10.1021/acsomega.0c01735.s001
Yemineni S L V Narayana
Yemineni
S L V Narayana
Takefumi Yoshida
Takefumi
Yoshida
Manas Kumar Bera
Manas Kumar
Bera
Sanjoy Mondal
Sanjoy
Mondal
Masayoshi Higuchi
Masayoshi
Higuchi
Ni(II)-Based Metallosupramolecular Polymer with Carboxylic
Acid Groups: A Stable Platform for Smooth Imidazole Loading and the
Anhydrous Proton Channel Formation
American Chemical Society
2020
Ni
scanning electron microscopy measurement
loading
powder X-ray diffraction
proton conduction pathway formation
Smooth Imidazole Loading
imidazole molecules
Anhydrous Proton Channel Formation
-9H
polyNi-Im
polyNi
carboxylic acid groups
polymer
2020-06-13 00:13:23
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Ni_II_-Based_Metallosupramolecular_Polymer_with_Carboxylic_Acid_Groups_A_Stable_Platform_for_Smooth_Imidazole_Loading_and_the_Anhydrous_Proton_Channel_Formation/12476459
The
Ni(II)-based metallosupramolecular polymer with carboxylic
acid groups (<b>polyNi</b>) 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 <b>polyNi</b> proceeded
with the help of the carboxylic acid groups to form the imidazole-loaded <b>polyNi</b> (<b>polyNi-Im</b>). Thermogravimetric analysis
of <b>polyNi-Im</b> revealed that approximately three imidazole
molecules were incorporated per repeating unit of <b>polyNi</b>. The Fourier transform infrared spectrum of <b>polyNi-Im</b> showed a new peak at 3219 cm<sup>–1</sup>, which shows an
∼73 cm<sup>–1</sup> 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 <b>polyNi-Im</b> was almost the same
as that of <b>polyNi</b> 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. <b>PolyNi-Im</b> exhibited good proton conductivity (1.05 × 10<sup>–2</sup> mS/cm) at a high temperature (120 °C), which is around 7 orders
of magnitude higher than that of pristine <b>polyNi</b> because
of the proton conduction pathway formation along the polymer chains
by the incorporated imidazole molecules.