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.