TY - JOUR
T1 - In Situ Encapsulation of Imidazolium Proton Carriers in Anionic Open Frameworks Leads the Way to Proton-Conducting Materials
AU - Wang, Kangcai
AU - Qi, Xiujuan
AU - Wang, Zhi
AU - Wang, Ruihao
AU - Sun, Jie
AU - Zhang, Qinghua
N1 - Publisher Copyright:
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2017/4/26
Y1 - 2017/4/26
N2 - Three anionic open frameworks, formulated as [Him]2Eu2(ox)4(H2O)2·2H2O (1), [Him]2Tb2(ox)4(H2O)2·2H2O (2), and [Hmim]2Eu2(ox)4(H2O)2·2H2O (3; ox = oxalate, im = imidazole, mim = methylimidazole), have been synthesized by a solvent-free method. In these solvent-free processes, in situ encapsulation of imidazolium in the channels of the anionic open frameworks was successfully achieved. These compounds show 1D channels with extensive hydrogen-bonding networks created between the guest molecules and adjacent oxalate oxygen atoms; the imidazolium or methylimidazolium cations are regularly arranged within the channels. Alternating current (AC) impedance measurements revealed that the three compounds display high proton conductivities (>10–3 S cm–1) at 298 K and 98 % relative humidity, with compound 2 showing the highest proton conductivity of 5.0 × 10–3 S cm–1 at 298 K. The high proton conductivities of compounds 1–3 may be attributed to the extensive hydrogen-bonding networks existing in the open frameworks, which are constructed by water molecules, protonated imidazole or methylimidazole molecules, and adjacent oxalate oxygen atoms. This work provides an efficient synthetic strategy for the construction of high-performance solid proton conductors.
AB - Three anionic open frameworks, formulated as [Him]2Eu2(ox)4(H2O)2·2H2O (1), [Him]2Tb2(ox)4(H2O)2·2H2O (2), and [Hmim]2Eu2(ox)4(H2O)2·2H2O (3; ox = oxalate, im = imidazole, mim = methylimidazole), have been synthesized by a solvent-free method. In these solvent-free processes, in situ encapsulation of imidazolium in the channels of the anionic open frameworks was successfully achieved. These compounds show 1D channels with extensive hydrogen-bonding networks created between the guest molecules and adjacent oxalate oxygen atoms; the imidazolium or methylimidazolium cations are regularly arranged within the channels. Alternating current (AC) impedance measurements revealed that the three compounds display high proton conductivities (>10–3 S cm–1) at 298 K and 98 % relative humidity, with compound 2 showing the highest proton conductivity of 5.0 × 10–3 S cm–1 at 298 K. The high proton conductivities of compounds 1–3 may be attributed to the extensive hydrogen-bonding networks existing in the open frameworks, which are constructed by water molecules, protonated imidazole or methylimidazole molecules, and adjacent oxalate oxygen atoms. This work provides an efficient synthetic strategy for the construction of high-performance solid proton conductors.
KW - Conducting materials
KW - Hydrogen bonds
KW - Metal-organic frameworks
KW - Proton transport
KW - X-ray diffraction
UR - http://www.scopus.com/inward/record.url?scp=85018922439&partnerID=8YFLogxK
U2 - 10.1002/ejic.201700157
DO - 10.1002/ejic.201700157
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AN - SCOPUS:85018922439
SN - 1434-1948
VL - 2017
SP - 2295
EP - 2300
JO - European Journal of Inorganic Chemistry
JF - European Journal of Inorganic Chemistry
IS - 16
ER -