Inorganic Chemistry Commons^™

Study Of Multielectron Redox Chemistry Through Multiple Bonded Bimetallic Species Of The Type M2-L-M, Nancy Rodríguez, Dino Villagrán

COURI Symposium Abstracts, Summer 2012

Multielectron redox chemistry is fundamental for the activation of small molecules, such as H₂O, N₂ and CO₂. Currently, these multielectron redox processes are not well understood and are presently the subject of active research throughout the world due to the evident energy and environmental implications of these small molecules. The goal of this project is the study of multielectron redox chemistry on compounds of the type M₂-L-M. We want to manipulate the reactivity of a M (M=Zn, Co, Ni, Rh, Ir) redox center by a quadruply bonded Mo₂ dimolybdenum core through a …

Electronic Communication Between Dimolybdenum Units And Ruthenium As A Metal Center Linked By Dimethyloxamide, Daniel D. Anchondo, Dino Villagran

COURI Symposium Abstracts, Summer 2012

Multi-electron redox reactions are important in chemistry. They are crucial in biochemical reactions such as photosynthesis and in many enzymatic processes in nature. Typical examples can be the electrolysis of water which is a four electron process, nitrogen fixation which is a six electron process. Multi-electron redox reactions are also important in industrial processes, such as the reduction of ores to obtain metals and to produce electrochemical cells. Therefore it is vital to study multi-electron redox reactions. We use dimolybdenum units bridged to a ruthenium atom as a platform to study these reactions by measuring the electron communication between two …

Interaction Of Human Telomeric Dna With N-Methyl Mesoporphyrin Ix, John Michael Nicoludis , '12, Steven Paul Barrett , '13, J.-L. Mergny, Liliya A. Yatsunyk

Chemistry & Biochemistry Faculty Works

The remarkable selectivity of N-methyl mesoporphyrin IX (NMM) for G-quadruplexes (GQs) is long known, however its ability to stabilize and bind GQs has not been investigated in detail. Through the use of circular dichroism, UV-visible spectroscopy and fluorescence resonance energy transfer (FRET) melting assay we have shown that NMM stabilizes human telomeric DNA dAG(3)(TTAG(3))(3) (Tel22) and is selective for its parallel conformation to which it binds in 1:1 stoichiometry with a binding constant of similar to 1.0 x 10(5) M-1. NMM does not interact with an antiparallel conformation of Tel22 in sodium buffer and is the second example in the …

Hierarchy Of Supramolecular Synthons In The Of Design Multi-Component Crystals, Padmini Kavuru

USF Tampa Graduate Theses and Dissertations

Most of the biological systems in nature are sustained by molecular self-assemblies which are the finest examples of supramolecular architectures. Non-covalent interactions are key concepts which govern these molecular assemblies. Inspired by these examples crystal engineering emerged as an important tool in supramolecular chemistry which aids in the invention of new molecular structures with desired properties. Understanding of how the molecules interact at the molecular levels enables one to rationally design novel solid forms with modulated physicochemical properties. This feature of crystal engineering has heightened its position in materials chemistry and is currently one of the most well studied fields …

Investigating The Electron Transport And Light Scattering Enhancement In Radial Core-Shell Metal-Metal Oxide Novel 3d Nanoarchitectures For Dye Sensitized Solar Cells, Gayatri Sahu

LSU New Orleans Theses and Dissertations

Dye-sensitized solar cells (DSSCs) have attained considerable attention during the last decade because of the potential of becoming a low cost alternative to silicon based solar cells. Electron transport is one of the prominent processes in the cell and it is further a complex process because the transport medium is a mesoporous film. The gaps in the pores are completely filled by an electrolyte with high ionic strength, resulting in electron-ion interactions. Therefore, the electron transport in these so called state-of-the-art systems has a practical limit because of the low electron diffusion coefficient (D_n) in this mesoporous film …

Synthesis, Structure, And Characterization Of Hybrid Solids Containing Polyoxometalates And Ruthenium Polypyridyl Complexes, Yanfen Ll

Masters Theses & Specialist Projects

Polyoxometalates (POMs), which are inorganic metal oxide cluster anions with discrete structures, have been extensively studied in recent years due to their large variety of applications such as medicine, biology, catalysis, material sciences and chemical analysis. Ruthenium polypyridyl complexes have been extensively studied for their applications as photosensitizers in solar energy conversion and photoelectronic materials. Recently, ruthenium heterocyclic ligand complex-based building blocks have been used for the synthesis of hybrid organic-inorganic solids through the self-assembly. We are interested in the synthesis of ruthenium polypyridyl complexes and polyoxometalate anions through different ways such as coordination bonds, hydrogen bonds and ionic bonds …

The Impact Of Ligand Design On The Coordination Chemistry And Reactivity Of Metal Pincer Complexes, Sarath Wanniarachchi

Dissertations (1934 -)

Pincer ligands are uninegative tridentate metal-coordinating agents of the form [XZY]- where Z is the central, anchoring Lewis donor while X and Y are flanking Lewis donors. Ever since initial reports of transition metal pincer complexes were published in the late 1970's, there has been burgeoning interest in such complexes because of their desirable robust nature, generally simple syntheses, and the spectacular chemical transformations that they can mediate. In this research project, two new sets of pincer ligands with a diarylamido anchor and either two pyrazolyl nitrogenous flanking donors (NNN pincer) or one pyrazolyl and one diphenylphosphine donor (NNP pincer) …

Optical And Electrochemical Properties Of Monolayer Protected Gold Clusters Modified With Fluorophores, Mary Sajini Devadas

Dissertations

My research focused on the synthesis, characterization and the investigation of the optical and electrochemical properties of monolayer-protected quantum-sized gold clusters. Significant research attention was focused on the solution phase optical and electrochemical properties of these clusters. Highly monodisperse Au clusters with different types of ligands were successfully synthesized with sizes varying from 1 nm to 13 nm. These preformed gold clusters were modified with fluorophores and pseudo-rotaxanes for developing better nonlinear optical materials for sensing and biological imaging purposes. We have tried to focus on the interaction of the outer ligand shell, made up of –S-Au-S-Au-S- bonds, with the …

Optical And Electrochemical Sensors For The Detection Of Metal Ions And Nerve Gas Mimics Via Fluorescein And Coumarin Derivatives, Fasil Adefris Abebe

Dissertations

Trace element detection of metals, for example, iron, Copper and zinc, are important in biological systems and in the environment. Many of us are aware that our cells contain metal ions that are “tied” up in proteins. However, chelatable or “free” trace elements can also be found in small quantities, and can have a negative impact on our bodies. Despite the increasing surge in developing sensors for metals and nerve gas agents, efficient detection still remains a challenge. Among the various sensors developed so far, fluorescence sensors play an important role due to their simplicity. I design fluorescein-based chemosensors for …

Proton-Coupled Electron Transfer (Pcet) With Bimetallic Systems, Maripaz A. Calderon ^, Dino Villagran *

COURI Symposium Abstracts, Spring 2012

Electron-transfer (ET) is one of the simplest chemical events, yet, it is a vital process for chemical reactivity. Proton-coupled electron transfer (PCET) is the concerted transfer of protons and electrons which is fundamental in chemical and biological systems and processes in electrochemistry, photosynthesis, and enzymatic activity. Similarly, mixed-valence (MV) systems are pervasive in nature and provide a platform for multiple electron transfers systems in nature. While both fields have been studied extensively, little work has been done on the intersection of the two. This project explores the elegant use of MV bimetallic systems through hydrogen bonded networks. A variety compounds …

Synthesis And Characterization Of Iron(Ii) Complexes Modeling The Active Site Structure Of Nonheme Iron Dioxygenases, Jacob Baus

Master's Theses (2009 -)

The aerobic degradation of polycyclic aromatic compounds, which are widespread contaminants in soils and groundwaters, is carried-out in large part by various Fe-containing dioxygenases that perform the cis-dihydroxylation and oxidative cleavage of aromatic rings. Recently, a new Fe dioxygenase family emerged that catalyzes a remarkable set of transformations; the distinguishing feature of these enzymes is that their monoiron(II) centers are coordinated by three histidines residues (i.e., imidazole ligands) in a facial geometry - a departure from the "canonical" 2-histidine-1-carboxylate facial triad that is dominant among nonheme monoiron enzymes. Members of the "3His family" are capable of oxidatively cleaving C-C bonds …

Investigation And Synthesis Of Novel Graphene-Based Nanocomposites For Hydrogen Storage, Anthony Joseph D'Angelo

USF Tampa Graduate Theses and Dissertations

It is of great interest to develop and utilize a high surface area material with optimized hydrogen sorption properties. The need for a renewable energy source to replace automobile gasoline has become more critical in the past decade. Hydrogen is a viable fuel source for automobile usage; however, the question of how hydrogen will be safely and efficiently stored still remains. Critical factors for optimum hydrogen storage include ambient conditions and low activation temperature for adsorption and desorption phenomena. In order for optimum hydrogen adsorption to be achieved, the properties of (1) high surface area, (2) optimum hydrogen adsorption energy, …

Synthesis, Characterization And Computational Study Of [4]Octamethylferrocenophane, Benjamin Mark Wilson

Theses, Dissertations and Capstones

This thesis reports the synthesis of an organic molecule, 1,4-bis(2,3,4,5-tetramethylcyclopentadienyl)butane by two different methods, in about 75% and 85% crude yield. Deprotonation of this molecule followed by reaction with FeCl2 generated the tethered ferrocene, [4]octamethylferrocenophane. Although the yield was low in the first attempt (2%), this molecule has been characterized through NMR spectroscopy, X-ray crystallography, electronic spectroscopy, elemental analysis, and decomposition temperature. A computational study was performed to determine the energy gap between each minimum energy structure. It was found that the energy barrier was not high enough to prevent a rapid interconversion between the two structures of minimum energy …

Transmetallation Of A Lithium Porphyrin With Iron(Ii), Kidus Debesai

The Corinthian

Synthesis and characterization of the iron(III) derivative of the 2,3,7,8,12,13,17,18-octabromo-meso-tetrakis(N-methylpyridium-4-yl)porphyrin was accomplished via metal metathesis of the lithium porphyrin and iron(II) ion. Preliminary molecular orbital analysis of the iron(II) and iron(III) derivatives demonstrate that the iron(III) porphyrin exists at a lower energy state.

Synthesis, Spectroscopic, And Electrochemical Properties Of 3d Metal And Ruthenium Complexes With Phenolate And Catecholate Ligands, Frank Donald Lesh

Wayne State University Dissertations

The integration of amphiphilic properties into transition metal coordination systems is a pertinent step toward the development of candidate metallosurfactant precursors for the formation of responsive monolayer films. This concept is intended to preserve the solution-observed redox, spectroscopic, and magnetic responses onto solid surfaces for potential application. Selected metal ions and various ligand designs are investigated to address the effect of coordination and protonation preferences on amphiphilic behavior, the aspects of new modular approaches for Langmuir film precursors of differentiated topologies to extend amphiphilicity and redox behavior, and the introduction of photosensitizing properties into electroactive metallosurfactant precursors. In an attempt …

Synthesis And Characterization Of Size Controlled Transitionmetal Phosphide Nanoparticles And Their Hydrodesulfurization Catalytic Activity, Galbokka Hewage Layan Savithra

Wayne State University Dissertations

Transition metal phosphides are promising catalysts for hydrodesulfurization (HDS). The size-dependent catalytic activity of these metal phosphides for hydrodesulfurization (HDS) remains unstudied because the traditional temperature programmed reduction (TPR) method used in catalyst preparation results in highly polydisperse particles.

The main goals of this dissertation research are (1) synthesize metal phosphide nanoparticles (Ni²P, Rh²P, and Pd⁵P²) with control of size and morphology using a solution based arrested precipitation method; (2) develop large scale synthesis of mesoporous silica encapsulated nanoparticles (Ni²P and Pd⁵P²) with controlled loading to …

Synthesis And Characterization Of Group 5 Metal Complexes Containing Pyrazolate, Amidate, And Related Ligands As Potential Precursors For Thin Film Growth By Atomic Layer Deposition, Thuduwage Hiran Perera

Wayne State University Dissertations

Atomic Layer Deposition (ALD) is an advanced variant of Chemical Vapor Deposition (CVD) and is used to deposit smooth and conformal thin films for applications in the microelectronics industry. ALD requires metal precursors that are sufficiently volatile and thermally stable at elevated temperatures. Several group 5 ALD and CVD precursors were reported in the literature, which have been used to deposit TaN, NbN, Nb2O5, and Ta2O5 thin films. Synthesis of low and mid valent group 5 metal ALD precursors might give us access to deposit NbO2, Nb2O3, Ta2O3, and TaO2 thin films by low temperature ALD pathways upon applying mild …

Metal Catalyzed Activation Of E-H Bonds, E = Si, Ge, Sn, Renzo Nelson Arias Ugarte

Open Access Theses & Dissertations

The present project covers the use of complexes of the type: (C5H5)M(CO)nLMe, (M = Fe, n = 1; L = CO, Ph3P; M = Mo, n = 2; L = CO, Ph3P); M(CO)6, (M = Cr, Mo, W) and M(CO)5NMe3 as catalysts for the activation of E-H bonds (E = Si, Ge and Sn). The work is divided in three sections; the first two involves dehydrogenation and the last one amide reduction.

Synthesis And Flame Retardant Testing Of New Boronated And Phosphonated Aromatic Compounds, Vladimir Benin, Sravanthi Durganala, Alexander Morgan

Chemistry Faculty Publications

The present report describes the preparation and use of some dimethyl terephthalate derivatives in transition metal-catalyzed coupling reactions to produce new reactive flame retardants. Dimethyl iodoterephthalate and dimethyl 2,5-diiodoterephthalate were successfully employed in the preparation of phosphonic and boronic esters and acids. The latter were tested for heat release with a microcombustion calorimeter (ASTM D7309) to determine the potential for heat release reduction of these flame retardant molecules. The results showed that the addition of boronic or phosphonic acids greatly lowered the heat release, due to a condensed phase (char formation) mechanism. Adding ester groups to the boronic acids or …

Quantitative Analysis Of Some Important Metals And Metalloids In Tobacco Products By Inductively Coupled Plasma-Mass Spectrometry (Icp-Ms), Syed Ghulam Musharraf, Muhammad Shoaib, Amna Jabbar Siddiqui, Muhammad Najam-Ul-Haq, Aftab Ahmed

Pharmacy Faculty Articles and Research

Background: Large scale usage of tobacco causes a lot of health troubles in human. Various formulations of tobacco are extensively used by the people particularly in developing world. Besides several toxic tobacco constituents some metals and metalloids are also believed to pose health risks. This paper describes inductively coupled plasma-mass spectrometric (ICP-MS) quantification of some important metals and metalloids in various brands of smoked, sniffed, dipped and chewed tobacco products.

Results: A microwave-assisted digestion method was used for sample preparation. The method was validated by analyzing a certified reference material. Percentage relative standard deviation (% R.S.D.) between recovered …