Shuang-Quan Zang

Highly selective Fe3+ sensing and proton conduction in a water-stable sulfonate–carboxylate Tb–organic-framework

A new 3D porous terbium–organic framework {[Tb4(OH)4(DSOA)2(H2O)8]·(H2O)8}n (Tb-DSOA) has been successfully assembled by Tb3+ ions and a sulfonate–carboxylate linker disodium-2,2′-disulfonate-4,4′-oxydibenzoic acid (Na2H2DSOA). In this metal–organic framework (MOF), tetranuclear terbium clusters can be sensitized by the organic linker to generate the characteristic photoluminescence of TbIII ions. Noncoordinated sulfonate oxygen atoms functionalize its channels, which act as basic sites leading to highly selective Fe3+ ion sensing by luminescence quenching, and also act as hopping sites for proton transfer, resulting in a proton conductivity of 1.66 × 10−4 S cm−1 at 98% RH. Exceptional water-stability makes this MOF compatible for these applications in aqueous solution.

A Novel Sensitive Turn-on Fluorescent Zn2+ Chemosensor Based on an Easy To Prepare C3-Symmetric Schiff-Base Derivative in 100% Aqueous Solution

A C(3)-symmetric Schiff-base example of the new simple, low cost, highly water soluble, and sensitive turn-on fluorescent Zn(2+) chemosensor is described. The sensor was successfully applied to the detection of intracellular Zn(2+). Moreover, the sensor could also serve as a potential recyclable component in sensing materials. Notably, the color change is so obvious that all of the recycling process can be seen clearly by the naked eye.

Selective Sensing of Fe3+ and Al3+ Ions and Detection of 2,4,6‐Trinitrophenol by a Water‐Stable Terbium‐Based Metal–Organic Framework

A water-stable luminescent terbium-based metal-organic framework (MOF), {[Tb(L1 )1.5 (H2 O)]⋅3 H2 O}n (Tb-MOF), with rod-shaped secondary building units (SBUs) and honeycomb-type tubular channels has been synthesized and structurally characterized by single-crystal X-ray diffraction. The high green emission intensity and the microporous nature of the Tb-MOF indicate that it can potentially be used as a luminescent sensor. In this work, we show that Tb-MOF can selectively sense Fe(3+) and Al(3+) ions from mixed metal ions in water through different detection mechanisms. In addition, it also exhibits high sensitivity for 2,4,6-trinitrophenol (TNP) in the presence of other nitro aromatic compounds in aqueous solution by luminescence quenching experiments.

Hypersensitive dual-function luminescence switching of a silver-chalcogenolate cluster-based metal–organic framework

Silver(i) chalcogenide/chalcogenolate clusters are promising photofunctional materials for sensing, optoelectronics and solar energy harvesting applications. However, their instability and poor room-temperature luminescent quantum yields have hampered more extensive study. Here, we graft such clusters to adaptable bridging ligands, enabling their interconnection and the formation of rigid metal-organic frameworks. By controlling the spatial separation and orientation of the clusters, they then exhibit enhanced stability (over one year) and quantum yield (12.1%). Ultrafast dual-function fluorescence switching (<1 s) is also achieved, with turn-off triggered by O2 and multicoloured turn-on by volatile organic compounds. Single-crystal X-ray diffraction of the inclusion materials, obtained by single-crystal-to-single-crystal transformation, enables precise determination of the position of the small molecules within the framework, elucidating the switching mechanism. The work enriches the cluster-based metal-organic framework portfolio, bridges the gap between silver chalcogenide/chalcogenolate clusters and metal-organic frameworks, and provides a foundation for further development of functional silver-cluster-based materials.

Syntheses, structures, tunable emission and white light emitting Eu3+ and Tb3+ doped lanthanide metal–organic framework materials

A series of novel lanthanide metal-organic frameworks, namely, {[Ln2(L)2]·(H2O)3·(Me2NH2)2}n (Ln = La (1), Ce (2), Pr (3), Nd (4), Sm (5), Eu (6), Gd (7), Tb (8), Ho (9), Er (10)), have been synthesized with hydro(solvo)thermal conditions based on a flexible multicarboxylic acid (H4L = 5-(3,5-dicarboxybenzyloxy)isophthalic acid). Single crystal X-ray diffraction reveals that all of them are isomorphous and possess a (6,6) topological net with a Schläfli symbol of {4(8)·6(7)}. Considering the blue-emission of compound 1 and the intense emission of the Eu and Tb compounds, we successfully construct isostructural Eu(3+) doped Tb compounds whose color can be tuned easily by adjusting the different concentration of the doped ions, and we also obtained white light emitting materials through the doping of Eu and Tb ions in the La compounds.

Ferroelectric switchable behavior through fast reversible de/adsorption of water spirals in a chiral 3D metal-organic framework.

A polar homochiral 3D MOF [{Co2(L)(bpe)(H2O)}·5H2O]n constructed with cobalt(II) and a new ligand N-(1,3-dicarboxy-5-benzyl)-carboxymethylglycine (H4L) accommodates ordered helical water streams in its helical grooves. It provides the first example of switchable ferroelectric and optical behavior through two-step reversible single-crystal to single-crystal transformation (SCSC) upon desorption/adsorption of water spirals and coordinated water molecules, respectively.

Aqueous- and vapor-phase detection of nitroaromatic explosives by a water-stable fluorescent microporous MOF directed by an ionic liquid

A water-stable fluorescent microporous metal–organic framework (MOF), [Tb(L)(OH)]·x(solv) (1), has been designed and successfully synthesized under a combination of hydro/solvothermal and ionothermal conditions (H2L = 5-(4-carboxyphenyl)pyridine-2-carboxylate). The crystal structure reveals that complex 1 consists of cubane-shaped tetranuclear terbium building units, which are further bridged by the multicarboxylate ligands to give a (3,12)-connected topology with the point symbol (420·628·818)(43)4. More importantly, the excellent hydrolytic stability allows it to be used in an aquatic system, which is highly desirable for practical applications. Activated 1 shows high selectivity and sensitivity towards nitroaromatic explosives in both aqueous and vapor phases. The sizes of the pore windows (11.2 × 11.2 A2) in 1, which are larger than the sizes of the selected nitroaromatics, could permit easy diffusion of analytes inside the channel, keeping the electron rich framework and electron deficient analytes in close proximity.

A tetranuclear Cu4(μ3-OH)2-based metal–organic framework (MOF) with sulfonate–carboxylate ligands for proton conduction

A new tetranuclear Cu4(μ3-OH)2-based metal-organic framework (MOF) with sulfonate-carboxylate ligands features large hydrophilic channels. This MOF exhibits proton conductivity over 10(-3) S cm(-1) at 85-100 °C and 98% relative humidity and colossal dielectric constant.

Thermochromic Luminescent Nest‐Like Silver Thiolate Cluster

A novel discrete open high-nuclearity nest-like silver thiolate cluster complex, [Ag33 S3 (StBu)16 (CF3 COO)9 (NO3 )(CH3 CN)2 ](NO3 ) (1), has been isolated with nitrate and S(2-) anions acting as structure-directing templates. Its similar nest-like structure has been assembled into an extended layer [Ag31 S3 (StBu)16 (NO3 )9 ]n (2) by adjustment of auxiliary ligand. More interestingly, both complexes exhibit temperature-dependent luminescence of high sensitivity with a large fluorescence enhancement (12-fold for 1, 21-fold for 2), which can be easily recognized by the naked-eye (dramatic red-shift Δ=104 nm for 1, larger Δ=113 nm for 2 at 77 K compared to those at 298 K). The correlation between luminescent thermochromism and temperature-dependent variation of the coordination modes of template NO3 (-) anion, Ag⋅⋅⋅S and Ag⋅⋅⋅Ag distances are also elucidated through variable-temperature single-crystal X-ray crystal structure (VT-SCXRD) analyses.

Assembly of Silver(I)−Organic Networks from Flexible Supramolecular Synthons with Pendant Ethynide Arms Attached to a Naphthyl Skeleton

Five new ligands bearing terminal ethynide moieties attached via pendant arms to a naphthyl skeleton have been used in the synthesis of eight silver(I) complexes. In these compounds, the invariable appearance of the mu 4 and mu 5 ligation modes of the ethynide moiety reaffirms the general utility of the silver-ethynide supramolecular synthons R-CC supersetAg n and Ag n subsetCC-R-CC supersetAg n ( n = 4, 5) in coordination network assembly, even when the R group is conformationally flexible. Besides the silver-ethynyl and silver-aromatic interactions, several unconventional intermolecular interactions (argentophilicity, anion-pi, C-H...pi, and CN...pi) also make their appearance.