Study of charge-transfer interaction in biomolecules

Abstract

The interaction of the antibiotic drugs tetracycline and oxytetracycline with purines, pyrimidines and amino acids were studied spectrophotometrically in water, ethylene glycol and propylene glycol. In each case a new absorption band was located and denoted as a charge-transfer band. The formation constants for the charge-transfer complexes were determined using Benesi–Hildebrand's method followed by an iterative procedure. Different linear plots for hv against the highest filled π-molecular orbital of the donors (purines, pyrimidines and amino acids) were obtained indicating different stabilization energies for each system.