Charge-transfer complexes of purines and pyrimidines

Abstract

The spectra of 20 purines and pyrimidines with chloranil, bromanil, and p-benzoquinone in dimethyl sulphoxide were studied. Most of the systems exhibited absorption bands which were concluded to be charge transfer in nature. The ionization energies of the molecules, derived from the positions of the bands, correlated well with the highest occupied molecular orbital energies calculated using the simple Hückel method and were also in good agreement with ionization energy values calculated by a semi-empirical self-consistent field method.