Design of Chiral Zeolite Frameworks with Specified Channels through Constrained Assembly of Atoms

A computational method for the design of chiral zeolite frameworks has been developed through constrained assembly of atoms around a specified channel-like forbidden zone. The forbidden zone, corresponding to a channel pattern, is first defined in a unit cell under a chiral space group, and then, atoms are placed outside of the forbidden zone on the basis of specified symmetries and distance constraints. In employing such a method, a diverse range of hypothetical chiral zeolite frameworks has been generated through the enumeration of combinations of different channel sizes, different numbers of unique T atoms, and different unit cell parameters. The framework energies of these generated hypothetical structures are calculated by using a molecular mechanics method, as compared with those of the 161 known zeolite frameworks. The framework densities and the coordination sequences are also calculated for both the hypothetical structures and the known ones. These calculation results reveal that there exists not only the correlation between the framework energy and the framework density but also the correlation between the framework energy and the fourth shell of coordination sequences. On the basis of these correlations, feasible hypothetical zeolite frameworks could be predicted. This method provides a fast search of feasible chiral zeolite frameworks with desired channel geometries and will be an aid for a synthetically oriented chemist.