Porous materials, such as zeolites and metal–organic frameworks (MOFs), or zeolitic-organic frameworks (ZIFs), are frequently considered for shape-selective separations, molecular storage, and catalysis applications, mainly due to their hollow structures. The amount and chemical nature of sorbate molecules that may be fitted inside their cavities depend on their internal structure, that is, on their surface areas, available volumes, and shapes of their porosities. However, while the structure can be elucidated, the access to such precise structural information is somewhat limited both experimentally and computationally. Moreover, the large number of reported structures makes computational geometry-based techniques particularly attractive to identify the most suitable structures for a desired application.
In this context, Delta Chem is both a method and a program designed to quickly analyze porous structures, relying solely on their Cartesian coordinates, and characterize the shapes of their cages using regular convex polyhedra. The program provides a systematic approach to determine the positions of the porosity centers, the atoms that contribute to the internal surfaces, volumes and surface areas. It also includes a routine to compute the irreducible volumes of the cages, i.e., minimal regions of the cavities that can be used to represent the whole porosity shape via symmetry operations. The capabilities of the program are tested on well-studied porous systems, namely, C-60 fullerene, MOF-5, HKUST-1, UiO-66, and ZIF-8.
Our approach is compared against other widely used polyhedra-based approaches for porous materials. Delta Chem is a novel and systematic way of characterizing routinely porous materials and hollow molecules. Besides potential applications to systematically simplify computational studies of shape-dependent properties, Delta Chem can be used in many studies to generate basic geometrical models.

Delta Chem: A new geometric approach of porosity for symmetric porous materials

Where thousands of chemistry professionals meet to share ideas and advance scientific and technical knowledge. Spring 2023 abstracts, posters, and presentations will launch at the end of March.

ACS Spring 2023

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.