Question

The molecule below has been designed as a FRET-based sensor for Lead (II) (Pb+2) cations. It contains a coumarin group that absorbs 321 nm light and emits at 385 nm. It also includes a 4-trifluoromethylaminocoumarin group that absorbs at 375 nm and emits at 490 nm on the other end of the molecule. When running fluorescence spectra with this compound, one peak dominates initially, but a different peak becomes the largest after the addition of Pb+2 salt to the solution. Answer the following questions about this

A. Explain in detail why the major peak is changing depending on solvent

B. Draw what you expect the spectra to look like before and after Pb+2 addition

10. The molecule below has been designed as a FRET-based sensor for Lead (II) (Pb+2) cations. It contains a coumarin group that absorbs 321 nm light and emits at 385 nm. It also includes a 4-trifluoromethylaminocoumarin group that absorbs at 375 nm and emits at 490 nm on the other end of the molecule. When running fluorescence spectra with this compound, one peak dominates initially, but a different peak becomes the largest after the addition of Pb+2 salt to the solution. Answer the following questions about this. (10 points) A. Explain in detail why the major peak is changing depending on solvent B. Draw what you expect the spectra to look like before and after Pb+2 addition CF3 yºyooooooo ur coumarin 4-trifluoromethylaminocoumarin

Answer 1

A. This is because of the solvetochromism. In the polar Solvent the polar excited State become more stabilize. As a result the gap between ground State and excited State decrease. So it became red shift. On the other way in non polar Solvent it became reverse.

B.