Yanli Gai

Visible and NIR Photoluminescence Properties of a Series of Novel Lanthanide–Organic Coordination Polymers Based on Hydroxyquinoline–Carboxylate Ligands

A series of novel two-dimensional (2D) lanthanide coordination polymers with 4-hydroxyquinoline-2-carboxylate (H(2)hqc) ligands, [Ln(Hhqc)(3)(H(2)O)](n)·3nH(2)O (Ln = Eu (1), Tb (2), Sm (3), Nd (4), and Gd (5)) and [Ln(Hhqc)(ox)(H(2)O)(2)](n) (Ln = Eu (6), Tb (7), Sm (8), Tm (9), Dy (10), Nd (11), Yb (12), and Gd (13); H(2)ox = oxalic acid), have been synthesized under hydrothermal conditions. Complexes 1-5 are isomorphous, which can be described as a two-dimensional (2D) hxl/Shubnikov network based on Ln(2)(CO(2))(4) paddle-wheel units, and the isomorphous complexes 6-13 feature a 2D decker layer architecture constructed by Ln-ox infinite chains cross-linked alternatively by bridging Hhqc(-) ligands. The room-temperature photoluminescence spectra of complexes Eu(III) (1 and 6), Tb(III) (2 and 7), and Sm(III) (3 and 8) exhibit strong characteristic emissions in the visible region, whereas Nd(III) (4 and 11) and Yb(III) (12) complexes display NIR luminescence upon irradiation at the ligand band. Moreover, the triplet state of H(2)hqc matches well with the emission level of Eu(III), Tb(III), and Sm(III) ions, which allows the preparation of new optical materials with enhanced luminescence properties.

Photophysical studies of europium coordination polymers based on a tetracarboxylate ligand.

Reaction of europium sulfate octahydrate with p-terphenyl-3,3″,5,5″-tetracarboxylic acid (H4ptptc) in a mixed solvent system has afforded three new coordination polymers formulated as {[Eu(ptptc)0.75(H2O)2]·0.5DMF·1.5H2O}n (1), {[Me2H2N]2 [Eu2(ptptc)2(H2O)(DMF)]·1.5DMF·7H2O}n (2), and {[Eu(Hptptc)(H2O)4]·0.5DMF·H2O}n (3). Complex 1 exhibits a three-dimensional (3D) metal-organic framework based on {Eu2(μ2-COO)2(COO)4}n chains, complex 2 shows a 3D metal-organic framework constructed by [Eu2(μ2-COO)2(COO)6](2-) dimetallic subunits, and complex 3 features a 2D layer architecture assembling to 3D framework through π···π interactions. All complexes exhibit the characteristic red luminescence of Eu(III) ion. The triplet state of ligand H4ptptc matches well with the emission level of Eu(III) ion, which allows the preparation of new optical materials with enhanced luminescence properties. The luminescence properties of these complexes are further studied in terms of their emission quantum yields, emission lifetimes, and the radiative/nonradiative rates.

Chlorine‐Induced Assembly of a Cationic Coordination Cage with a μ5‐Carbonato‐Bridged MnII24 Core

Chlorine caged in! The chlorine-induced assembly of six shuttlecock-like tetranuclear Mn(II) building blocks generated in situ based on p-tert-butylthiacalix[4]arene and facial anions gave rise to a novel truncated distorted octahedral cationic coordination cage with a μ(5)-carbonato-bridged Mn(II)(24) core.

Thiacalix[4]arene-Supported Kite-Like Heterometallic Tetranuclear ZnIILnIII3 (Ln = Gd, Tb, Dy, Ho) Complexes

Four kite-like tetranuclear Zn(II)Ln(III)3 (Ln= Gd 1, Tb 2, Dy 3, Ho 4) clusters supported by p-tert-butylthiacalix[4]arene (H4BTC4A) have been prepared under solvothermal conditions and structurally characterized by single crystal X-ray diffraction and powder X-ray diffraction (PXRD). In the structures of these four complexes, each of them is capped by two tail-to-tail p-tert-butylthiacalix[4]arene molecules to form a bent sandwich-like unit. The photoluminescent analyses reveal that the H4BTC4A is an efficient sensitizer for Tb(3+) ions in 2. The magnetic properties of complexes 1-4 are also investigated, in which complex 3 exhibits slow magnetization relaxation typical for single molecule magnets.

Open Pentameric Calixarene Nanocage

A novel open helmetlike coordination cage has been synthesized based on Co4-calixarene shuttlecock-like secondary building units and in situ generated phosphate anions, where the opening of the cage comprises a large 16-membered ring. The above unprecedented Co20 nanocage presents the first pentameric calixarene coordination compound. Sorption behavior and magnetic properties are also investigated.

The 3D porous metal–organic frameworks based on bis(pyrazinyl)–trizole: structures, photoluminescence and gas adsorption properties

Two novel 3D porous metal–organic frameworks, {[Zn2(bpt)(btc)]·4H2O}n (1) and {[Cd2(bpt)(btc)(H2O)]·(DMA)2}n (2) (DMA = N,N-dimethylacetamide), were prepared based on 3,5-bis(pyrazinyl)-1,2,4-trizole (Hbpt) with the auxiliary ligand 1,3,5-benzenetricarboxylic acid (H3btc). Complex 1 could be described as a (3,6)-connected binodal 3D network with rutile topology and Schlafli symbol of (4.62)2(42.610.83), where its coordination framework exhibits a high thermal stability up to 420 °C as well as excellent boiling-water resistance. Complex 2 shows a (3,6,8)-connected trinodal 3D framework with a Schlafli symbol of (4.62)2(414.612.82)(44.610.8), which has not been reported previously. Interestingly, the gas-adsorption investigation discloses that complex 1 possesses a high enthalpy of H2 adsorption (9.6 kJ mol−1). Intensive solid-state fluorescence spectra of complexes 1 and 2 have also been determined.

Rapid and discriminative detection of nitro aromatic compounds with high sensitivity using two zinc MOFs synthesized through a temperature-modulated method

Two 3D MOFs (1 and 2) have been solvothermally synthesized by introducing a π-electron conjugated fluorescent aromatic polycarboxylate ligand under the modulation of reaction temperature. Intriguingly, complex 2 shows an unusual fluorescence thermochromism. Upon decreasing the temperature, the emission bands exhibit different variation behaviors which result in dramatic changes of the emission color. The fluorescence of 1 and 2 dispersed in DMF (N,N-dimethylformamide) can be selectively and sensitively quenched by using nitro aromatic compounds (NACs) with a fast response time of just 10 s, indicating that 1 and 2 are potential real-time response candidates for detecting NACs. More interestingly, when DNP (2,4-dinitrophenol) and PNA (p-nitroaniline) are introduced, distinctive fluorescence signals, which can discriminate them from other NACs, are observed, making 1 and 2 the rare materials that can distinguish different nitro aromatic molecules.

From 3D interpenetrated polythreading to 3D non-interpenetrated polythreading: SBU modulation in a dual-ligand system

Self-assembly of Co(II)/Cd(II) with 4,4′-sulfonyldibenzoic acid and bis(4-pyridylmethyl)piperazine has produced 3D interpenetrated and non-interpenetrated polythreading networks with non-trivial linkages.

Structural evolution via modifying (6,3) layer: from inclined polycatenation to parallel polyrotaxane-like interpenetration

An example of structural evolution from inclined polycatenation to parallel polyrotaxane-like interpenetration is demonstrated by modifying the (6,3) layer. Notably synergies of co-ligand binding mode and metal coordination geometry provide the appropriate constituent motifs necessary to instill this entanglement variation.

CCDC 869252: Experimental Crystal Structure Determination

Related Article: Kecai Xiong, Feilong Jiang, Yanli Gai, Daqiang Yuan, Lian Chen, Mingyan Wu, Kongzhao Su and Maochun Hong|2012|Chemical Science|3|2321|doi:10.1039/C2SC20264F