Copper(I)-containing ionic liquids for high-rate electrodeposition

New metal-containing ionic liquids Cu(CH(3)CN)(n)]Tf(2)N] (n=2, 4; Tf(2)N=bis(trifluoromethylsulfonyl)- amide) have been synthesised and used as a non-aqueous electrolyte for the electrodeposition of copper at current densities greater than 25 A dm(-2). The tetrahedral copper(I)-containing cation in Cu(CH(3)CN)(4)]Tf(2)N] is structurally analogous to quaternary ammonium and phosphonium ionic liquids and overcomes problems of metal solubility and mass transport. Two CH(3)CN ligands are removed at elevated temperatures to give Cu(CH(3)CN)(2)]Tf(2)N], which can be used as a concentrated non-aqueous electrolyte. The structural and electrochemical characterisation of these compounds is described herein.