The first heteropoly blue-embedded metal–organic framework: crystal structure, magnetic property and proton conductivity

Abstract

The first heteropoly blue-embedded metal–organic framework (MOF) compound [Cu₃(BTC)₂(H₂O)₃]₄[SiW₁₁Mo^VO₄₀](C₄H₁₂N)₅·30H₂O (BTC = 1,3,5-benzenetricarboxylate) has been synthesized by a one-pot hydrothermal reaction method. The heteropoly blue-based MOFs were characterized by elemental analysis, single-crystal X-ray diffraction, IR spectroscopy, diffuse reflectance UV-vis spectroscopy, magnetic measurement, and thermal gravimetric analysis. Both the diffuse reflectance UV-vis spectra and magnetic study demonstrate that the reduction state of Mo(V) was still retained in the heteropoly blue-based MOFs. The performance in humidity-dependent proton conduction of the compound was also investigated, showing enhanced proton conductivity with increasing humidity; this may find potential applications in proton conductors.