Modulating Excited Charge-Transfer States of G‑Quartet Self- Assemblies by Earth Alkaline Cations and Hydration
Abstract
Guanine self-assemblies are promising supramolecularplatforms for optoelectronic applications. The study (Hua et al., J. Phys. Chem. C 2012, 116, 14,682−14,689) reported that alkaline cations cannot modulate the electronic absorption spectrum of G-quadruplexes, although a cation effect is observableduring electronic relaxation due to different mobility of Na+ and K+ cations. In this work, we theoretically examined whether divalent Mg2+ and Ca2+ cations and hydration might shift excited charge-transfer states of a cation-templated stacked G-quartet to the absorption red tail. Our results showed that earth alkaline cationsblue-shifted nπ* states and stabilized charge-transfer ππ* states relative to those of complexes with alkaline cations, although the number of charge-separation states was not significantly modified. Earth alkaline cations were not able to considerably increase theamount of charge-transfer states below the Lb excitonic states. Hydration shifted charge-transfer states of... the Na+-coordinated Goctet to the absorption red tail, although this part of the spectrum was still dominated by monomer-like excitations. We found Goctet electron detachment states at low excitation energies in aqueous solution. These states were distributed over a broad range of excitation energies and could be responsible for oxidative damage observed upon UV irradiation of biological G-quadruplexes.
Keywords:
Charge-Transfer States / G-Quartet / Band structure / G-Quadruplex / Guanine / DFT / Electronic absorption spectrum / Hydration Effects / Excited statesSource:
The Journal of Physical Chemistry A, 2020, 124, 40, 8101-8111Publisher:
- USA : American Chemical Society
Projects:
- VRE for regional Interdisciplinary communities in Southeast Europe and the Eastern Mediterranean (EU-675121)
- Ministry of Education, Science and Technological Development, Republic of Serbia, Grant no. 451-03-68/2020-14/200146 (University of Belgrade, Faculty of Physical Chemistry) (RS-200146)
Note:
- This is the peer-reviewed version of the article: Branislav Milovanović, Ivana M. Stanković, Milena Petković, and Mihajlo Etinski, Modulating Excited Charge-Transfer States of G‑Quartet Self- Assemblies by Earth Alkaline Cations and Hydration, The Journal of Physical Chemistry A, 2020, 124, 40, 8101-8111, DOI: https://doi.org/10.1021/acs.jpca.0c05022
- The published version: https://cer.ihtm.bg.ac.rs/handle/123456789/3733
DOI: 10.1021/acs.jpca.0c05022
ISSN: 1089-5639; 1520-5215
PubMed: 32936636