Theoretical study on the electronic spectra in cyclic 1,2-diketones

The structural and electronic properties of some α-diketones have been investigated theoretically by performing both Hartree–Fock and density functional theory calculations at HF/6-31G(d,p) and B3LYP/6-31G(d,p) levels of theory.The electronic spectra were calculated by ZINDO and TD methods at each level of theory. The wavelength of the n → π1 electronic transitions was correlated with the torsion angle between the two carbonyl groups in these compounds. The study revealed that the n → π1 electronic transitions in the studied compounds are functions of the torsion angles between the two carbonyl groups within the linkage CO–CO.