Effect of Anions on the Framework Formation of Novel Ag^I Coordination Polymers with Angular Bridging Ligands

Coordination networks based on the organic ligand 2,5-bis(4-pyridyl)-1,3,4-thiadiazole (L) or 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (L) and various inorganic silver(I) salts were prepared and characterized by single-crystal X-ray analysis. Reaction of AgPF₆ or AgClO₄·H₂O and L¹ in CH₃OH/CHCl₃ medium afforded a unique two-dimensional coordination polymer {[Ag(L¹)](PF₆)}_∞ (1) or {[Ag(L¹)](ClO₄)}_∞ (2) with (2/4,3) topology. However, with the replacement of AgPF₆ or AgClO₄·H₂O with AgNO₃ in the above reaction, an interesting three-dimensional coordination architecture {[Ag₄(L¹)₄(NO₃)₂](NO₃)₂}_∞ (3) constructed through weak interactions between nitrate ions and two different one-dimensional motifs was obtained. Furthermore, two one-dimensional coordination chains {[AgL¹](CF₃SO₃)}_∞ (4) and {[Ag(L²)] (CF₃SO₃)}_∞ (5), with different structural geometries, were obtained by the reactions of AgCF₃SO₃ with L¹ and L², respectively. The structural diversities of these complexes demonstrate that counteranions play essential roles in the construction of such supramolecular frameworks.