Dynamic DMF Binding in MOF‑5 Enables the Formation of Metastable Cobalt-Substituted MOF‑5 Analogues

• Published in: ACS central science Vol. 1; no. 5; pp. 252 - 260
• Main Authors: Brozek, Carl K, Michaelis, Vladimir K, Ong, Ta-Chung, Bellarosa, Luca, López, Núria, Griffin, Robert G, Dincă, Mircea
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 26-08-2015
• ISSN: 2374-7943; 2374-7951
• DOI: 10.1021/acscentsci.5b00247

Multinuclear solid-state nuclear magnetic resonance, mass spectrometry, first-principles molecular dynamics simulations, and other complementary evidence reveal that the coordination environment around the Zn2+ ions in MOF-5, one of the most iconic materials among metal–organic frameworks (MOFs), is not rigid. The Zn2+ ions bind solvent molecules, thereby increasing their coordination number, and dynamically dissociate from the framework itself. On average, one ion in each cluster has at least one coordinated N,N-dimethylformamide (DMF) molecule, such that the formula of as-synthesized MOF-5 is defined as Zn4O­(BDC)3(DMF) x (x = 1–2). Understanding the dynamic behavior of MOF-5 leads to a rational low-temperature cation exchange approach for the synthesis of metastable Zn4–x Co x O­(terephthalate)3 (x > 1) materials, which have not been accessible through typical high-temperature solvothermal routes thus far.