A Robust Nanoporous Supramolecular Metal-Organic Framework Based on Ionic Hydrogen Bonds

Hydrogen-bond assembly of tripod-like organic cations [H-3-MeTrip](3+) (1,2,3-tri(4'-pyridinium-oxyl)-2-methylpropane) and the hexa-anionic complex [Zr-2(oxalate)(7)](6-) leads to a structurally, thermally, and chemically robust porous 3D supramolecular framework showing channels of 1 nm in width. Permanent porosity has been ascertained by analyzing the material at the single-crystal level during a sorption cycle. The framework crystal structure was found to remain the same for the native compound, its activated phase, and after guest resorption. The channels exhibit affinities for polar organic molecules ranging from simple alcohols to aniline. Halogenated molecules and I-2 are also taken up from hexane solutions by this unique supramolecular framework.