Nanotubular Metal−Organic Frameworks with High Porosity Based on T-Shaped Pyridyl Dicarboxylate Ligands

Abstract

Two nanotubular metal−organic frameworks (MOFs), {Cu(L1)·2H2O·1.5DMF}∞ (1) and {Cu2(L2)2(H2O)2·7H2O·3DMF}∞ (2), with novel topologies have been constructed based on Cu2+, 5-(pyridin-4-yl)isophthalic acid (L1) and 5-(pyridin-3-yl)isophthalic acid (L2), respectively. Two MOFs were characterized by IR spectroscopy, thermogravimetry, single-crystal, and powder X-ray diffraction methods. Network analysis reveals a two-nodal (3,6)-connected (4·62)2(42·610·83) net and a three-nodal (3,4)-connected (4·82)4(42·82·102)2(84·122) net. Interpenetration is inherently prevented by both of the topologies of the frameworks. The porosity of MOF 1 was confirmed by N2 and CO2 gas adsorption investigations. MOF 1 exhibits remarkable hydrogen sorption hysteresis at low pressure and a H2 uptake capacity of 1.05 wt % at 77 K and 1 atm