Synthesis of two-photon active cinnamoyl coumarins for high-contrast imaging of cancer cells and their photophysical characterization

A series of two-photon (TP) active 4-dimethylaminocinnamoyl coumarins were synthesized. These compounds exhibit red shift in absorption and considerable Stokes shift in emission spectra in comparison to the parent coumarin. Large TP absorption cross-sections were measured for all the coumarins in dilute solutions. A correlation between the chemical structure and TP characteristics was established. TP confocal microscopy revealed that these coumarin derivatives can be internalized by cancer cells rendering them a potential candidate as a label in TP confocal imaging.