Inorganic Chemistry Commons^™

Structural Impacts Of Canonical And Non-Canonical Oligonucleotide Modifications, Deepak Shrestha

Wayne State University Dissertations

Nucleic acids, including DNA (deoxyribonucleic acid) and RNA (ribonucleic acids), are the fundamental building blocks of living organisms. The events that cause modification of DNA/RNA are of interest because they impact the nucleic acid function. Targeting DNA is important for treating diseases such as cancer. Cisplatin (cisPt) is a well-studied drug that targets DNA and blocks replication, but its use is limited by adverse side effects and cellular resistance. Prevoius research addressed some of these challenges through development of platinum analogues such as carboplatin and oxaliplatin. Amino acid-linked platinum analogues (AAPt) are the focus of this thesis work. AAPt complexes …

Halide Exchange And Transport In Halide Perovskite Lattices, Temban Acha Billy

Department of Chemistry: Dissertations, Theses, and Student Research

In recent years, metal-halide perovskites (MHPs) have risen quickly to prominence as promising materials across a variety of fields, from photovoltaics to optoelectronics in general. We show here a facile solution growth for creating a variety of mixed halide MAPbBr_3-xI_x crystals, which we will use to study halide exchange and transport in halide perovskites. We generated a calibration curve between the optical response and chemical composition in mixed Br/I MHPs at room temperature. All mixed Br/I MHP crystals were subjected to measurements of photoluminescence (PL) and Raman spectroscopy. A subset of mixed-halide MHP crystals exhibited multiple emission …

Calcium Bistriflimide-Mediated Sulfur (Vi)–Fluoride Exchange (Sufex): Mechanistic Insights Toward Instigating Catalysis, Nicholas Ball, Brian Han, Samuel R. Khasnavis, Matthew Nwerem, Michael Bertagna, O Maduka Ogba

Pomona Faculty Publications and Research

We report a mechanistic investigation of calcium bistriflimide-mediated sulfur(VI)–fluoride exchange (SuFEx) between sulfonyl fluorides and amines. We determine the likely pre-activation resting state─a calcium bistriflimide complex with ligated amines─thus allowing for corroborated calculation of the SuFEx activation barrier at ∼21 kcal/mol, compared to 21.5 ± 0.14 kcal/mol derived via kinetics experiments. Transition state analysis revealed: (1) a two-point calcium-substrate contact that activates the sulfur(VI) center and stabilizes the leaving fluoride and (2) a 1,4-diazabicyclo[2.2.2]octane additive that provides Brønsted-base activation of the nucleophilic amine. Stable Ca–F complexes upon sulfonamide formation are likely contributors to inhibited catalytic turnover, and a proof-of-principle redesign …

Visible Light Generation And Mechanistic Investigation Of High-Valent Metal-Oxo Species Supported By Different Ligands, Seth Ellis Klaine

Masters Theses & Specialist Projects

Numerous transition metal catalysts have been designed as biomimetic model compounds for the active site of metalloenzymes found throughout Nature, most notably cytochrome P450 monooxygenases that carry out the oxidative transformations of organic substrates with near-perfect chemo-, regio-, and stereo-selectivity. The primary active oxidants in catalytic and enzymatic cycles are fleeting high-valent metal-oxo intermediates where the oxo ligand can transfer to an organic substrate in a process known as oxygen atom transfer (OAT).

In the present work, porphyrin-manganese(III), salen-chromium(III), and salenmanganese( III) derivatives were successfully synthesized and spectroscopically characterized using 1H NMR and UV-Vis spectroscopies. A facile photochemical approach was …

Leaving Ligand Effects On Reactivity And Solubility Of Monofunctional Platinum(Ii) Anticancer Complexes, Heidi Linn Hruska Millay

Masters Theses & Specialist Projects

Monofunctional platinum(II) complexes, such as phenanthriplatin and pyriplatin, have notably different characteristics from the bifunctional anticancer complexes, such as cisplatin and oxaliplatin, which have detrimental toxicities and resistance associated with them. The unique properties of the monofunctional complexes may be exploited to target cancer cells without producing the toxic side effects associated with the current FDA-approved platinum-based anticancer drugs. To advance the understanding of these monofunctional platinum(II) complexes, this study replaced the chloride leaving ligand with an acetate group, which should increase solubility and alter the rate of reactivity with key amino acid and nucleotide targets. Phenanthriplatin and pyriplatin compounds …

Electrochemical Investigation Of The Kinetics Of Chloride Substitution Upon Reduction Of [Ru(Porphyrin)(No)Cl] Complexes In Thf., Jeremy R. Zink, E G. Abucayon, Anthony R. Ramuglia, Arghavan Fadamin, James E. Eilers, George B. Richter-Addo, Michael J. Shaw

SIUE Faculty Research, Scholarship, and Creative Activity

The electrochemistry of several ruthenium porphyrin nitrosyl chloride complexes [Ru(por)(NO)Cl] have been examined in tetrahydrofuran. The complexes undergo 1-electron irreversible reductions which result in the diffusion-limited substitutions of the chloride ligands for THF. This chloride metathesis is reversible in the presence of added NBu₄Cl, and equilibrium constants and rate constants for chloride loss have been estimated. These parameters correlate with the NO stretching frequencies of the parent complexes, with more electron-donating porphyrin ligands favouring chloride loss from the reduced complexes. The [Ru(por)(NO)(THF)] products of the reductions can be detected by IR, EPR and visible spectroscopies. These species undergo …

Synthesis, Kinetic And Catalytic Studies Of Manganese Complexes With Corrole And Porphyrin Ligands, Haleh Jeddi

Masters Theses & Specialist Projects

High-valent transition metal-oxo intermediates play a significant role in the catalytic cycle of the ubiquitous cytochrome P450 enzymes and in biomimetic catalytic systems. In this work, manganese(III) porphyrin and corrole systems (2) were synthesized and characterized by UV-vis absorbance and 1H-NMR, matching literaturereported spectroscopic data. Manganese(V)-oxo corroles (3) and a manganese(IV)-oxo porphyrin (4) were successfully generated by chemical oxidation using mchloroperoxybenzoic acid (m-CPBA), and their oxidation reactions with organic reductants were comparatively investigated. Results from single-turnover kinetic studies indicate that in the tris(pentafluorophenyl)corrole system (3a), the active oxidizing intermediate differs in different solvents. The active oxidizing intermediate in acetonitrile is …

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 reaction.

The isomerization from …

Exploring Conditions For The Enhancement Of Acene Semiconductors Through The Use Of The Diels-Alder Reaction, Brittni Qualizza Qualizza

Dissertations

This dissertation demonstrates the application of SAMs to the surface of acene crystals, specifically of tetracene and rubrene, using the Diels-Alder reaction. The second chapter details preliminary reaction results and two analytical methods which were employed to confirm adsorption of the dienophile on the surface of single crystals, tetracene and rubrene. These were mass spectrometry and X-ray photoelectron spectroscopy (XPS). Mass spectrometry experiments distinguish the chemical identity of adduct on the crystals and also it discerned chemi- and physisorbed molecules from one another. XPS was used to prove face selectivity of the reaction by the detection of dichloromaleic anhydride. From …

A Study Of The Kinetics Of A Reaction Between Vo(Hedta)-1 And Hydrogen Peroxide, Elaina B. Campbell

Undergraduate Honors Theses

Vanadium is commonly used as an agent to make tools rust-resistant. As a transition metal, it can be used as a catalyst due to its ability to change oxidation states. VO(HEDTA)^-1, a complex of the vanadyl ion, VO²⁺ and HEDTA (N-(2-Hydroxyethyl)ethylenediamine-N,N’,N’-triacetic acid) was readily formed. This complex containing vanadium in the +4 oxidation state was reacted with hydrogen peroxide to form a vanadate complex. This vanadate complex was formed as a first step in simulating the vanadate(V)-dependent haloperoxidases in marine algae, a yet uncharacterized reaction. Electron absorption spectroscopy (UV-Vis) was used to observe the oxidation of V(IV) …