Laser Dye Spectroscopy of Some Pyrromethene-BF2 Complexes
Abstract
To improve the laser-action properties of the pyrromethene-BF2 complexes (P-BF2 complexes), we studied substitution effects at different positions of the dye molecule on the electronic spectra of several derivatives. Specifically, we used laser photoselection spectroscopy to measure the triplet-triplet (T-T) absorption and polarization spectra as well as the fluorescence and visible absorption (S-S) spectra of the following compounds: 1,2,3,5,6,7,8- heptamethyl; 8-acetoxymethyl-1,3,5,7-tetramethyl-2,6-diethyl; 1,3,5,7- tetramethyl-8-p-methoxyphenyl; 3,5-dimethyl-1,7-diphenyl; and 1,3,5,7,8- pentamethyl-2,6-diphenyl P-BF2 complexes. The 1,3,5,7-tetramethyl P-BF2 complex itself exhibits weak T-T absorption, which stretches from the green to the near IR spectral region. This band consists of two overlapping (differently polarized) T-T transitions. Short molecular axis (i.e., 8- and 1,7-positions) substitution causes the positively polarized T-T transition to gain considerably in intensity. Significantly, the negatively, long axis polarized T-T transition was unaffected by the long-axis 2,6-position disubstitution. Therefore, only 2, 6-position disubstitution is expected to produce superior new P-BF2 complex laser dyes. Substitution effects from strongly interacting groups with chromophores on singlet-singlet (S-S) as well as T-T absorption spectra, together with cw laser photoselection spectroscopy, are briefly reviewed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 02, 1992
- Accession Number
- ADA251184
Entities
People
- G. Sathyamoorthi
- J. H. Boyer
- K. Thangaraj
- M. L. Soong
- M. P. Shah
- T. G. Pavlopoulos
Organizations
- University of New Orleans