Computationally Assisted Mechanistic Analysis Of The Protonolysis Of A Pt–Me Bond,
2024
Reed College
Computationally Assisted Mechanistic Analysis Of The Protonolysis Of A Pt–Me Bond, Clement Dasilva
Student Research Symposium
Mechanistic study of the protonolysis of (cod)PtMe2 could give insight into the activation of C-H bonds by platinum because it is the microscopic reverse reaction. Two possible mechanisms for the protonolysis of dimethyl platinum complexes have been proposed, with experimental and computational data supporting the single step, SE2, over the multistep, SE(ox) mechanism. New experimental work from our group supports a multi-step mechanism with multiple acid molecules. In this work, the SE2 mechanism as well as a proposed SE(ox) mechanism were computationally modeled with a single equivalent of acid, TFAH, and two equivalents using density functional theory. The modeled pathways …
Model Of The Effect Of Voltage On Contact Angle In An Electrolytic Cell Reaction,
2024
Brigham Young University
Model Of The Effect Of Voltage On Contact Angle In An Electrolytic Cell Reaction, Aaron Essilfie
Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE)
This paper investigates the hypothesis that the contact angle at the meniscus of an electrode-electrolyte can be altered during a redox reaction through the coupled understanding of electrowetting and capillarity rise. Recent studies in electrowetting have focused on dielectric surfaces but research on contact angle at the electrode-electrolyte surface is lacking. The study employs a basic electrolytic cell. By applying principles of electrowetting and capillary rise the research aims to understand the relationship between applied voltage and contact angle, to advancements in electrochemistry and microfluidics.
Earth Abundant Catalyst For Evironmental Sustainability Applications,
2024
University of Texas at El Paso
Earth Abundant Catalyst For Evironmental Sustainability Applications, Javier Hernandez
Open Access Theses & Dissertations
The development of experimental methodologies for synthesizing a diverse range of metallic and metal oxide nanoparticles tailored for sustainable water treatment applications was investigated. These nanoparticles are prepared using environmentally friendly and scalable synthesis methods, underscoring their potential for large-scale production. Synthesized nanoparticles are harnessed for various processes, including catalysis and electrocatalysis, with a primary objective of degrading and removing organic pollutants from water. Key to this research is the encapsulation of nanoparticles within solid supports. Multiple methodologies are explored to engineer supports that ensure nanoparticle stabilization, monodispersion, and prevent unintended release into the environment. Two alternative approaches were evaluated …
Computational Investigation Of Transition Metal Photoredox Catalysis: Redox Property Tuning Via Ligand Modification,
2024
University of Texas at El Paso
Computational Investigation Of Transition Metal Photoredox Catalysis: Redox Property Tuning Via Ligand Modification, Christian Fernando Sandoval Pauker
Open Access Theses & Dissertations
In the last decade, photoredox catalysis has become a powerful tool in synthetic chemistry. It relies on the ability of catalytic systems that facilitate energy-demanding redox reactions thanks to photoinduced electron transfer processes. This dissertation focuses on the computational investigation of the redox properties of transition metal photoredox catalysts using density functional theory (DFT) calculations. The research systematically explores the effects of altering redox-active ligands on the thermodynamics of electron transfer events in the photoredox cycle. The electronic structure changes throughout oxidative and reductive quenching cycles are analyzed, with a particular focus on Cu(I) complexes. Through computational techniques, insights into …
Synthesis And Characterization Of Indole-Based Zinc Dipyrrin Photosensitizers,
2024
East Tennessee State University
Synthesis And Characterization Of Indole-Based Zinc Dipyrrin Photosensitizers, Jean-Pierre Sanza
Electronic Theses and Dissertations
Metal complexes of dipyrromethene (dipyrrins) used as sensitizers in photocatalysis offer a way to harness solar energy in chemical bonds to create new fuels. This offers the dual role of reducing fossil fuel dependence and atmospheric CO2 levels. Traditionally, metal dipyrrin complexes are synthesized using substituted pyrroles, aldehydes, and transition metals. Indoles have a more expanded pi-electron system and their dipyrrin-type complex may exhibit visible light absorption, suggesting that they can act as photosensitizers for CO2 reduction processes. A novel indoledipyrromethene was synthesized using unsubstituted indole and mesitaldehyde. The complex exhibits visible light absorption at 422 nm. Its …
3d-Printed Microfluidic Devices For Electrochemiluminescence Detection Of Mirna,
2024
University of Connecticut
3d-Printed Microfluidic Devices For Electrochemiluminescence Detection Of Mirna, Oscar Clement
Honors Scholar Theses
This thesis outlines the research conducted over the past two years on the production and application of microfluidic devices (MFDs) in electrochemiluminescent-based bioanalytical assays. The work is categorized into two main projects: designing and manufacturing MFDs and developing electrochemiluminescent (ECL) assays for detecting Alzheimer's disease (AD) associated microRNAs (miRNAs) using CRISPR technology. The process of learning to design MFDs involved acquiring proficiency in computer-aided design (CAD) software, stereolithography (SLA) 3D printing, and iterative design techniques. The development of the ECL-based assay for AD miRNA was a multidisciplinary endeavor, combining elements of inorganic and biological chemistry. Although the research on the …
Studies Of Novel And Well-Defined Dinickel Architectures Utilizing An N-Atom Bridge,
2024
The University of Texas Rio Grande Valley
Studies Of Novel And Well-Defined Dinickel Architectures Utilizing An N-Atom Bridge, David Anthony De Los Santos
Theses and Dissertations
There has been a growing interest in organometallic chemistry to utilize late Earth-abundant metals towards challenging molecular functionalization of abundant feedstocks to value-added products. There is precedent of utilizing cooperativity to try and address some of the shortcomings of traditional mononuclear complexes by integrating metal-metal and or metal-ligand cooperativity to facilitate multi-electron transformations. The utility of a redox-noninnocent scaffold allows for the metal centers to be stable over a range of oxidation states, using the ligand to store electrons. Despite recent progress, complexes harnessing cooperative states towards challenging transformations is still an emerging field. Our group has synthesized a multinucleating …
Synthesis, Electrical Conductivity, Electrocatalytic Activity For Water Splitting, And Pseudocapacitive Properties Of Perovskite Oxide Derivatives.,
2024
University of Louisville
Synthesis, Electrical Conductivity, Electrocatalytic Activity For Water Splitting, And Pseudocapacitive Properties Of Perovskite Oxide Derivatives., Kinithi Meththa Kumari Wickramaratne
Electronic Theses and Dissertations
Developing green and sustainable energy solutions is crucial to addressing the energy and environmental challenges. Hydrogen is an attractive candidate given its high energy density and low carbon emission compared to gasoline and coal. Electrochemical water splitting through a water electrolyzer is recognized as a green method for generating hydrogen and oxygen gases. Developing cost-effective electrocatalysts to reduce overpotential in hydrogen and oxygen generation is essential for the overall process. The growing interest in perovskite oxides as versatile and sustainable catalysts is driven by their compositional flexibility, tunable electronic structure, earth abundance, and inherent catalytic performance. In our research, we …
Utilizing Metal Ligand Cooperativity To Activate Small Molecules.,
2024
University of Louisville
Utilizing Metal Ligand Cooperativity To Activate Small Molecules., Christine Burgan
Electronic Theses and Dissertations
The problems created from the excessive use of fossil fuels can be approached from two directions: capture the CO2 from the atmosphere or develop alternative energy sources. The current industrial standards for these are environmental and/or health hazards and utilize precious metals, respectively. Metal ligand cooperativity (MLC) has emerged as a promising alternative to using precious metals to activate small molecules. In this dissertation, we focus on a series of metal complexes based on the ligand diacetyl-2-(4-methyl-thiosemicarbazone)-3-(2-hydrazinopyridine) (H2L1) for either hydrogen evolution or CO2 capture. The novel complexes were characterized by 1H NMR, …
Engineering Multifunctional Silicon Nanostructures From Biorenewable Cellulose Nanocrystals,
2024
Clemson University
Engineering Multifunctional Silicon Nanostructures From Biorenewable Cellulose Nanocrystals, Nancy Chen
All Dissertations
The imperative search for alternative materials to address the pressing demand for advance energy storage is underscored by the escalating environmental predicaments. Lithium-ion batteries (LIBs) with graphite anodes have become the benchmark in energy storage; however, they are approaching a saturation point in terms of energy density. Silicon emerges as a promising contender to supplant graphite, owing to its profuse availability, cost-effectiveness, and impressive specific capacity of 4200 mAh g-1. By integrating silicon anodes, LIBs stand to undergo a radical transformation, markedly diminishing in weight and size, thus heralding a novel wave of compact, lightweight energy storage systems. …
Structure-Property Relationship Studies Of Electrically Conductive Metal-Organic Framework Materials,
2024
Clemson University
Structure-Property Relationship Studies Of Electrically Conductive Metal-Organic Framework Materials, Shiyu Zhang
All Dissertations
Electrically conductive metal-organic frameworks (EC-MOFs) are among the most promising materials due to their tunable structures, properties, and diverse functions. However, the lack of comprehensive understanding of their structure-property relationship hinders the development of EC-MOFs. My dissertation focuses on the design, construction, and structure-property relationship studies of EC-MOFs.
Chapter 1 describes how MOFs' structural features and compositions affect the electronic properties and demonstrates conductive mechanisms and the corresponding design strategies to develop EC-MOFs.
Chapter 2 describes the synthesis, characterization, electronic and optical properties of four novel alkali-metal-based (Na, K, Rb, and Cs) 3D-MOFs with continuous tetrathiafulvalene tetracarboxylate (TTFTC) π-stacks, systematicly …
Synthesis And Characterization Of Silver(I) And Manganese(Ii) Complexes With Thione Imidazoles,
2024
Harding University
Synthesis And Characterization Of Silver(I) And Manganese(Ii) Complexes With Thione Imidazoles, Shannon Keyser, Audrey Lawrence, Jaime M. Murphy Ph.D.
Honors Theses
Coordination polymers are chemical complexes with versatile applications such as catalysts, electrical conduc-tors, non-linear optics, magnetics, chemical sensing, and molecular storage. The polymers are comprised of a repeating series of metal-ligand complexes, which form various structures in varying ratios depending on the metal and ligand used. Certain metal-ligand combinations have shown particular promise as potentially being polymers or, if not polymers, possessing other useful features such as electromagnetic conductivity. Complexes were synthesized using silver(I) and manganese(II) with the ligands methimazole, 2-mercaptoimidazole, and thiocarbanilide with counterions of either chloride or nitrate. These com-plexes were characterized using elemental analysis, infrared spectroscopy, and …
Investigation Of Surface Chemistry From Electron Irradiation Of Synthetic Schreibersite,
2024
Kennesaw State University
Investigation Of Surface Chemistry From Electron Irradiation Of Synthetic Schreibersite, Tyler Davis
Master's Theses
While phosphorus is one of the key elements for life on Earth, it has relatively low abundance in extraterrestrial environments, making it a target for astronomers and astrobiologists interested in the possibility of life beyond our planet. Schreibersite (Fe,Ni)3P is one of the first P-containing minerals to condense during planetary cooling and one of the primary P-containing minerals in iron and stony-iron meteorites. Therefore, it is a likely P-bearing mineral in cometary cores and dust grains within the interstellar medium and circumstellar envelopes. Experiments in this project were performed with the aim of observing the formation of small …
Molybdenum Alkylidyne Complexes With Phenoxide Ligands For Alkyne Metathesis,
2024
Louisiana State University and Agricultural and Mechanical College
Molybdenum Alkylidyne Complexes With Phenoxide Ligands For Alkyne Metathesis, Marvin L. Stewart Jr
LSU Doctoral Dissertations
Abstract
Alkyne metathesis is a powerful synthetic tool, which provides easy access to complex organic molecules in a single-step. It is a dynamic covalent reaction that scrambles alkynes, carbon-carbon triple bonds (C≡C). Molybdenum- or tungsten-alkylidyne (Mo≡C, W≡C) complexes are typically used as catalyst to cleave and reform alkyne bonds. Our goal has been to gain a deeper understanding of the intrinsic differences between functional ligands by the development of novel phenoxide ligands.
In chapter 2 we explore the detailed synthesis of novel phenoxide podand ligands in an effort to identify their mo-alkylidyne complexes. We were able to synthesize a variety …
Synthesis Of Trisubstituted Bismuth Complexes For Future Research,
2024
Bellarmine University
Synthesis Of Trisubstituted Bismuth Complexes For Future Research, Cassidy Belk
Undergraduate Theses
Bismuth, a relatively inexpensive heavy metal with low toxicity, has the potential to be used in medicines and anticancer drugs. This project is exploring bismuth complexes with ligands based on chalcones, which are a type of small organic molecules with known anticancer properties. Preliminary results on a bismuth-chalcone complex indicate that substituted aryl bismuth complexes have better anticancer activity than triphenylbismuth or the chalcone ligand on its own. A series of trisubstituted bismuth molecules were synthesized using a BiCl3 Grignard reaction under a nitrogen atmosphere with different substituents to provide electron donating groups, electron withdrawing groups or bulk. X-ray …
Structure Of Native Four-Repeat Satellite Iii Sequence With Non-Canonical Base Interactions,
2024
Swarthmore College
Structure Of Native Four-Repeat Satellite Iii Sequence With Non-Canonical Base Interactions, Erin Chen , '23, M. Trajkovski, Hyun Kyung Lee , '21, Samantha Nyovanie, Kailey N. Martin, W. L. Dean, M. Tahiliani, J. Plavec, Liliya A. Yatsunyk
Chemistry & Biochemistry Faculty Works
Tandem-repetitive DNA (where two or more DNA bases are repeated numerous times) can adopt non-canonical secondary structures. Many of these structures are implicated in important biological processes. Human Satellite III (HSat3) is enriched for tandem repeats of the sequence ATGGA and is located in pericentromeric heterochromatin in many human chromosomes. Here, we investigate the secondary structure of the four-repeat HSat3 sequence 5′-ATGGA ATGGA ATGGA ATGGA-3′ using X-ray crystallography, NMR, and biophysical methods. Circular dichroism spectroscopy, thermal stability, native PAGE, and analytical ultracentrifugation indicate that this sequence folds into a monomolecular hairpin with non-canonical base pairing and B-DNA characteristics at concentrations …
Killing Cancer: Manipulating Hydrophobic Vanadium Complexes To Improve Anti-Cancer Activity,
2024
Fort Hays State University
Killing Cancer: Manipulating Hydrophobic Vanadium Complexes To Improve Anti-Cancer Activity, Levi Ausherman, Debbie C. Crans, Peter A. Lay, Maggi Braasch-Turi
SACAD: Scholarly Activities
Hydrophobic vanadium complexes have recently shown improved anti-cancer activities compared to cisplatin. The hydrophobicity and anti-proliferative activity of [VO(Hshed)(dtb)] ([Hshed= N-(salicylideneaminato)-N’-(2-hydroxyethyl)-1,2-ethanediamine and dtb= 3,5-di(tert-butyl)catechol)]) have inspired the development of a library of hydrophobic vanadium complexes. Increasing the steric bulk of the catechol ligand has been shown to have a direct impact on hydrophobicity and anti-proliferative activities. Currently at Fort Hays State University, the Braasch-Turi group is synthesizing VO(HSHED)(dtb) to build up material to support the chemical analysis and biological assay performed by our collaborators at Colorado State University and the University of Sydney, Australia, respectively. In the future, we plan …
Chiral Recognition Of Chiral (Hetero)Cyclic Derivatives Probed By Tetraaza Macrocyclic Chiral Solvating Agents Via ¹H Nmr Spectroscopy,
2024
Missouri University of Science and Technology
Chiral Recognition Of Chiral (Hetero)Cyclic Derivatives Probed By Tetraaza Macrocyclic Chiral Solvating Agents Via ¹H Nmr Spectroscopy, Yu Wang, Hongmei Zhao, Chunxia Yang, Lixia Fang, Li Zheng, Hehua Lv, Pericles Stavropoulos, Lin Ai, Jiaxin Zhang
Chemistry Faculty Research & Creative Works
In the Field of Chiral Recognition, Chiral Cyclic Organic Compounds, Especially Heterocyclic Organic Compounds, Have Attracted Little Attention and Have Been Rarely Studied as Chiral Substrates by Means of 1H NMR Spectroscopy. in This Paper, Enantiomers of Thiohydantoin Derivatives, Representing Typical Five-Membered N,N-Heterocycles, Have Been Synthesized and Utilized for Assignment of Absolute Configuration and Analysis of Enantiomeric Excess. All Enantiomers Have Been Successfully Differentiated with the Assistance of Novel Tetraaza Macrocyclic Chiral Solvating Agents (TAMCSAs) by 1H NMR Spectroscopy. Surprisingly, Unprecedented Nonequivalent Chemical Shift Values (Up to 2.052 Ppm) of the NH Proton of Substrates Have Been Observed, a New …
Magnetic Properties And Biological Relevance Of Scorpionate-Based Transition Metal Complexes,
2024
Marquette University
Magnetic Properties And Biological Relevance Of Scorpionate-Based Transition Metal Complexes, Laxmi Devkota
Dissertations (1934 -)
There are two major components to this research dissertation. The first component describes the synthesis and characterization of high-spin, first-row transition metal complexes supported by facially-coordinating “scorpionate” ligands. These studies have sought to uncover fundamental relationships between molecular structure and magnetic properties, with the ultimate aim of assisting in the design of single molecule magnets (SMMs). To this end, comprehensive series of four and five-coordinated M(II)-X complexes (M = Co, Fe, and Cu; and X = F, Cl, Br, and I) were prepared using hydrotris(pyrazol-1-yl)borate ligands (TpR,R’; where R and R’ indicate substituents at the 3- and 5-position of the …
Nitrene-Transfer Chemistry To C-H And C═C Bonds Mediated By Triangular Coinage Metal Platforms Supported By Triply Bridging Pnictogen Elements Sb(Iii) And Bi(Iii),
2024
Missouri University of Science and Technology
Nitrene-Transfer Chemistry To C-H And C═C Bonds Mediated By Triangular Coinage Metal Platforms Supported By Triply Bridging Pnictogen Elements Sb(Iii) And Bi(Iii), Meenakshi Sharma, Reece M. Fritz, Joseph O. Adebanjo, Zhou Lu, Thomas R. Cundari, Mohammad A. Omary, Amitava Choudhury, Pericles Stavropoulos
Chemistry Faculty Research & Creative Works
Tripodal Ligands (TMG3trphen-E) That Feature Heavy Pnictogen Elements (E = Sb(III), Bi(III)) And Tetramethylguanidinyl (TMG) Arms Have Been Explored In Stabilizing Cu(I) And Ag(I) Sites And Facilitating Nitrene-Transfer Chemistry. Compounds [(TMG3trphen-E)M3(Μ-X)3] (M = Cu(I), Ag(I); X = Cl, Br, I) Have Been Generated Upon Extraction Of M3(Μ-X)3 Units From MX Sources, Exhibiting Support Of The Crown-Shaped M3(Μ-X)3 Fragment By M-NTMG Bonds And Triply Bridging E → M3 Interactions. Orbital Interactions Between Cu(I) Sites And NTMG Residues Are More Dominant Than Sb/Bi → Cu3 Donor Interactions Between The Sb 5s Or Bi 6s Orbitals And Admixed Cu 4s/3d Orbitals, With Larger …
