Synthesis of {AlMo₁₄O₄₄}-Based Supramolecular Structures with High Proton Conductivity

Polyoxometalates (POMs) are esteemed for their remarkable stability and exceptionally high proton conductivity, rendering them ripe for extensive exploration owing to their research significance. Herein, we synthesized two bimolybdenum-capped {AlMo^VI₈Mo^V₆O₄₄} cluster-based coordination polymers through a solvothermal method. Single-crystal X-ray diffraction analysis elucidates that H[(H₂bimb)₃(AlMo^VI₈Mo^V₆O₄₄)] [bimb = 1,4-bis(imidazole-1-ylmethyl)benzene, compound 1] is the POMs-organic supramolecular structure. The introduction of zinc ions into the reaction environment facilitated the connection of initially dispersed ligands, which yielded the well-ordered structure H₃[Zn₂(bimb)₄(AlMo^VI₈Mo^V₆O₄₄)]·4H₂O (compound 2) with a layer distance of 11.8 Å. The proton conductivities (σ) of two compounds were measured under conditions of 85 °C and 98% relative humidity (RH), resulting in values of 3.89 × 10^-2 and 4.76 × 10^-2 S·cm^-1, respectively. This study presents a novel approach to fabricating POMs as proton conductors through structural design and manufacturing adjustments.