Reductive carbonylation of bis(cyclopentadienyl)titanium dichloride in a room temperature chloroaluminate molten salt

Abstract

A room temperature chloroaluminate molten salt, or ionic liquid, has been employed as an effective medium for the reduction carbonylation of Cp 2TiCl 2. The room temperature melt was composed of aluminum chloride and 1-ethyl-3-methylimidazolium chloride (EMIC) with an AlCl 3:EMIC molar ratio greater than one, termed an acidic melt. Addition of sodium metal to the acidic melt produced an active aluminum reagent which effectively reduced Cp 2TiCl 2 to the Ti(III) complex Cp 2Ti(AlCl 4) 2 −. Exposure of this Ti(III) complex to carbon monoxide gas produced a Ti(III) carbonyl having the proposed formula Cp 2Ti(CO) 2 +. This Ti(III) dicarbonyl can be subsequently reduced to Cp 2Ti(CO) 2.