The benzotriazinyl radical is a highly stable organic radical that is known to
possess fast and reversible oxidation and reduction electrochemical processes. Such
properties make it an ideal candidate for use as an anodic or cathodic charge storage
material in a new class of high-power secondary batteries known as organic radical
batteries. Towards this application, several new benzotriazinyl radical derivatives were
synthesized and fully characterized using electronic absorption, EPR, and IR
spectroscopy as well as elemental analysis and mass spectrometry. The electrochemical
properties of the radicals were studied using cyclic voltammetry.
The introduction of electron donating groups onto the structure of the radical was
found to result in cathodic shifts in both of the electrochemical processes, without loss of
reversibility. It was also found that in some cases functional groups led to the
destabilization of the radical to a known chemical oxidation pathway that resulted in the
formation of closed-shell iminoquinone compounds. These materials demonstrated good
multi-electron accepting properties, undergoing two reversible one-electron reduction
processes.
Synthetic methodologies were developed for the preparation of two new classes
of benzotriazinyl biradicals. One class used an expansion of a known benzotriazinyl
radical synthesis to prepare a m-phenylene-bridged biradical, while the other class used
microwave-assisted synthesis to prepare biradicals bridged by electron accepting
aromatic diimides. Spectroscopic studies of both classes of biradical showed electronic
isolation of the two radicals within each molecule, consistent with computational
predictions. This resulted in minimal perturbation of the electrochemistry of these
compounds from that of typical benzotriazinyl radicals.
The solid state properties of a selection of benzotriazinyl radical derivatives were
studied. Structural information obtained through single crystal X-ray diffraction studies
showed significant intermolecular π-π and hydrogen bonding interactions. These solid
state interactions were found to provide pathways for magnetic exchange, as determined
using SQUID magnetometry. Additionally, preliminary conductivity studies indicated
semiconducting behaviour in the compounds that were studied, warranting further
studies.
Anionic polymerization of a vinyl-functionalized benzotriazinyl radical was
investigated as a method for the synthesis of a pendant benzotriazinyl polyradical with a
saturated backbone. The electrochemistry of the putative polymer was identical to the
monomer, maintaining reversibility of both the oxidation and reduction processes and
verifying that the polymer could be used as an anodic or cathodic charge storage material.
SQUID magnetometry was used to estimate a polymer spin content to be ~ 44 %. / Graduate / 0485
| Identifer | oai:union.ndltd.org:uvic.ca/oai:dspace.library.uvic.ca:1828/4965 |
| Date | 27 September 2013 |
| Creators | Oakley, Nicholas Alfred |
| Contributors | Frank, Natia L. |
| Source Sets | University of Victoria |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Rights | Available to the World Wide Web |
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