College at Brockport
Integration And Optimization Of A 3d Printed Continuous Flow Reactor In An Inorganic Complexation Reaction, Calli Burnell
Senior Honors Theses
Current inorganic lab setups do not allow students to use time in lab efficiently and does not allow students to do repeat runs of reactions due to time and material restraints. By implementing a 3D printed continuous flow reactor into the experiment students would be able to redo experiments in class without creating large amounts of waste, all while using a system that was created on campus at a reasonable price. It was found that a mixing chamber with an isobaric design created an environment that allowed complete mixing before reaching a point at which measurements are taken.
Ru(Ii)-Diimine Complexes And Cytochrome P450 Working Hand-In-Hand, Celine Eidenschenk, Lionel Cheruzel
Faculty Publications, Chemistry
With a growing interest in utilizing visible light to drive biocatalytic processes, several light-harvesting units and approaches have been employed to harness the synthetic potential of heme monooxygenases and carry out selective oxyfunctionalization of a wide range of substrates. While the fields of cytochrome P450 and Ru(II) photochemistry have separately been prolific, it is not until the turn of the 21st century that they converged. Non-covalent and subsequently covalently attached Ru(II) complexes were used to promote rapid intramolecular electron transfer in bacterial P450 enzymes. Photocatalytic activity with Ru(II)-modified P450 enzymes was achieved under reductive conditions with ...
An Investigation Of Antenna, Ligand Side-Chain, And Metal Ion Effects On The Optical And Mri Properties Of Bimodal Lanthanide (Iii) Complexes, 2020 The University of San Francisco
An Investigation Of Antenna, Ligand Side-Chain, And Metal Ion Effects On The Optical And Mri Properties Of Bimodal Lanthanide (Iii) Complexes, Marisa Poveda
Magnetic Resonance Imaging (MRI) is a leading anatomical imaging modality for disease diagnosis. With the aid of Gd3+ based contrast agents, high resolution images of biological structures can be obtained. However, there is an increased need for contrast agents that are responsive to specific analytes and chemical environments. Paramagnetic Chemical Exchange Saturation Transfer (PARACEST) agents that utilize a paramagnetic lanthanide ion chelated with a ligand have shown great promise in this area. Lanthanide ions also possess luminescence properties that do not suffer from common limitations of conventional optical imaging agents such as autofluorescence and photobleaching. The projects described in ...
Synthesis And Assessment Of Radiotherapy-Enhancing Nanoparticles, 2020 Portland State University
Synthesis And Assessment Of Radiotherapy-Enhancing Nanoparticles, Hayden Winter
Dissertations and Theses
Radiation Therapy (RT) is a common treatment for cancerous lesions that acts by ionizing matter in the affected tissue, causing cell death. The disadvantage of RT is that it is most often delivered via an external beam of radiation which must pass through healthy tissues to reach the target site, ionizing matter within healthy tissues as well. To address this drawback, techniques are being developed for increasing RT-induced cell death in a target tissue while minimizing cell death in surrounding tissues. This effect is known as radiation dose enhancement or RT enhancement.
The approach to RT enhancement studied in this ...
Computational Elucidation Of The "Coloring Problem" In Rhenium Aluminum Silicon Compounds, 2020 Missouri State University - Springfield
Computational Elucidation Of The "Coloring Problem" In Rhenium Aluminum Silicon Compounds, Alec George Neeson
MSU Graduate Theses
Re1Si1Al1 and its related compounds are potential thermoelectric materials. Previously, it was reported to adopt a MoSi2-type structure with Si and Al atoms statistically sharing the same crystallographic sites. This recent study indicates otherwise – Si and Al are segregated and occupy different sites when mixed with a 1:1:1 stoichiometry. To confirm and rationalize the segregation between Si and Al, this research studied this compound with first-principle calculations. Several model structures have been constructed for Re1Si1Al1 including a number of different super-cell models. Energy analysis confirmed that ...
Doping Effects On Transition-Metal Silicides: Crystal Structures And Physical Properties Of Aluminium Doped Rhenium Silicide, 2020 Missouri State University
Doping Effects On Transition-Metal Silicides: Crystal Structures And Physical Properties Of Aluminium Doped Rhenium Silicide, Victoria Decocq
MSU Graduate Theses
Semiconductive transition-metal silicides (e.g., ReSi) express weak thermoelectric properties. These properties can improve through n-type or p-type doping (e.g., Al), resulting in altered crystal structures. Binary rhenium silicide (ReSi1.75) exhibits promising thermoelectric properties and an intriguing crystal structure. Previous research has shown ReSi1.75 changes from a commensurate supercell MoSi2-type structure to an incommensurate superspace group structure, when doped with aluminium to ReAl0.074Si1.67. ReSi1.75 expresses a figure of merit (ZT) of 0.70 at 800°C, which improves to a ZT of 0.95 at 150 ...
How Oxygen-Binding Affects Structural Evolution Of Even-Sized Gold Anion Clusters. (Size Range 20 To 34), 2020 University of Nebraska - Lincoln
How Oxygen-Binding Affects Structural Evolution Of Even-Sized Gold Anion Clusters. (Size Range 20 To 34), David Brunken-Deibert
Student Research Projects, Dissertations, and Theses - Chemistry Department
We report a joint anion photoelectron spectroscopy (PES) and theoretical study to investigate the effect of O2-binding on the mid-sized even-numbered gold clusters, Aun− (n = 20−34), a special size region of bare gold clusters that entail rich forms of structural evolution and transformation. Specifically, within this size range, bare Au20− is a highly-symmetric pyramidal cluster, bare Au21-25− are flat-planar or hollow-tubular clusters, bare Au26− is the smallest core-shell gold cluster, while bare Au34− is a magic-number/fluxional core-shell cluster with the high-symmetry tetrahedral Au4 core. In light of the strong size-dependent ...
Visualization Without Vision – How Blind And Visually Impaired Students And Researchers Engage With Molecular Structures, 2020 University of California, Davis
Visualization Without Vision – How Blind And Visually Impaired Students And Researchers Engage With Molecular Structures, Croix J. Laconsay, Henry B. Wedler, Dean J. Tantillo
Journal of Science Education for Students with Disabilities
This article examines the tools and techniques currently available that enable blind and visually impaired (BVI) individuals to visualize three-dimensional objects used in learning chemistry concepts. How BVI individuals engage with and visualize molecular structure is discussed and recent tactile (or haptic) and auditory methods for visualization of various chemistry concepts are summarized. Remaining challenges for chemistry education researchers are described with the aim of highlighting the potential value of educational research in further enabling BVI students to pursue careers in science, technology, engineering, and mathematics (STEM) fields.