Organometallic MFU‑4l(arge) Metal–Organic Frameworks

Ligand exchange reactions at the Kuratowski-type secondary building unit in MFU-4l(arge) metal–organic frameworks (MOFs) result in organometallic porous compounds with metal–carbon bonds of the general formula [Zn5LxCl4–x(BTDD)3] (4 ≥ x > 3; L = methanido, ethanido, n-butanido, tert-butanido, 3,3-dimethyl-1-butyn-1-ido; H2-BTDD = bis­(1H-1,2,3-triazolo­[4,5-b]­[4′,5′-i])­dibenzo­[1,4]­dioxin) and [Zn1.5Co3.5Me3.1Cl0.9(BTDD)3]. The compounds were characterized by FT-IR, EDX spectroscopy, X-ray powder diffraction (XRPD), and argon adsorption measurements. VT-XRPD, TGA, and TG-MS measurements were applied to investigate the thermal and oxidative stability of the organometallic Zn-MFU-4l derivatives. The hydrolytic stability of all compounds was examined, and a conversion of the methanide to hydroxide ligands is observed in the cobalt-containing compound. DRIFTS measurements of the resulting framework with the composition [Zn1.4Co3.6(OH)3.1Cl0.9(BTDD)3] revealed a mechanism of carbon dioxide binding similar to that of carbonic anhydrase.