Dopant-Defect Engineering In Strontium Titanate-Based Materials, 2017 University of Massachusetts Amherst
Dopant-Defect Engineering In Strontium Titanate-Based Materials, Keith Lehuta
Strontium titanate is a wide gap oxide perovskite that has been studied for numerous applications. Its potential use as a photocatalyst is limited due to only being able to utilize UV light. The introduction of metal dopant ions has been shown to alter the band structure to allow visible light photocatalysis, as well as alter the materials properties for other applications. This work will look to better explain the process of transition metal dopant ion incorporation and how the dopant ion can affect the defect chemistry of the material.
The use of dopant specific spectroscopies, such as electron paramagnetic resonance ...
Relationship Between Structure And Function In Nickel Proteins And Enzymes, 2017 University of Massachusetts Amherst
Relationship Between Structure And Function In Nickel Proteins And Enzymes, Carolyn Carr
Nickel is a rarely used but biologically important metal that is utilized in all three domains of life. In nickel utilizing organisms there is a corresponding trafficking system specifically designed to capture nickel, deliver, and export excess nickel to prevent toxic effects. It is critical to understand the mechanisms by which organisms achieve metal selectivity to duplicate or disrupt this process for the benefit of human health and to further understanding of regulation mechanisms in biology.
RcnR is a Ni(II) and Co(II) responsive transcriptional regulator in E. coli. The research reported in this dissertation focuses on the relationship ...
Investigation Of Host-Sensitized Luminescence Of Trivalent Lanthanide Doped Yttrium Phosphate Using Vuv Spectroscopy, 2017 Central Washington University
Investigation Of Host-Sensitized Luminescence Of Trivalent Lanthanide Doped Yttrium Phosphate Using Vuv Spectroscopy, Zachary Way
All Master's Theses
Host-sensitized luminescence of yttrium phosphate doped with trivalent lanthanide elements prepared via two synthetic approaches was studied using VUV spectroscopy. A correlation between an unusually intense 150 nm excitation intensity and the ground state energy level of select trivalent lanthanide elements was proposed. Using spectroscopy, the host-to-activator transfer efficiencies of YPO4:Ln3+ (Ln3+ = Sm3+, Eu3+ and Tb3+) were evaluated for two synthetic approaches. Electron-hole pair trapping efficiencies and Sloss values were calculated using published kinetic models.
Thermally Stable Encapsulated Intermetallic And Bimetallic Nanoparticles For Heterogeneous Catalysis, 2017 Iowa State University
Thermally Stable Encapsulated Intermetallic And Bimetallic Nanoparticles For Heterogeneous Catalysis, Raghu Maligal Ganesh
Graduate Theses and Dissertations
Intermetallic compounds have shown promise as efficient heterogeneous catalysts, displaying improved performance over their monometallic parent metals for chemical transformations. Furthermore, colloidal intermetallic nanoparticles (iNPs) afford additional improvements via increased catalyst surface area and enhanced catalytic performance. However, these iNPs are not efficiently protected against sintering during thermal treatment procedures such as catalyst regeneration, resulting in a loss of their active surface area. Herein, we have successfully developed porous encapsulation strategies using inert silica that afford monodisperse iNPs that address this concern. These iNPs are highly stable thermally and the inert silica-based mesoporous encapsulation doesn't present mass transfer obstacles ...
Reactivity And Electronic Structures Of Uranium Complexes With Nitrogen And Oxygen Donors In Axial Symmetries, 2017 University of Pennsylvania
Reactivity And Electronic Structures Of Uranium Complexes With Nitrogen And Oxygen Donors In Axial Symmetries, Kimberly C. Mullane
Publicly Accessible Penn Dissertations
The effects of the ligand field are generally on the same order of magnitude as spin-orbit coupling for uranium complexes. However, significant impacts on the electronic structure, reactivity, and stability of uranium complexes have been observed as a result of changing the ligand framework. In the work presented here, uranium complexes in a variety of ligand frameworks are synthesized, and their unique electronic structures and reactivities are studied. Uranium imido complexes with varying substitution at the imido nitrogen are contrasted with uranium oxo complexes, showing that their ability to impart an inverse trans influence, a thermodynamic phenomenon in which strong ...
An Investigation Of Solutions Of Sulfur In Oleylamine By Raman Spectroscopy And Their Relation To Lead Sulfide Quantum Dot Synthesis, 2017 University of Colorado, Boulder
An Investigation Of Solutions Of Sulfur In Oleylamine By Raman Spectroscopy And Their Relation To Lead Sulfide Quantum Dot Synthesis, Michael Lynch
Undergraduate Honors Theses
The first Raman spectrum of oleylamine was obtained after a multistep purification procedure based on acid-base chemical exchange techniques. The purification was needed because commercially available oleylamine shows photoluminescence in the Raman spectrum, obscuring the Raman peaks. Using the purified oleylamine, sulfur in oleylamine solutions were studied by resonance Raman, UV-vis, absorbance, NMR, and IR spectroscopy. Additionally, the time dependence of sulfur species present in these solutions was studied over several days using Raman spectroscopy. Based on the changes in the Raman spectra over time, it is hypothesized that the concentration of the polysulfide species S42- increases, while ...
Real Time Monitoring Of Photocatalysis: An Application And Expansion Of The Quartz Crystal Microbalance, 2017 James Madison University
Real Time Monitoring Of Photocatalysis: An Application And Expansion Of The Quartz Crystal Microbalance, Perrin Godbold
Senior Honors Projects, 2010-current
There are many applications of photocatalytic chemistry, with hundreds of researchers investigating photocatalytic materials. Another method of investigation could aid these researchers and contribute significantly to this field. This study attempts to develop a new method of analysis by expanding the capabilities of the Quartz Crystal Microbalance (QCM) into the realm of photocatalysis. We coated QCM crystals with the stable and well-known photocatalyst, titanium dioxide, and utilized these coated crystals to begin to develop an analysis procedure for our modified instrument. Some indication of the QCM’s sensitivity was seen, but the UV irradiation elicited a frequency change independent of ...
Size And Shape Control In Metal Nanoparticles And Nanocomposites, 2017 Wilfrid Laurier University
Size And Shape Control In Metal Nanoparticles And Nanocomposites, Tomendro Subedi
Theses and Dissertations (Comprehensive)
This thesis describes major findings on the shape transformation of the precursor silver decahedral nanoparticles (AgDeNPs) with pentagonal symmetry and twin defects into silver pentagonal prism nanoparticles (AgPPNPs) using Br¯ as a shape selective reagent. Silica-encapsulation of the gold-plated AgDeNPs was also carried out forming ordered arrays of silica encapsulated gold-plated AgDeNPs (SiO2@Au@AgDeNPs) of different sizes. At first, synthetic procedures for AgDeNPs (pentagonal bipyramids), silver pentagonal rod nanoparticles (AgPRNPs) and gold-plating of AgDeNPs (Au@AgDeNPs) were optimized. Gold plating enhances the chemical stability of AgDeNPs and preserves the superior plasmonic properties of silver. This thesis deals with ...
Sol-Gel Chemistry: An Advanced Technique To Produce Macroscopic Nanostructures Of Metal And Semiconductor Colloids, Lamia Nahar
Theses and Dissertations
The fascinating physical properties that arise in materials limited to dimensions of 1-100 nm have gained noteworthy interest from the scientific community. Accordingly, there has been a lot of attention paid to the synthesis of discrete nanoparticles (NPs) and they are being investigated for a range of advanced technologies. Nonetheless, efficient use of nanomaterials in device applications require them to be assembled into solid state macro-structures while retaining their unique, nanoparticulate properties. To date, most commonly investigated assembling techniques include: covalent coupling of NPs surface groups, control evaporation of the solvent to produce ordered supercrystals or non-ordered glassy films, and ...
Proceedings Of The 2nd Resrb 2017 Conference, June 19-21, 2017, Wrocław, Poland, 2016 Wojciech Budzianowski Consulting Services
Proceedings Of The 2nd Resrb 2017 Conference, June 19-21, 2017, Wrocław, Poland, Wojciech M. Budzianowski
No abstract provided.
Separation Of Nitrito- And Nitropentamminecobalt (Iii) Chloride By High Performance Liquid Chromatography, 2016 Seton Hall University
Separation Of Nitrito- And Nitropentamminecobalt (Iii) Chloride By High Performance Liquid Chromatography, Tisha Hutchinson
Seton Hall University Dissertations and Theses (ETDs)
Reversed phase high performance liquid chromatography, chosen because of its ability to collect many data points over a long period of time with minimal involvement, was used to separate pentaamminenitritocobalt(III) chloride and pentaamminenitrocobalt(III) chloride. Pentaamminenitritocobalt(III) chloride was prepared, made into a concentrated solution, divided into aliquots and allowed to isomerize to pentaamminenitrocobalt(III) chloride over a period of twelve to eighteen hours. An injection was made approximately every forty-five minutes. The samples were analyzed at three wavelengths, 254 nm, 460 nm and 490 nm. The absorbance was collected and was used to determine the kinetics of the ...
Synthesis Of Metal-Containing Phosphines And Their Use In Coordination, Polymer, And Materials Chemistry, 2016 The University of Western Ontario
Synthesis Of Metal-Containing Phosphines And Their Use In Coordination, Polymer, And Materials Chemistry, Amir Rabiee Kenaree
Electronic Thesis and Dissertation Repository
This thesis describes the investigation of a novel strategy for the synthesis of metal-containing small molecules, polymers, and nanomaterials. In this context, a new family of air-stable, homo- and heterometallic primary, secondary, and tertiary phosphines were prepared via the radical-initiated hydrophosphination reaction of PH3 with vinylferrocene and/or vinylruthenocene. The full characterization of the phosphines confirmed their targeted structures and proved that the properties of the starting metallocenes are reflected in those of the resulting phosphines.
To study the coordination behavior of this family of phosphines, primary, secondary, and tertiary ethylferrocene phosphines were reacted with Group 6 metal carbonyl ...
Creating Functional Materials With Phosphorus, 2016 The University of Western Ontario
Creating Functional Materials With Phosphorus, Tyler John Cuthbert
Electronic Thesis and Dissertation Repository
Understanding the relationship between small molecules or polymers and how they affect the properties of materials they compose is the basis of materials science. Using unique and versatile components can impart useful and interesting properties to materials. Here, we aimed to extend this understanding to phosphorus, and the known properties it possesses. This included the production of photopolymerizable coatings containing phosphonium molecules and polymers for antifouling and antibacterial applications. The synthesis and characterization of these phosphonium components was completed and materials were produced utilizing UV curing technology. Addition of these components produced coatings that could resist bacteria attachment and efficiently ...
First-Row Organometallics For Heavy-Metal Applications, And An Atomically-Precise Iron Oxide Nanocluster, 2016 University of Wyoming
First-Row Organometallics For Heavy-Metal Applications, And An Atomically-Precise Iron Oxide Nanocluster, Jonathan Kephart
Honors Theses AY 16/17
Undergraduate research has been a cornerstone to my education at the University of Wyoming. In this text, I review my research experiences and independent projects in inorganic chemistry. Specifically I discuss my experience with iron organometallics for [2+2+2] cycloaddition, photoredox-activated C-N formation using nickel organometallics, and iron organometallics with bifunctional ligand frameworks for olefin metathesis. Another area of my research focuses on a class of nanomaterials known as magic number clusters. I discuss my work in the Hulley Group regarding the synthesis and characterization of an atomically-precise iron oxide cluster, Fe9O6(Np)6(TMEDA)3.
Synthesis Of Metal-Containing Polymers And Stable Organic Radical-Containing Polymers And Their Use As Advanced Functional Materials, 2016 The University of Western Ontario
Synthesis Of Metal-Containing Polymers And Stable Organic Radical-Containing Polymers And Their Use As Advanced Functional Materials, Joseph A. Paquette
Electronic Thesis and Dissertation Repository
The work presented in this thesis details the synthesis and characterization of two different families of multifunctional polymers. The first family involved the incorporation of stable 6-oxoverdazyl radicals into polymer scaffolds. This was originally achieved by the polymerization of the radical precursors, phenyl- and isopropyl-6-oxotetrazanes, followed by post-polymerization oxidation to afford the phenyl- and isopropyl-6-oxoverdazyl polymers. A second methodology involved the direct polymerization of isopropyl-6-oxoverdazyl radicals using ring-opening metathesis polymerization (ROMP) to afford polymers with controlled molecular weights and narrow molecular weight distributions. The polymers were characterized by the close comparison of the physical and spectroscopic properties ...
Over Or Under: Hydride Attack At The Metal Versus The Coordinated Nitrosyl Ligand In Ferric Nitrosyl Porphyrins., 2016 University of Oklahoma
Over Or Under: Hydride Attack At The Metal Versus The Coordinated Nitrosyl Ligand In Ferric Nitrosyl Porphyrins., E G. Abucayon, R L. Khade, D R. Powell, Michael J. Shaw, Y Yang, G B. Richter-Addo
SIUE Faculty Research, Scholarship, and Creative Activity
Hydride attack at a ferric heme–NO to give an Fe–HNO intermediate is a key step in the global N--‐cycle. We demonstrate differential reactivity when six--‐ and five--‐coordinate ferric heme--‐NO models react with hydride. Although Fe–HNO formation is thermodynamically favored from this reaction, Fe–H formation is kinetically favored for the 5C case.
Design And Synthesis Of Novel Octacarboxy Porphyrinic Metal-Organic Frameworks, 2016 University of Nebraska - Lincoln
Design And Synthesis Of Novel Octacarboxy Porphyrinic Metal-Organic Frameworks, Jacob A. Johnson
Student Research Projects, Dissertations, and Theses - Chemistry Department
Metal-Organic Frameworks (MOFs) are a class of nanoporous crystalline materials constructed via the interconnection between metal-ions/inorganic clusters and organic ligands. Since the surface area, pore size and distribution, and chemical functionalities of MOFs are highly tunable via the judicious combinations of inorganic clusters and organic ligands, MOFs have attracted intensive interests for a variety of applications including gas adsorption and separation, catalysis, chemical sensing, and drug delivery among others. Porphyrin based ligands are of particular interest for building functional MOFs due to their unique photo-, electro-, and catalytic properties. In addition, the four-fold symmetry of porphyrin ligands offers an ...
Synthesis, Reactivity, And Nmr Trends Of Early Transition Metal Compounds, 2016 University of Tennessee, Knoxville
Synthesis, Reactivity, And Nmr Trends Of Early Transition Metal Compounds, Tabitha Marie Cook
This dissertation focuses of three different subjects. The first is the synthesis and characterization of heptacoordinate amidinate compounds. Heptacoordinate compounds are not common, but their structures have been studied. Group 4 amidinate compounds have been used as precursors in the CVD/ ALD processes. Ancillary ligands, such as amidinates, have been used to reduce air-sensitivity of complexes. Reactions of these complexes with water have been used to make metal oxide thin films.
In the first study, the complexes Zr[MeC(NiPr)2]3Cl [zirconium trisamidinate chloride], Hf[MeC(NiPr)2]3Cl [hafnium trisamidinate chloride], Zr ...
Development Of An F-Element Separation Chemistry Using Solid Electrolytes, 2016 University of Tennessee, Knoxville
Development Of An F-Element Separation Chemistry Using Solid Electrolytes, Kristian Guy Myhre
The f‒elements (lanthanides and actinides) have numerous applications and are critically important to many industries, including the energy, security, and medical industries. One of the barriers to increased use and availability of the f‒elements is the difficulty in separating them from each other due to their similar chemistries. This is especially true of the trivalent f‒elements (lanthanides and minor actinides). The development of separation techniques that maximize the differences in the physicochemical properties of the f‒elements is therefore an important area of research. For these reasons, an effort was undertaken to explore the use of solid ...
Synthesis And Characterization Of Novel Ligand For Use On Rhodium Paddlewheel Complexes, 2016 University of Tennessee, Knoxville
Synthesis And Characterization Of Novel Ligand For Use On Rhodium Paddlewheel Complexes, Gavin J. Rustin
Dirhodium (II) paddlewheel complexes have proven to be useful catalysts in many transformations including C-H insertions, cyclopropanation, and silane insertion reactions. One deficiency of these catalysts is the inability to modulate the enantioselectivity with reactive diazo compounds. One avenue for potential improvement of paddlewheel complexes is coordinating ligands in the axial site to increase enantioselectivity. The axial site has been occupied by various ligands including Nheterocyclic carbenes, nitrogen compounds, and phosphorous compounds. This work examines compounds that can be used as ligands on dirhodium complexes that have a pendant chain containing a dibenzyl phosphite and dibenzyl phosphate, both of which ...