- Theoretical study on complex systems using “ab initio” methods.
- Development of MOF-FF, a first-principles parametrized force field for metal-organic frameworks (MOFs)
- Structural prediction of MOFs using MOF-FF and reverse topology approach (RTA)
MOF-FF
MOF-FF is a first principles parametrized forcefield for metal-organic frameworks (MOFs). The parameters are adjusted to reproduce structure and potential energy surface (PES) curvature information of non-periodic model systems, computed on dispersion-corrected hybrid DFT level. Genetic algorithm (GA) global optimization strategy has been used to automate and optimized the MOF-FF parameters.

Parameterization of MOF-FF
Structural prediction by reverse topology approach (RTA)
The theoretical structure predictions for metal–organic frameworks (MOFs) and covalent organic frameworks (COFs) are studied by using the reverse topological approach (RTA). In some cases, organic linkers or secondary building units (SBUs) have a lower symmetry than the symmetry of the nodes found in an expected topology. This leads, in principle, to the formation of multiple isoreticular isomers, which have been screened by a genetic global minimum search algorithm together with the first-principles parameterized force field MOF-FF for structure optimization and ranking.
It is found that isoreticular isomerism does, in this case, not lead to disorder but to a number of well-defined structurally distinct phases. They all share the same network topology but have substantially different pore shapes and properties.

Reverse topology approach for structural prediction
Structural prediction of MOFs and COFs
Pyrdine incorporated covalent organic framework, Py@COF-1 (Py = pyridine, COF-1 = C
3H
2BO) is capable for quantum sieving of hydrogen isotopes at cryogenic temperatures. However, its structure is unknown.
We successfully predict its structure using RTA and MOF-FF.

Predicted structure of Py@COF-1
We also performed the theoretical structure prediction for a series of 4,4-connected copper paddle-wheel metal–organic frameworks, starting from the nbo-b topology. The mismatch in symmetry between organic linkers and vertices in nbo-b leads, in principle, to the formation of multiple isoreticular isomers. We screened all possible structures by GA together with MOF-FF for structure optimization and ranking. It is found that in all cases, the experimentally observed structure is correctly predicted.

Examples of predicted 4,4-connected copper paddle-wheel MOFs, starting from the nbo-b topology. NBO-1-I is the most stable phase.
- Bureekaew S., Balwani V., Amirjalayer S., Schmid R., CrystEngComm 17, 344-352 (2015).
- Peksa M., Burrekaew S., Schmid R., Lang J., Stallmach F., Micropor. Mesopor. Mat., 216, 75-81(2015).
- Bureekaew S., Amirjalayer S., Tafipolsky M., Spickermann C., Roy T. K., Schmid R., Phys. Stat. Sol. B, 250, 1128-1141(2013).
- Bureekaew S., Schmid R. Cryst. Eng. Comm., 15, 1551-1562 (2013).
- Oh H., Kalidindi S. B., Um Y., Bureekaew S., Schmid R., Fischer R. A., Hirscher M., Angew. Chem. Int. Ed., 52, 13219-13222 (2013).
Dr. Sareeya Bureekaew (Lecturer)
Dr. Makoto Ogawa (Professor)
Dr. Chularat Wattanakit (Lecturer)
Dr. Kanokwan Kongpatpanich (Lecturer)
Dr. Sarawoot Impeng (Postdoctoral Research Fellow)
Ms. Thanadporn Tanasaro
Mr. Warat Pratanpornlerd
Ms. Wararat Tranganphaibul
Mr. Siwarut Siwaipram
International Research Collaborator:
Prof. Susumu Kitagawa
Kyoto University, Japan
Prof. Masahiro Ehara
Institute for Molecular Science, Japan