Synthesis and proton conductivity of azole-substituted cyclic and polymeric phosphazenes

Abstract

In this paper we describe the synthesis, characterization and proton conductivity of azole-substituted cyclic and polymeric phosphazenes. All of the cyclic compounds HTCP, OTCP and polymer, PVTP were fully characterized by elemental analysis, FT-IR, 1H, 13C and 31P NMR spectroscopy. Thermal properties of newly synthesized compounds were investigated with TGA&DSC and the anhydrous proton conductivity was measured by impedance spectroscopy at selected temperatures. It was found that, maximum proton conductivity of 0.043 S cm−1 was obtained for PVTP, which is doped with trifluoromethane sulfonic acid, at 150 °C without decomposition. The cyclic derivative HTCP has been obtained as triclinic crystals in P − 1 space group with two water molecules in asymmetric unit. The X-ray structural characterization result supported that the proton transfer has been ensured by Grotthuss mechanism.