Xiuyan Wan

An unusual bifunctional Tb-MOF for highly sensitive sensing of Ba2+ ions and with remarkable selectivities for CO2–N2 and CO2–CH4

An unusual bifunctional Tb-MOF (TbL) was synthesized by solvothermal method. Luminescent measurements show that the TbL compound exhibits high sensitivity for Ba2+ ions in DMF solution. Moreover, TbL presents significant selective capture of CO2 from the mixtures of CO2–N2 and CO2–CH4, based on the studies of gas sorption capability. To the best of our knowledge, it is the first reported Tb-MOF with such highly sensitive luminescence response for Ba2+ ions and excellent selectivities for CO2–N2 and CO2–CH4.

Structural variability, unusual thermochromic luminescence and nitrobenzene sensing properties of five Zn(II) coordination polymers assembled from a terphenyl-hexacarboxylate ligand

Reactions of the terphenyl-hexacarboxylate ligand [1,1′;4′,1′′]terphenyl-3,5,2′,5′,3′′,5′′-hexacarboxylic acid (H6L) with Zn(NO)3 in the mixed solvents under low-temperature solvothermal conditions afforded five new coordination networks, namely, {[Me2NH2]2[Zn5(L)2(H2O)4]·16H2O}n (1), {[Me2NH2][Zn(H3L)(H2O)]·C2H5OH·5H2O}n (2), {[Me2NH2]2[Zn2(L)(H2O)2]·2DMF·2H2O}n (3), {[Zn4(L)(COO)2(DMF)2(H2O)2]·2C2H5OH·2DMF·2H2O}n (4), and {[Zn4(L)(DMF)4(C2H5OH)(H2O)](OH)2·DMF·2H2O}n (5) (DMF = N,N-dimethylformamide). Compounds 1 and 3–5 possess 3D frameworks, while compound 2 exhibits a 2D grid layer network. Photoluminescence properties of these five compounds have been investigated in solid state at room temperature and low temperature. These five compounds exhibit two kinds of emission modes at room temperature, and compounds 3–5 turn out to have interesting responses to temperature. The sensing properties of compound 1 also have been explored, which show high selectivity and sensitivity to trace amounts of nitrobenzene.

Using cuprophilicity as a multi-responsive chromophore switching color in response to temperature, mechanical force and solvent vapors

A novel strategy is provided in this paper to design multi-stimuli-responsive luminescent materials by taking a multi-responsive chromophore which responds to multiple environmental stimuli instead of constructing multi-chromophore systems. Herein, we have successfully prepared a tri-stimuli-responsive luminescent material, [Cu4I4(4-dpda)4] (1), with reversible and independent thermochromism, mechanochromism and vapochromism simultaneously by applying cuprophilic interactions as a multi-responsive chromophore. The organic ligand 4-dpda is chosen to amplify the perturbation toward metallophilic interations for steric hindrance, and many of the molecular interactions of its multi-phenyl moieties are sensitive to tiny disturbances and will translate the effects to the Cu4I4 core of compound 1. Structural and spectrographic investigations show that the changes in luminescence result from the disturbed cuprophilic interactions.

A family of doped lanthanide metal–organic frameworks for wide-range temperature sensing and tunable white light emission

A family of lanthanide MOFs (LnL) with high thermal and air stability have been successfully synthesized. Based on this robust framework, a series of binary and ternary co-doped LnMOFs, EuxTbyL (y = 1−x) and EuxTbyGd1−x−yL, are achieved for use as ratiometric temperature sensors and white-light-emitting materials. In a binary co-doped system, Eu0.0066Tb0.9934L and Eu0.0089Tb0.9911L show good linear responses to temperature with high sensitivities over a very wide range (from 77 K to 450 K), of which Eu0.0066Tb0.9934L exhibits a maximum relative sensitivity (Sm) of 3.76% K−1 at 450 K. This value is comparable to those of other excellent LnMOF thermometers reported recently whereas the response temperature range is greatly enlarged. The ternary mixed LnMOFs based on energy transfer of different lanthanide ions as ratiometric luminescent thermometers are firstly investigated, in which Eu0.013Tb0.060Gd0.927L displays an extremely high sensitivity (Sm = 6.11% K−1), representing one of the largest values reported so far in mixed LnMOFs. Furthermore, by virtue of carefully adjusting the composition of the mixed LnMOFs and the wavelength of excitation, the emission color can be systematically modulated and a tunable white light emission material, Eu0.0062Tb0.0087Gd0.9851L, is successfully developed.

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.

Five novel Zn(II)/Cd(II) coordination polymers based on bis(pyrazinyl)-triazole and varied polycarboxylates: syntheses, topologies and photoluminescence

Five novel Zn(II)/Cd(II) coordination polymers (CPs) based on the V-shaped ligand 1H-3,5-bis(pyrazinyl)-1,2,4-triazole (Hbpt) and different polycarboxylates, {[Cd(bpt)(H2O)]·ClO4·H2O} (1), {[Cd4(bpt)2(suc)2.5(OH)]·3H2O} (2), {[Cd4(bpt)3(1,3-bdc)2.5]·4H2O} (3), {[Cd9(bpt)6(1,4-bdc)6(H2O)2]·4H2O} (4) and {[Zn2(bpt)(H3bhc)(H2O)6]·H2O} (5) (H2suc = succinic acid, 1,3-H2bdc = isophthalic acid, 1,4-H2bdc = terephthalic acid, H6bhc = benzene-1,2,3,4,5,6-hexacarboxylic acid), have been successfully synthesized. Their structures have been characterized using single-crystal X-ray crystallography, powder X-ray diffraction (PXRD) analyses, elemental analyses, IR spectroscopy, and thermogravimetric analyses (TGA). Complex 1 bears a two-dimensional (2D) layered (3,3) network, which is further extended into the resulting three-dimensional (3D) supramolecular architecture via π⋯π stacking interactions between the terminal pyrazine groups of bpt− ligands. In 2, Cd(II) ions and bpt− ligands construct a 2D Cd-bpt layer and two 1D zigzag chains, which are further connected by suc2− ligands to form a 2D + 1D → 3D (4,5)-connected framework. Complex 3 contains two kinds of grids, and their alternating arrangement gives a final complicated 3,4,5-connected network with a stoichiometry of (3-c)6(4-c)9(5-c)2. In 4, the bpt− ligands act as tetradentate ones to connect neighbouring Cd(II) ions into an infinite 1D Cd-bpt chain. The completely deprotonated 1,4-bdc2− ligands further link the adjacent Cd-bpt chains to generate a novel 3,4,6-connected 3D topological network with (3-c)2(4-c)14(6-c). Complex 5 displays an infinite 1D coordination chain. There are strong π⋯π stacking interactions between adjacent chains in 5 with a centroid–centroid distance of 3.860 A and 3.862 A, resulting in a 3D supramolecular structure. The results show that Hbpt can act as a versatile building block for the construction of various coordination polymers. Moreover, the fluorescence properties of 1–5 in the solid state have also been investigated.

Diverse architectures and luminescence properties of two novel copper(I) coordination polymers assembled from 2,6-bis[3-(pyrid-4-yl)-1,2,4-triazolyl]pyridine ligands

Two attractive Cu(I) coordination polymers with unique structures, namely, {[Cu8(bptp)4]·6H2O} (1) and {[Cu5(bptp)2(CN)]·2H2O} (2), have been successfully synthesized based on a V-shaped multidentate N-containing ligand 2,6-bis[3-(pyrid-4-yl)-1,2,4-triazolyl]pyridine (H2bptp). The structural analysis reveals that complex 1 displays a Cu8 cluster-based infinite 1D ladder chain, in which each H2bptp ligand links four or five Cu(I) ions through nitrogen atoms of pyridine/triazole groups. Complex 2 features an unusual (3,4,5)-connected 3D topological network with the Schlafli symbol (42·54·63·7)(42·63·7)(5·6·8)(5·62·7·82), which has not been reported before. The structural and dimensional diversity of the two complexes indicates that H2bptp exhibits strong coordination ability and diverse coordination modes. It is worth mentioning that the Cu⋯Cu distances in 1 and 2 are shorter than the sum of the van der Waals radii of copper(I) (2.80 A), implying the metal–metal bonding interactions. What is more, the solid-state luminescence bands of 1 and 2 have also been investigated between 298 and 10 K. Interestingly, the low-energy emission bands of 1 and 2 exhibit yellow/orange-red luminescence, and their intensities increase gradually upon cooling.

Fabricating a super stable luminescent chemosensor with multi-stimuli-response to metal ions and small organic molecules through turn-on and turn-off effects

A luminescent Ln-MOF (1) with a combination of exceptionally high thermal, air and chemical stabilities has been synthesized. The multi-stimuli-responsive luminescence of 1 makes it a multifunctional chemosensor for metal ions and small organic molecules, which can selectively detect Cd2+/Mn2+ ions as well as methanol/diethyl ether solvent molecules through turn-on/turn-off effects. Compound 1 can also be utilized as a luminescent probe for diethyl ether vapor and the material can be conveniently reactivated for regeneration.

Self-assembly of two high-nuclearity manganese calixarene-phosphonate clusters: diamond-like Mn16 and drum-like Mn14

Two novel high-nuclearity manganese clusters, [Mn14(BSC4A)3(tBuPO3)6(μ4-OH)3Cl(H2O)(CH3OH)]·1.5CH3OH (1) and [Mn16(BSC4A)3(PhPO3)7(HPO4)(μ4-OH)3Cl(H2O)(CH3OH)4]·4.5CH3OH (2) (H4BSC4A = p-tert-butylsulfonylcalix[4]arene; tBuPO3H2 = tert-butylphosphonic acid; PhPO3H2 = phenylphosphonic acid) have been solvothermally obtained and structurally characterized. Crystal structural analyses reveal that the phosphonate ligands have a large influence on the structures of the polynuclear manganese clusters: complex 1 possesses a drum-like MnII14 core, which is constructed from three Mn4–BSC4A molecular building blocks (MBBs) and six tBuPO32− ligands and capped by two MnII ions; while complex 2 has a diamond-like MnII16 core, which also consists of three Mn4–BSC4A MBBs, but connected by seven PhPO32− linkers and a tetrahedral Mn4 cluster housing a phosphate anion generated in situ. To the best of our knowledge, complex 2 gives the first calixarene-based cluster linked by both organic phosphonate and inorganic phosphate ligands, and also presents the highest nuclearity manganese complex with the H4BSC4A ligand to date. Magnetic measurements suggest the presence of antiferromagnetic interactions between the adjacent MnII spin carriers for both complexes.

CCDC 1505267: Experimental Crystal Structure Determination

Related Article: Yan Yang, Lian Chen, Feilong Jiang, Muxin Yu, Xiuyan Wan, Bo Zhang, Maochun Hong|2017|J.Mater.Chem.C|5|1981|doi:10.1039/C6TC05316E