Abstrakt

DFT Study of Cu+-Thymine and Zn2+ -Thymine Complexes in the Gas Phase : Homo-Lumo Approach

Raghab Parajuli

DFT study of the interaction of DNA base thymine with Zn2+ and Cu+ ion is carried out. Most favourable sites of attachment of these ions in thymine are determined with the help of metal ion affinity (MIA) values. There are two susceptible sites of attachments of metal ions in thymine. Mulliken population analysis (MPA) method is used to determine the Mulliken charges of basic sites as well as the metal ions in all complexes. Possible correlation between the MIA and the retained charges of metal ions is thoroughly explored. Energies of frontier orbitals also correlate with the MIA values. Higher the energy gap between the HOMO and LUMO, higher is the stability of metal ion-thymine complexes