Photoactive Homomolecular bis(n)-Lophine dyads: Multicomponent synthesis, Photophysical properties, Theoretical investigation, Docking and interaction studies with biomacromolecules

Abstract This work reports the synthesis of four homomolecular bis(n)-Lophines dyads achieved by a one-pot four component reaction. The dyads show absorption maxima below 300 nm and present intense fluorescence emission, with large Stokes shift, around 380 nm. Intercalation phenomenon and hydrophobic forces can be predicted for dyads, according to the results observed by the analysis via UV-Vis and AO competition assay by emission fluorescence technique. For HSA/BSA-binding analysis, quenching of tryptophan residue and conformational changes around the tryptophan binding site can be occurs. Molecular docking results suggested that all dyads can interact into DNA strands via an intercalative process into the minor groove, while sites I and III of HSA and BSA are considered as the main binding pocket, reinforcing experimental static fluorescence quenching mechanism. The compounds were also studied with Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT). The wB97XD was employed with the cc-pVDZ/cc-pVDZ basis set for geometry optimizations and the cc-pVDZ/jun-cc-pVDZ for vertical transitions energy. Implicit solvent effect was considered with PCM in all calculations.