Date of Award

5-2011

Level of Access

Campus-Only Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Advisor

Mitchell Bruce

Second Committee Member

Alice Bruce

Third Committee Member

Carl Tripp

Abstract

Thiolate-disulfide exchange is a fundamental biochemical reaction. It was reported that thiolate-disulfide reactions occur at slower rates in high dielectric environments such as water due to thiolate anion stabilization, leading to increased energy of the transition state. However, transition metals may alter the fundamental thiolate-disulfide exchange reaction as transition metals are expressed in biological systems.

In Chapter 2, we describe the dependency of the exchange reaction particularly on Zn(II). Mechanistic details were obtained using DFT for the Zn(II)-assisted thiolate-disulfide exchange reaction in the gas-phase as well as in water and methanol. The DFT results support a mechanistic pathway for Zn(II)-assisted thiolate-disulfide exchange that differs from non-metal assisted thiolate disulfide exchange. In Chapter 3, we describe the influence of Au(I) on a thiolate-disulfide exchange reaction. These calculations suggest mechanistic details for both Zn(II) and Au(I)-assisted thiolate-disulfide that are fundamentally different from non-metal assisted thiolate disulfide exchange.

An infrared based detection method for detecting Hg(II) in aqueous solutions is explained in Chapter 4. Due to the advanced and complex nature of the current detection methods used in Hg(II) analysis, a simple, yet powerful and reliable method is a timely necessity. A novel method that utilizes solid phase extraction (SPE) coupled with FTIR spectroscopy to detect Hg(II) is described. The SPE material is derivatized with a thiosemicarbazide, which undergoes a reaction in the presence of aqueous Hg(II) and is monitored by IR spectroscopy. Mesoporous silica chips with total surface area of about 0.200 m2 per chip show theoretical detection limits of 5 ppb using Hg(OOCCH3)2. This system shows a high selectivity towards aqueous Hg(II) over other thiophilic heavy metal ions such as Pb(II), Cd(II), Fe(III) and Zn(II).

Fabrication of conductive polymer (PANi)/metal nano composite materials for cathodes in rechargeable Li-ion batteries is explained in Chapters 5-7. The general approach uses a linker to protect the metal surface and attach PANi to the substrate. In Chapter 5, 4-aminophthalic acid (4-APA) is used as a linker on nickel. In Chapter 6, silane linkers on nickel are described. In Chapter 7, we describe a graphite linker to attach PANi to aluminum.

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