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Updated: Sep 6, 2025
The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes
Published on: April 10, 2015
Proton Conduction at High Temperature in High-Symmetry Hydrogen-Bonded Molecular Crystals of RuIII Complexes with Six
Makoto Tadokoro1, Masaki Itoh1, Ryota Nishimura1
1Department of Chemistry, Faculty of Science, Tokyo University of Science, Kagurazaka 1-3, Shinjuku-ku, Tokyo, 162-8601, Japan.
Abstract:
A new H-bonded crystal [RuIII (Him)3 (Im)3 ] with three imidazole (Him) and three imidazolate (Im- ) groups was prepared to obtain a higher-temperature proton conductor than a Nafion membrane with water driving. The crystal is constructed by complementary N-H⋅⋅⋅N H-bonds between the RuIII complexes and has a rare Icy-c* cubic network topology with a twofold interpenetration without crystal anisotropy. The crystals show a proton conductivity of 3.08×10-5 S cm-1 at 450 K and a faster conductivity than those formed by only HIms. The high proton conductivity is attributed to not only molecular rotations and hopping motions of HIm frameworks that are activated at ∼113 K, but also isotropic whole-molecule rotation of [RuIII (Him)3 (Im)3 ] at temperatures greater than 420 K. The latter rotation was confirmed by solid-state 2 H NMR spectroscopy; probable proton conduction routes were predicted and theoretically considered.
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