Supramolecular Isomerism of Metal−Organic Frameworks Derived from a Bicarboxylate Linker with Two Distinct Binding Motifs

Abstract

Two novel metal−organic frameworks (MOFs), Cu(3,4′-bpdc)(H2O)·DMF·2H2O (1) and Cu(3,4′-bpdc)(H2O)·2DMF·4.5H2O (2), have been solvothermally synthesized by the reaction of a unsymmetrically substituted carboxylate ligand 3,4′-biphenyldicarboxylic acid (3,4′-bpdc) and Cu(NO3)2·2.5H2O. X-ray crystal structural analyses reveal that both MOFs possess the binuclear paddle-wheel units [Cu2(O2CR)4], which are linked by the biphenyl connectors, to give two different three-dimensional (3-D) frameworks. The structural diversities are due to the different coordinated arrangements of the two distinct carboxylate groups. In 1, the noncentral symmetrical A−A−B−B arrangement leads to an uncommon twisted Cu-paddlewheel unit, which favors a tetrahedral configuration to generate a 3-fold interpenetrating 3-D framework with a diamond topology. In 2, the paddle-wheel unit constructed by the central symmetrical A−B−A−B arrangement of the ligand acts as a square-planar 4-connected node to give a 2-fold interpenetrating 3-D framework with an NbO topology. These two polymorphs are very rare in MOFs that exhibit similar metal local coordination geometry and the same secondary building units (SBU) but different ligands linking modes. Furthermore, both 1 and 2 possess large one-dimensional channels and show the ability to adsorb H2.

Two‐Dimensional Crystals from Reduced Symmetry Analogues of Trimesic Acid

“…The carboxylate version of molecule 4 has been used as the organic linker in two isomeric MCPs 11. Both isomers are comprised of copper paddlewheels of two meta ‐ and two para ‐carboxylates and vary in the coordination modes of the carboxylates at the paddlewheels.…”

“…The carboxylate version of molecule 4 has been used as the organic linker in two isomeric MCPs. [11] Both isomers are comprised of copper paddlewheels of two meta-a nd two para-carboxylates and vary in the coordination modes of the carboxylates at the paddlewheels. In one structure the carboxylate substitutions alternate aroundt he Cu-Cua xis in a meta-parameta-para arrangement.…”

Recent Advances in Zeolite‐like Cluster Organic Frameworks

“…By using paddlewheel Cu 2 (COO) 4 (H 2 O) 2 clusters as 4‐connected nodes, Zhou et al. reported Cu(3,4′‐bpdc)(H 2 O) ⋅ DMF ⋅ 2 H 2 O (3,4′‐bpdc=3,4′‐biphenyldicarboxylic acid) as a dia‐type threefold interpenetrated ZCOF . Besides, Zou et al.…”

Poly[aqua(μ2-benzene-1,4-dicarboxylato)(μ2-4,4′-bipyridineN,N′-dioxide)cadmium(II)], a threefold interpenetrating diamond net

“…Although many diamond-related nets displaying various interpenetration modes ranging from twofold to 11-fold have been reported, threefold interpenetrating MOFs in the presence of mixed organic ligands with different lengths is relatively rare (Batten, 2001;O'Keeffe et al, 2008;Carlucci et al, 2003) (Long et al, 2002) and [Cu(3,4 0 -bpdc)(H 2 O)]ÁDMFÁ2H 2 O (3,4 0 -bpdc is biphenyl-3,4 0 -dicarboxylate and DMF is dimethylformamide) (Feng et al, 2009), have been reported. The structure of (I) is entirely different from that of the related structure [Cu 2 (bpy) 2 (Hbpy)(H 2 O)][PW 12 O 40 ], which shows an unprecedented threefold interpenetrating diamondlike network in polyoxometalate chemistry.…”