title: Superacidity in sulfated metal-organic framework-808.
abstract: Superacids, defined as acids with a Hammett acidity function H0 ≤ -12, are useful materials, but a need exists for new, designable solid state systems. Here, we report superacidity in a sulfated metal-organic framework (MOF) obtained by treating the microcrystalline form of MOF-808 [MOF-808-P: Zr6O5(OH)3(BTC)2(HCOO)5(H2O)2, BTC = 1,3,5-benzenetricarboxylate] with aqueous sulfuric acid to generate its sulfated analogue, MOF-808-2.5SO4 [Zr6O5(OH)3(BTC)2(SO4)2.5(H2O)2.5]. This material has a Hammett acidity function H0 ≤ -14.5 and is thus identified as a superacid, providing the first evidence for superacidity in MOFs. The superacidity is attributed to the presence of zirconium-bound sulfate groups structurally characterized using single-crystal X-ray diffraction analysis.
authors.affiliation: Department of Chemistry, University of California, Berkeley and Kavli Energy NanoSciences Institute at Berkeley , Berkeley, California 94720, United States.
authors.forename: Juncong
authors.initials: J
authors.lastname: Jiang
authors.forename: Felipe
authors.initials: F
authors.lastname: Gándara
authors.forename: Yue-Biao
authors.initials: YB
authors.lastname: Zhang
authors.forename: Kyungsu
authors.initials: K
authors.lastname: Na
authors.forename: Omar M
authors.initials: OM
authors.lastname: Yaghi
authors.forename: Walter G
authors.initials: WG
authors.lastname: Klemperer