Density Functional Theory studies of purine bases adenine and guanine

Subject Areas : The Application of Chemistry in Environment

Leile  Rahimi Ahar ¹ (Department of Chemistry, Faculty of Science, Islamic Azad University, Ahar branch, Ahar, Iran)
Zahra  Javanshir ² (Department of Chemistry, Faculty of Science, Islamic Azad University, Ahar Branch, Ahar, Iran)

Received: 2022-10-09 Accepted : 2022-10-10 Published : 2021-07-23

Keywords: DFT, Guanine, Adenine, HOMO–LUMO energy gap, purine bases,

Abstract :

In the present investigation, HOMO-LUMO energy gap, polarizability, structural parameters, molecular mass, hardness, softness, chemical potential of the purine bases adenine and guanine in the gas phase were calculated. Density Functional Theory calculations were performed by the B3LYP method with 6-311G basis set on the compounds. Adenine and guanine present polarizability of 80.49572 and 86.061264 a.u. at the B3LYP method, respectively. The HOMO–LUMO energy gap of 5.356154 and 5.44758 ev were obtained for the adenine and guanine using B3LYP method, respectively. According to the calculations, HOMO–LUMO energy gap, hardness, dipole moment and polarizability of guanine, and softness of adenine in the gas phase have the largest values. According to the HOMO values, guanine is more reactive in the reactions with electrophiles and according to the values of LUMO, adenine is more reactive against reactions with nucleophiles. The adenine and the guanine have the most negative charge on N5 and N1 atoms and N4 and O10 atoms have the most negative electrical potential, respectively.