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Electrogenerated chemiluminescence (ECL) studies were performed on several interesting compounds. A series of silole-based (silacyclopentadiene) chromophores was examined to understand the effects of their structure on the electrochemistry and spectroscopy of these compounds. A case was observed in which high steric hindrance improved ECL by inhibiting internal conversion and protecting radicals from secondary reactions. Another case was observed in which steric effects induced a rotation in the silole substituents, increasing secondary reactions and lowering quantum efficiency ([Phi subscript PL]). Spiro-FPA, which consists of two DPA centers, exhibits excimer formation despite high steric hindrance, due to its ability to form di-ions, which have a greater electrostatic attraction to one another than mono-ions. The compound (dppy)BTPA is a highly solvatochromic, boron-containing chromophore that was examined in a variety of solvents. Of note is the emission in pure acetonitrile, which is prominent in the ECL spectrum, but barely visible in the photoluminescence. Finally, B⁸ amide, a compound based on the laser dye, BODIPY, was examined. It exhibited unusual ECL characteristics. These include a strong, long-wavelength emission and transients that are clearly visible for 20 min or more, but display dramatically varying light intensities with each pulse. Evidence for the contribution of a film formed with the oxidation product is presented. Additionally, ECL simulations are performed using a general physics software package to better understand some of the observed phenomena.

Chapter 1 in this thesis provides a short introduction to the biochemistry and chemistry of iron-sulphur systems, particularly in relation to biological nitrogen fixation and the inhibition of nitrogenases and hydrogenases by carbon monoxide. Chapter 2 describes some results bearing on the interaction of the inhibitor CO with simple iron-sulphur and iron-sulphur-vanadium systems under reducing conditions. It is shown that in the presence of CO an Fe454-centre can be reduced to carbonylated {Fe252} and {Fe35}-fragments. The crystal structure of [Fe35(CO)g ][PPh4]2 is described. Chapter 3 describes infra-red/electrolysis studies of the [Fe4S4 (5Ph)4 ]2-/CO system and of related Fe-S species. Evidence is presented for the occurrence of [Fe454(CO)12]2- as an intermediate in the pathway of reduction of [Fe454 (5Ph)4 ]2- to [Fe252 (CO)612- under an atmosphere of co. Chapter 4 describes the fortuitous isolation of [V(52)2(terpyridine)] from a reaction of 2,2',2"-terpyridine with [VFe3S4Cl3 (dmf)]- and its rational synthesis from 2,2' ,2"-terpyridine and [V54 ]3-. Some physical and chemical and electrochemical properties of this compound are described together with a description of its X-ray crystallographic structure.

Conjugated polymers are widely used and rapidly developed in practical polymer-based light-emitting electronic devices. Understanding the electrochemical reaction of conjugated polymer has become essential in the design and operation of devices such as electrochemical light-emitting diodes. In particular, we have studied the dynamics and kinetics of oxidation/reduction behavior of conjugated polymer single-molecules and nanoparticles in order to obtain the molecular level properties of deeply trapped holes in organic semiconductor devices. Theoretical calculations suggest the penetration of ions and solvent molecules effectively stabilizes the injected charges, which allows homogeneous charge distribution and further hole injection. The formation and decay of deep traps have been explored by changing the charging rate and duration. We found that the laser excitation significantly promotes the untrapping of deep holes. Electrogenerated chemiluminescence of single nanoparticles has been investigated to unravel the effects due to particle heterogeneity, which are masked in bulk electrochemical studies of nanoparticles. Bigger particles showed more intense light and longer duration time than smaller ones. Co-reactant, tripropylamine can facilitate the formation of electrogenerated chemiluminescence as well as alleviate the polymer oxidation and following irreversible electrochemical reaction. Electrochemically generated light waves from the conjugated polymer thin films have been visualized to obtain microscopic level understanding on the complex reaction mechanism. Electrochemical reaction occurs at local defects and propagates isotropically over macroscopic distances with a sharp wave front. The initially injected holes (oxidized polymers) drag counter-ions into the film, thereby induce a phase-transition-like swelling that enhances transport of ions and solvent and move forward the double layer and corresponding propagation of the wave. / text

Research was compiled in regards to the effect of various changes in the development and fabrication of the ultracapcitor. The binder was changed from Teflon to a mix of Teflon and Nafion. Results demonstrated that an increase in capacitance was seen in the ultracapcitor and is may be attributed to the structure of Nafion. Furthermore water soluble graphene, graphene oxide, and ionic liquid graphene was tested in order to determine the effects of those alterations on the overall capacitance. / text

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published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

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