A Kinetic and Thermodynamic Study of Exciplex Fluorescence Quenching by Ion Pairs

Tetraalkylammonium salts are shown to quench the fluorescence of the pyrene-N,N-dimethylaniline exciplex in solvents of low dielectric constant. Linear Stern-Volmer plots are obtained for quenching of both lifetime and intensity in dioxane. However, mechanistic complications are implied by intercepts exceeding unity and by the unequal slopes of these plots. Qualitatively similar behavior is observed when the solvents and electrolytes are varied. Historic conductivity data indicate that the quenching species Q in dioxane are aggregates of electrolyte ions, probably ion pairs or quadrapoles. A proposed kinetic model is both qualitatively consistent with the experimental observations and quantitatively self-consistent. An emitting complex formed at a diffusion-controlled rate by an encounter between Q and an exciplex is postulated. The emitting complex is apparently quenched by subsequent encounters with additional Q at rates considerably below the encounter-limited value.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Hartley, Rolfe John

• Chemistry, Analytical

Identifier

(UMI)AAI8623313

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/70325