Effect of Carboxylate Coligands with Different Rigidity on Supramolecular Architectures Based on One Rigid Didentate Linear Ligand

Six new metal–organic frameworks, namely, {[Cd(bpbenz)(pim)] }n (1), {[Cd(bpbenz)(sea)]·(H2O)2}n (2), {[Cd(bpbenz)(hfipbb)]·(H2O)3}n (3), {[Co(bpbenz)(4,4′-sdb)]·(H2O)2.75}n (4), {[Ni(bpbenz)(4,4′-sdb) (H2O)3]·(H2O)2}n (5), and {[Co(bpbenz)(Hbtc)]·(H2O) }n (6), [bpbenz = 1,4-bis(4-pyridyl)benzene, pim = pimelic acid, sea = sebacylic acid, H2hfipbb = 4,4′-(hexafluoroisopropylidene)bis(benzoic acid), 4,4′-sdb = 4,4′-sulfonyldibenzoate, H3btc = 1,3,5-benzenetricarboxylate, and DMF = N,N-dimethylacetamide], have been synthesized under hydrothermal conditions. These compounds were characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. Compound 1 is a 3D network composed of layers of pentagonal-bipyramidal coordinated Cd atoms bridged by pimelic anions in syn–anti configurations and bpbenz molecules between layers with {412.63} pcu topology. In compound 2, the bpbenz and sebacylic anions act as bidentate ligands assembling with Cd(NO3)2 to a 2D framework. Compound 3 is a 2D network composed of chains, which is bridged by the [Cd2(CO2)4]2L2 SBUs and hfipbb2- anions, and with bpbenz molecules between chains. For compound 4, the bpbenz and 4,4′-sdb coordinate to Co cations to form a three-dimensional{65.8} cds uninodal network. Compound 5 features 2D structure with inclined polycatenation (1D + 1D → 2D). For compound 6, a 2D network with side arms leads to the formation of a polythreaded network, which exhibits a 2-fold interpenetrating 3D array if H-bonds are taken into account. Magnetic susceptibility measurements indicate that compounds 4 and 6 have dominating antiferromagnetic couplings between metal ions. Furthermore, thermal stabilities for 1–6 and luminescent properties for 1–3 are also discussed in detail.