The march of progress: structures of the adducts of potassium dicyanidoaurate(I) with 2,2'-bipyridyl (redetermination) and 1,10-phenanthroline

The structure of the 2,2'-bipyridyl adduct poly[(μ₂-2,2'-bipyridyl-κ³N,N':N)di-μ₃-cyanido-κ⁶C:N:N-gold(I)potassium(I)], [AuK(CN)₂(C₁₀H₈N₂)]_n, (1) (space group P2₁), has been redetermined [previous determination: Jones et al. (1980). Acta Cryst. B36, 160-162]. The bipyridyl ligands coordinate only the potassium ion, which has a coordination sphere consisting of seven N-atom donors; gold(I) remains in the form of linear dicyanidoaurate(I) ions. The extended structure consists of layers in which the Au^I atoms form chains parallel to the short a axis, with Au...Au contacts of 3.7286 (1) Å, whereas the chains of potassium ions, which are also parallel to a, are bridged by bipyridyl and dicyanidoaurate residues. The analogous 1,10-phenanthroline adduct, namely poly[di-μ₃-cyanido-κ⁶C:N:N-(μ₂-1,10-phenanthroline-κ³N,N':N)gold(I)potassium(I)], [AuK(CN)₂(C₁₂H₈N₂)]_n, (2), crystallizes as nonmerohedral twins in the space group C2/c. The packing is closely related to that of (1), but the chains are now parallel to the short b axis and the layers are parallel to (10\overline{1}). The two independent Au^I atoms occupy special positions on inversion centres and twofold axes; the Au...Au contacts are 3.6771 (2) Å.