TY - JOUR
T1 - Ni(II)-Based Metallosupramolecular Polymer with Carboxylic Acid Groups
T2 - A Stable Platform for Smooth Imidazole Loading and the Anhydrous Proton Channel Formation
AU - Narayana, Yemineni S.L.V.
AU - Yoshida, Takefumi
AU - Bera, Manas Kumar
AU - Mondal, Sanjoy
AU - Higuchi, Masayoshi
N1 - Funding Information:
We would like to thank the JST-CREST project funding for the research (no. JPMJCR1533) and the High Energy Accelerator Research Organization (KEK, Proposal no. 2018G117) for XAFS analysis. We also thank the AIST Nano-Processing Facility, supported by the “Nanotechnology Platform Program” of the Ministry of Education, Culture, Sports, Science, and Technology (MEXT), Japan, for XPS studies.
PY - 2020/6/23
Y1 - 2020/6/23
N2 - The Ni(II)-based metallosupramolecular polymer with carboxylic acid groups (polyNi) was synthesized via a 1:1 complexation of Ni(II) salt with (4,4′-(9,9-dihexyl-9H-fluorene-2,7-diyl)bis(pyridine-2,6-dicarboxylic acid) for the first time. The divalent state of Ni(II) in the polymer was confirmed by the X-ray absorption fine structure analysis. Smooth loading of imidazole molecules into polyNi proceeded with the help of the carboxylic acid groups to form the imidazole-loaded polyNi (polyNi-Im). Thermogravimetric analysis of polyNi-Im revealed that approximately three imidazole molecules were incorporated per repeating unit of polyNi. The Fourier transform infrared spectrum of polyNi-Im showed a new peak at 3219 cm-1, which shows an ∼73 cm-1 enhancement to -N-H of pristine imidazole. The peak suggests the formation of an imidazolium cation in the polymer. Powder X-ray diffraction indicated no degradation of the polymer structure during the imidazole loading because the diffraction pattern of polyNi-Im was almost the same as that of polyNi except for the presence of peaks corresponding to the imidazole molecules. Interestingly, the scanning electron microscopy measurement showed a large morphological change to uniform spherical particles by loading imidazole to the polymer. PolyNi-Im exhibited good proton conductivity (1.05 × 10-2 mS/cm) at a high temperature (120 °C), which is around 7 orders of magnitude higher than that of pristine polyNi because of the proton conduction pathway formation along the polymer chains by the incorporated imidazole molecules.
AB - The Ni(II)-based metallosupramolecular polymer with carboxylic acid groups (polyNi) was synthesized via a 1:1 complexation of Ni(II) salt with (4,4′-(9,9-dihexyl-9H-fluorene-2,7-diyl)bis(pyridine-2,6-dicarboxylic acid) for the first time. The divalent state of Ni(II) in the polymer was confirmed by the X-ray absorption fine structure analysis. Smooth loading of imidazole molecules into polyNi proceeded with the help of the carboxylic acid groups to form the imidazole-loaded polyNi (polyNi-Im). Thermogravimetric analysis of polyNi-Im revealed that approximately three imidazole molecules were incorporated per repeating unit of polyNi. The Fourier transform infrared spectrum of polyNi-Im showed a new peak at 3219 cm-1, which shows an ∼73 cm-1 enhancement to -N-H of pristine imidazole. The peak suggests the formation of an imidazolium cation in the polymer. Powder X-ray diffraction indicated no degradation of the polymer structure during the imidazole loading because the diffraction pattern of polyNi-Im was almost the same as that of polyNi except for the presence of peaks corresponding to the imidazole molecules. Interestingly, the scanning electron microscopy measurement showed a large morphological change to uniform spherical particles by loading imidazole to the polymer. PolyNi-Im exhibited good proton conductivity (1.05 × 10-2 mS/cm) at a high temperature (120 °C), which is around 7 orders of magnitude higher than that of pristine polyNi because of the proton conduction pathway formation along the polymer chains by the incorporated imidazole molecules.
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U2 - 10.1021/acsomega.0c01735
DO - 10.1021/acsomega.0c01735
M3 - Article
AN - SCOPUS:85087433781
VL - 5
SP - 14796
EP - 14804
JO - ACS Omega
JF - ACS Omega
SN - 2470-1343
IS - 24
ER -