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  • A flexible, porous, cluster-based Zn-pyrazolate-dicarboxylate framework showing selective adsorption properties

    • 摘要:

      A flexible Zn-pyrazolate-carboxylate framework [ZnO (deppy)(oba)]·2.5DMF·2H O (1) (Hdeppy = 3,5-diethyl-4-(4′-pyridyl)pyrazole, H oba = 4,4′-oxobisbenzoic acid) was synthesized by solvothermal reaction. Single-crystal X-ray diffraction indicated that 1 possesses a 10-connected bct topological network based on a rare heptanuclear zinc(ii) cluster. Comparison of crystal structures of 1 determined at 300 K and 150 K illustrated the conformational flexibility of deppy ligands. Thermogravimetry analyses and powder X-ray diffraction measurements showed that 1 has high thermal stability and good water stability. Gas and liquid sorption experiments of 1 not only showed stronger adsorption of CO compared with N, but also demonstrated highly efficient separation of n-propylbenzene from other CH alkylbenzene isomers 1,2,4-trimethylbenzene and 1,3,5-trimethylbenzene. © 2014 The Partner Organisations.

    • 作者:

      Chen Kai-Jie    Chunting He    聊培钦    Wei Yong-Sheng    Zhang Peng-Xiang    Xue Wei    Weixiong Zhang    Jiepeng Zhang    陈小明    

    • 刊名:

      New Journal of Chemistry

    • 在线出版时间:

      2014

  • Metal-organic frameworks: From design to materials

    • 摘要:

      Metal-organic frameworks are a new class of advanced porous materials, which have several important characteristics, such as highly periodical, diverse and designable structures, high porosity, unique and modifiable pore surface, as well as framework flexibility. In this chapter, we give a brief account focusing on the molecular design, synthetic strategies and interesting properties and applications of metal-organic frameworks with a number of selected examples. © 2014 Springer-Verlag Berlin Heidelberg.

    • 作者:

      Jiepeng Zhang    陈小明    

    • 刊名:

      Structure and Bonding

    • 在线出版时间:

      2014

  • Structural transition in the perovskite-like bimetallic azido coordination polymers: (NMe)[b'·b"(n) ] (b' = cr, fe; B" = na, k)

    • 摘要:

      Through in situ variable-temperature single-crystal X-ray diffraction analysis, a solid-solid structural phase transition induced by the successive displacements of the [NMe] guest and a subsequent abrupt order-disorder transform for both the cationic guest and the cage-like framework was tracked in four perovskite-like bimetallic azido coordination polymers: (NMe)[B'·B"(N) ] (B' = Cr, Fe; B" = Na, K). Such structural transition was also confirmed by differential scanning calorimeter measurement, variable-temperature powder X-ray diffraction analysis, and variable-temperature dielectric permittivity measurement, as well as molecular dynamics simulation. Conclusively, these compounds provide a good host-guest model for understanding and modulating the thermal motion behavior of the [NMe] guest in various confined spaces constructed by the perovskite-like azido frameworks. © 2014 American Chemical Society.

    • 作者:

      Ziyi Du    Zhao Ying-Ping    Chunting He    Wang Bao-Ying    Xue Wei    Zhou Hao-Long    Jie Bai    Huang Bo    Weixiong Zhang    陈小明    

    • 刊名:

      Crystal Growth and Design

    • 在线出版时间:

      2014

  • Drastic enhancement of catalytic activity via post-oxidation of a porous Mn triazolate framework

    • 摘要:

      Mn is a powerful active site for catalytic oxidation of alkyl aromatics, but it can be only stabilized by macrocyclic chelating ligands such porphyrinates. Herein, by using benzobistriazolate as a rigid bridging ligand, a porous Mn azolate framework with a nitrogen-rich coordinated environment similar to that of metalloporphyrins was synthesized, in which the Mn ions can be post-oxidized to Mn to achieve drastic increase of catalytic (aerobic) oxidation performance. Later could be better: A robust and redox-active, porous coordination framework has been designed and constructed, in which the Mn ions on the pore surface can be post-oxidized to form unstable Mn sites with drastically enhanced activity for catalytic oxidation of alkylaromatics (see figure; TBHP=tert-butyl hydroperoxide). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

    • 作者:

      聊培钦    Li Xu-Yu    Jie Bai    Chunting He    Zhou Dong-Dong    Weixiong Zhang    Jiepeng Zhang    陈小明    

    • 刊名:

      Chemistry - A European Journal

    • 在线出版时间:

      2014

  • Drastic enhancement of catalytic activity via post-oxidation of a porous MnII triazolate framework

    • 摘要:

      Mn(III) is a powerful active site for catalytic oxidation of alkyl aromatics, but it can be only stabilized by macrocyclic chelating ligands such porphyrinates. Herein, by using benzobistriazolate as a rigid bridging ligand, a porous Mn(II) azolate framework with a nitrogen-rich coordinated environment similar to that of metalloporphyrins was synthesized, in which the Mn(II) ions can be post-oxidized to Mn(III) to achieve drastic increase of catalytic (aerobic) oxidation performance.

    • 作者:

      Liao Pei-Qin    Li Xu-Yu    Bai Jie    He Chun-Ting    Zhou Dong-Dong    Weixiong Zhang    Zhang Jie-Peng    陈小明    

    • 刊名:

      Chemistry (Weinheim an der Bergstrasse, Germany)

    • 在线出版时间:

      2014

  • Turning on the flexibility of isoreticular porous coordination frameworks for drastically tunable framework breathing and thermal expansion

    • 摘要:

      To study the potential flexibility of the (3,9)-connected xmz frameworks, a series of isoreticular metal carboxylate frameworks [M33-OH)(L)3], namely MCF-18(L,M), were constructed by 3-connected, tripodal pyridyl-dicarboxylate ligands (H2L1 = pyridine-3,5-dicarboxylic acid; H2L2 = 4,4′-(pyridine-3,5-diyl) dibenzoic acid; H2L3 = 2,6-di-p-carboxyphenyl-4,4′-bipyridine) and 9-connected, tricapped trigonal-prismatic M33-OH) (O2CR)6(py)3 (M = Fe, Co, Ni; py = pyridyl group) clusters. Powder and single-crystal X-ray diffraction studies showed that, while other isoreticular analogs do not show framework flexibility, the newly designed material MCF-18(L3,Ni) can drastically swell 70-105% in volume and 75-121% in length upon inclusion of different guests, the latter of which is the highest reported value to date. Comparison study showed that the nearly uniaxial framework breathing is generated by the special regulation effect of the xmz topology, but can only be activated by a ligand with a suitable shape. Moreover, the thermal expansion profile of MCF-18(L3,Ni) can be drastically tuned by guest, showing extremely large thermal expansion coefficients up to 430 × 10-6 K-1. The guest-included crystals also show water-like thermal expansion behaviors depending on the cooling rate, which is unanticipated for intrinsic crystalline materials. © The Royal Society of Chemistry 2013.

    • 作者:

      Wei Yong-Sheng    Chen Kai-Jie    聊培钦    Zhu Bao-Yong    Ruibiao Lin    Zhou Hao-Long    Wang Bao-Ying    Xue Wei    Jiepeng Zhang    陈小明    

    • 刊名:

      Chemical Science

    • 在线出版时间:

      2013

  • New Zn-aminotriazolate-dicarboxylate frameworks: Synthesis, structures, and adsorption properties

    • 摘要:

      Three Zn-triazolate-dicarboxylate frameworks, namely, [Zn (atz)(ipa)] (1, Hatz = 3-amino-1,2,4-triazole, H ipa = isophthalic acid), [Zn(datz)(ipa)] (2, Hdatz = 3,5-diamino-1,2,4-triazole), and [Zn(atz)(oba)] (3, Hoba = 4,4′-oxobisbenzoic acid), have been synthesized by solvothermal reactions. Crystal-structure analyses demonstrated that 1-3 are isoreticular three-dimensional porous structures consisting of Zn-triazolate layers and dicarboxylate pillars. The major differences of three compounds are the lengths and orientations of the pillars. Thermogravimetry analyses and powder X-ray diffraction measurements showed that 1-3 have high thermal stability and good water stability. The adsorption properties of 1-3 were investigated by N, CO, and CH sorption experiments. Because 3 has exposed amino groups and distinct pore shape, it has the highest CO uptake and CO/N and CO /CH selectivities at 273 K. © 2013 American Chemical Society.

    • 作者:

      Chen Kai-Jie    Ruibiao Lin    聊培钦    Chunting He    Jianbin Lin    Xue Wei    Yuebiao Zhang    Jiepeng Zhang    陈小明    

    • 刊名:

      Crystal Growth and Design

    • 在线出版时间:

      2013

  • Significant improvement of surface area and CO adsorption of Cu-BTC via solvent exchange activation

    • 摘要:

      The surface area, pore volume and adsorption characteristics of metal-organic frameworks (MOFs) are significantly affected by preparation and activation procedures. In this work, we explore one such key synthesis parameter influencing the characteristic of Cu-BTC. We used a solvothermal method to synthesize copper based MOFs (Cu-BTC) using six different solvents (chloroform, dichloromethane, acetone, ethanol, methanol and water) in the activation process. The effects of different activation solvents on the thermal stability, porous structure and CO adsorption of Cu-BTC were investigated. Using methanol as an activation solvent will produce a highly crystalline and nearly solvent-free Cu-BTC, leading to the largest pore volume (0.823 cm g) and greatest CO adsorption (6.95 mmol g at 25 °C and 132 kPa). © 2013 The Royal Society of Chemistry.

    • 作者:

      Ying Yang    Shukla Pradeep R.    王少彬    Victor RUDOLPH    陈小明     Zhonghua Zhu   

    • 刊名:

      RSC Advances

    • 在线出版时间:

      2013

  • Two new polar coordination polymers with diamond networks: Interpenetration and thermal phase transition

    • 摘要:

      Two new polar coordination polymers, [Cu(Hmpc)] (1) and [Cu(mpc)(DMA)] (2), were synthesized by solvothermal reactions of a ligand 3,5-dimethyl-1H-pyrazole-4-carboxylic acid (H mpc) with Cu(NO). Single-crystal X-ray analysis reveals that 1 crystallizes in the orthorhombic, polar space group Fdd2. Each square-planar coordinated Cu ion is linked to four adjacent Cu ions by mono-deprotonated Hmpc ligands, resulting in a severely distorted 4-connected diamond network, inside which the methyl groups of the ligands are densely packed. In 2, non-centrosymmetric binuclear Cu units serve as 4-connecting nodes, forming a non-porous polar structure consisting of 2-fold-interpenetrated diamond networks. A thermal structural phase transition was detected in 2 at around 323 K. At 298 K, 2 crystallizes in the tetragonal chiral space group P4 (2α), with a = 10.9931 (6) Å, c = 18.0850(9) Å, and Z = 4, whereas at a higher temperature (438 K) it is transferred to the tetragonal non-centrosymmetric space group P4nm (2β), with a = 10.9857(5) Å, c = 9.1031(9) Å, and Z = 2. By repeating in situ single-crystal X-ray diffraction, this phase transition was found to be reversible between a non-twinning non-centrosymmetric crystal (2β) and a racemic-twinning chiral crystal (2α). The symmetry of the diamond network was increased from C to D in the heating process, so that two fold interpenetrated networks become strictly parallel along the c-axis at about 323 K, and the c-axis was halved in 2β. At the same time, 2-fold disordered coordinated DMA molecules in 2α were found to be 8-fold disordered in 2β. According to aizu notation, 2 can be classified as 4mmF4 species, which are potentially secondary ferroic. © 2013 The Royal Society of Chemistry.

    • 作者:

      Qi Xiao-Lin    Zhang Chi    Wang Bao-Ying    Xue Wei    Chunting He    Liu Si-Yang    Weixiong Zhang    陈小明    

    • 刊名:

      CrystEngComm

    • 在线出版时间:

      2013

  • A flexible porous Cu(ii) bis-imidazolate framework with ultrahigh concentration of active sites for efficient and recyclable CO capture

    • 摘要:

      By virtue of planar Cu(μ-OH) cluster units, a flexible porous metal azolate framework not only adsorbs large amounts of CO (19.6 wt% or 266 g L at 298 K and 1 atm) with a high zero-coverage adsorption enthalpy (-47 kJ mol), but also desorbs quickly at very low temperatures. © 2013 The Royal Society of Chemistry.

    • 作者:

      Zhou Dong-Dong    Chunting He    聊培钦    Xue Wei    Weixiong Zhang    Zhou Hao-Long    Jiepeng Zhang    陈小明    

    • 刊名:

      Chemical Communications

    • 在线出版时间:

      2013

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