Photophysics of 5,10,14c,15-tetra-azabenzo[a]naphth[1,2,3-de]anthracene (tricycloquinazoline, TCQ) and some of its derivatives
- 1 January 1982
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics
- Vol. 78 (5) , 737-750
- https://doi.org/10.1039/f29827800737
Abstract
The photophysical properties of [the plant constituents] tricycloquinazoline (TCQ) and its 2-methyl (2-Me-TCQ) and 2-bromo (2-Br-TCQ) derivatives in various solvents at different temperatures were investigated and are similar except for those of the triplet states. Absorption spectra, fluorescence and phosphorescence spectra, polarization properties, fluorescence and phosphorescence yields and their corresponding lifetimes were measured and characterized. The S1 and S2 states are .pi., .pi.* in nature. The S1 .tautm. S0 transition is symmetry forbidden whereas the S0 .tautm. S2 transition is symmetry allowed. The presence of an S0-0 peak in absorption and fluorescence arises from a solvent-dependent perturbation. A hot band arising from an S0v0 .rarw. S2v0 transition was detected in fluorescence emission. The total rate of radiationless deactivation from S1 involves temperature-dependent processes. The T1-state is .pi., .pi.* in nature and phosphorescence from T1 is symmetry allowed.This publication has 0 references indexed in Scilit: