The failure of available density functional (DFT) methods to compute accurate reaction enthalpies of common organic reactions is well documented. While newly developed dispersion corrected and long-range corrected density functionals offer improved results, the errors are often greater than 5 kcal/mol for many reactions. Moreover, the lack of a universal DFT or a generic protocol to assess DFT errors has also been a source of confusion in quantum chemistry. Herein, we demonstrate that the disparate results from different functionals stem from the systematic errors in the underlying elementary reactions that represent the changes in the bonding environment between reactants and products. We have developed a rigorous protocol to correct for these systematic errors and obtain dramatically improved results with deviations of only 1–2 kcal/mol for most density functionals. A benchmark set of organic reactions of medium and large molecules has been composed to evaluate the performance of quantum chemical methods. The performance of a range of DFT methods for a benchmark set of complex organic reactions is described and assessed in this seminar.

Solving the density functional conundrum: Elimination of systematic errors to derive accurate reaction enthalpies of complex organic reactions

256th National Meeting (2018)

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