2024-03-28T17:34:34Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/1862652022-12-14T08:33:02Zcom_10261_89com_10261_3col_10261_342
Cuerva, Cristián
Campo, José A.
Cano, Mercedes
Sanz, J.
Sobrados, Isabel
Díez-Gómez, Virginia
Rivera-Calzada, Alberto
Schmidt, Rainer
2019-07-17T10:55:41Z
2019-07-17T10:55:41Z
2016-07-18
Inorganic Chemistry 55(14): 6995-7002 (2016)
http://hdl.handle.net/10261/186265
10.1021/acs.inorgchem.6b00728
In this work we report on water-free proton conductivity in liquid-crystal pyridylpyrazolate-based Pt(II) and Pd(II) complexes [M(pz)] (pz = 3-(3,5-dialkyloxyphenyl)-5-(pyridin-2-yl)pyrazolate, R(n,n) = CH(OCH); n = 4, 12, 16, M = Pd; n = 12, M = Pt) with potential application as electrolyte materials in proton exchange membrane fuel cells. The columnar ordering of the complexes in the liquid-crystalline phase opens nanochannels, which are used for fast proton exchange as detected by impedance spectroscopy and NMR. The NMR spectra indicate that the proton conduction mechanism is associated with a novel C-H···N proton transfer, which persists above the clearing point of the material. The highest conductivity of ∼0.5 μS cm at 180 °C with an activation energy of 1.2 eV is found for the Pt(II) compound in the mesophase. The Pd(II) complexes with different chain length (n = 4, 12, and 16) show lower conductivity but smaller activation energies, in the range of 0.74-0.93 eV.
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Water-free proton conduction in discotic pyridylpyrazolate-based Pt(II) and Pd(II) metallomesogens
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