Date of Graduation

Summer 2016

Degree

Master of Science in Chemistry

Department

Chemistry

Committee Chair

Mark Richter

Keywords

enhanced electrogenerated chemiluminescence (ECL), coreactants, melatonin, 1, 5-I-Aedans, Ru(bpy)32+

Subject Categories

Chemistry

Abstract

The photoluminescent (PL), electrochemical, and electrogenerated chemiluminescent (ECL) properties of 1,5-I-Aedans (N-(iodoacetylaminotheyl)-1-naphthylamine-5-sulfonic acid) in aqueous buffered (KH2PO4) and 50:50 (v/v) acetonitrile:KH2PO4 solutions were obtained. Tri-n-propylamine (TPrA) was used as the oxidative-reductive coreactant. The PL efficiencies (em) were 1.83 in KH2PO4 and 4.81 in mixed solvent compared to Ru(bpy)32+ standard solutions (em = 1.0). 1,5-I-Aedans displayed quasi-reversible oxidative electrochemistry in aqueous solutions and irreversible to quasi-reversible oxidation in mixed solvent. ECL efficiencies (ecl) were obtained by comparison to a Ru(bpy)32+/TPrA (bpy = 2,2'-bipyridine) standard (ecl = 1) and were higher in KH2PO4 (ecl = 6.8 x 10-4) than in the mixed solvent system (ecl = 0.072 x 10-4). A second project studied the ECL of the Ru(bpy)32+/TPrA system when melatonin (N-acetyl-5-methoxytryptamine; MLT) is present in aqueous buffered solution. MLT displays weak ECL when TPrA is used as the oxidative-reductive coreactant, but when micromolar concentrations of MLT were added to the system, up to 2.5-fold enhancement was seen. PL efficiencies did not change in the presence of MLT unless the solution underwent electrochemical bulk oxidation. Spectroscopic, electrochemical and spectro-electrochemical studies indicate that the mechanism involves oxygen scavenging by MLT oxidation products. This scavenging prevents quenching of the *Ru(bpy)32+ excited states.

Copyright

© Sarah Michelle Roughton

Open Access

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