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

被引：33

作者：

Tadokoro, Makoto ^{[1
]}

Ohhata, Yuki ^{[1
]}

Shimazaki, Yuriko ^{[1
]}

Ishimaru, Shin'ichi ^{[2
]}

Yamada, Teppei ^{[3
]}

Nagao, Yuki ^{[4
]}

Sugaya, Tomoaki ^{[5
]}

Isoda, Kyosuke ^{[1
]}

Suzuki, Yuta ^{[6
]}

Kitagawa, Hiroshi ^{[7
]}

Matsui, Hiroshi ^{[6
]}

机构：

[1] Tokyo Univ Sci, Dept Chem, Fac Sci, Shinjuku Ku, Tokyo 1628601, Japan

[2] Tokyo Denki Univ, Sch Engn, Dept Environm Mat Sci, Adachi Ku, Tokyo 1208551, Japan

[3] Adv Inst Sci & Technol, Sch Mat Sci, Dept Mat Sci New Mat Design & Synth Japan, Nomi, Ishikawa 9231292, Japan

[4] Kyushu Univ, Grad Sch Engn, Dept Chem & Biochem, Nishi Ku, Fukuoka 8190395, Japan

[5] Waseda Univ, Grad Sch Adv Sci & Engn, Dept Appl Chem, Shinjuku Ku, Tokyo 1698555, Japan

[6] Tohoku Univ, Grad Sch Sci, Dept Phys, Aoba Ku, Sendai, Miyagi 9808578, Japan

[7] Kyoto Univ, Grad Sch Sci, Dept Chem, Sakyo Ku, Kyoto 6068502, Japan

来源：

CHEMISTRY-A EUROPEAN JOURNAL | 2014年 / 20卷 / 42期

关键词：

hydrogen bonds; phase transitions; proton conductivity; supramolecules; water; METAL-ORGANIC FRAMEWORKS; POT SELF-ORGANIZATION; COORDINATION POLYMERS; HYDROGEN; COMPLEXES; SUPERSTRUCTURES; TRANSITION; TECTONICS; ICE;

D O I：

10.1002/chem.201402900

中图分类号：

O6 [化学];

学科分类号：

0703 ;

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(2)bim)(3)](3+) (H(2)bim: 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 H2O, 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 H2O 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 H2O 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 300K with an activation energy of 0.30eV) through a proton-hole mechanism was observed for pellet samples using the alternating impedance method. The proton conductivity exhibits a slight enhancement of about 0.1x10(-5)Scm(-1) at 274K 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 H2O 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(2)bim)(3)](3+).

引用

页码：13698 / 13709

页数：12