Effect of external electric field on H-bonding and π-stacking interactions in guanine aggregates.
The structure and electronic properties of guanine oligomers and π stacks of guanine quartets (G-quartets) with circulene are investigated under an external field through first-principles calculations. An electric field induces nonplanarity in the guanine aggregates and also leads to an increase in the H-bond distances. The calculations reveal that the binding energy of the circulenes with G-quartets increases on application of an electric field along the stacking direction. The HOMO-LUMO gap decreases substantially under the influence of an external field. The contribution of a simple dipole-dipole interaction to the stability of the stacked system is also analyzed. The electric field along the perpendicular axis increases the dipole moments of the guanine dimer, trimer, and quartet. Such an increase in the dipole moment facilitates stacking with circulenes. The stability of G-quartet-circulene π stacks depends on the phase of the dipole moment (in-phase or out-of-phase) induced by an external electric field. The stability of stacks of bowl-shaped circulenes with G-quartets depends on the direction of the applied field.
School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, CET Campus, Thiruvananthapuram 695016, Kerala, India.
Akkarapattiakal K
AK
Jissy
Ayan
A
Datta
D004560:Electricity; D054856:G-Quadruplexes; D006147:Guanine / Q000737:chemistry*; D006860:Hydrogen Bonding; D007364:Intercalating Agents / Q000737:chemistry*
D007364:Intercalating Agents; D006147:Guanine