UV spectroscopic studies of charge transfer complexes of 2-hydroxy-1,4-naphthoquinone

Charge transfer complexes of 2-hydroxy-1,4-naphthoquinone with 2,3 and 4-picoline, 4-picolylamine, 2-aminopyrimidine and 2-aminopyridine were studied and their absorption spectra were recorded. In each case one charge transfer (CT) band was observed. These investigations were made in three different solvents (CCl4, CH2Cl2 and CHCl3) at four different temperatures (20, 25, 30 and 35 degrees C). The values of association constant (K-AD), molar extinction coefficient (epsilon(AD)) and absorption band of charge transfer complexes (h upsilon(CT)) were calculated. The ionization potentials of the donors (I-D) were calculated from the complex band energy. Thermodynamic parameters i.e. changes in standard free energy (Delta G(0)), standard entropy (AS) and standard enthalpy (Delta H-0) for all these CT complexes were also calculated.