Design, Synthesis, and Electrical Performance of Three-Dimensional Hydrogen-Bonded Imidazole-Octamolybdenum-Oxo Cluster Supramolecular Materials

Polyoxometalate (POM)-type supramolecular materials have unique structures and hold immense potential for development in the fields of biomedicine, information storage, and electrocatalysis. In this study, (NH₄)₃ [AlMo₆O₂₄H₆]·7H₂O was employed as a polyacid anion template, pentacyclic imidazole molecules served as organic ligands, and the moderate-temperature hydrothermal and natural evaporation methods were used in combination for the design and synthesis of two octamolybdenum-oxo cluster (homopolyacids containing molybdenum-oxygen structures as the main small-molecular structures)-based organic-inorganic hybrid compounds, [(C₃N₂H₅)(C₃N₂H₄)][(<i>β</i>-Mo₈O₂₆H₂)]_0.5 (<b>1</b>) and {Zn(C₃N₂H₄)₄}{[(<i>γ</i>-Mo₈O₂₆)(C₃N₂H₄)₂]_0.5}·2H₂O (<b>2</b>). Structural and property characterization revealed that both compounds crystallized in the <i>P</i>-1 space group with relatively stable three-dimensional structures under the action of hydrogen bonding. Upon temperature stimulation, the [Zn(C₃N₂H₄)₄]²⁺ cation and water molecules in <b>2</b> exhibited obvious oscillations, leading to significant dielectric anomalies at approximately 250 and 260 K when dielectric testing was conducted under heating conditions.