Jilin University China Research Articles

Piezochromism in Dynamic Three-Dimensional Covalent Organic Frameworks.

Piezochromic materials with pressure-dependent photoluminescence tuning properties are important in many fields, such as mechanical sensors, security papers, and storage devices. Covalent organic frameworks (COFs), as an emerging class of crystalline porous materials (CPMs) with structural dynamics and tunable photophysical properties, are suitable for designing piezochromic materials, but there are few related studies. Herein, we report two dynamic three-dimensional COFs based on aggregation-induced emission (AIE) or aggregation-caused quenching (ACQ) chromophores, termed JUC-635 and JUC-636 (JUC = Jilin University China), and for the first time, study their piezochromic behavior by diamond anvil cell technique. Due to the various luminescent groups, JUC-635 has completely different solvatochromism and molecular aggregation behavior in the solvents. More importantly, JUC-635 with AIE effect exhibits a sustained fluorescence upon pressure increase (~3 GPa), and reversible sensitivity with high-contrast emission differences (Δλem = 187 nm) up to 12 GPa, superior to other CPMs reported so far. Therefore, this study will open a new gate to expand the potential applications of COFs as exceptional piezochromic materials in pressure sensing, barcoding, and signal switching.

Piezochromism in Dynamic Three‐Dimensional Covalent Organic Frameworks

AbstractPiezochromic materials with pressure‐dependent photoluminescence tuning properties are important in many fields, such as mechanical sensors, security papers, and storage devices. Covalent organic frameworks (COFs), as an emerging class of crystalline porous materials (CPMs) with structural dynamics and tunable photophysical properties, are suitable for designing piezochromic materials, but there are few related studies. Herein, we report two dynamic three‐dimensional COFs based on aggregation‐induced emission (AIE) or aggregation‐caused quenching (ACQ) chromophores, termed JUC‐635 and JUC‐636 (JUC=Jilin University China), and for the first time, study their piezochromic behavior by diamond anvil cell technique. Due to the various luminescent groups, JUC‐635 has completely different solvatochromism and molecular aggregation behavior in the solvents. More importantly, JUC‐635 with AIE effect exhibits a sustained fluorescence upon pressure increase (≈3 GPa), and reversible sensitivity with high‐contrast emission differences (Δλem=187 nm) up to 12 GPa, superior to other CPMs reported so far. Therefore, this study will open a new gate to expand the potential applications of COFs as exceptional piezochromic materials in pressure sensing, barcoding, and signal switching.

A stable mesoporous metal-organic framework as highly efficient sorbent of dispersive micro solid-phase extraction for the determination of polycyclic aromatic hydrocarbons by HPLC.

Owing to the large molecular sizes of polycyclic aromatic hydrocarbons, their adsorption using microporous sorbents leads to a low adsorption capacity. Here, to increase the extraction capacity and detection sensitivity of polycyclic aromatic hydrocarbons, a highly efficient dispersive micro solid-phase extraction method was developed based on a stable mesoporous metal-organic framework named Jilin University China 48. Jilin University China 48 is a super hybrid with large one-dimensional hexagonal nanotube-like channels of 24.5×27.9Å, which exhibits high potential to be an efficient sorbent of dispersive micro solid-phase extraction to adsorb polycyclic aromatic hydrocarbons. By combining with high-performance liquid chromatography, a sensitive method was developed for the determination of seven polycyclic aromatic hydrocarbons. The synthesized Jilin University China 48 exhibited excellent characteristics of stability, good morphology, large surface area, and open adsorption sites. Under the optimized extraction conditions, better extraction results were obtained than that of other methods reported previously. The proposed method exhibited high sensitivity with the limit of detections in the range of 0.021-0.13ng/mL, good linearity in the range of 0.068-50ng/mL with related coefficients of >0.9988, satisfactory precision with relative standard deviation of <4.3%, and adequate recoveries between 85.8 to 109.55% for all the target compounds.

Constructing three new metal–organic frameworks based on a mixed-donor ligand: Topological analysis and fluorescence properties

Three new metal–organic frameworks (MOFs), [Zn2(TZI)(μ3-OH)(H2O)2]·(CH3)2NH (JUC-165), [Cd5(TZI)3(μ3-OH)(H2O)7]·4H2O (JUC-166), and [Cd(TZI)]·(CH3)2NH2·H2O (JUC-167) (JUC=Jilin University China) have been synthesized by self-assembly of Zn2+/Cd2+ ions and a prominent ligand, 5-tetrazolylisophthalic acid (H3TZI). JUC-165 exhibits fascinating three-dimensional (3D) structure containing 1D rectangular channels with dimensions of 6.5×3.0Å2 and it performs (5,5)-connected topology with a Schläfli symbol of 4664, JUC-166 displays a 2D sandwich-layer which further forms into a 3D supermolecular structure by H-bonds reactions and JUC-167 exhibits (4,4)-connected 3D frameworks with a Schläfli symbol of 42638. Furthermore, we research the fluorescence properties of these new MOFs measured at room temperature, and the results reveal that JUC-165, JUC-166 and JUC-167 display strong main emission spectra peaks at 410, 437 and 415nm, respectively.

ZIF-derived in situ nitrogen decorated porous carbons for CO2capture

Various N-doped hierarchical porous carbons were prepared by using a new mixed-ligand ZIF (zeolitic imidazolate framework) (JUC-160) as the precursor in a one-step synthetic route without any additional carbon sources or purification steps. The effect of the ZIF precursor crystal size on the textural properties of the derived porous carbons was systematically studied. Microporosity was dominant in micron-sized JUC-160 crystal derived porous carbons, while more mesopore volume was present in porous carbons obtained from nanometre-sized JUC-160 crystals. The mJUC160-900 sample, which had a high nitrogen content and micropore volume, exhibited the highest CO2 uptake, which is 5.50 and 3.50 mmol g−1 at 273 and 298 K, respectively. Moreover, the analysis based on the ideal adsorbed solution theory (IAST) exhibited a high adsorption selectivity for CO2/N2 at 298 K and 1 bar (Sads = 29). Introduction to the international collaboration State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, at Jilin University China, has a long term cooperation with the Laboratory of Catalysis and Spectroscopy in Caen, at CNRS-France. Recently, Prof. Shilun Qiu's group and Prof. Valentin Valtchev's group had an international collaborative researching project entitled “Microporous materials: green synthesis for green applications”, which was supported by the National Natural Science Foundation of China (21261130584) and the French Science Foundation (ANR-12-IS08-0001-01). This project is focused on the design and synthesis of porous materials such as zeolites, metal organic frameworks (MOFs), covalent organic frameworks (COFs), porous aromatic frameworks (PAFs) and porous carbon materials that can find applications for clean energy storage, carbon capture, catalysis, and molecular selective sorption and separation.

Three‐Dimensional Porous Heterometallic‐Organic Frameworks: Synthesis, Luminescent, Magnetic, Adsorption and Hydrogen Storage Properties

AbstractTwo three‐dimensional (3D) porous heterometal‐organic frameworks (HMOFs) with isostructures, [Zn2Cd(OH)(BTC)2(DMF)(H2O)2]·(H3O) (JUC‐155A) and [ZnCo2(OH)(BTC)2(DMF)(H2O)2]·(H3O) (JUC‐155B) (JUC=Jilin University China, BTC=1,3,5‐benzenetricarboxylate and DMF=N,N‐dimethylformamide), have been successfully synthesized by utilizing two kinds of 3d metal ions (Zn(II) and Cd(II) or Zn(II) and Co(II)) under conformable conditions. X‐ray crystallography reveals that both HMOFs consist of trinuclear metal‐carboxylate secondary building units (SBUs), and these SBUs are interlinked by the phenyl groups of BTC ligands to generate 3D open‐frameworks with two types of channels of about 6.3 and 10.7 Å. Both HMOFs show the multifunctional properties in photoluminescence and adsorption. JUC‐155B also exhibits an antiferromagnetic interaction, owing to the presence of dinuclear cobalt centers. Additionally, the high‐pressure hydrogen storage of JUC‐155A has been also examined at 77 K. By using mixed metal centers in clustered SBUs, it is a good strategy to construct those isostructures with heterometallic systems, and it is believed that the presence of such HMOFs will further facilitate the exploration of multifunctional materials.

Carbon dioxide selective adsorption within a highly stable mixed-ligand Zeolitic Imidazolate Framework

A new mixed-ligand Zeolitic Imidazolate Framework Zn4(2-mbIm)3(bIm)5·4H2O (named JUC-160, 2-mbIm=2-methylbenzimidazole, bIm=benzimidazole and JUC=Jilin University China) was synthesized with a solvothermal reaction of Zn(NO3)2·6H2O, bIm and 2-mbIm in DMF solution at 180°C. Topological analysis indicated that JUC-160 has a zeolite GIS (gismondine) topology. Study of the gas adsorption and thermal and chemical stability of JUC-160 demonstrated its selective adsorption property for carbon dioxide, high thermal stability, and remarkable chemical resistance to boiling alkaline water and organic solvent for up to one week.

Syntheses, structures and luminescence properties of three metal–organic frameworks based on 5-(4-(2H-tetrazol-5-yl)phenoxy)isophthalic acid

Three metal–organic frameworks (MOFs), namely [Zn2(TPIA)(OH)(H2O)]·H2O (JUC-114), [Cd2(TPIA)(OH)(H2O)2]·H2O (JUC-115), and [Co2(TPIA)(OH)(H2O)2]·H2O (JUC-116) (JUC = Jilin University China), based on a new ligand, 5-(4-(2H-tetrazol-5-yl)phenoxy)isophthalic acid (H3TPIA), were synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction, elemental analysis, IR spectroscopy, TGA analysis and powder X-ray diffraction. JUC-114, JUC-115 and JUC-116 all possess 3D frameworks with (4,8)-connected fluorite (flu) topology based on similar tetranuclear metal centers as secondary building unit (SBU). Furthermore, the luminescence of the ligand H3TPIA and compounds was measured at room temperature.

Solvothermal Synthesis, Structure, Fluorescence and Magnetism Properties of a Novel 3D Metal-Organic Framework Based on Tetranuclear Copper Secondary Building Units

A novel 3D metal-organic framework based on tetranuclear copper Secondary Building Units, [Cu2(μ3-OH)(4-oip)(DMF)]·DMF·2H2O (JUC-76) (4-oip = 4-hydroxyisophthalic, DMF =N,N-dimethylformamide, and JUC = Jilin University China), has been synthesized under solvothermal conditions. It crystallizes in monoclinic symmetry with space groupP21/n. JUC-76 possesses a three-dimensional network with one-dimensional rhombic channels of approximately 13.6 × 8.5 Å2along the [100] direction. The resulting structure of JUC-76 is a distorted rutile topology with one 3-connected organic node and one 6-connected inorganic node. And its Schläfli symbol is (4·62)2(42·610·83). In addition, JUC-76 exhibits fluorescence emission at 446 nm, and a dominant anti-ferromagnetic interaction between the Cu (II) ions.

Synthesis, structures, fluorescence and magnetism of two lanthanide metal-organic frameworks with CaF2 topology based on silicon-centered tetrahedral ligand

Two 3D multifunctional lanthanide metal-organic frameworks(MOFs), Pr(HTCPS)(H2O)·2DMF·C2H5OH·5H2O(JUC-93) and Pr3(TCPS)2(NO3)(H2O)4(DMA)2·2DMA·C2H5OH·3H2O(JUC-94)[H4TCPS=tetrakis(4-carboxyphenyl)silane, DMF=N,N′-dimethylformamide, DMA=N,N′-dimethylacetamide and JUC=Jilin University China] were synthesized by the self-assembly of a rigid silicon-centered tetrahedral carboxylate ligand H4TCPS and Pr(III) ions in different solvothermal reactions. X-Ray crystallography revealed that they exhibited a rare CaF2 topology framework, constructed from the 4-connected tetrahedral TCPS unit with the 8-connected dinuclear praseodymium cluster unit and trinuclear praseodymium cluster unit, respectively. In addition, the luminescent and magnetic properties of the two compounds were investigated.

A unique (4,12)-connected lanthanide metal-organic framework based on tetranuclear building blocks: Topological analysis, fluorescence and magnetism properties

A 3D multifunctional lanthanide metal-organic framework (MOF), Er4(TCPS)3(H2O)6·10DMF·4H2O (JUC-99) (H4TCPS = tetrakis(4-carboxyphenyl)silane, DMF = N,N′-dimethylformamide and JUC = Jilin University China) has been synthesized by self-assembly of Er(III) ions and rigid silicon-centered tetrahedral carboxylate ligands under solvothermal reactions. X-ray crystallography reveals that JUC-99 exhibits a unique trinodal (4,12)-connected topology, constructed from tetranuclear erbium clusters as 12-connected nodes and tetrahedral ligands TCPS as 4-connected nodes. To the best of our knowledge, JUC-99 is the first example of lanthanide MOFs with trinodal (4,12)-connected topology structure. In addition, the luminescent and magnetic properties of the compound are investigated.

Hydrothermal synthesis, structure, fluorescence property of a novel 3D metal-organic framework with high thermal stability

A novel 3D metal-organic framework (MOF) with remarkable thermal stability, Ni(BIC)2·2.5H2O (JUC-86) (HBIC = 1-H-benzimidazole-5-carboxylic acid and JUC = Jilin University China), has been synthesized under hydrothermal conditions. It crystallizes in tetragonal symmetry with P43212 space group. The 3D structure consists of channels assembled from triple helices with a 4.5 × 4.5 A2 aperture, which are formed by the parallel alignment of three infinite helical chains. The thermogravimetric analysis (TGA) and powder X-ray diffractions (PXRD) indicate JUC-86 with high thermal stability (up to 350 °C).

A rare 3D lanthanide metal–organic framework with the rutile topology: Synthesis, structure and properties

A 3D lanthanide metal–organic framework (MOF) with the rutile topology, Yb(CTC)(DMF)·(H 2O) 2 (JUC-57) (CTC = cis, cis-1, 3, 5-cyclohexanetricarboxylic acid, DMF = N, N′-dimethylformamide, and JUC = Jilin University China), have been synthesized under mild conditions. It crystallizes in monoclinic symmetry with space group P2 1/ n. The structure can be considered to be built up from six-connected inorganic and three-connected organic Secondary Building Units (SBUs) with the rutile topology, Schläfli symbol of which is (4 2·6 10·8 3)(4·6 2) 2. This lanthanide MOF possesses 11.8 × 6.9 Å 2 channels along the [1 0 0] direction, and 6.8 × 6.1 Å 2 channels along the [0 1 1] and [0 1 −1] direction, respectively. The fluorescent and magnetic properties of JUC-57 are characterized and the result reveals that it could be potentially utilized as the multifunctional material.

Structure, Hydrogen Storage, and Luminescence Properties of Three 3D Metal−Organic Frameworks with NbO and PtS Topologies

Three 3D multifunctional microporous metal−organic frameworks (MOFs), Cu2(ABTC)(H2O)2·(DMF)2(H2O) (JUC-62), Cd2(ABTC)(DMF)3·(DMF)2 (JUC-63), and Mn(H2ABTC)(DMF)2 (JUC-64) (H4ABTC = 3,3′,5,5′-azobenzenetetracarboxylic acid, DMF = N,N′-dimethylformamide, and JUC = Jilin University China) have been synthesized by self-assembly of a rigid tetra-carboxylate ligand H4ABTC and corresponding transition metal salts under mild conditions. X-ray crystallography reveals that their topologies are based on NbO (JUC-62) and PtS (JUC-63 and JUC-64) nets, constructed of 4-connected rectangular ABTC4− units with 4-connected square paddle-wheel Cu2(CO2)4(H2O)2 secondary building units (SBUs), tetrahedral bimetallic Cd2(CO2)4(DMF)3 SBUs, and tetrahedral monometallic Mn(CO2)4(DMF)3 SBUs, respectively. High-pressure hydrogen sorption of the activated JUC-62 reveals a type I profile at 77 K, which is saturated at 40 bar with a hydrogen uptake of about 4.71 wt%. Photoluminescence investigations reveal that JUC-62 and JUC-63 disp...