Inorganic Chemistry Commons^™

Mida Boronates Are Hydrolysed Fast And Slow By Two Different Mechanisms, Jorge A. Gonzalez, O. Maduka Ogba, Gregory F. Morehouse, Nicholas Rosson, Kendall N. Houk, Andrew G. Leach, Paul H.-Y. Cheong, Martin D. Burke, Guy C. Lloyd-Jones

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

MIDA boronates (N-methylimidodiacetic boronic acid esters) serve as an increasingly general platform for building-block-based small molecule construction, largely due to the dramatic and general rate differences with which they are hydrolysed under various basic conditions. Yet the mechanistic underpinnings of these rate differences have remained unclear, hindering efforts to address current limitations of this chemistry. Here we show that there are two distinct mechanisms for this hydrolysis: one is base-mediated and the other neutral. The former can proceed more than three orders of magnitude faster, and involves rate-limiting attack at a MIDA carbonyl carbon by hydroxide. The alternative ‘neutral’ hydrolysis …

Electrochemistry And Spectroscopy Of A Molybdenum Porphyrin Compound, Jay S. Bhanot, Kyle A. Grice

DePaul Discoveries

Carbon dioxide has been a problematic greenhouse gas since the beginning of the industrial age. In an effort to remediate its effects on the climate, multiple techniques have been utilized in the chemical and electrochemical reduction of CO₂. Homogeneous electrocatalysis for carbon dioxide reduction has been a topic of increasing interest. However, a full examination of the catalytic performance of early transition metals supported by macroligands has yet to be done. The research reported involves synthesis of a chelate of molybdenum within a tetraphenylporphyrin, and then synthesis, purification, and characterization of its ability to reduce carbon dioxide. The …

Synthesis And Studies Of Cyclopentadienyl Molybdenum Complexes, Cesar Saucedo, Kyle A. Grice

DePaul Discoveries

The synthesis and electrochemical responses of [CpMo(CO)₃]₂, CpMo(CO)₃I, CpMo(CO)₃(OTf), and [CpMo(bpy)(CO)₂] (Cp = cyclopentadienyl, bpy = 2,2’-bipyridine, OTf = trifluoromethansulfonate) in organic solvent are reported. Transition metal compounds such as Re(bpy)(CO)₃Cl have been shown to be effective carbon dioxide reduction catalysts. The molybdenum metal complexes studied herein were examined under argon and carbon dioxide gas for the potential reduction of carbon dioxide. Proton Nuclear Magnetic Resonance (NMR) spectroscopy, infrared (IR) spectroscopy and an electrochemical method know as cyclic voltammetry were used to gather data on the complexes. Electrochemical …

Layered Xerogel Films Incorporating Monolayer Protected Cluster Networks On Platinum Black Modified Electrodes For Enhanced Sensitivity In 1st Generation Uric Acid Biosensing, Mulugeta B. Wayu, Michael J. Pannell, Michael C. Leopold

Chemistry Faculty Publications

Amperometric uric acid (UA) biosensing schemes incorporating networks of alkanethiolate‐protected gold nanoparticles, monolayer protected clusters (MPCs), and platinum black (Pt‐B) electrode modification through the layer‐by‐layer construction of xerogels are investigated. MPC doping and Pt‐B augmentation are implemented within hydroxymethyltriethoxysilane xerogel bilayers at platinum electrodes. The first xerogel adlayer is doped with an MPC network and houses uricase for the enzymatic reaction required for first‐generation schemes. Polyluminol–aniline and polyurethane are used as selective/stabilizing interfacial layers. The sensing performance with and without Pt‐B and/or MPC doping is assessed by amperometry with standardized UA injections. The use of each individual material results in …

Synthetic Investigation On The Biomimetic Metal-Catalyzed Sulfoxidations And Photochemical Generation Of A Highly Reactive Ruthenium(V)-Oxo Porphyrin, Weilong Luo

Masters Theses & Specialist Projects

Catalytic oxidation plays a crucial role in current chemical and pharmaceutical industries which is also a leading technology for green chemical processes. In Nature, the ubiquitous cytochrome P450 enzymes can catalyze a wide variety of oxidation reactions with high efficiency and selectivity. Many transition metal catalysts are designed as the biomimetic model of cytochrome P450 enzymes. In this work, series of metalloporphyrins and metallocorroles have been successfully synthesized to investigate and develop catalytic selective oxidation of sulfides to sulfoxides.

Manganese(III) porphyrin complexes (2) and manganese(III) corrole complexes (6) with iodobenzene diacetate [PhI(OAc)2] as a mild oxygen source exhibited remarkable catalytic …

Synthesis And Applications Of Lanthanide Sulfides And Oxides, Christopher Marin

Department of Chemistry: Dissertations, Theses, and Student Research

This dissertation focuses on two of the key fields where lanthanides find ready application: as optically active materials with a focus on the lanthanide sulfides, and as catalytic materials with a focus on cerium oxide.

The lanthanide sulfides have attracted considerable interest for their potential as solar energy conversion materials, pigments, infrared window materials, and phosphor host media. However, applications of these materials remain limited due to their synthetic difficulty along with their not well understood properties compounded by both their difficulty in manufacturing as well as in simulating largely due to the need to take into account f-shell electrons. …

Iron Uptake And Accumulation Is A Target Of Nickel Toxicity During The Lag Phase In Escherichia Coli, Geoffrey Tuttle Ford

Theses and Dissertations

Various transition metals are essential to all forms of life, and are only required in trace amounts. But this dependence comes as a double-edged sword. All organisms must maintain a careful intracellular quota that does not traverse outside an acceptable range. One transition metal in particular is nickel. The importance of this transition metal has been debated widely and its function varies greatly between organisms, including bacteria. However, the adverse effects caused by over exposure to this metal have been the center of much experimentation in recent years. Still, the mechanisms of nickel toxicity and the subsequent effects on cellular …

Dendrimer Modified Silica Nanoparticles As Fluorescent Chemosensors For The Detection Of Copper And Cyanide Ions, Alicia Luhrs

Master's Theses

A series of silica nanoparticle-based fluorescent chemosensors were synthesized for the sensitive and selective detection of Cu²⁺ ions in aqueous solution and subsequent CN^- ion detection. Silica nanoparticles (SNP) were modified with branching polyamidoamine (PAMAM) dendrimers, which function as selective turn-off Cu²⁺ ion chelators and platforms for the attachment of rhodamine isothiocyanate (RITC) or fluorescein isothiocyanate (FITC) fluorescent dyes. In the presence of Cu²⁺ ions, the emission of the fluorescent dye is quenched by Forster resonance energy transfer (FRET) and is dependent upon dendrimer generation, pH, fluorescent dye, and surface charge. The quenching effectiveness was analyzed …

Epoxy Siloxane Self-Cleaning Coating Using F64pczn/Tio2 Photocatalyst Composite, James F. Sullivan

Seton Hall University Dissertations and Theses (ETDs)

A new photocatalytic composite powder incorporated into a siloxane epoxy polymer has been shown to yield a highly efficient self-cleaning coating. The composite, which makes greater use of light in the visible/near-infrared (NIR) region, was prepared by coating a nano-particle photocatalytic TiO₂ with 3% w/w of F₆₄PcZn photosensitizer resulting in a dark green powder. The F₆₄PcZn/P25 TiO₂ composite exhibited a greater photo-induced degradation of methyl red, a model surface contaminant, compared to traditional nano-particle photocatalytic TiO₂. Singlet oxygen (¹Δ_g ¹O₂), generated form the F₆₄PcZn, …

Synthesis And Topochemical Manipulation Of New Layered Perovskites, Lea Gustin

LSU New Orleans Theses and Dissertations

Metastable layered perovskites containing interlayer transition metals can readily be obtained by simple ion exchange reactions on receptive hosts, such as those of the Dion-Jacobson and Ruddlesden-Popper structure types. In this work, we focused on adding to the library of layered perovskites by not only creating new compounds, but by also showing their ability to be further manipulated, and by studying the stability of the series through thermal behavior studies.

The reactions with transition metal halides are particularly interesting since they often lead to novel architectures and magnetic behavior. On subsequent heat treatment, these exchange products typically decompose to thermodynamically …

The Effects Of Hydrogen Bonding On The Reactivity Of Synthetic Ada Repair Protein Analogues, Josiah G. Elsberg

Boise State University Theses and Dissertations

The study of bioinorganic chemistry is an important field, as it can provide insight as to why Nature has chosen certain active sites and structures within different kinds of metalloproteins. Ada repair protein, a zinc-containing metalloprotein, is one such topic of interest. Although it is known that Ada RP is able to repair methyl-phosphotriester backbone damage by self-methylation of one of its cysteine groups, the mechanism is not fully understood. Two pathways have been proposed: a dissociative pathway where the Zn-S bond becomes a zinc/sulfur ion pair, and an associative pathway where a four ringed σ-metathesis occurs. Previous research has …

A Chemical Sensor For Cyanide, Rachel E. Lambert

Honors Theses

The cyanide ion and its gaseous form, hydrogen cyanide, are extremely toxic. Cyanide impairs cellular respiration by inhibiting cytochrome c oxidase, an enzyme in the electron transport chain, leading to cell death.

In a previous study, we synthesized an optical sensor that detects cyanide selectively. The aim of this project is to increase the sensitivity of this sensor. This can be achieved by utilizing the unique spectroscopic properties of lanthanide ions.

The lanthanide metal (europium or terbium) was added to a coumarin-glycine chemodosimeter in a DMSO solvent system. The sensor was titrated with several monodentate analytes including, nitrate, octylamine, 1-pentanethiol, …

Biodegradable Copolymers Made With Magnesium Complexes, Reile M. Slattery, Joseph M. Fritsch

Seaver College Research And Scholarly Achievement Symposium

In this study, a bis-ligated magnesium complex was used to initiate the ring opening copolymerization of L-lactide (L-LA) and ϵ-caprolatone (ϵCL) and the isolated polymeric materials were characterized with NMR spectroscopy. First, the simultaneous feeding of both monomers resulted in the synthesis of homopolymer poly-lactic acid (PLA). Polymerization experiments with sequential addition of L-LA and ϵCL yielded surprising results. The ring opening polymerization of ϵCL yielded poly-caprolactone (PCL) which with the addition of L-LA yielded a di-block copolymer of PCL and PLA. The presence of the two homopolymer blocks in the copolymer was identified with ¹³C NMR where …

Synthesis And Characterization Of Organic-Inorganic Hybrid Materials For Thermoelectric Devices, Paige M. Huzyak

Masters Theses & Specialist Projects

The development of organic-inorganic hybrid materials is of great interest in thermoelectrics for its potential to combine the desirable characteristics of both classes of materials. Thermoelectric materials must combine low thermal conductivity with high electrical conductivity, but in most materials, thermal and electrical conductivity are closely related and positively correlated. By combining the low thermal conductivity, flexibility, facile processing, and low cost of organic components with the high electrical conductivity and stability of inorganic components, materials with beneficial thermoelectric properties may be realized.

Here, we describe the synthesis and characterization of anthracene-containing organic-inorganic hybrid materials for thermoelectric purposes. Specifically, POSS-ANT …

Synthesis And Characterization Of Biologically Relevant Fe(Ii) Complexes Containing Redox-Active (Hydro)Quinone Ligands, Amanda Elizabeth Baum

Dissertations (1934 -)

Redox-active p-(hydro)quinones work in concert with transition-metal centers to facilitate electron transfers in numerous biological contexts. While p-(hydro)quinones are known to interact with both heme and nonheme iron cofactors, the nonheme systems are particularly relevant to photosynthetic and bioremediation processes. In photosynthesis, two p-quinones facilitate an electron transfer away from the photoexcited P680 cofactor via a non-heme Fe(II) center. Based on EPR results, this interaction results in formation of transient Fe(II)/p-semiquinone (pSQ) species. In addition, a superoxo-iron(II)-pSQ species has been proposed as an intermediate of the oxidative cleavage mechanism of hydroquinone dioxygenases (HQDOs), which play a central role in the …

Investigation Of The Interactions Between Pt(Ii) And Pd(Ii) Derivatives Of 5,10,15,20-Tetrakis (N-Methyl-4-Pyridyl) Porphyrin And G-Quadruplex Dna, Navin C. Sabharwal , '14, O. Mendoza, John Michael Nicoludis , '12, Thomas Ruan , '16, J.-L. Mergny, Liliya A. Yatsunyk

Chemistry & Biochemistry Faculty Works

G-quadruplexes are non-canonical DNA structures formed by guanine-rich DNA sequences that are implicated in cancer and aging. Understanding how small molecule ligands interact with quadruplexes is essential both to the development of novel anticancer therapeutics and to the design of new quadruplex-selective probes needed for elucidation of quadruplex biological functions. In this work, UV–visible, fluorescence, and circular dichroism spectroscopies, fluorescence resonance energy transfer (FRET) melting assays, and resonance light scattering were used to investigate how the Pt(II) and Pd(II) derivatives of the well-studied 5,10,15,20-tetrakis(N-methyl-4-pyridyl)porphyrin (TMPyP4) interact with quadruplexes formed by the human telomeric DNA, Tel22, and by the G-rich sequences …

Development Of New Ligand Scaffolds For The Preparation Of Heterobimetallic Complexes, Alexander Richard Treleven

Master's Theses (2009 -)

There is currently much interest in the development of methods to harness sustainable, CO2 neutral, non-fossil fuel based energy sources due to diminishing worldwide supply of fossil fuels and concerns over historically high levels of CO2 in the atmosphere, which may have a devastating impact on the world’s climate. One such avenue is through the conversion of atmospheric CO2 into useful, high-energy density, organic fuel sources. Photosynthesis is the biological process by which plants convert sunlight, water, and CO2 into the reduced organic materials that we extract from the earth and burn (completing the cycle back to CO2) to release …

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 …

Synthesis, Structural Characterization And Catalytic Activity Of Indenyl Tris-N-Pyrrolyl Phosphine Complexes Of Ruthenium, Matthew J. Stark, Michael J. Shaw, Nigam P. Rath, Eike B. Bauer

SIUE Faculty Research, Scholarship, and Creative Activity

The synthesis, characterization and catalytic activity of new ruthenium complexes of the tris-N-pyrrolyl phosphine ligand P(pyr)3 is described. The new ruthenium complexes [RuCl(ind)(PPh3){P(pyr)3}] and [RuCl(ind){P(pyr)3}2] (ind = indenyl ligand η5-C9H7−) were synthesized in 73% and 63% isolated yield, respectively, by thermal ligand exchange of [RuCl(ind)(PPh3)2] with P(pyr)3. The electronic and steric properties of the new complexes were studied through analysis of the X-Ray structures and through cyclic voltammetry. The new complexes [RuCl(ind)(PPh3){P(pyr)3}] and [RuCl(ind){P(pyr)3}2] and the known complex [RuCl(ind)(PPh3)2}] differed only slightly in their steric properties, as seen from the comparable bond lengths and angles around the ruthenium …

Nitrous Oxide In The Atmosphere: First Measurements Of A Lower Thermospheric Source, Patrick E. Sheese, Kaley A. Walker, Chris D. Boone, Peter F. Bernath, Bernd Funke

Chemistry & Biochemistry Faculty Publications

Nitrous oxide (N₂O) is an important anthropogenic greenhouse gas, as well as one of the most significant anthropogenic ozone-depleting substances in the stratosphere. The satellite-based instrument Atmospheric Chemistry Experiment-Fourier Transform Spectrometer has been observing the Earth's limb since 2004 and derives profiles of N₂O volume mixing ratios in the upper troposphere to the lower thermosphere. The resulting climatology shows that N₂O is continuously produced in the lower thermosphere via energetic particle precipitation and enhanced N₂O is present at all latitudes, during all seasons. The results are consistent with an N₂O …