Highly conducting ionic liquids based on l-ethyl-3-methylimidazolium cation

Highly conducting EMI-based room-temperature (RT) ionic liquids containing transition metals [EMI][M(III)Cl4] (M = Fe, Fe0.5Ga0.5 and Ga) were prepared, and their thermal and physical properties were well investigated, where EMI is l-ethyl-3-methylimidazolium, All the salts are liquid at RT and show a wide liquid range. High ionic conductivities (1.8-2.0x10−2 S cm−1 at 20 °C) and low viscosities (12–14 cP at 30 °C) are comparable to those of N(CN)2 and C(CN)3 salts. The FeCU and Fco.5Gao.5Cl4 melts exhibit a Curie-like behavior arising from the = 5/2 spins on iron(III) ions, indicating the first conductive-paramagnetic biftinctional RT ionic liquids. On cooling, the solidified FeCl4 salt passes through an antiferromagnetic transition at 4.2 K. On the basis of sixteen EMI-based RT ionic liquids including the present salts, it has become apparent that the conductivity is proportional to the reciprocal of the product of the anion weight and the viscosity.