catena-Poly[[disilver(I)(Ag—Ag)-bis[μ-1,1′-(butane-1,4-di­yl)diimidazole-κ²N³:N^3′]] bis­(perchlorate)]: a double helix stabilized by ligand-unsupported argentophilic inter­actions

The title compound, {[Ag₂(C₁₀H₁₄N₄)₂](ClO₄)₂}_n, is a one-dimensional coordination polymer formed by Ag^I atoms linearly bridged by 1,1′-(butane-1,4-di­yl)diimidazole mol­ecules. The chains have a helical arrangement and pairs of chains are held together by the rarely reported ligand-unsupported Ag—Ag inter­action [2.966 (1) Å], which results in a double-helix structure. The double helix contains twisted 24-membered metallomacrocycles, which are composed of four Ag atoms and two ligands. The Ag atoms lie on twofold axes.