Synthesis and conductivity of hybrid materials based on germanium-containing polyoxometalates and ionic liquids

Abstract

Three new compounds, [MIMPS]₅GeW₁₁VO₄₀, [MIMPS]₅GeW₁₀MoVO₄₀, and [MIMPS]₅GeMo₁₁VO₄₀, have been synthesized from 1-(3-sulfonic group) propyl-3-methyl imidazolium (MIMPS, C₇H₁₃N₂O₃) and germanium-containing heteropoly acids H₅GeW₁₁VO₄₀, H₅GeW₁₀MoVO₄₀, and H₅GeMo₁₁VO₄₀. IR spectra indicate the formation of the hybrid molecular compounds showing fingerprint vibrational bands of both heteropolyanions and MIMPS cations. The products exhibit high conductivity and small conductive activation energies; conductivities increase with higher temperature. Their conductivities are as follows: [MIMPS]₅GeW₁₁VO₄₀ > [MIMPS]₅GeW₁₀MoVO₄₀ > [MIMPS]₅GeMo₁₁VO₄₀. The sequence is opposite for their conductive activation energies. The results show that the conductivity and conductive activation energies are closely related to their component elements. The W-containing material exhibits higher conductivity and smaller conductive activation energy than Mo-containing material.

Keywords:

• Polyoxometalate
• Ionic liquid
• Quasi-solid-state
• Conductivity
• Activation energy

Acknowledgements

This work was funded by the National Nature Science Foundation of China (21071124, 21173189), the Foundation of NSFC-RFBR (21211120160), the Foundation of State Key Laboratory of Inorganic Synthesis and Preparative Chemistry of Jilin University (2013-06), the Foundation of National Student Research Program, and SRTP Foundation of Zhejiang University (201210335026).