Synthesis and characterization of three novel 3D metal–organic frameworks constructed from semi-rigid V-shaped ligands

• Synthesis and characterization of three new MOFs based on semi-rigid V-shape ligand
• Different coordination models of the semi-rigid ligands result in diverse structure.
• Compound 1 has potential application in the field of photoactive materials.

Three new 3D metal-organic frameworks (MOFs) [Ni3(L1)2(4,4′-bipy)4(H2O)6]∙6H2O (1), [Ni(HL2)(4,4′-bipy)(H2O)3]∙(4,4′-bipy) (H2O) (2) and [Mn3(L2)2(H2O)(DMF)2] (3) based on the semi-rigid V-shaped ligands, 4-(4-carboxyphenoxy) phthalic acid (H3L1) and 3-(4-carboxyphenoxy)phthalic acid (H3L2), have been successfully synthesized under the hydrothermal and solvothermal condition, and characterized by elemental analysis, thermal studies, and powder and single-crystal X-ray diffraction. The results indicate that in compound 1, the H3L1 ligands adopt bis-monodentate coordination mode to connect the two kinds of 1D Ni-4,4′-bipy-Ni chains, giving a 3D network with rare (42·63·8)2(6·84·10) topological structure. In compound 2, H3L2 ligand acts as the terminal mode while the 4,4′-bipy ligands bridge the Ni(II) ions to generate infinite Ni-4,4′-bipy-Ni zig-zag chains, which furthermore through intermolecular OH⋯O, OH⋯N hydrogen bonds form a three-dimensional (3D) supramolecular structure. While in compound 3, H3L2 ligand exhibits u6—η1: η1: η2: η1: η1: η2 coordination mode to bridge six Mn (II) ions, leading to a 3D open framework. Further photoluminescence measurement indicates that compound 1 could be a potential candidate as photoactive material.

Three new MOFs, [Ni3(L1)2(4,4′-bipy)4(H2O)6]∙6H2O (1), [Ni(HL2)(4,4′-bipy)(H2O)3]∙(4,4′-bipy) (H2O) (2) and [Mn3(L2)2(H2O)(DMF)2] (3), have been obtained under hydrothermal and solvothermal conditions. Single-crystal X-ray diffraction reveals that the formed structural architectures are strongly dependent on the configuration and coordination models of the V-shaped semi-rigid ligands. Furthermore, photoluminescence experimental results suggest compound 1 as a potential purple-emitted photoactive material.Figure optionsDownload as PowerPoint slide