Study of Proton Conductivity of a 2D Flexible MOF and a 1D Coordination Polymer at Higher Temperature

We report the proton conduction properties of a 2D flexible MOF and a 1D coordination polymer having the molecular formulas {[Zn­(C₁₀H₂O₈)_0.5(C₁₀S₂N₂H₈)]·5H₂O]}_n (1) and {[Zn­(C₁₀H₂O₈)_0.5(C₁₀S₂N₂H₈)]·2H₂O]}_n (2), respectively. Compounds 1 and 2 show high conductivity values of 2.55 × 10^–7 and 4.39 × 10^–4 S cm^–1 at 80 °C and 95% RH. The conductivity value of compound 1 is in the range of those for previously reported flexible MOFs, and compound 2 shows the highest proton conductivity among the carboxylate-based 1D CPs. The dimensionality and the internal hydrogen bonding connectivity play a vital role in the resultant conductivity. Variable-temperature experiments of both compounds at high humidity reveal that the conductivity values increase with increasing temperature, whereas the variable humidity studies signify the influence of relative humidity on high-temperature proton conductivity. The time-dependent measurements for both compounds demonstrate their ability to retain conductivity up to 10 h.