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The exploitation of photo-responsive metal–organic frameworks (MOFs) is important in the field of optical switching, advanced detection, and molecular machines. However, it remains challenging due to the heavy dependence on conventional organic photochromic molecules. Herein, a novel photochromic MOF based on benzophenone units, [Zn4(μ2-O)(μ3-O)(cdip)2(DMF)]n (H4cdip = 5,5′-carbonyldiisophthalic acid) (1), has been successfully synthesized. Compound 1 exhibits instant and reversible photochromic behavior under 365 nm UV and X-ray irradiation through the radical formation of benzophenone units. Furthermore, the fluorescence of 1 can be reversibly modulated during the photochromic process. The excellent stability and reproducibility make it suitable for inkless erasable printing paper. [ABSTRACT FROM AUTHOR]

High sensitivity and selectivity for the detection of metal ions are very important to protect human health. Fluorescent metal–organic frameworks (MOFs) as new sensing materials have attracted more and more attention. Herein, a pillar-layered fluorescent metal–organic framework, {[H2N(CH3)2]2[Cd5(TCPE)3(4,4′-bpy)2(MeOH)2(H2O)4]}n (NKM-102) (H4TCPE = tetrakis(4-carboxyphenyl)ethylene acids, 4,4′-bpy = 4,4′-bipyridine), has been synthesized through utilization of the H4TCPE ligand with typical AIE characteristics. NKM-102 exhibits excellent fluorescence emission performance and detects Al3+ ions with high selectivity through turn-off effect and emission color change. Moreover, the detection limit of NKM-102 can reach 158 ppb, which is lower than the maximum limit of Al3+ ions in drinking water recommended by the United States Environmental Protection Agency (200 ppb). Therefore, the NKM-102 probe is a prominent candidate for the visual detection of Al3+ ions with high sensitivity and selectivity. [ABSTRACT FROM AUTHOR]

In our continuous efforts to explore the effects of metal ions, ligands and counter anions on the structures and properties of metal–organic complexes, six transitional metal complexes with two structurally related ligands, 1,4-bis(1,2,4-triazol-1-ylmethyl)naphthalene (L1) and 4,4′-bis(1,2,4-triazol-1-ylmethyl)biphenyl (L2), [Cd(L1)2(NO3)2(H2O)]∞(1), [Hg(L1)0.5(Br)2] (2), {[Mn(L1)2Cl2](H2O)8}∞(3), {[Cu(L1)2Cl2](H2O)8}∞(4), {[Cd(L2)2(CH3OH)2(NO3)2](H2O)}∞(5) and [Cd(L2)3(CH3OH)2(ClO4)2(CHCl3)]∞(6), were synthesized and structurally characterized. 1has an infinite two-dimensional (2D) network structure and the 2D network further assembled into a 3D interpenetrating structure, 2is a dinuclear structural molecule, 3and 4are neutral molecules with 1D chain structures and the same packing modes, and 5and 6have a similar structure, consisting of a 1D neutral coordination chain, but the coordination geometry around the CdIIion in 6is different from that in 5. The results indicated that the structural differences among them are attributable to the difference of metal ions, counter-anions and ligands frameworks. All the complexes are air stable at room temperature. L1and L2adopt trans–gaucheas well as gauche–gaucheconformation with the shortest NN distance between the two donors in all complexes. Furthermore, the fluorescent properties of complexes 1, 5, 6and all ligands have been investigated and discussed. [ABSTRACT FROM AUTHOR]

Two metal–organic frameworks, {(NH2Me2)[Zn(Pycia)]}n (MOF-1) and {(NH2Me2)[Zn2(Pycia)(PBA)]}n (MOF-2), have been synthesized based on pyrazole functionalized carboxylic acid ligands for organic dye adsorption. The enlarged pore dimension of MOF-2 suggests the advantage of additional linear auxiliary ligand for the structure tuning of the MOFs. Furthermore, the anionic frameworks of the MOFs endow them with size selective adsorption toward different cationic organic dyes. [ABSTRACT FROM AUTHOR]

The supermolecular recognition properties of a 2D coordination polymer, namely, [Cd2(3-tpt)(bpta)(H2O)3] (1) (3-tpt = 2,4,6-tris(3-pyridyl)-1,3,5-triazine and H4bpta = 1,1′-biphenyl-2,2′,6,6′-tetracarboxylic acid), are reported herein. Complex 1 shows a porous supermolecular framework with strong inter-layer π–π interaction from the triazine moieties of 3-tpt ligands. By utilizing its porous nature and triazine induced π–π interaction, complex 1 reveals specific supramolecular recognition and structure transformation toward benzene homologues, which is proved straightforwardly by structure investigations. Furthermore, the altered inter-layer π–π interaction of 1 in response to the molecule recognition also affects its emission properties, which indicates its potential in sensing applications. [ABSTRACT FROM AUTHOR]

Two highly porous metal–organic frameworks are successfully constructed through the assembling of Co/Ni ions and mixed ligands. From the contribution of the uncoordinated tetrazolate N atoms of the ligand the two complexes show high CO2 adsorption capacities, serving as potential CO2 adsorption materials. [ABSTRACT FROM AUTHOR]

A novel “cage-in-cage” metal–organic framework based on nested cages originated from two-fold interpenetrated networks was reported, which indicates the potential of interpenetration in structure modulation of cage-based MOFs. [ABSTRACT FROM AUTHOR]

A three-dimensional (3D) heterometallic metal–organic framework containing cubic-like cages, namely {[Co3Na6(TzDC)4(H2O)6]·7H2O}n (1) (H3TzDC = 1,2,3-triazole-4,5-dicarboxylate), has been synthesized by the edge-directed self-assembly of TzDC3−, Co2+ and Na+ ions. Crystal data reveals that one hydrous Co2+ cation is embedded in the central cavity of a cubic-like cage [Co8(TzDC)12]20− with eight Co2+ cations as the corners and twelve TzDC3− ligands as the edges. The cages are further bridged by Na+ ions to result in a 3D framework with pcu topology. Magnetic investigation indicates that besides the spin–orbit coupling of Co2+ ions, an antiferromagnetic exchange interaction was found to exist between the Co2+ ions in the Co9 cluster of 1. [ABSTRACT FROM AUTHOR]

In our continuous efforts to explore the effects of metal ions, ligands and counter anions on the structures and properties of metal–organic complexes, six transitional metal complexes with two structurally related ligands, 1,4-bis(1,2,4-triazol-1-ylmethyl)naphthalene (L1) and 4,4′-bis(1,2,4-triazol-1-ylmethyl)biphenyl (L2), [Cd(L1)2(NO3)2(H2O)]∞(1), [Hg(L1)0.5(Br)2] (2), {[Mn(L1)2Cl2](H2O)8}∞(3), {[Cu(L1)2Cl2](H2O)8}∞(4), {[Cd(L2)2(CH3OH)2(NO3)2](H2O)}∞(5) and [Cd(L2)3(CH3OH)2(ClO4)2(CHCl3)]∞(6), were synthesized and structurally characterized. 1has an infinite two-dimensional (2D) network structure and the 2D network further assembled into a 3D interpenetrating structure, 2is a dinuclear structural molecule, 3and 4are neutral molecules with 1D chain structures and the same packing modes, and 5and 6have a similar structure, consisting of a 1D neutral coordination chain, but the coordination geometry around the CdIIion in 6is different from that in 5. The results indicated that the structural differences among them are attributable to the difference of metal ions, counter-anions and ligands frameworks. All the complexes are air stable at room temperature. L1and L2adopt trans–gaucheas well as gauche–gaucheconformation with the shortest NN distance between the two donors in all complexes. Furthermore, the fluorescent properties of complexes 1, 5, 6and all ligands have been investigated and discussed. [ABSTRACT FROM AUTHOR]

The reaction of LnIII salts with 1,5-naphthalenedisulfonate (1,5-NDS) or 2,7-naphthalenedisulfonate (2,7-NDS), and phenanthroline (phen) under hydrothermal conditions gave a series of new 2-D complexes {[Ln(1,5-NDS)1.5(phen)2(H2O)2]·3H2O}n [Ln = EuIII (1), GdIII (2), NdIII (3), TbIII (4)] and dinuclear compounds [Ln2(2,7-NDS)2(μ2-OH)2(phen)4(H2O)2]·4H2O [Ln = EuIII (5), GdIII (6), TbIII (7)], respectively. 1–4 are puckered (6,3) networks with 1,5-NDS as a bridge and phen chelating to LnIII ions. 5–7 are hydroxyl bridged dinuclear entities, which extend to 2-D networks by H-bonds. [ABSTRACT FROM AUTHOR]