Structure of copper(II) complexes grown from ionic liquids - 1-ethyl-3-methyl-imidazolium acetate or chloride.

Crystals of four new copper(II) complexes have been grown from copper(II) acetate/chloride-1-ethyl-3-methyl-imidazolium acetate/chloride-water systems and characterized by X-ray analysis. The first complex, bis-(1-ethyl-3-methyl-imidazolium) tetra-μ-acetato-bis[chloridocuprate(II)], [Emim][Cu(CHO)Cl] () (Emim is 1-ethyl-3-methyl-imidazolium, CHN), contains [Cu(CHO)Cl] coordination anions with a paddle-wheel structure and ionic liquid cations. Two of the synthesized complexes are one-dimensional polymers, namely -poly[1-ethyl-3-methyl-imidazolium [[tetra-μ-acetato-dicuprate(II)]-μ-chlorido] monohydrate], {[Emim][Cu(CHO)Cl]·HO} (), and -poly[1-ethyl-3-methyl-imidazolium [[tetra-μ-acetato-dicuprate(II)]-μ-acetato]], {[Emim][Cu(CHO)]} (). In these compounds, the Cu(CHO) units with a paddle-wheel structure are connected to each other through chloride (in ) or acetate (in ) anions to form parallel chains, between which cations of ionic liquid are situated. The last compound, bis-(1-ethyl-3-methyl-imidazolium) tetra-μ-acetato-bis[aquacopper(II)] tetra-μ-acetato-bis[acetatocuprate(II)] dihydrate, [Emim][Cu(CHO)(HO)][Cu(CHO)]·2HO (), contains two different binuclear coordination units (neutral and anionic), connected through hydrogen bonds between water mol-ecules and acetate ions.