Synthesis of fluorescent chalcones, photophysical properties, quantitative structure-activity relationship and their biological application

The development of fluorescent pigments is an area of interest in several research fields due to their high sensitivity. In the current study-eight known and three new N,N-dimethylamino-chalcones (12a-k) were syn-thesized with good yields using the Claisen-Schmidt reaction. For each molecular system, the photophysical properties, including the maximum absorption wavelength (XAbsorption), molar absorption coefficient (c), maximum excitation wavelength (XExcitation), maximum emission wavelength (XEmission), Stokes Shift (AX), fluo-rescence quantum yield (43fl), fluorescence lifetime (-rfl), radiative and non-radiative rate constants (kR and kNR, respectively) were evaluated. Variations in each of these properties were analyzed depending on the substituents present on each compound. To relate the chemical structures of the synthesized compounds to their photo -physical properties, Hansch analysis (2D-QSPR) was applied. As a result of Hansch analysis, we found different photophysical properties related to molecular orbitals and the energy of their derivatives (Highest Occupied Molecular Orbital-HOMO, Lowest Unoccupied Molecular Orbital-LUMO, Difference between LUMO-HOMO-ALH, Chemical potential-mu, Hardness-eta, Softness-S, and electrophilic global index-o)) as well as to the atomic charges on atoms C5, C alpha, C beta, and CO. The application of this type of analysis has made it possible to understand and subsequently design new molecules with defined photophysical properties. Finally, the compounds were use as fluorescent pigment to get living cell imaging on breast cancer cells, obtaining the compound 12a as promissory alternative.

Automated summary

In this study, 11 new fluorescent pigments were synthesized and their photophysical properties were analyzed. It was found that the chemical structure of the compounds plays a crucial role in determining their properties. The compounds were also applied as fluorescent pigments in living cell imaging, with compound 12a showing potential as an alternative.