The tautomer-specific excited state dynamics of 2,6-diaminopurine using resonance-enhanced multiphoton ionization and quantum chemical calculations

0583715 - BFÚ 2024 RIV US eng J - Journal Article
Gate, G. - Williams, A. - Boldissar, S. - Šponer, Jiří - Szabla, R. - de Vries, M. S.
The tautomer-specific excited state dynamics of 2,6-diaminopurine using resonance-enhanced multiphoton ionization and quantum chemical calculations.
Photochemistry and Photobiology. Roč. 2023, DEC 20 2023 (2023). ISSN 0031-8655. E-ISSN 1751-1097
R&D Projects: GA ČR(CZ) GA21-23718S
Institutional support: RVO:68081707
Keywords : ultrafast internal-conversion * nonradiative decay * ab-initio * radiationless deactivation * electronic relaxation * isolated adenine * 2-aminopurine * spectroscopy
OECD category: Biochemistry and molecular biology
Impact factor: 3.3, year: 2022
Method of publishing: Open access
https://onlinelibrary.wiley.com/doi/10.1111/php.13897

2,6-Diaminopurine (2,6-dAP) is an alternative nucleobase that potentially played a role in prebiotic chemistry. We studied its excited state dynamics in the gas phase by REMPI, IR-UV hole burning, and ps pump-probe spectroscopy and performed quantum chemical calculations at the SCS-ADC(2) level of theory to interpret the experimental results. We found the 9H tautomer to have a small barrier to ultrafast relaxation via puckering of its 6-membered ring. The 7H tautomer has a larger barrier to reach a conical intersection and also has a sizable triplet yield. These results are discussed relative to other purines, for which 9H tautomerization appears to be more photostable than 7H and homosubstituted purines appear to be less photostable than heterosubstituted or singly substituted purines.
Permanent Link: https://hdl.handle.net/11104/0351709