Research data supporting 'Selective Functionalisation of 5-Methylcytosine by Organic Photoredox Catalysis'

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Simpson, Mathew 
Goodman, Jonathan 
Balasubramanian, Shankar 

Gaussian 16 density functional theory (DFT) calculation outputs supporting 'Selective Functionalisation of 5-Methylcytosine by Organic Photoredox Catalysis'

In this study, we report a xanthone-photosensitised process that introduces a 4-pyridine modification at a C(sp3)-H bond in the methyl group of 5-methylcytosine. We propose a reaction mechanism for this type of reaction based on density functional calculations and apply transition state analysis calculations to rationalise differences in observed reaction efficiencies between cyanopyridine derivatives. The reaction is initiated by single electron oxidation of 5-methylcytosine followed by deprotonation to generate the methyl group radical. Cross coupling of the methyl radical with 4-cyanopyridine installs a 4-pyridine label at 5-methylcytosine.

We present key DFT structures from the study in this dataset.

Software / Usage instructions
Density functional theory (DFT) calculations were performed with Gaussian 16 (Revision B.01). Structural optimizations and frequency calculations were conducted with the B3LYP-D3 functional and the 6-31G(d) basis set. The presented structures are the most stable DFT structure upon re-optimization of force field structures from conformational searches. The following script is used to process the output from conformational searches: Conformational searches were conducted in MacroModel (v11.7) with Maestro (release 2019-01) using the Merck Molecular Force Field (MMFF) with the mixed torsional / low-mode sampling method. A setting of 1000 as the maximum number of steps and the maximum number of steps per rotatable bond was used. Conformers within an energy window of 5.02 kcal/mol (21 kJ/mol) were saved.
C--H functionalization, computational organic chemistry, DFT, nucleic acids, photocatalysis, radicals, reaction mechanisms