Photophysical Characterization of Isoguanine in a Prebiotic-Like Environment

Authors

Naishka E. Caldero-Rodríguez, Case Western Reserve University
Carlos E. Crespo-Hernández, Case Western Reserve UniversityFollow

Document Type

Article

Publication Date

1-24-2023

Abstract

It is intriguing how a mixture of organic molecules survived the prebiotic UV fluxes and evolved into the actual genetic building blocks. Scientists are trying to shed light on this issue by synthesizing nucleic acid monomers and their analogues under prebiotic Era-like conditions and by exploring their excited state dynamics. To further add to this important body of knowledge, this study discloses new insights into the photophysical properties of protonated isoguanine, an isomorph of guanine, using steady-state and femtosecond broadband transient absorption spectroscopies, and quantum mechanical calculations. Protonated isoguanine decays in ultrafast time scales following 292 nm excitation, consistently with the barrierless paths connecting the bright S1 (ππ*) state with different internal conversion funnels. Complementary calculations for neutral isoguanine predict similar photophysical properties. These results demonstrate that protonated isoguanine can be considered photostable in contrast to protonated guanine, which exhibits 40-fold longer excited state lifetimes.

Keywords

ab initio calculations, excited state dynamics, modified nucleobases, nucleobase ancestors, prebiotic chemistry

Language

English

Publication Title

Chemistry A European Journal

Grant

1800052

Rights

© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH. This is an open access work distributed under the terms of the Creative Commons Attribution-Non-Commercial (https://creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is properly cited.

Creative Commons License

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License

Recommended Citation

J. Ortín-Fernández, N. E. Caldero-Rodríguez, C. E. Crespo-Hernández, L. Martínez-Fernández, I. Corral. Photophysical Characterization of Isoguanine in a Prebiotic-Like Environment. Chem. Eur. J. 2023, 29, e202203580.