Digital Commons Network^™

Exploring The Reactivity Of Metal-Ligand Cooperative Complexes With Dioxazolones, Terminal Alkynes, And 2-Ethynylbenzyl Alcohol, Megan A. Hoffer Miss

Electronic Thesis and Dissertation Repository

N-Acyl ketenimines were attempted to be synthesized catalytically by [Ru(Cp)(P^Ph₂N^Ph₂)(NCMe)]PF₆ with phenylacetylene and 3-phenethynyl-1,2,4-dioxazol-5-one. Trapping agents were employed to identify the major product of the reaction, as many products were formed. [Ru(Cp)(P^Ph₂N^Ph₂)(NCMe)]PF₆ reacts with 3-phenethynyl-1,2,4-dioxazol-5-one generating an isocyanate via the Curtius rearrangement, confirmed by a forced Curtius rearrangement with 3-phenethynyl-1,2,4-dioxazol-5-one and 1,2,4-triazole. Rates of vinylidene formation using [Ru(Cp)(P^Ph₂N^Ph₂)(NCMe)]PF₆ and various terminal alkynes of different sterics and electronics were evaluated using a Hammett analysis for and simple rate comparisons. …

Approaches In Molecular Engineering To Optimize The Desired Properties Of Photoactive Molecules, Douglas Joseph Breen

Chemistry and Chemical Biology ETDs

Within this dissertation, photochemical systems that bear significance to next-generation photonic materials and devices are explored. Notable advances in the design, synthesis, and characterization of three distinct groups of photoactive molecules are achieved through molecular design and spectroscopic analysis. First, novel ruthenium sulfoxide complexes bearing substituted phosphine ligands are found to provide extraordinary control over photoisomerization quantum yields. A comparison of these complexes reveals ground-state characteristics that are instrumental in this reactivity, while a novel spectroscopic technique provides rare structural evidence for an O-bonded metastable isomer. Ruthenium complexes bearing chelating carbene-sulfoxide ligands rapidly thermally revert from the O-bonded metastable isomer …

The Photophysical Studies Of Transition Metal Polyimines Encapsulated In Metal Organic Frameworks (Mof’S), Jacob M. Mayers

USF Tampa Graduate Theses and Dissertations

Light harvesting systems provide a platform that converts solar energy into other forms of energy. One of the most common examples of photon capturing and conversion into chemical energy is observed in photosynthetic organisms in both Eurkaroyic and Prokaryotic domains. Nature provides a model for successful light harvesting platforms which includes the compartmentalization of antenna complexes that contain separated donor and acceptor pairs that participate in efficient electron transfer processes. In order to mimic such systems, crystalline porous materials that exhibits regular cavities and pore dimensions provides an excellent starting place. Metal organic frameworks (MOFs) are a class of porous …

A Compendium Of Inorganic Photochemistry: Synthetic And Spectroscopic Discoveries, Sebastian B. Vittardi

Chemistry and Chemical Biology ETDs

This dissertation reports and examines contributions made in the advancement of inorganic photochemistry. Empirically driven assessments are allotted to the interplay between ligand sets, excited states, and photochemistry observed in metal complexes. A methodical spectroscopic examination is provided for oligothiophene-sensitized lanthanides. Their excited state dynamics were elucidated by femtosecond pump-probe spectroscopy and used to develop a model explaining their wavelength-dependent dual functionality. Iron (II) cyanide and isocyanides are evaluated to identify the efficacy of strong-field ligands in promoting charge-transfer excited states. Fundamentals of ligand field theory helped conceptualize the synthetically tunable parameters and effects transposed to their absorption dynamics. Transition …

Scope And Mechanistic Studies Of Ruthenium Catalyzed C-N Bond Activation Reactions, Pandula Taepith Kirinde Arachchige

Dissertations (1934 -)

Primary aliphatic amines which are ubiquitous in natural products, traditionally considered as inert to substitution reactions. Recent studies clearly demonstrated that the aliphatic deaminative coupling chemistry can be used to make valuable scaffolds through C–N bond activation on transition metal complexes. The catalytic system generated in situ from the tetranuclear Ru–H complex with a catechol ligand (2-9/2-16) and independently synthesized ruthenium catecholate complex 2-11 was found to be effective for the direct deaminative coupling of primary amines. The catalytic system formed in-situ from the reaction of cationic Ru–H complex 2-10 with 3,4,5,6-tetrachloro-1,2-benzoquinone 2-12 was found to mediate a regioselective deaminative …

Mixed-Valent Heterometallic Molecular Precursors : Expansion Into 4d Transition Metals, Jesse Caleb Carozza

Legacy Theses & Dissertations (2009 - 2024)

Hydrogen fuel can provide an ideal carbon-free energy carrier wherever water is available, be that on Earth or throughout the solar system. The use of water electrolysis to split water molecules into contaminant-free hydrogen gas, suitable for use in fuel cells, and oxygen gas allows also for storage of excess electrical energy during periods of high production and low demand, and an easy path to release that stored energy when demand is high and active supply is low. However, liberating hydrogen from water is an energy-intensive process, and effective electrocatalysts that reduce the amount of energy wasted by the reaction …

Selective Catalysis By Polymer-Supported Ruthenium Nanoparticlesand New Ligand Design For Cooperative And Bimetallic Catalysis, Seyed Hadi Nazari

Theses and Dissertations

The abstract is the summary of three different projects all centered around the generalidea of catalysis which is the general theme of research in the Michaelis laboratory. The firstproject focuses on development of a new heterogeneous catalyst for selective catalysis. In theMichaelis lab, we were interested in the potential of nanoparticle catalysts for regioselectivetransformations. We showed that polymer supported ruthenium nanoparticles performed as areliable catalyst for regioselective reduction of azide to amine. In our study of regioselectivereduction of multiple azide containing substrates, we observed that in presence of ourruthenium nanoparticle catalysts, the least sterically hindered azide group reduced to aminefunctional …

Ruthenium Catalyzed Deaminative Coupling Reaction Of Amines Via C-N Bond Activation, Pandula T. Kirinde Arachchige

Master's Theses (2009 -)

C–N bond activation via transition-metal catalyst has attracted much attention during the past two decades. This strategy has become one of the most promising way to generate secondary amines, which are very important in a broad spectrum of applications in pharmaceutical industry, synthetic organic chemistry and material science. The secondary amines can be utilized as an important synthetic intermediate for further manipulations. The in-situ formed catalytic system generated from the tetranuclear Ru–H complex with 4-(1,1-dimethylethyl)-1,2-benzenediol ligand was found to be effective for the synthesis of secondary amines from the direct deaminative coupling of amines. The ruthenium catalyst was highly effective …

Ruthenium-Catalyzed Dehydrogenative And Dehydrative C-H Coupling Reactions Of Arenes With Alcohols And Carbonyl Compounds, Hanbin Lee

Dissertations (1934 -)

Despite their outstanding achievements, the requirement of preformed functional groups and wasteful byproduct formation are inherent disadvantages associated with the transition metal catalyzed cross-coupling methods. Inspired by the needs for green and sustainable chemistry, transition metal catalyzed dehydrogenative and dehydrative coupling methods have been recognized as environmentally sustainable and atom economical synthetic routes for the new C-C bond formation. The catalytic activation of C-H and C-O bonds allows the formation of coupling products from ubiquitous hydrocarbon substrates by releasing hydrogen or water byproduct. However, these novel protocols require relatively harsh conditions due to their low reactivity of C-H and C-O …

Design, Synthesis And Analysis Of Potential Photo-Activatable Cathepsin K Inhibitors, Khalin Evania Nisbett

Wayne State University Theses

Abstract

DESIGN, SYNTHESIS AND ANALYSIS OF POTENTIAL PHOTO-ACTIVATABLE CATHEPSIN K INHIBITORS

by

KHALIN NISBETT

May 2017

Advisor: Dr. Jeremy Kodanko

Major: Chemistry

Degree: Master of Science

Tightly regulated cysteine CA proteases play a major role in maintaining the homeostasis within cells. Subsequently, when these proteases are dysregulated and mislocalized they disrupt healthy cell dynamics and contribute to many life-threatening pathologies such arteriosclerosis, osteoporosis and cancer. As such many pharmaceutical companies and research teams are highly interested in these proteases as targets. One emergent strategy is the spatiotemporal control of biological processes. In relation to this, a series of spatiotemporally controlled …

Synthetic And Mechanistic Studies Of Ruthenium Catalyzed C-C And C-O Bond Activation Reactions, Junghwa Kim

Dissertations (1934 -)

Etherification of alcohols is one of the most fundamental transformations in organic synthesis. Williamson ether synthesis is the most well-known synthetic method of unsymmetrical ether synthesis which is still being used in both industrial and academic laboratories. We have developed a novel catalytic etherification reaction using two different alcohols by using a well-defined cationic ruthenium catalyst. The reaction scope as well as the mechanistic study of the reaction are described.Hydroacylation is considered to be a powerful synthetic transformation for producing functionalized ketones from relatively simple olefin substrates. Despite remarkable progress in intra and intermolecular hydroacylations, the substrate scope of the …

Synthesis And Mechanistic Investigations Of Transition Metal Complexes And Ligands For Chemotherapeutic Applications, Jimmie Lee Bullock Jr.

Chemistry & Biochemistry Theses & Dissertations

Transition metal complexes have played a critical role in antitumor therapy with many complexes incorporating platinum, ruthenium, and lanthanum having been investigated in preclinical and clinical trials. The best known transition metal therapeutic is cisplatin, which is utilized in nearly 50% of all cancer therapies, despite its significant toxic side effects. The toxic side effects of current FDA approved platinum-based chemotherapeutics are often overlooked due to the “special status” granted to these drugs due to their ability to fight, what is often considered an incurable disease with life expectancies often measured in months. Oncology drug development has therefore now focused …

Photochemistry Of A Series Of Weakly Coupled Dinuclear Ruthenium(Ii) Complexes, Latisha Michelle Puckett

Graduate Theses and Dissertations

An improved synthetic method was developed for symmetric ruthenium(II) polypyridine complexes with the form L2Ru(diphen)RuL2. The scope of the reaction was investigated in regards to the ligands, bridging ligands, and starting materials. Several ligands were successful in the synthesis, including 2,2’-bipyridine (bpy), 4,4’-dimethyl-2,2’-dipyridyl (dmb), 1,10-phenanthroline (phen), 4,7-diphenyl-1,10-phenanthroline (dpphen), and 3,4,7,8-tetramethyl-1,10-phenanthroline (tmphen). Ligands that did not react to form symmetric dimeric complexes were 2,2’-bipyrazine, bpz, and 2,2’-bipyrimidine, bpm.

Dpp, 2,3-bis(2-pyridyl)-pyrazine, effectively replaced diphen as the bridging ligand to produce (phen)2Ru(dpp)Ru(phen)24+. However, replacing the [Ru(CO)2Cl2]n with Ru(DMSO)4Cl2 did not prove successful. The newly developed synthesis was also applied to the synthesis of …

Asymmetric Transfer Hydrogenation Of Secondary Allylic Alcohols, Christopher Olugbenga Olusegun Shoola

Seton Hall University Dissertations and Theses (ETDs)

This dissertation highlights the developments and optimization of a new reaction method that transforms racemic secondary allylic alcohols into optically active secondary alcohols. The key step in this methodology occurs through a ruthenium catalyzed tandem isomerization and asymmetric transfer hydrogenation reaction. This reaction is a one pot, two-step process, which utilizes the unique ability of a transition metal catalyst to effect a combined reduction of the C-C double bond and the carbonyl group in a selected class of secondary allylic alcohols.

With a-vinyl benzyl alcohol as substrate, the optimal catalyst for this reaction was generated in situ from a …

Synthesis, Characterisation, Electrochemical, And Spectroscopic Studies Of Cobaloximes: Unique Clues Of Cobalt(I) Species In Various Solvents, Michael John Celestine

Chemistry & Biochemistry Theses & Dissertations

With the dwindling amount of fossil fuels in the world’s reserve is said to run out in the future. The use of alternative fuels such as hydrogen can be produced from renewable sources. One source is the use of first row transition metal complexes that can harness the power of the sun to reduce protons to hydrogen. In this thesis we investigated a well-known hydrogen evolution catalyst in a quest to understand the behavior of different oxidation states that occur during the catalytic cycle.

In an attempt to synthesize a binuclear ruthenium(II) complex, [{Ru(phen)2}2{µmes(1,4-phO-Izphen)3}](PF6)4, as a possible photosensitizer for the …

Metal-Ligand Cooperative Catalysis And Methods For Metal Removal From Organic Transformations, John-Paul J. Bow

Electronic Thesis and Dissertation Repository

Organometallic catalysis has revolutionized the synthesis of complex organic molecules. Methods for C-C, C-X and C-H bond formation and cleavage are exploited throughout the areas of fine chemicals synthesis, with major applications for pharmaceuticals. This situation raises duel challenges: 1) high-performance catalysts for environmentally and economically sustainable synthesis and 2) efficient methods of catalyst (i.e. metal) removal must be identified. This work tackles both of these areas. The highly tunable cooperative P^R₂N^R'₂ ligands have been implemented for the first time for catalytic organic transformations. I show that [Ru(Cp)(P^tBu₂N^Bn₂)(MeCN)][PF_{6 …}

Electrolyte Effects On The Kinetics Of Comproportionation Electron-Transfer Reactions And On Intervalence Charge-Transfer Band Energies Of Binuclear Ruthenium Ammine Complexes, Zhiji Han

Master's Theses

Chapter 1 describes an overview of electron-transfer reactions. The kinetic equations for ET reactions have also been described in detail.

Chapter 2 describes a series of novel kinetic accelerations which deviate strongly from the predictions of the classical Debye-Huckle theory with a range of different added “inert” electrolytes. The greater catalytic effects seen with the heavier halides and other catalytic electrolytes (especially certain dicarboxylates) indicate an important role for hole-transfer superexchange in the ET transition state. The hypothesis of a catalytic ternary association complex, [RuII--X--RuIII] has also been explored by kinetic modeling of the reaction. An increasing ratio of anion-catalyzed …

Design And Synthesis Of Isatin-Based Caspase Inhibitors For Ruthenium Caging Applications, Kasun Chinthaka Ratnayake

Wayne State University Theses

ABSTRACT

DESIGN AND SYNTHESIS OF ISATIN BASED CASPASE INHIBITORS FOR RUTHENIUM CAGING APPLICATIONS

by

KASUN CHINTHAKA RATNAYAKE

August 2015

Advisor: Jeremy J. Kodanko, Ph.D.

Major: Chemistry (Organic)

Degree: Master of Science

Apoptosis is the energy dependent programmed cell death. Improper function of apoptosis could lead to diseases such as cancers, strokes, Alziemer’s disease. Caspases are the enzymes involved in the later stage of this process. Peptidyl and non-peptidyl caspase inhibitors have been synthesized recently. These non-peptidyl compound classes which consist of pyrrolidinyl-5-sulfo isatins have showed a greater potency against executioner caspases, caspase-3 and -7. According to literature and for further …

(I)Chromatographic Methods For Solute Descriptor Determinations (Ii)Ruthenium Substrate-Catalyzed Growth Of Nickel Nitride Thin Films By Atomic Layer Deposition, Thiloka Chandima Ariyasena

Wayne State University Dissertations

Determination of distribution levels of environmentally important compounds in various environmental compartments is a major procedure in many fields including environmental risk assessment, food and drug safety, and the perfumery industry. Models for direct estimation of environmental properties were developed using gas chromatography and liquid-liquid partitioning. The developed models were used to derive descriptor values for environmentally important organic compounds. The accuracy of the developed models and descriptor values were demonstrated by the application to the estimation of standard environmental properties and by comparison with experimental solute property values.

Quantitative structure property relationships were constructed for totally organic biphasic partition …

Metal Nanoparticles Immobilized On Basic Supports As Catalysts For Hydrogenation And Dehydrogenation Reactions Of Relevance To Cleaner Fossil Fuels And Alternative Sources Of Energy, Reena Rahi

Dissertations, Theses, and Capstone Projects

We developed a series of catalysts, composed of metal nanoparticles immobilized on basic supports for the hydrogenation of heteroaromatics of relevance to cleaner fossil fuels and biodiesel, and for the dehydrogenation of heteroaromatics of relevance to hydrogen storage in organic liquids. Our catalyst design involves nanostructured catalysts composed of metal particles immobilized on basic supports capable of ionic mechanism that may avoid catalyst poisoning and enhance catalytic activity.

We prepared a new catalyst composed of Pd nanoparticles immobilized on MgO by NaBH4 reduction of Na2PdCl4 in methanol in the presence of the support. TEM measurements revealed well-dispersed 1.7 nm Pd …

An Investigation Of The Electronic Coupling In Some Dimeric Ruthenium (Ii) Polypyridine Complexes, Roland Ngebichie Njabon

Graduate Theses and Dissertations

A detailed understanding of respiration at the molecular level requires an understanding of the many electron transfer steps involved in the process. These electron transfer processes are extremely fast and are impossible to measure by simple rapid mixing techniques. In order to get around this problem, scientists have used laser flash photolysis. This technique relies on the fact that under proper conditions, a reactant can be generated by a very short laser pulse. Once generated, the course of the reaction can be monitored by various techniques capable of very rapid time response. Many applications of this methodology rely on the …

Development Of Ruthenium/Terpyridine Complexes For Water Oxidation, Dakshika Chandrashani Wanniarachchi

Wayne State University Dissertations

The work presented in the dissertation is focused on developing catalysts for water oxidation. In this regard, a series of unsysmmetrical ruthenium complexes of type [Ru(terpy-R)(phen-X)Cl]PF6 where terpy-R= 4'-(4-methylmercaptophenyl)-2,2':6'2"-terpyridine and phen-X=H (1), X= 5-nitro (2), X=5,6-dimethyl (3), and X= 3,4,7,8-tretramethyl (4) was synthesized as precursors for self-assembled monolayers. Water oxidation properties of these complexes were evaluated in the presence of (NH4)2[Ce(NO3)6] as the sacrificial oxidant by measuring catalytic turnover number (TON) after 24 h of reaction time and rate of dioxygen evolution in solution during early stages of catalysis. The results revealed that all complexes 1 - 4 are catalytic …

Quenching Of The Fluorescence Of Tris (2 2-Bipyridine) Ruthenium(Ii) [Ru(Bipy)3]2+ By A Dimeric Copper(Ii) Complex., Kevin E. Cummins

Electronic Theses and Dissertations

The quenching of the [Ru(bipy)₃]²⁺ by Cu₂L²⁺ was studied and the data were plotted with the Stern-Volmer equation. The plot showed a break and was divided into 2 regions, <0.5 and >0.5 Cu₂L²⁺: [Ru(bipy)₃]²⁺ molar ratio. Quenching above the 0.5 Cu₂L²⁺: [Ru(bipy)₃]²⁺ molar ratio was slower (330 x 10^-6 M^-1s^-1) than the quenching rate reaction below 0.5 ratio (387 x 10^-6 M^-1s^-1).

With Cu₂L²⁺ being a dimeric complex the …

Activation Of Propargylic Alcohols By Piano-Stool Ruthenium Complexes Bearing Phosphoramidite Ligands, Stephen Andrew Costin

Dissertations

Various piano-stool ruthenium complexes bearing phosphoramidite ligands have been synthesized and characterized spectroscopically and in some cases structurally. Reaction of phosphoramidite ligands with an appropriate metal precursor gives new piano-stool ruthenium complexes [RuCl(L)(arene)(phosphoramidite)], where L = Cl, PPh3, or others. The novel complexes are tested for their ability to activate propargylic alcohols catalytically as well as stoichiometrically. Specifically, catalytic substitution of propargylic alcohols via allenylidene intermediates is envisioned. Stoichiometric reactions designed to form stable, isolable allenylidenes are sought as well. h6-p-cymene complexes of the type [RuCl2(h6-p-cymene)(phosphoramidite)] activate propargylic alcohols in the reaction with carboxylic acids to form b-oxo esters. The …

Synthesis And Characterization Of An Oligothiophene-Ruthenium Complex And Synthesis And Optical Properties Of Oligothiophene-Ruthenium Complexes Bound To Cdse Nanoparticles, Nathan A. Bair

Theses and Dissertations

Oligothiophenes are of increasing interest in organic based electronic devices in part due to their high electron and hole mobilities. In an organic photovoltaic (OPV) device, the electronic properties of oligothiophenes make them advantageous as charge transfer junctions. To serve as charge transfer junctions, oligothiophenes must be functionalized to bind to the donor and acceptor parts of the device. The donor and acceptor parts are different materials and the synthesis of asymmetric oligothiophenes is of great interest. Previous researchers in our lab synthesized four asymmetric oligothiophenes, two with two thiophene subunits and two with four. Each set of oligothiophenes contained …

Analysis Of The Effect Of Various Ligands On The Hydrolysis Of Ruthenium (Iii) Complexes And Interpretation Of Kinetics Of Hydrolysis Profiles By Uv-Visible Spectrophotometry, Sudheer Koneru

Master's Theses and Doctoral Dissertations

Cancer is one of the major causes of death in the world. Discovery of platinum metal-based drugs like cisplatin and carboplatin have proved to be successful in cancer treatment. Due to subsequent development of resistance, side effects, and fewer toxic effects of these drugs, the usage of these drugs has been limited. Novel drugs were being synthesized utilizing the transition metals like ruthenium, osmium, and copper.

In this research, ruthenium metal complexes of the formula HL[RuCl4L2] (where L= ligand) were synthesized. These ruthenium-based drugs exist in prodrug forms which are activated into antitumor drugs by means of hydrolysis, redox reactions, …

Synthesis And Optical Properties Of Four Oligothiophene-Ruthenium Complexes And Synthesis Of A Bidentate Ligand For C-F Bond Activation, Joseph S. Bair

Theses and Dissertations

Photovoltaic cells and fluorescence sensing are two important areas of research in chemistry. The combination of photon-activated electron donors with electron acceptors provides a strong platform for the study of optical devices. A series of four oligothiophene-ruthenium complexes has been synthesized. Variation in oligothiophene length and bipyridine substitution allowed comparison of these variables on electronic properties. The longer oligothiophenes display lower energy absorption and emission compared to the shorter ones. Aromatic conjugation appears more complete with para-, rather than meta-, substitution. Oligothiophenes and Ru(bpy)32+ are highly fluorescent individually, but fluorescence is quenched when connected. Bonds of carbon to fluorine are …

Ruthenium-Catalyzed Hydrogenation Of Aqueous Sodium Bicarbonate, Duane P. Covino

Retrospective Theses and Dissertations

This research report investigated the ruthenium-catalyzed hydrogenation of aqueous sodium bicarbonate. Subjects of the investigation included: the "blank" effect of the 316 stainless steel reactor in the batch mode; the catalytic activities at 150°C for unsupported ruthenium, including ruthenium purge and the metal produced from the in situ reduction of RuCl3·1-3H2O and Ru(IV)O2·H2O; the catalytic activities at 150°C for supported ruthenium including 4.05% w/w ruthenium on alumina, 5.25 and 20.85%w/w ruthenium on molecular sieve SK-41 (ammonium - substituted Y-type), 3.34 and 17.48% w/w ruthenium on SK-41 (prepared by the in situ reduction of the RuCl3·1-3H2O exchange sieve); orders of reaction …