UV studies of nucleic acid vase complexation with isoproterenol in different solvents

Charge transfer complex formation between nucleic acid bases and isoproterenol was demonstrated from UV absorption measurements. The solvent polarity effects on equilibrium constants were investigated. The solvent systems containing 0.1 N HCl were 20% aqueous ethanol, water, and water containing sodium chloride. The equilibrium constants, calculated from UV absorption data by the application of the Benesi-Hildebrand equation, were small and increased with increasing ionic strength. Equilibrium constant wavelength dependence was demonstrated in some cases.