Photophysical Effects of Stereoisomers in Thiacarbocyanine Dyes.
Abstract
Fluorescence, excitation and transient absorption were used to characterize two stereoisomers in 3,3'-dimethylthiacarbocyanine and 3,3'-dimethyl-9-ethylthiacarbocyanine. The trans isomer fluoresces at room temperature with increasing intensity at lower temperatures. The cis isomer fluoresces in alcoholic glasses at - 196C. Substitution of an ethyl group for a proton in the 9 position greatly increases the cis concentration but has little affect on the absorption spectra of the stereoisomers. The rate of ground electronic state cis-trans isomerization was measured as a function of temperature, and a new fluorescence peak was observed at high laser powers that is attributed to excimer formation. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 28, 1974
- Accession Number
- AD0781284
Entities
People
- Edward M. Eyring
- J. Thomas Knudtson
Organizations
- University of Utah