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Exciplexes in fluorescence quenching of aromatic hydrocarbons by tertiary aliphatic amines

Citation

Van, Shui Pong (1970) Exciplexes in fluorescence quenching of aromatic hydrocarbons by tertiary aliphatic amines. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechTHESIS:09032015-150910276

Abstract

Strong quenching of the fluorescence of aromatic hydrocarbons by tertiary aliphatic amines has been observed in solution at room temperature. Accompanying the fluorescence quenching of aromatic hydrocarbons, an anomalous emission is observed. This new emission is very broad, structureless and red-shifted from the original hydrocarbon fluorescence.

Kinetic studies indicate that this anomalous emission is due to an exciplex formed by an aromatic hydrocarbon molecule in its lowest excited singlet state with an amine molecule. The fluorescence quenching of the aromatic hydrocarbons is due to the depopulation of excited hydrocarbon molecules by the formation of exciplexes, with subsequent de-excitation of exciplexes by either radiative or non-radiative processes.

Analysis of rate constants shows the electron-transfer nature of the exciplex. Through the study of the effects on the frequencies of exciplex emissions of substituents on the hydrocarbons, it is concluded that partial electron transfer from the amine molecule to the aromatic hydrocarbon molecule in its lowest excited singlet state occurs in the formation of exciplex. Solvent effects on the exciplex emission frequencies further demonstrate the polar nature of the exciplex.

A model based on this electron-transfer nature of exciplex is proposed and proves satisfactory in interpreting the exciplex emission phenomenon in the fluorescence quenching of aromatic hydrocarbons by tertiary aliphatic amines.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Chemistry
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Restricted to Caltech community only
Research Advisor(s):
  • Hammond, George Simms
Thesis Committee:
  • Unknown, Unknown
Defense Date:8 December 1969
Funders:
Funding AgencyGrant Number
CaltechUNSPECIFIED
Record Number:CaltechTHESIS:09032015-150910276
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:09032015-150910276
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9137
Collection:CaltechTHESIS
Deposited By: Leslie Granillo
Deposited On:04 Sep 2015 16:56
Last Modified:04 Sep 2015 16:56

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