Related Experiment Video
Updated: Apr 24, 2026

Author Spotlight: Quantitative Detection of DNA Protein Crosslinks and Their Post-Translational Modifications
Published on: April 21, 2023
Quantum chemical investigations on the nonradiative deactivation pathways of cytosine derivatives
Akira Nakayama1, Shohei Yamazaki, Tetsuya Taketsugu
1Catalysis Research Center, Hokkaido University , Sapporo 001-0021, Japan.
Abstract:
The nonradiative deactivation pathways of cytosine derivatives (cytosine, 5-fluorocytosine, 5-methylcytosine, and 1-methycytosine) and their tautomers are investigated by quantum chemical calculations, and the substituent effects on the deactivation process are examined. The MS-CASPT2 method is employed in the excited-state geometry optimization and also in the search for conical intersection points, and the potential energy profiles connecting the Franck-Condon point, excited-state minimum energy structures, and the conical intersection points are investigated. Our calculated vertical and adiabatic excitation energies are in quite good agreement with the experimental results, and the relative barrier heights leading to the conical intersections are correlated with the experimentally observed excite-state lifetimes, where the calculated barrier heights are in the order of cytosine < 5-methylcytosine < 5-fluorocytosine.
Related Concept Videos
Deactivation Processes: Jablonski Diagram
meta-Directing Deactivators: –NO2, –CN, –CHO, –⁠CO2R, –COR, –CO2H
Bioactivation and Tissue Toxicity
Overview of DNA Repair
Chemically...
Spontaneous and Induced Mutations
ortho–para-Directing Deactivators: Halogens

