Research

Development of Reaction Path Search Methods

Topic Overview

Every substance is an assembly of atoms. If atoms could be joined together freely like building blocks, it should be easy to make any desired material or medicine. However, this degree of control is not possible because we do not have the entirepicture of the movement of atoms, which is crucial for designing the atom-combining chemical reaction.

In order to predict the unknown “entire picture of the movement of atoms,” a computational method that allows us to automatically search for chemical reaction pathways beyond the range of our imagination is necessary, the “Artificial Force Induced Reaction” (AFIR) method developed at ICReDD1,2. The AFIR method induces structural changes by introducing a virtual, artificial intermolecular or intramolecular force between fragments consisting of a few selected atoms. By repeating this procedure systematically for various combinations of fragments, it is possible to calculate all reaction pathways along which given reactants are converted into unknown products. The analysis of the obtained reaction path network enables the prediction of unknown reactions.

A conceptual diagram of the AFIR method (left) and an example of a reaction path network obtained by the AFIR method (right)

Furthermore, because of the computationally simple algorithm the AFIR method is based on, we could demonstrate its applicability to a wide variety of chemical reactions, such as organic synthesis reactions, photoreactions, nanoparticle catalysts, heterogeneous catalysts, and phase transition reactions3.

Types of chemical reactions to which the AFIR method has been applied

Development at ICReDD

ICReDD realizes an unprecedented reaction discovery scheme that analyzes the reaction path network obtained by the AFIR method using information science techniques, and then experimentally verifies the unknown reactions predicted. This new reaction discovery scheme is expected to dramatically expand the potential for reaction discovery that has been achieved through experimental trial and error. The AFIR method is a key technology in this reaction discovery scheme. Currently, this new reaction discovery scheme has been implemented for the synthesis of simple organic molecules. We will apply this technology to more complex molecules by advancing the development of the AFIR method and making increased use of information science technologies.

References
  1. Maeda, S.; Ohno, K.; Morokuma, K. Phys. Chem. Chem. Phys. 2013, 15, 3683.
  2. Maeda, S.; Harabuchi, Y.; Takagi, M.; Taketsugu, T.; Morokuma, K. Chem. Rec. 2016, 16, 2232.
  3. Maeda, S.; Harabuchi, Y.; Takagi, M.; Saita, K.; Suzuki, K.; Ichino, T.; Sumiya, Y.; Sugiyama, K.; Ono, Y. J. Comput. Chem. 2018, 39, 233.