Inorganic Chemistry Commons^™

Application Of Niobium Enriched Ormosils As Thermally Stable Coatings For Aerospace Aluminium Coatings, P.C. Rajath Varma, Mohamed Oubaha, Pradeepan Periyat, Colette Mcdonagh, Brendan Duffy

Articles

The aim of this experimental research is to study the ability of niobium rich sol-gel coatings to withstand thermal stress, while remaining impermeable to corrosive agents for the protection of aerospace alloys. The coating material is developed via polymeric sol-gel synthesis employing 3-(trimethoxysilyl)propylmethacrylate (MAPTMS) and niobium ethoxide precursors as a source of silicon and niobium, respectively. The beneficial effect of niobium inclusion within coating was characterised spectroscopically, calorimetrically and electrochemically. The thermal cycling effects of the coating were studied using microscopic and accelerated test methods. Electrochemical tests showed that corrosion current of the material was 2 orders lower in magnitude …

Crystallisation And Phase Transition Characteristics Of Sol-Gel-Synthesized Zinc Titanates, Suresh Pillai, Michael Seery, Nicholas Nolan

Articles

No abstract provided.

Developing Dimetal Paddlewheel Complexes For Catalytic Applications, Margaret E. Napier

Legacy Theses & Dissertations (2009 - 2024)

Although there are countless examples of rhodium-catalyzed organic reactions in the chemical literature, the field continues to develop at a steady pace, as focus shifts taking advantage of economy of resources while maintaining efficiency of the catalytic reactions. The work presented is separated into three chapters, with each describing a specific approach to the development of new materials which can provide either a direct economy of resources and reagents or can be used for heterogenization of catalytic systems.

Fabrication And Catalytic Property Of Cerium Oxide Nanomaterials, Keren Jiang

Department of Chemistry: Dissertations, Theses, and Student Research

Cerium oxide, or ceria (CeO_x: x = 1.5 to 2), has been widely used as a heterogeneous catalyst. Ceria has several properties make it high catalytic active: the fluctuating valence of cerium, the high oxygen storage capacity and high oxygen mobility in the nonstoichiometric ceria. With the high abundance of cerium on earth crust, ceria is a highly effective alternative of the noble metal catalysts. Research has been focused on designing nanostructured ceria and ceria related materials in recent years. The catalytic activity of ceria can be enhanced by the nanoscale effect which can be applied for various …

Supramolecular Organization Of Nanoparticles, Brenda M. Porta Linnell

Open Access Theses & Dissertations

The study of supramolecular structures with nano-architectures has become an active area of research in recent years. They have the potential to generate functional materials with applications in medicine and emerging technologies. In this dissertation, the supramolecular organization of gold nanoparticles (AuNP) and other nano-scale structures such as discrete styrene-based polymers was investigated. The synthesis and characterization of metal-mediated AuNPs systems using pendant ligands on the AuNP such as 11-diethylenetriamine-undecane-1-thiol, 11-Mercapto-undecanoic acid [2-(2-amino-ethylamino)-ethyl]-amide, Bis(11-oxo-nicotinic acid, undecine)disulfide, and 11-mercaptoundecanoic acid, and using Cu(II) to mediate the formation of supramolecular AuNP systems with sizes of 200 nm ¡V 3 fÃ?m, are …

Crystal Engineering Of Pharmaceutical Cocrystals, Sreya Mukherjee

USF Tampa Graduate Theses and Dissertations

Pharmaceutical cocrystals use principles of crystal engineering for the design of crystalline forms of drugs and can improve their solubility, bioavailability, stability and other important properties without changing the efficacy of the drug. Herein reported are pharmaceutical cocrystals of two API's, caffeine and Pentoxifylline.

Research has indicated that caffeine has the ability to reverse AB; plaque deposition in the brain (believed to be the primary cause of Alzheimer's pathogenesis) and thus revert memory and improve cognitive impairment. But owing to the fast absorption rate and short half life, a controlled release formulation of caffeine would be clinically beneficial. Thus, novel …

Reactivity Studies Of Cyclopentadienyl Complexes Of Group 6 Metals With Arylsulfides, Organo P-S And P-Se Heterocycles And Arylthiolate Phosphine Ligands., Ooi Mei Lee

Student Works (2010-2019)

The reactivity of [CpM(CO)3]2 (M = Cr (1), Mo (3)) together with their congeners, [CpM(CO)2]2 (M = Cr (2), Mo (4)) towards alkyl sulfides such as bibenzyl di- and trisulfide, organophosphorus chalcogen heterocycles such as 2,4-bis(ptolylthio) 1,3-dithia-2,4-diphosphetane-2,4-disulfide (Davy’s reagent), 1,3,2,4- dithiadiphosphetane 2,4-diselenides (Woollins’ Reagent) and thioarylphosphines have been investigated. Reactions that occurred under mild conditions for 1 was found to proceed via the highly reactive monomer radical, CpCr(CO)3·. However, the reactions with 2 and 4 required more forcing conditions at elevated temperature. Forty metal complexes were synthesized and characterized in this work. All the products were elucidated via IR, 1H, …

Localized Surface Plasmon Resonance Of Single Silver Nanoparticles Studied By Dark-Field Optical Microscopy And Spectroscopy, Wei Cao, Tao Huang, Xiao-Hong Nancy Xu, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

Localized surface plasmon resonance (LSPR) of Ag nanoparticles (NPs) with different shapes and disk-shaped Ag NP pairs with varying interparticle distance is studied using dark-field optical microscopy and spectroscopy (DFOMS). Disk-, square-, and triangular-shaped Ag NPs were fabricated on indium tin oxide-coated glass substrates by electron beam lithography. The LSPR spectra collected from single Ag NPs within 5×5 arrays using DFOMS exhibited pronounced redshifts as the NP shape changed from disk to square and to triangular. The shape-dependent experimental LSPR spectra are in good agreement with simulations using the discrete dipole approximation model, although there are small deviations in the …

Synthesis, Assembly, And Characterization Of Monolayer-Protected Gold Nanoparticle Films For Protein Monolayer Electrochemistry,, Tran T. Doan, Michael H. Freeman, Adrienne R. Schmidt, Natalie T. Nguyen, Michael C. Leopold

Chemistry Faculty Publications

Colloidal gold nanoparticles protected with alkanethiolate ligands called monolayer protected gold clusters (MPCs) are synthesized and subsequently incorporated into film assemblies that serve as adsorption platforms for protein monolayer electrochemistry (PME). PME is utilized as the model system for studying electrochemical properties of redox proteins by confining them to an adsorption platform at a modified electrode, which also serves as a redox partner for electron transfer (ET) reactions. Studies have shown that gold nanoparticle film assemblies of this nature provide for a more homogeneous protein adsorption environment and promote ET without distance dependence compared to the more traditional systems modified …

Biomimetic Synthesis Of Oligostilbenoids And Its Mechanistic Implications., Saraswati S. Velu

Student Works (2010-2019)

Oligostilbenoids are a class of polyphenolic compounds known for their interesting biological activities and structural diversities. They are found in abundance in Malaysian timber trees. Oligostilbenoids syntheses were undertaken in the hope of mimicking what nature does. This study was initiated by preparing 15 different stilbene monomer analogues possessing resorcinol i.e. 3,5-dihydroxy or methoxy substitution, and 3-hydroxy or methoxy pattern (resveratrol analogues) via the commonly used Heck cross coupling. To obtain analogues of natural dimers from stilbene monomers, two different oxidation techniques were employed: anodic oxidations and chemical oxidation mainly by means of various one electron oxidants. Firstly, constant …

Preliminary Analysis Of Thermally Induced Condensed Phase Electron Transfer Reactions Of Cadmium Chloride And Lead Chloride With Electropositive Metals, Vamshi Addaguduru

Student Theses and Dissertations

The thermal stabilities and thermal decomposition for the metal halides, cadmium chloride and lead chloride with electropositive metals like Mn, Zn, Cr and Fe were studied at elevated temperatures using thermal analysis techniques, thermogravimetry and differential thermal analysis using TG/DTA apparatus. The reactions of cadmium chloride and lead chloride with electropositive metals were conducted in Cu pans and found that Zinc metal may show a reaction with both CdCl2 and PbCl2; Manganese may not react with CdCl2 and may react with PbCl2; iron may react with CdCl2 but not with PbCl2 and chromium may not react with both the metal …

Preliminary Analysis Of Thermally Induced Condensed Phase Electron Transfer Reactions Of Nickel Chloride With Electropositive Metals, Rajeshwari Devi Kamineni

Student Theses and Dissertations

The thermal decomposition, dehydration and thermal stability studies of nickel (II) chloride hexahydrate and nickel (II) chloride hexahydrate with electropositive metals cobalt, cadmium, iron, chromium, zinc and manganese have been investigated by non-isothermal method using TG/DTA under argon gas flow. The thermal decomposition and dehydration reactions reveal that there is loss of six water molecules from NiCl2.6H2O. A catalytic action of Cu from Cu pans in thermal decomposition reactions of NiCl2.6H2O and NiCl2.6H2O with electropositive metals was also observed. The change in enthalpy (∆H) of the Fe and Co with NiCl2.6H2O was calculated from the TG/DTA plot onset temperature, using …

Preliminary Analysis Of Themally Induced Condensed Phase Electron Transfer Reactions Of Zinc Chloride, Chromium Chloride And Lead Chloride With Electropositive Metals., Manasa Anumula

Student Theses and Dissertations

The thermal stabilities and thermal decomposition at elevated temperatures for the metal halides zinc chloride, chromium chloride and lead chloride with electropositive metals were studied. The reaction of zinc chloride with Mn is conducted in both Cu and alumina pans. It was postulated that zinc chloride might be reacting with Cu in Cu pan. The reaction between zinc chloride and Mn is also observed. The reactions of chromium chloride and chromium chloride hexahydrate with Zn and Mn are conducted in Cu pans. The obtained TG/DTA plots showed reactions in all the cases. The reactions with chromium chloride hexahydrate are observed …

Synthesis And Catalytic Activity Of Nanostructured Cerium Oxide, Neil J. Lawrence

Department of Chemistry: Dissertations, Theses, and Student Research

Cerium oxide (ceria, CeO_2-x where x is 0 to 0.5) has been one of the most widely used heterogeneous catalysts particularly in three way catalytic converters. Most of the catalytic traits can be attributed to two properties of ceria: first, the high mobility and storage capacity of oxygen within the lattice; second, the ease with which cerium changes between Ce³⁺ and Ce⁴⁺ states. These properties, combined with the abundance of cerium on earth, make ceria a low-cost highly effective alternative to noble metal catalysts. Recent research has been focused on the nanoscale properties of ceria.

The effect …

Electrochemical Investigation Of Azurin Thermodynamic And Adsorption Properties At Monolayer-Protected Cluster Film Assemblies – Evidence For A More Homogeneous Adsorption Interface, Tran Doan, Morgan Lynn Vargo, John K. Gerig, Chris P. Gulka, Matthew L. Trawick, Jonathan D. Dattelbaum, Michael C. Leopold

Chemistry Faculty Publications

Thermodynamic and adsorption properties of protein monolayer electrochemistry (PME) are examined for Pseudomonas aeruginosa azurin (AZ) immobilized at an electrode modified with a networked film of monolayer-protected clusters (MPCs) to assess if nanoparticle films of this nature offer a more homogeneous adsorption interface compared to traditional self-assembled monolayer (SAM) modified electrodes. Specifically, electrochemistry is used to assess properties of surface coverage, formal potential, peak broadening, and electron transfer (ET) kinetics as a function of film thickness. The modification of a surface with dithiol-linked films of MPCs (Au225C675) provides a more uniform binding interface for AZ that results in voltammetry with …

Enhanced Electrochemistry Of Nanoparticle-Embedded Polyelectrolyte Films: Interfacial Electronic Coupling And Distance Dependence, Callie E. Dowdy, Michael C. Leopold

Chemistry Faculty Publications

Factors affecting the electronic communication believed to be responsible for the enhanced solution electrochemistry observed at electrodes modified with hybrid polyelectrolyte–nanoparticle (PE–NP) film assemblies were systematically investigated. Specifically, the faradaic current and voltammetric peak splitting recorded for cyclic voltammetry of ferricyanide redox species (Fe(CN)63−/4−) at films constructed with various architectures of citrate-stabilized gold NPs embedded in polyelectrolyte films composed of poly-l-lysine and poly-S-styrene were used to establish the relative importance of both distance and electronic coupling. Layer-by-layer construction of PE–NP films allowed for the position and density of NPs to be varied within the film to assess electronic coupling between …

Preliminary Analysis Of Thermally Induced Condensed Phase Electron Transfer Reactions Of Copper Chloride With Electropositive Metals, Indrani Kothuru

Student Theses and Dissertations

The thermal stabilities and thermal decomposition of copper metal and its chlorides with electropositive metals such as Pb, Sn, Ni, Co, Cd, Fe, Cr and Mn at non standard temperatures was investigated. The heat capacities and change in enthalpy (ΔH) of the reactions were calculated using the onset temperatures obtained from DTA/TGA plot using Kirchhoff‟s Law. In the case of Co, it was observed that the calculated ΔH values at elevated temperatures gives a negative value indicating the reaction is exothermic but their respective DTA/TGA plots of CuCl2 + Co shows no sign of exothermic peak. However, in the case …

Cyanoscorpionates And Transition Metal Complexes., Donald Martin Johnson

Electronic Theses and Dissertations

The new dihydrobis(4-cyano-3-tert-butylpyrazolylborate) ligand has been synthesized. Isolated crystals of the thallium complex were collected and structurally characterized by X-ray diffraction. Transition metal complexes of the ligand are currently under investigation.

High Temperature Rare Earth Compounds: Synthesis, Characterization And Applications In Device Fabrication, Joseph R. Brewer

Department of Chemistry: Dissertations, Theses, and Student Research

As the area of nanotechnology continues to grow, the development of new nanomaterials with interesting physical and electronic properties and improved characterization techniques are several areas of research that will be remain vital for continued improvement of devices and the understanding in nanoscale phenomenon. In this dissertation, the chemical vapor deposition synthesis of rare earth (RE) compounds is described in detail. In general, the procedure involves the vaporization of a REClx (RE = Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho) in the presence of hydride phase precursors such as decaborane and ammonia at high temperatures and low …

Synthesis And Reactions Of A Tungsten Dioxo Complex, Deborah Bryant

Master's Theses (2009 -)

Metal dioxo complexes are largely known for their ability to epoxidize olefins. The importance of these reactions is reflected in the patents for the ARCO and Halcon processes from the late 1960's. It is very difficult to find literature that shows other indications for metal dioxo complexes.

Catalytic olefin dimerization has become significant in the realm of green chemistry for "atom economical" reactions. Many transition metals have been examined as catalysts for olefin dimerization, but the largest volume of work has been performed using group 8 transition metals, particularly nickel, palladium and platinum. This is especially true for the specific …