Humidity-triggered single-crystal-to-single-crystal structural transformations in a Zn(ii) coordination polymer displaying unusual activation energy change in proton conductivity.

Single-crystal-to-single crystal structural conversions occur in a Zn(ii) coordination polymer, uniquely induced by fine-tuned relative humidity. Proton conductivity depends on the number of hydrogen bonds in the structures. Slope change in the Arrhenius plot is uncommon among coordination-based conductors and associated with temperature-dependent phase changes.