화학공학소재연구정보센터
Journal of Physical Chemistry, Vol.98, No.6, 1532-1543, 1994
Influence of the Substitution on Intramolecular Exciplex Formation Between Pyrene and Indole Moieties
Using stationary fluorescence spectroscopy and single-photon timing, intramolecular exciplex formation between pyrene and indole, connected by a propyl chain, was investigated in isooctane, diethyl ether, and acetonitrile. Three different compounds, where the propyl chain was connected to the 1-, 2-, and 3-position of the indole chromophore, respectively were compared to evaluate the influence of the position of the linking chain on the energetic and kinetic aspects of the intramolecular exciplex formation. While 1-(1-pyrenyl)-3-(1-indolyl)propane follows over a large range of solvents, a kinetic behavior analogous to that proposed for intermolecular exciplexes such a behavior is for 1-(1-pyrenyl)-3-(2-indolyl)propane only observed in isooctane. For 1-(1-pyrenyl)-3-(2-indolyl)propane in more polar solvents and 1-(1-pyrenyl)-3-(3-indolyl)propane in all solvents studied at least three different kinetic species can be distinguished in the excited state. Compartmental analysis in the presence of a quencher allowed one to determine without any a priori assumption the different decay parameters of 1Py2In in isooctane at room temperature. The more complicated excited state kinetics of 1Py3In did not allow a more detailed analysis.