Circular dichroism of nucleoside derivatives. VII. The electronic structure and spectra of some simple nucleoside derivatives

Abstract

The electronic structures and spectra of some simple nucleoside derivatives with the formal structure of cytosine nucleoside are presented. The experimental spectroscopic information is obtained from the circular dichroism and absorption spectra. The first four circular dichroism bands of pi-pi* origin possess the same sign pattern previously reported for most cytosine nucleoside derivatives. The four electronic states that produce the characteristic circular dichroism spectra are correlated with the B2u, B1u, and E1u states of benzene. Pariser-Parr-Pople calculations are also presented which qualitatively explain the trends in both the circular dichroism and absorption spectra. Configuration interaction involving single electron excitations between the five highest occupied and the three lowest unoccupied molecular orbitals has been included in the calculations.