Six New 2D or 3D Metal–Organic Frameworks Based on Bithiophene-Containing Ligand and Dicarboxylates: Syntheses, Structures, and Properties

Six new metal–organic frameworks (MOFs), namely, {[Cd­(BPBP)0.5(hfipbb)]·0.5DMF}n (1), {[Zn­(BPBP)0.5(hfipbb)]}n (2), {[Co­(BPBP)0.5(hfipbb)·0.5DMF]}n (3), {[Zn­(BPBP)­(trans-chdc)]·H2O}n (4), {[Zn2(BPBP)­(4,4′-sdb)2]}n (5), and {[Zn2(BPBP)­(oba)2]·H2O·DMA}n (6) (BPBP = 5,5′-bis­(4-pyridyl)-2,2′-bithiophene, H2hfipbb = 4,4′-(hexafluoroisopropylidene)­bis­(benzoic acid), trans-H2chdc = trans-1,4-cyclohexanedicarboxylic acid, 4,4′- H2sdb = 4,4′-sulfonyldicarboxylic acid, H2oba = 4,4′-oxybis­(benzoic acid), DMF = N,N-dimethylformamide, DMA = N,N-dimethylacetamide), have been hydrothermally synthesized. These compounds were characterized by IR spectroscopy, elemental analysis and X-ray single-crystal diffraction. Compounds 1–3 are isostructural and display 3D 2-fold interpenetrating frameworks with rare {44.610.8} mab topologies. Compound 4 exhibits a 3D diamond-type (dia, 66) framework of 6-fold interpenetration. Compound 5 shows a 2D network with {44·62}-sql topology, which consists of 1D [Zn2(4,4′-sdb)2]n chains. Compound 6 possesses a 3-fold interpenetrating 3D framework with 6-connected {412·63} pcu topology. Magnetic studies reveal that compound 3 exhibits antiferromagnetic behavior. Thermal stabilities for 1–6 and photoluminescence properties of the compounds 1, 2, 4, 5, and 6 have been examined in solid states at room temperature. Furthermore, the UV–vis absorption spectra and optical energy gap of 3 were also investigated.