Revitalizing the Hammett Equation: Machine Learning Breathes New Life into an 86-Year-Old Formula

Brazilian researchers are using machine learning algorithms and computational methods to expand and improve the 86-year old Hammett equation, a chemical theory that explains the electron-donating or withdrawing nature of aromatic substituents. By combining density functional theory (DFT) methods and machine learning techniques, the researchers were able to calculate new Hammett constants and unlock previously unknown values. While the study has limitations due to the availability of DFT data, experts believe that acquiring more data could improve the accuracy of the machine learning approach. Overall, this work provides a valuable tool for experimentalists to access previously unknown Hammett constants.