ORGANOMETALLIC SYNTHESIS IN AMBIENT-TEMPERATURE CHLOROALUMINATE(III) IONIC LIQUIDS - LIGAND-EXCHANGE REACTIONS OF FERROCENE

The ambient temperature ionic liquid system [bmim]Cl-AlCl3 (where [bmi m](+) = 1-butyl-3-methylimidazolium cation) has been used to prepare a number of arene(cyclopentadienyl)iron(II) complexes of the type [Fe(C 5H5)(arene)](+) from ferrocene. The ionic liquid acts as both solvent and Lewis acid source ([Al2Cl7](-)). The products were only formed on addition of a proton source, [bmim][HCl2](2), confirming mechanistic f ormulations involving a combination of Lewis and Bronsted acid activit y. The X-ray crystal structure analysis of [Fe(eta(5)-C5H5)(eta(6)-C6H 5C6H4Br)][PF6] is also reported. The structure clearly shows both pi-p i stacking interactions between neighbouring cations and hydrogen bond s between the cations and anions.