This tool provides polarity (ω) and bond dissociation energy (BDE) for any organic radical.
Draw a molecule or radical above (or enter a SMILES string) and search. The ω values are obtained from our 1-million-radical DFT database and GNN model, and BDE from the open-source ALFABET model.

Three functions are available:

• Search: returns ω and BDE for every radical in a molecule (by DFT and ML).
• Substructure Search: retrieves ω values for related radicals already in the DFT database.
• Experimental Analysis: correlates predicted ω and BDE with user-provided experimental data (rate, yield, ee) to identify which factor most influences reactivity or selectivity.

Radical polarity (ω):

Alturaifi, T. M., Mikhaeel, K. N., Hutchison, G. R., Liu, P., Nagib, D. A. Rapid Prediction of Radical Polarity and Reactivity.
Unpublished.

Garwood, J. J. A., Chen, A. D., Nagib, D. A. Radical Polarity. J. Am. Chem. Soc. 146, 28034–28059 (2024).
https://doi.org/10.1021/jacs.4c06774

De Vleeschouwer, F., Van Speybroeck, V., Waroquier, M., Geerlings, P., De Proft, F. Electrophilicity and Nucleophilicity Index for Radicals. Org. Lett. 9, 2721–2724 (2007).
https://doi.org/10.1021/ol071038k

Bond dissociation energy (BDE), via ALFABET model:

St. John, P. C., Guan, Y., Kim, Y., Kim, S., Paton, R. S. Prediction of organic homolytic bond dissociation enthalpies at near chemical accuracy with sub-second computational cost. Nat Commun 11, 2328 (2020).
https://doi.org/10.1038/s41467-020-16201-z

St. John, P. C., Guan, Y., Kim, Y., Etz, B. D., Kim, S., Paton, R. S. Quantum chemical calculations for over 200,000 organic radical species and 40,000 associated closed-shell molecules. Sci Data 7, 244 (2020).
https://doi.org/10.1038/s41597-020-00588-x

Sowndarya, S. S. V., Kim, K., Kim, S., St. John, P. C., Paton, R. S. Expansion of Bond Dissociation Prediction with Machine Learning to Medicinally and Environmentally Relevant Chemical Space. Digit. Discov. 2, 1900–1910 (2023).
https://doi.org/10.1039/D3DD00169E