Melatonin charge transfer complex with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone: Molecular structure, DFT studies, thermal analyses, evaluation of biological activity and utility for determination of melatonin in pure and dosage forms

Charge transfer reaction between melatonin (e-donor) and DDQ (e-acceptor) was prepared and structurally characterized by different spectral methods like IR and mass spectra. Geometry optimization and molecular electrostatic potential were calculated by DFT studies. Electronic structure was investigated by TD-DFT method. Thermal stability was studied by TG and DTG analyses.203