• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Chemistry: A European journal >Anomalous Enhancement of Proton Conductivity for Water Molecular Clusters Stabilized in Interstitial Spaces of Porous Molecular Crystals
【24h】

Anomalous Enhancement of Proton Conductivity for Water Molecular Clusters Stabilized in Interstitial Spaces of Porous Molecular Crystals

机译：多孔分子晶体间隙空间中稳定的水分子簇的质子电导率异常增强

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

In an investigation into the proton conductivity of crystallized water clusters confined within low-dimensional nanoporous materials, we have found that water-stable nanoporous crystals are formed by complementary hydrogen bonding between [Co~(III)(H_2bim)_3]~(3+) (H2bim: 2,2'-biimidazole) and TATC~(3-) (1,3,5- tricarboxyl-2,4,6-triazinate); the O atoms in the -COO~- groups of TATC~(3-) in the porous outer wall are strongly hydrogen bonded with H_2O, forming two types of WMCs (water molecular clusters): a spirocyclic tetramer chain (SCTC) that forms infinite open 1D channels, and an isolated cyclic tetramer (ICT) present in the void space. The ICT is constructed from four H_2O molecules as a novel C_2-type WMC, which are hydrogen bonded with four-, three-, and two-coordination spheres, respectively. The largest structural fluctuation is observed at elevated temperatures from the two-coordinated H_2O molecules, which begin to rapidly and isotropically fluctuate on heating. This behavior can be rationalized by a simple model for the elucidation of pre-melting phenomena, similar to those in ice surfaces as the temperature increases. Moreover, high proton conductivity of SCTCs (ca. 10~(-5) Scm~(-1) at 300 K with an activation energy of 0.30 eV) through a proton-hole mechanism was observed for pellet samples using the alternating impedance method. The proton conductivity exhibits a slight enhancement of about 0.1×10~(-5_ Scm~(-1) at 274 K due to a structural transition upon approaching this temperature that elongates the unit cell along the b-axis. The proton-transfer route can be predicted in WMCs, as O(4) of an H_2O molecule at the center of an SCTC shows a motion that rotates the dipole in the b-axis direction, but not the c-axis; the thermal ellipsoids of O(4) based on anisotropic temperature factors obtained by X-ray crystallography reflect a structural fluctuation along the b-axis direction induced by [Co~(III)(H_2bim)_3]~(3+).
机译：在对低维纳米多孔材料中结晶水团簇的质子传导性的研究中，我们发现水稳定的纳米多孔晶体是由[Co〜（III）（H_2bim）_3]〜（3+ ）（H2bim：2,2'-联咪唑）和TATC〜（3-）（1,3,5-三羧基-2,4,6-三叠氮化物）;多孔外壁TATC〜（3-）的-COO〜-基团中的O原子与H_2O牢固地氢键结合，形成两种WMC（水分子簇）：形成无限长的螺环四聚体链（SCTC）开放的1D通道，并且在空隙空间中存在孤立的环状四聚体（ICT）。 ICT由四个H_2O分子构成，作为一种新颖的C_2型WMC，它们分别与四个，三个和两个配位球氢键合。在高温下，由两个配位的H_2O分子观察到最大的结构波动，该分子在加热时开始快速各向同性地波动。这种现象可以通过一个简单的模型来合理化，以阐明预融化现象，这与温度升高时冰表面的现象相似。此外，使用交变阻抗法，通过颗粒的质子-孔机理观察到了SCTC的高质子传导性（在300 K下约为10〜（-5）Scm〜（-1），活化能为0.30 eV）。由于在接近该温度时质子传导率在274 K处显示出约0.1×10〜（-5_ Scm〜（-1）的轻微增加，这是沿b轴拉长了晶胞的温度。可以在WMC中进行预测，因为SCTC中心的H_2O分子的O（4）显示出使偶极子沿b轴方向而不是c轴旋转的运动; O（4）的热椭圆体基于X射线晶体学获得的各向异性温度因子，反映了由[Co〜（III）（H_2bim）_3]〜（3+）引起的沿b轴方向的结构波动。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号