Hello. I am studying photophysical characteristics of a compound, and have observed that it is nearly non-fluorescent in low polar solvent like DCM, however, if the solvent is switched towards high polarity, like DMF and DMSO, the fluorescence turns on with increasing quantum yield of around 0.4% in DMF to 1.5% in DMSO. Moreover, the fluorescence lifetime also increases as polarity of solvent increases from DMF to DMSO. What could be the possible reason behind this? Any expert advice/suggestion is grateful.
- Bidyut
There is a whole chapter on effects of solvents on florescence emission spectra in Joseph Lakowicz's textbook "Principles of Fluorescence Spectroscopy" (Chapter 7 in the 1st edition). He divides solvent effects into general and specific types. The following is an excerpt from p. 189.
"By general solvent effects we mean those which result from the refractive index (n) and dielectric constant (epsilon)....Specific solvent effects refer to specific chemical interactions between the fluorophore and the solvent molecule, such as hydrogen bonding and complexation."
The rest of the chapter goes into details.
