Water-assisted proton conduction in a highly stable 3D lead(II) MOF constructed by imidazole dicarboxylate and oxalate ligands

Compared with the proton-conducting metal-organic frameworks (MOFs) constructed by transition metals and rare earth metals, there are fewer main group metal-based MOFs with proton-conducting ability. From the point of view of basic research, it is extremely important to prepare more main group metal-based MOFs to explore their proton conductivity and mechanism. Herein, a new highly stable three-dimensional Pb(II) MOF, [Pb-2(p-IPh-H2IDC)(2)(C2O4)](n) (1) (p-IPhH3IDC = p-N-imidazole-1-yl)-phenyl-1H-imidazole-4,5-dicarboxylic acid) constructed by imidazole dicarboxylate and oxalate ligands was solvothermally prepared, which can hold its structural rigid after soaking in water or acidic and basic solutions. Its water-assisted proton conductivity was examined under different relative humidities and variable temperatures, and boosted with increasing temperature and humidity. In terms of crystal structural analysis, calculated activation energy (E-a) value, H2O vapor absorption and powder X-ray diffraction (PXRD) determinations, the proton conducting mechanism of 1 was speculated as well.

Automated summary

In this study, a new highly stable three-dimensional Pb(II) MOF was prepared and its proton conductivity was examined under different humidities and temperatures. The proton conducting mechanism was speculated based on crystal structural analysis and calculated activation energy.