Physical Sciences and Mathematics Commons^™

Assessing The Magnitude And Impact Of Seawater/Pore Water Exchange In Salt Marsh Systems, Carrie Lee Milliken

Theses and Dissertations

Submarine groundwater discharge is a hydrological process that is important to study and understand as it impacts biogeochemical processes and hydrological cycles. Particularly in coastal salt marsh systems, it is an important process to analyze as these systems serve as crucial interfaces between terrestrial and marine waters and particulates. There is evidence that these systems, typically thought to have little exchange across the interface due to impermeable sediments, could actually allow for significant flow of water and particulates at shallow depths. In order to measure and quantify this flow, a method using 224Ra as a tracer has been tested. The …

A Silylation-Based Kinetic Resolution Of Hydroxy Lactones And Lactams With Subsequent Mechanistic Investigations, Robert W. Clark

Theses and Dissertations

The work contained herein focuses on the methodology and design of new reactions for the production of stereoenriched compounds. The primary focus of research discussed is kinetic resolution, a classic and powerful methodology for the separation of a single enantiomer from a racemic mixture. In 2011, a silylation-based resolution catalyzed by a chiral isothiourea produced synthetically useful selectivity factors for mono-functional secondary alcohols. In chapter 2, this methodology was subsequently expanded to include α-hydroxy lactones with selectivity factors up to 100. This study resulted in the most selective reaction reported to date for the aforementioned silylation-based resolution. In addition to …

Iridium – Bismuth Carbonyl Cluster Complexes: New Directions For Chemistry And Selective Oxidation Catalysis, Gaya R. Elpitiya

Theses and Dissertations

CHAPTER 2 The reaction of Ir3(CO)9(μ3-Bi), 2.1, with BiPh3 has yielded a iridium−bismuth cluster complex Ir5(CO)10(μ3-Bi)2(μ4-Bi), 2.2. The first examples of bimetallic iridium−bismuth nanoparticles have been subsequently synthesized from 2.1 and 2.2, and these have been securely anchored onto the inner walls of mesoporous silica. These isolated, bimetallic iridium−bismuth nanoparticles display a superior catalytic performance, when compared to their analogous monometallic counterparts and equivalent physical mixtures, in the C−H activation of 3-picoline to yield niacin.

CHAPTER 3 The reaction of Ir3(CO)9(μ3-Bi) with Ph3GeH yielded the compound Ir3(CO)6(GePh3)3(μ3-Bi)(μ-H)3 3.1 When 3.1 was heated to reflux in hexane, it was transformed into …

The Development Of Efficient Geminal-Based Methods For Quantum Chemical Calculations, Brett Allen Cagg

Theses and Dissertations

Incorporation of electron correlation to improve the accuracy of computations remains a driving force in quantum chemical method development. Traditionally, electron correlation effects are divided into static and dynamic correlation parts, and the inclusion of both results in methods that are impractical for large chemical systems. The goal of this doctoral research is to develop a method that efficiently accounts for both components of electron correlation in a separate but balanced manner. The approach focuses on combining a geminal method, called the antisymmetrized product of singlet-type, strongly orthogonal geminals (SSG), with dynamic correlation by either density functionals or a recently …

Chemical Processes Governing The Equilibrium Between Organic And Inorganic Carbon: Probing The Mechanisms Of Iron Catalyzed Reactive Oxygen Species Production, Joy Kelechi Ihekweazu

Theses and Dissertations

This study examines the oxidation of organic carbon that occurs concurrently with the autoxidation of Fe(II) to determine the role that geochemical constituents have on both the autoxidation of Fe(II) and subsequent ROS production. The reaction between reduced carbon and oxygen is thermodynamically favorable, but kinetically proceeds slowly. Fe(II) facilitates the equilibration of reduced carbon and oxygen. This equilibration occurs naturally in saline estuaries, where oxygen rich seawater mixes with anoxic groundwater. We characterized a saline estuary at the Baruch Institute and used those characterizations to recreate natural water conditions in the lab. Using simulated natural water we then examined …

Modification Of Nanoparticles For Designed Interfaces, Tony Lee Neely, Jr.

Theses and Dissertations

The work contained herein, is focused on the design, synthesis, and characterization of polymer nanocomposite interfaces and the property enhancement afforded from said interface design. Through the use of reversible addition fragmentation chain transfer (RAFT) polymerization for the grafting of polymer chains to silica nanoparticles, the surface of silica nanoparticles can be manipulated to tune the properties of the nanocomposite as a whole.

In the first part of this work, heterogeneity is introduced onto the surface of silica nanoparticles via a sequential RAFT polymerization to afford a bimodal brush system. A densely grafted, short brush population is polymerized from the …

The Role Of Intermembrane Space Redox Factors In Glutathione Metabolism And Intracellular Redox Equilibrium, Hatice Kubra Ozer

Theses and Dissertations

The mitochondrial intermembrane space (IMS) is a unique subcellular compartment that houses key thiol-dependent redox pathways such as protein transport, mitochondrial respiration, and detoxification of ROS (reactive oxygen species). These pathways are all dependent on cysteine-rich proteins, thus maintaining thiol-disulfide balance in this organelle is crucial for cellular functions. An IMS protein import pathway called the Mia40-Erv1 disulfide relay system uses disulfide bond formation for the import and retention of substrate proteins in the IMS. Erv1 is also suggested to be involved in maturation of cytosolic Fe-S cluster proteins and regulation of iron homeostasis in S. cerevisiae. However, these studies …