Hyungphil Chun1, Danil N. Dybtsev1, Hyunuk Kim1, Kimoon Kim1
1Pohang University of Science and Technology, Pohang, South Korea
Tóm tắt
AbstractA systematic modulation of organic ligands connecting dinuclear paddle‐wheel motifs leads to a series of isomorphous metal‐organic porous materials that have a three‐dimensional connectivity and interconnected pores. Aromatic dicarboxylates such as 1,4‐benzenedicarboxylate (1,4‐bdc), tetramethylterephthalate (tmbdc), 1,4‐naphthalenedicarboxylate (1,4‐ndc), tetrafluoroterephthalate (tfbdc), or 2,6‐naphthalenedicarboxylate (2,6‐ndc) are linear linkers that form two‐dimensional layers, and diamine ligands, 4‐diazabicyclo[2.2.2]octane (dabco) or 4,4′‐dipyridyl (bpy), coordinate at both sides of Zn2 paddle‐wheel units to bridge the layers vertically. The resulting open frameworks [Zn2(1,4‐bdc)2(dabco)] (1), [Zn2(1,4‐bdc)(tmbdc)(dabco)] (2), [Zn2(tmbdc)2(dabco)] (3), [Zn2(1,4‐ndc)2(dabco)] (4), [Zn2(tfbdc)2(dabco)] (5), and [Zn2(tmbdc)2(bpy)] (8) possess varying size of pores and free apertures originating from the side groups of the 1,4‐bdc derivatives. [Zn2(1,4‐bdc)2(bpy)] (6) and [Zn2(2,6‐ndc)2(bpy)] (7) have two‐ and threefold interpenetrating structures, respectively. The non‐interpenetrating frameworks (1–5 and 8) possess surface areas in the range of 1450–2090 m2g−1 and hydrogen sorption capacities of 1.7–2.1 wt % at 78 K and 1 atm. A detailed analysis of the sorption data in conjunction with structural similarities and differences concludes that porous materials with straight channels and large openings do not perform better than those with wavy channels and small openings in terms of hydrogen storage through physisorption.
