Two entangled photoluminescent MOFs of naphthalenedisulfonate and bis(benzimidazole) ligands for selective sensing of Fe3+

Study on the host-guest complex of dicyclohexanocucurbit[6]uril and 2-phenylbenzimidazole, and its recognition effect toward Fe3

This paper has selected dicyclohexanocucurbit[6]uril (CyH2Q[6]) as the host and 2-phenylbenzimidazole (G) as the guest to investigate the host-guest interaction mode between CyH2Q[6] and G. Under acidic conditions, the complex was characterized using nuclear magnetic resonance, ultraviolet and fluorescence spectroscopy. The results show that the molecular ratio of CyH2Q[6] to G is 2 : 1. The crystals were cultured with ZnCl2 as a structural inducer under acidic conditions and single crystal X-ray diffraction showed that the molecular ratio of CyH2Q[6] to G is 1 : 3. The G@CyH2Q[6] was used as a fluorescent probe to identify metal cations. The probe exhibits a good selective recognition effect toward Fe3+ ions, which involves a reduced fluorescence intensity with a limit of detection of 1.321 × 10-6 mol l-1.

Two new CdII MOFs of 1,4-bis(1H-benzimidazol-1-yl)butane and flexible dicarboxylate ligands: luminescence sensing towards Fe3

Two new Cd^II MOFs, namely, two-dimensional (2D) poly[[[μ₂-1,4-bis(1H-benzimidazol-1-yl)butane](μ₂-heptanedioato)cadmium(II)] tetrahydrate], {[Cd(C₇H₁₀O₄)(C₁₈H₁₈N₄)]·4H₂O}_n or {[Cd(Pim)(bbimb)]·4H₂O}_n (1), and 2D poly[diaqua[μ₂-1,4-bis(1H-benzimidazol-1-yl)butane](μ₄-decanedioato)(μ₂-decanedioato)dicadmium(II)], [Cd₂(C₁₀H₁₆O₄)₂(C₁₈H₁₈N₄)(H₂O)₂]_n or [Cd(Seb)(bbimb)_0.5(H₂O)]_n (2), have been synthesized hydrothermally based on the 1,4-bis(1H-benzimidazol-1-yl)butane (bbimb) and pimelate (Pim^2-, heptanedioate) or sebacate (Seb^2-, decanedioate) ligands. Both MOFs were structurally characterized by single-crystal X-ray diffraction. In 1, the Cd^II centres are connected by bbimb and Pim^2- ligands to generate a 2D sql layer structure with an octameric (H₂O)₈ water cluster. The 2D layers are further connected by O-H...O hydrogen bonds, resulting in a three-dimensional (3D) supramolecular structure. In 2, the Cd^II centres are coordinated by Seb^2- ligands to form binuclear Cd₂ units which are linked by bbimb and Seb^2- ligands into a 2D hxl layer. The 2D layers are further connected by O-H...O hydrogen bonds, leading to an 8-connected 3D hex supramolecular network. IR and UV-Vis spectroscopy, thermogravimetric analysis and solid-state photoluminescence analysis were carried out on both MOFs. Luminescence sensing experiments reveal that both MOFs have good selective sensing towards Fe³⁺ in aqueous solution.

Conductive MOFs with Photophysical Properties: Applications and Thin-Film Fabrication

Metal-organic frameworks (MOFs) are a class of hybrid materials with many promising applications. In recent years, lots of investigations have been oriented toward applications of MOFs in electronic and photoelectronic devices. While many high-quality reviews have focused on synthesis and mechanisms of electrically conductive MOFs, few of them focus on their photophysical properties. Herein, we provide an in-depth review on photoconductive and photoluminescent properties of conductive MOFs together with their corresponding applications in solar cells, luminescent sensing, light emitting, and so forth. For integration of MOFs with practical devices, recent advances in fabrication of photoactive MOF thin films are also summarized.

Two new NiII and ZnII metal-organic frameworks of glutarate and 1,4-bis[(2-methyl-1H-imidazol-1-yl)methyl]benzene ligands: syntheses, structures and luminescence sensing properties

Two new metal-organic frameworks (MOFs), namely, three-dimensional poly[diaquabis{μ₂-1,4-bis[(2-methyl-1H-imidazol-1-yl)methyl]benzene}bis(μ₂-glutarato)dinickel(II)] monohydrate], {[Ni₂(C₅H₆O₄)₂(C₁₆H₁₈N₄)₂(H₂O)₂]·H₂O}_n or {[Ni₂(Glu)₂(1,4-mbix)₂(H₂O)₂]·H₂O}_n, (I), and two-dimensional poly[[{μ₂-1,4-bis[(2-methyl-1H-imidazol-1-yl)methyl]benzene}(μ₂-glutarato)zinc(II)] tetrahydrate], {[Zn(C₅H₆O₄)(C₁₆H₁₈N₄)]·4H₂O}_n or {[Zn(Glu)(1,4-mbix)]·4H₂O}_n (II), have been synthesized hydrothermally using glutarate (Glu^2-) mixed with 1,4-bis[(2-methyl-1H-imidazol-1-yl)methyl]benzene (1,4-mbix), and characterized by single-crystal X-ray diffraction, IR and UV-Vis spectroscopy, powder X-ray diffraction, and thermogravimetric and photoluminescence analyses. Ni^II MOF (I) shows a 4-connected 3D framework with point symbol 6⁶, but is not a typical dia network. Zn^II MOF (II) displays a two-dimensional 4⁴-sql network with one-dimensional water chains penetrating the grids along the c direction. The solid-state photoluminescence analysis of (II) was performed at room temperature and the MOF exhibits highly selective sensing toward Fe³⁺ and Cr₂O₇^2- ions in aqueous solution.