ja507119n_si_001.pdf (1.41 MB)
Superacidity in Sulfated Metal–Organic Framework-808
journal contribution
posted on 2014-09-17, 00:00 authored by Juncong Jiang, Felipe Gándara, Yue-Biao Zhang, Kyungsu Na, Omar M. Yaghi, Walter G. KlempererSuperacids,
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.
