Synthesis of coumarin based dyes, experimental and theoretical investigation of their photophysical properties

In this study, three compounds (1a, 1b and 2) that contain coumarin and have donor-π-acceptor (D-π-A) structure were synthesized and their structures were characterized by 1H NMR, 13C-NMR, FT-IR and LC-MS spectroscopy methods. The photophysical properties of the synthesized compounds in different solvents were examined by UV-Vis and fluorescence spectroscopy methods. With the Michael addition of anions, it was predicted that the compounds would join the D-π-A system, stopping the intramolecular charge transfer, Therefore, interactions of molecules with various anions (F-, Cl-, Br-, I-, CN-, OH-, NO3-, AcO-, HSO4-, H2P04-) were investigated. It was determined experimentally that CN- anion was added to compounds 1a and 1b and the addition of CN- anion in DMSO was modeled using Density Function Theory. Structural properties, molecular electrostatic potential maps, frontier molecul orbitals and nonlinear optical properties of molecules were investigated using the YFT / B3LYP method and 6-31G + (d, p) basis set. The maximum absorption wavelengths of the compounds were calculated by the Time Dependent Density Function Theory (TD-DFT) method. The theoretical study results obtained were compared with the experimental results and interpreted.