Electronic Thesis and Dissertation Repository

Degree

Doctor of Philosophy

Program

Chemistry

Supervisor

Zhifeng Ding

Abstract

Electrogenerated chemiluminescence or electrochemiluminescence (ECL), produces light in the vicinity of a working electrode by the excited species of a luminophore formed via electron transfer between radical cations and anions, which are electrogenerated. In order for the ECL system to be efficient, the radicals must be stable in solution. This can be enhanced by adding co-reactants such as benzoyl peroxide (BPO) and tri-n-propylamine (TPrA) that produce strong oxidizing or reducing radicals upon redox reactions. ECL pairs electrochemical and spectroscopic methods and is a powerful analytical technique that is highly sensitive and selective.

A comprehensive, mechanistic study of ECL generation via annihilation and co-reactant paths has been completed for modified deoxycytidine (dC) nucleosides, thienyltriazole ligands, metal complexes containing iridium(III) and ruthenium(II), Au25 clusters, and boron-dipyrromethene (BDY) capped PbS nanoparticles (NPs). Spooling ECL spectroscopy was developed during this thesis work, and was used to future understand sophisticated mechanisms for ECL generation, tuning and controlling.

Specifically, the electrochemistry and spectroscopy of four modified dC nucleosides were studied to correlate their electronic structures with blue ECL. Four thienyltriazole ligands were synthesized and their electrochemical properties were analyzed and relative efficiencies determined. Eight iridium(III) complexes, four containing aryltriazole cyclometalled ligands, were found to show bright ECL while three iridium(III) complexes containing two dimethylamino substituents on the 2,2'-bipyridine ligand displayed self-enhancing ECL intensity up to 16 times with multiple excited states for light emission. A soft salt containing Ir(III) Ru(II) Ir(III) complexes demonstrated electronic communication between the [Ru]2+ and [Ir]- moieties thus reducing the energy required to produce ECL. Au25 clusters were discovered to emit in the near-infrared (NIR) region in both annihilation and co-reactant paths. Co-reactant BPO resulted in multiple strong excited states and the ECL mechanisms were elucidated using our newly developed spooling ECL spectroscopy. And lastly, BDY-capped PbS NPs were interrogated in the generation of both visible and NIR ECL via annihilation and co-reactant routes.

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