Related Experiment Video
Updated: Jun 19, 2026

Efficient Purification and LC-MS/MS-based Assay Development for Ten-Eleven Translocation-2 5-Methylcytosine Dioxygenase
Published on: October 15, 2018
Electron affinities of the radicals derived from cytosine
Qiong Luo1, Ji Li, Qian Shu Li
1Institute for Chemical Physics, Beijing Institute of Technology, Beijing, 100081, PR China.
Abstract:
Theoretical studies have been carried out to investigate the electron affinities (EAs) of five radicals derived from cytosine by removing a hydrogen atom (C(-H)*), using carefully calibrated computational methods. Significant structural differences are predicted between cytosine, its five radicals and the five corresponding anions. The largest bond distance differences between the radical and its analogous anion are 0.05 angstroms. The theoretical EAs (predicted using carefully calibrated methods) for the five cytosine radicals range from 2.22 eV to 3.00 eV. Among these the N-centred radical 2 has the largest adiabatic electron affinity (EA(ad) = 3.00 eV), and the carbon-centred radical 8 has the smallest (2.22 eV). These values are much larger than EA(ad) for the neutral closed-shell cytosine molecule. The largest EA(ad) value predicted for the cytosine radical isomers (C(-H)*) is comparable to those for radicals related to other nucleoside bases. The ordering for the four DNA bases is EA(T(-H)*) = 3.46 > EA(A)-(-H)*) = 3.26 > EA(C(-H)*)= 3.00 > EA(G(-H)*) = 2.99 eV.
Related Concept Videos
Radicals: Electronic Structure and Geometry
Accordingly, the structure of a trivalent radical lies between the geometries of carbocations and carbanions. An sp2-hybridized carbocation is trigonal planar, while an sp3-hybridized carbanion is trigonal pyramidal. Here, the difference in geometry is...
Radical Reactivity: Electrophilic Radicals
Radical Reactivity: Steric Effects
Along with electronic factors, steric factors also account...
Electron Paramagnetic Resonance (EPR) Spectroscopy: Organic Radicals
π Molecular Orbitals of the Allyl Radical
The allyl systems have identical molecular orbitals but differ in the number of π electrons.
Radical Reactivity: Overview

