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.