The reduction of dioxotetrachlororuthenate(VI) to hexachlororuthenate(IV) in a basic 1-butylpyridinium chloride-aluminium(III) chloride ionic liquid

Article abstract of DOI:10.1016/0277-5387(95)00139-J

The anion [RuO2Cl4](2-) is sufficiently stable in a basic [NBupy]Cl-AlCl3 ([NBupy]=1-butylpyridinium) ionic liquid (44.44 mol% AlCl3) at ambienttemperature to enable its solution electronic absorption spectrum to be recorded for the first time, but is slowly reduced (k=1.45E-5 s**-1; t( 1/2)=13.3 h) in a pseudo-first-order process to give predominantly [RuCl6](2-), according to [RuO2Cl4](2-) + 2[AlCl4](-) [RuCl6](2-) + 2 [AlOCl2](-) + Cl2. A by-product of the reduction process was tentatively identified as [Ru2OCl10](4-), and was believed to be formed according to 2[RuO2Cl4](2-) + 3[AlCl4](-) [Ru2OCl10](4-) + 3 [AlOCl2](-) + 2Cl2. This is the first documented irreversible transfer of an oxide ion from an isolable transition metal complex to tetrachloroaluminate in an ambient-temperature ionic liquid.