TY - JOUR
T1 - Introduction of an Ionic Liquid into the Micropores of a Metal-Organic Framework and Its Anomalous Phase Behavior
AU - Fujie, Kazuyuki
AU - Yamada, Teppei
AU - Ikeda, Ryuichi
AU - Kitagawa, Hiroshi
PY - 2014/10/1
Y1 - 2014/10/1
N2 - Controlling the dynamics of ionic liquids (ILs) is a significant issue for widespread use. Metal-organic frameworks (MOFs) are ideal host materials for ILs because of their small micropores and tunable host-guest interactions. Herein, we demonstrate the first example of an IL incorporated within the micropores of a MOF. The system studied consisted of EMI-TFSA (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide) and ZIF-8 (composed of Zn(MeIM)2; H(MeIM)=2-methylimidazole) as the IL and MOF, respectively. Construction of the EMI-TFSA in ZIF-8 was confirmed by X-ray powder diffraction, nitrogen gas adsorption, and infrared absorption spectroscopy. Differential scanning calorimetry and solid-state NMR measurements showed that the EMI-TFSA inside the micropores demonstrated no freezing transition down to 123K, whereas bulk EMI-TFSA froze at 231K. Such anomalous phase behavior originates from the nanosize effect of the MOF on the IL. This result provides a novel strategy for stabilizing the liquid phase of the ILs down to a lower temperature region.
AB - Controlling the dynamics of ionic liquids (ILs) is a significant issue for widespread use. Metal-organic frameworks (MOFs) are ideal host materials for ILs because of their small micropores and tunable host-guest interactions. Herein, we demonstrate the first example of an IL incorporated within the micropores of a MOF. The system studied consisted of EMI-TFSA (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide) and ZIF-8 (composed of Zn(MeIM)2; H(MeIM)=2-methylimidazole) as the IL and MOF, respectively. Construction of the EMI-TFSA in ZIF-8 was confirmed by X-ray powder diffraction, nitrogen gas adsorption, and infrared absorption spectroscopy. Differential scanning calorimetry and solid-state NMR measurements showed that the EMI-TFSA inside the micropores demonstrated no freezing transition down to 123K, whereas bulk EMI-TFSA froze at 231K. Such anomalous phase behavior originates from the nanosize effect of the MOF on the IL. This result provides a novel strategy for stabilizing the liquid phase of the ILs down to a lower temperature region.
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U2 - 10.1002/anie.201406011
DO - 10.1002/anie.201406011
M3 - Article
AN - SCOPUS:85027946340
VL - 53
SP - 11302
EP - 11305
JO - Angewandte Chemie - International Edition
JF - Angewandte Chemie - International Edition
SN - 1433-7851
IS - 42
ER -