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MM: Fachverband Metall- und Materialphysik
MM 10: Poster Session 1
MM 10.27: Poster
Montag, 5. September 2022, 18:00–20:00, P2
Charge distribution and electronic structure of ZIF-8 and its derivatives from first principles — •Joshua Edzards1, Holger-Dietrich Saßnick1, Ana Maria Valencia1,2 und Caterina Cocchi1,2 — 1nstitut für Physik, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg — 2nstitut für Physik and IRIS Adlershof, Humboldt-Universität zu Berlin, 12489 Berlin
Metal organic frameworks are novel materials with high potential in many fields of applications, ranging from gas storage and catalysis to optoelectronics. In spite of their growing popularity, there is still a lack of fundamental understanding of the physico-chemical properties of these materials, even in the most established subgroups such as the zeolitic imidazolate frameworks (ZIFs). To shed light into the nature of the chemical bonds in these systems, we performed a first-principles study based on density-functional theory investigating the charge distribution in ZIF-8 and its derivatives with Br, Cl, and H terminations replacing CH3. Our results indicate the presence of an ionic bond connecting the Zn atom to the organic scaffold, which is held together by covalent bonds. Control calculations performed on the building blocks of ZIF-8 indicate that the aforementioned characteristics are quantitatively influenced by the extended nature of the framework. The presence of halogen substituents, carrying around an excess of negative charge, leads only to a negligible redistribution of the charge density. On the other hand, the electronic structures computed for these systems indicate a reduction of about 0.5 eV of the band-gap in the Br- and Cl-terminated systems with respect to ZIF-8.