Herein we report on the facile and largeâscale syntheses and characterizations of a series of transition metalâcontaining ionic liquids (MILs), namely [C12MMIm]n[MCl4] (M=Fe3+, n=1; M=Cu2+, Co2+, Zn2+, Cd2+, n=2; C12MMIm=1âdecylâ2,3âdimethylimidazolium) by simply stoichiometrically mixing metal chlorides and the IL [C12MMIm]Cl. All of the compounds could be obtained in crystalline state at room temperature in nearly 100% yield. Singleâcrystal Xâray diffraction analysis reveals that all the MIL crystals belong to the space group of P21/c, consisting of [C12MMIm]+ cations and halometallate anions that interact with each other giving rise to supramolecular layered structures via CâHâ
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Cl hydrogen bonding and anionâĎ interactions. Thermal properties of the five compounds were studied by differential scanning calorimetry (DSC) and thermogravimetry (TG), revealing reversible phase transitions near room temperature. Interestingly, these MILs are airâ and moistureâstable when stored in ambient conditions. The [C12MMIm]n[MCl4] (M=Cu2+, Co2+ and Fe3+ ) crystals exhibited obvious colourâchange when exposed to ammonia (NH3) gas, indicating potential applications in ammonia detection.