Two Molecular Hybrids Based on Typical or Decorated Poly-Keggin-Anion Chains: Syntheses, Structures, and Proton-Conductivities

Abstract

Two proton-conductive molecular hybrids were constructed by introducing protonated water clusters, alkaline-earth metal ions and [PMo 12 O 40 ] 3-anions in the gallery of H-bonding networks based on isonicotinic acid N-oxide. Single-crystal X-ray diffraction analyses at 293 K revealed that two complexes crystallized in the orthorhombic space group Pnnm, exhibited very close unit cell parameters, and presented similar three-dimensional hydrogen-bonded networks with large one-dimensional (1D) channels. Interestingly, typical or decorated polyKeggin-anion chains are formed in the 1D channels. Surprisingly, the proton conductivities of two complexes in the temperature range of 85-100°C under 98% RH conditions reached good proton conductivities of 10 -3 S cm -1 . A possible mechanism of the proton conduction was proposed according to the experimental results.