title: Porous metal-organic frameworks based on an anthracene derivative: syntheses, structure analysis, and hydrogen sorption studies.
abstract: Solvothermal assembly of 5,5'-(9,10-anthracenediyl)di-isophthalate (H(4)adip) with in situ-generated dicopper and diiron paddlewheel secondary building units (SBUs) afforded two porous metal-organic frameworks (MOFs), designated as PCN-14 and PCN-15, respectively. The two MOFs crystallize in different structures, characterized by a difference in the dihedral angles between the anthracene and the phenyl rings of the adip ligand. PCN-14 retains permanent porosity under dehydration and contains nanoscopic cages while PCN-15 contains only one-dimensional hexagonal channels along the (0 0 1) direction which require solvent stabilization. The aromaticity of the anthracene rings of the adip ligand in conjunction with the nanoscopic cages grants PCN-14 high excess hydrogen adsorption capacity of 2.70 wt % at 77 K, 760 Torr (4.42 wt % at saturation), as well as high hydrogen affinity of 8.6 kJ/mol at low H(2) coverage. These values are compared to other tetracarboxylate-derived MOFs to better understand the role of the aromatic rings in hydrogen adsorption.
authors.affiliation: Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, USA. sma@anl.gov
authors.forename: Shengqian
authors.initials: S
authors.lastname: Ma
authors.forename: Jason M
authors.initials: JM
authors.lastname: Simmons
authors.forename: Daofeng
authors.initials: D
authors.lastname: Sun
authors.forename: Daqiang
authors.initials: D
authors.lastname: Yuan
authors.forename: Hong-Cai
authors.initials: HC
authors.lastname: Zhou