Exciplexes in fluorescence quenching of aromatic hydrocarbons by tertiary aliphatic amines


Autoria(s): Van, Shui Pong
Data(s)

1970

Resumo

<p>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.</p> <p>Kinetic studies indicate that this anomalous emission is due to an <u>exciplex</u> 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. </p> <p>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.</p> <p>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. </p>

Formato

application/pdf

Identificador

http://thesis.library.caltech.edu/9137/1/Van_sp_1970.pdf

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 <http://resolver.caltech.edu/CaltechTHESIS:09032015-150910276>

Relação

http://resolver.caltech.edu/CaltechTHESIS:09032015-150910276

http://thesis.library.caltech.edu/9137/

Tipo

Thesis

NonPeerReviewed