Inorganic Chemistry Commons^™

Influence Of Synthesis Conditions On The Physicochemical And Electrocatalytic Properties Of Non-Stoichiometric Ba2sr2la2ti4o12 Perovskites, Ofeliya Kostadinova, Iliyan Popov, Simeon M. Stankov, Hristo Kolev, Tamara Petkov

Karbala International Journal of Modern Science

Present work studies the influence of the pretreatment milling media (deionized water (BLTOS-H) and isopropanol (BLTOS-i)) on the surface characteristics, structure, chemical composition and catalytic activity of non-stoichiometric Ba2Sr2La2Ti4O12 perovskites. The IR spectroscopy and XRD analyses shows a difference in the structure and phase composition of the two materials. X-ray photoelectron spectroscopy detects a Ba2+- and La3+-enriched and Sr2+-depleted surface. The BLTOS-i sample appears to exhibit higher specific surface area (SSA) and pore volume in comparison to BLTOS-H. The electrochemical tests showed that BLTOS-H sample have similar behavior to platinum at current densi-ties up to 10 mA cm-2, while BLTOS-i …

Synthesis Of A Novel Terbium(Iii) Complex For Application In Metal Nanoparticle Surface Modification, Lauralee E. Hurst, Davon Ferrara, Justin Stace

Science University Research Symposium (SURS)

Lanthanide ions, such as terbium(III), exhibit bright luminescence when bound to organic ligands which strongly absorb light. This property has been used in creating chemical sensors or luminescent tags for microscopy. Complexes centered with terbium(III) exhibit a yellow-green luminescence upon excitation by shortwave ultraviolet light. In this work, a bifunctional ligand, 4-mercaptobenzoic acid (4mba), was chosen to selectively coordinate terbium(III) to the oxygens of the acid functional group, leaving the thiol group available for another compound. Thiol groups are effectively used in surface coordination to noble metal nanoparticles (NP). In efforts to create a novel 4mba-terbium(III)-NP system, a one pot …

Synthesis And Characterization Of Mixed Ligand Complexes Of Ruthenium(Ii) Containing 2,2’-Bipyridine And 3,3’-Dimethyl-1,1’- Methylenebisimidazolium Ligands; A New Synthetic Approach, Matthew Schneider

Theses and Dissertations

Research into solar cells has been prioritized given the global demand for better renewable energy technologies. This demand is a result of the long-term use of fossil fuels, which generates significant pollution in highly populated urban areas. One potential solar cell technology is the dye-sensitized solar cell (DSSC). This kind of solar technology utilizes organometallic dyes to expand the types of wavelengths solar cells can use to generate electricity.12 Ruthenium(II) metal complexes of this type have been investigated heavily for this purpose.13,14,36 The main reasoning behind this is the metal-to-ligand charge-transfer (MLCT) phenomenon that such complexes exhibit. MLCT has often …

Epitaxial Electrodeposition Of Ordered Inorganic Materials, Jay A. Switzer, Avishek Banik

Chemistry Faculty Research & Creative Works

Conspectus The quality of technological materials generally improves as the crystallographic order is increased. This is particularly true in semiconductor materials, as evidenced by the huge impact that bulk single crystals of silicon have had on electronics. Another approach to producing highly ordered materials is the epitaxial growth of crystals on a single-crystal surface that determines their orientation. Epitaxy can be used to produce films and nanostructures of materials with a level of perfection that approaches that of single crystals. It may be used to produce materials that cannot be grown as large single crystals due to either economic or …

Computational Investigation Of The Ionization Potential Of Lead Sulfide Quantum Dots, Jessica Beyer

Scripps Senior Theses

The purpose of this work was to determine the impact of quantum dot size on ionization potential and to determine how the presence of carbonyl-based ligands affect the ionization potential of lead sulfide quantum dot systems. Ionization potential (IP) is defined as the energy required to remove an electron from an atom, molecule, or material. IP helps scientists determine how reactive the material of interest is, which is crucial information when manufacturing nanomaterials. Accurate quantum chemical calculations of ionization potential are challenging due to the computational cost associated with the numerical solution of the Dyson equation. In this work, the …

Multiscale Molecular Modeling Studies Of The Dynamics And Catalytic Mechanisms Of Iron(Ii)- And Zinc(Ii)-Dependent Metalloenzymes, Sodiq O. Waheed

Dissertations, Master's Theses and Master's Reports

Enzymes are biological systems that aid in specific biochemical reactions. They lower the reaction barrier, thus speeding up the reaction rate. A detailed knowledge of enzymes will not be achievable without computational modeling as it offers insight into atomistic details and catalytic species, which are crucial to designing enzyme-specific inhibitors and impossible to gain experimentally. This dissertation employs advanced multiscale computational approaches to study the dynamics and reaction mechanisms of non-heme Fe(II) and 2-oxoglutarate (2OG) dependent oxygenases, including AlkB, AlkBH2, TET2, and KDM4E, involved in DNA and histone demethylation. It also focuses on Zn(II) dependent matrix metalloproteinase-1 (MMP-1), which helps …

S-Type Stars: Line List For The A²Π-X²Σ⁺ Band System Of Lao, P. F. Bernath, R. Dodangodage, J. Liévin

Chemistry & Biochemistry Faculty Publications

LaO bands are found in the spectra of cool S-type stars. The bands of the A²Π–X²Σ⁺ transition with v' ⩽ 3 and v'' ≤ 4 are rotationally analyzed, providing spectroscopic constants for the A²Π state. Line strengths are calculated using an ab initio transition dipole moment function, and radiative lifetimes for the A²Π state have also been computed. A line list for the A²Π–X²Σ⁺ transition of LaO is provided and can be used to determine LaO stellar abundances.

Exploration Of Metal-Carbonyl Complexes For Decarbonylation Reactions, Rebekah C. Krupa

Graduate Theses, Dissertations, and Problem Reports

In recent years, transition metal-mediated decarbonylation reactions have emerged as an alternative to conventional cross-coupling methods due to the advantages associated with the use of carbonyl-containing functionalities as coupling electrophiles instead of organohalides found in traditional cross-coupling reactions. This, coupled with the ubiquity of carbonyl-containing compounds in pharmaceuticals and non-biodegradable chemicals, has led to the interest in developing efficient systems for transition metal-catalyzed decarbonylation. However, these reactions are commonly limited to stoichiometric amounts of metal reagents due to the strong metal-carbonyl bond formed during transition metal-mediated decarbonylation. With the goal of gaining a better mechanistic understanding of CO dissociation in …

Ambient Ammonia Synthesis Via Microwave-Catalytic Materials And Plasma Chemistry, Siobhan Brown

Graduate Theses, Dissertations, and Problem Reports

Ammonia is critical to supporting human life on earth because of its use as fertilizer. The Haber-Bosch process to produce ammonia has been practiced for over 100 years. This process operates at high pressure and temperature to overcome the thermodynamic and kinetic limitations of the ammonia synthesis reaction thus researchers have tried to overcome it for decades. At present this process represents 1% of global energy usage and 2.5% of global CO₂ emissions. The proposed chemical looping ammonia synthesis approach seeks to reduce the environmental impact of this critical process and to elucidate microwave-catalytic principles.

This research aims to …

The Design And Characterization Of Gold Nanoclusters As Elementary Building Blocks, Heather Gaebler

Theses and Dissertations (Comprehensive)

Gold nanoclusters with diameters in the quantum size regime (< ~2 nm) are promising building blocks for the design of novel nanomaterials as they exhibit unique size-dependent properties that can be altered and fine-tuned. The research outlined in this PhD thesis employs density functional theory to construct and analyze small ligand-protected cage and rod-shaped nanoclusters. Chapter 2 reports stable halide-protected gold nanocages that were engineered to have a closed-shell valence electron count of 18. This study finds that nanocages comprised of 19 and 20 gold atoms can be converted into stable magic number species containing 18 valence electrons by modifying their charged states via adsorption of halide ligands to the cage’s surface. Chapter 3 reports stable ligand-protected gold nanoclusters with a tetrahedral Au₄ core that were engineered to have a closed-shell valence electron count of 2. This study investigates the structural and electronic effects of halide and alkoxy ligands on the tetrahedral nanocluster and concludes that the results support the broader conclusion that it’s possible to fine-tune the stability and electronic properties of small gold nanoclusters using appropriate ligands. Chapter 4 reports stable gold nanorods that have diameters in the quantum regime that were constructed from elementary building blocks that contain “halide-staples”. This study presents different orientations of the “halide-staple” motifs on …

Computational Comparison Of Platinum, Base Metals, And Binary Intermetallic Compounds’ Efficiency In Hydrogenation Catalysis, Lauren M. Sayler

MSU Graduate Theses

In the petroleum industry, platinum is used as a catalyst in hydrogenation reactions during petroleum refining. Although platinum is extremely effective as a catalyst, it is expensive. This is an investigation into platinum and what characteristics make it so efficient, with the end goal of finding intermetallic compounds composed of base metals that are as effective in hydrogenation catalysis. The metals used in this investigation are Fe, Co, Ni, Mo, and W. The research performed here is computational and used to support and direct decisions made in the laboratory. The computation is first-principle, which is accomplished using Vienna Ab initio …

Palladium (Ii)-Catalyzed Selective Reduction Of 4’-(Phenylethynl)Acetophenone In The Presence Of A Formic Acid-Triethylamine Mixture, Suzanne Chayya, Akram Hijazi, Anis Daou, Ali Alaaeddine, Mohamad Sakr, Ghassan Younes, Mohammad El-Dakdouki

BAU Journal - Science and Technology

An efficient and straightforward palladium acetylacetonate-catalyzed hydrogen transfer of 4'- (phenylethynyl)acetophenone was developed in this study. Formic Acid was found to be the best hydrogen source in this catalytic system in the presence of triethylamine. Excellent conversions and selectivity were obtained in reducing the starting internal aromatic alkyne to either (E)-1-(4- styrylphenyl)ethanone or an interesting cyclic product, 1-(phenanthrene-3-yl)ethenone, over the ketone functional group present. Over-reduction was rarely seen. The reaction conditions were optimized in terms of the choice of the palladium catalyst, temperature, solvent, and the H-donor/base combination. Using this catalytic system, a one-step synthetic pathway of the …

Gold (I) Tetrathiomolybdate Clusters: Synthesis, Characterization, Computational Studies, And Reactivity With Thiophenol And Selenophenol, Dhirgam Humaidy

Electronic Theses and Dissertations

This thesis describes the synthesis and reactivity of heterometallic complexes containing medicinally active Au(I) and tetrathiomolybdate, [MoS₄]^2-. The research is motivated by the idea of multifunctional drugs, which are designed to treat diseases through two or more mechanisms of action. Five clusters of the general form, [MoS₄(AuL)₂] were prepared: C-1 (L=IPr), C-2 (L=IBzMe), C-3 (L=IMes), C-4 (L=PPh₃), and C-5 (L=PEt₃). The clusters with NHC ligands, C-1, C-2, and C-3 were prepared for the first time and thoroughly characterized by ¹H NMR,¹³C{¹H} …

Effects Of Surface Ligation On Charge Extraction From Wurtzite Cadmium Selenide Quantum Platelets And Quantum Belts, Hailey Meyer

Arts & Sciences Electronic Theses and Dissertations

This dissertation presents the synthesis of flat, colloidal wurtzite CdSe quantum platelets and quantum belts for ligand exchange to novel and existing organic and inorganic L-, X-, and Z- type ligands. Use of these ligands in conjunction with the semiconductor nanocrystals allows for examination of their ligand exchange abilities, photoluminescence quenching efficiencies, and charge transfer properties.

First, zinc and cadmium dithiocarbamate compounds [M(S2CNR1R2)2] are used as ligands on wurtzite CdSe quantum belts. Complete ligand exchange is achieved when the belts are initially ligated with Cd(oleate)2, a Z-type ligand, prior to the exchange, as opposed to n-octylamine or ammonia, which are …

The Chemistry And Catalytic Activity Of Dehydrogenative Silylation And Hydroboration Of Complexes Bearing Semirigid Ligands With Group 14 Elements, Niroshani S. Abeynayake

Theses and Dissertations

Incorporation of silicon in the ligand backbone would yield electron-rich metal complexes upon coordination to transition metal complexes. The coordination chemistry of semirigid benzyl phosphines bearing a single or multiple phosphorus atoms and varying number of Si−H moieties has gained interest in recent years. This dissertation focuses on synthesizing silyl and germyl transition metal complexes of groups 9 and 10. Chapter II presents the synthesis of a family of four coordinated 14-electron rhodium complexes. The newly synthesized complexes were characterized in solution by multinuclear NMR spectroscopy and in the solid-state by single-crystal X-ray diffraction. These d⁶ complexes possess sawhorse …

Designing And Synthesizing A Warhead-Fragment Inhibitory Ligand For Ivyp1 Through Fragment-Based Drug Discovery, Samuel Moore

Symposium of Student Scholars

Fragment-based drug discovery (FBDD) is a powerful tool for developing anticancer and antimicrobial agents. Within this, magnetic resonance spectroscopy (NMR) provides a comprehensive qualitative and quantitative approach to screening and validating weak and robust binders with targeted proteins, making NMR among the most attractive strategies in FBDD. Inhibitor of vertebrate lysozyme (Ivyp1) of P. aeruginosa serves as an excellent target because of its active cellular location and implications in clinical prognosis for cystic fibrosis and immunocompromised patients. This study uses current NMR and biophysical techniques to develop a covalent, fragment-linked warhead inhibitor for Ivyp1 through synthetic methods, warhead linking, and …

Synthesis And Surface Modification Of Azide Decorated Silver Nanoclusters, Alexander H. Stöckli

Electronic Thesis and Dissertation Repository

In nanocluster research, easy modification of the cluster surface while maintaining the cluster core remains a key challenge. Herein we report the synthesis, structure, and properties of four targeted Ag₂₀ nanoclusters (NCs) with surface azide moieties, two of which have 8 azide moieties, [CO₃@Ag₂₀(S^tBu)₁₀(m-N₃-C₆H₄COO)₈(DMF)₄] and [CO₃@Ag₂₀(S^tBu)₁₀(p-N₃-C₆H₄COO)₈(DMF)₄], and two of which have 6 azide moieties, [CO₃@Ag₂₀(S …

Transition Metal Computational Catalysis: Mechanistic Approaches And Development Of Novel Performance Metrics, Brett Anthony Smith

Doctoral Dissertations

Computational catalysis is an ever-growing field, thanks in part to the incredible progression of computational power and the efficiency offered by our current methodologies. Additionally, the accuracy of computation and the emergence of new methods that can decompose energetics and sterics into quantitative descriptors has allowed for researchers to begin to identify important structure-function relationships that predict the properties of unexplored subspaces within the overall chemical space. Catalytic descriptors have been used frequently in data driven high-throughput computational screenings. With the use of machine learning, a large portion of the chemical space an be predicted in matter of minutes or …

Turning Ligands On Their Side: Computational Investigation Into The Binding Of N2o And N2 In Transition Metal Complexes, Cole Donald

Electronic Theses and Dissertations

Common greenhouse gas nitrous oxide (N₂O) is a thermodynamically potent and environmentally benign oxidant, making it a desirable target for metal center activation. Unfortunately, N₂O is a poor ligand for transition metals due to its weak sigma-donating and pi-accepting properties; as a result, few transition metal complexes capable of interacting with N₂O have been found. As the primary source of all nitrogen in organisms, abundant gas dinitrogen (N₂) is a crucially important tiny molecule and an essential part of daily existence. However, due to its inertness, it has limited practical uses in …

Computational And Experimental Investigations Of Alkali Cation Interactions At The Rutile – Water Interface, Isaac Johnston

All Dissertations

Overall, the objective of this dissertation was to investigate the degree of sorption for the alkali cations on rutile to ascertain the impact of different cation properties, such as ion size and charge density, on sorption mechanics as well as probe how the ion may alter the surface – aqueous interface. Initial molecular dynamic simulations and batch experiments showed minimal surface sorption for any alkali cation at relatively low concentrations while simultaneously suggesting the enthalpy of deprotonation shifts slightly in the presence of the alkali cations at different ionic strengths. The cations are likely causing small reorientations of the near-surface …