Inherent Proton Conduction in a 2D Coordination Framework

We synthesized a coordination polymer consisting of Zn2+, 1,2,4-triazole, and orthophosphates, and demonstrated for
the first
time intrinsic proton conduction by a coordination network. The compound
has a two-dimensional layered structure with extended hydrogen bonds
between the layers. It shows intrinsic proton conductivity along the
direction parallel to the layers, as elucidated by impedance studies
of powder and single crystals. From the low activation energy for
proton hopping, the conduction mechanism was found to be of the Grotthuss
fashion. The hopping is promoted by rotation of phosphate ligands,
which are aligned on the layers at appropriate intervals.