Structure Diversity of C₂@Ag_n Cages Consolidated by Heteroaromatic N‑Donor Ligands in Silver Ethynediide Complexes

Seven new silver ethynediide complexes containing ancillary heteroaromatic N-donor ligands, namely, Ag₂C₂·4AgCF₃CO₂­·(bipyH)­(CF₃CO₂)­·H₂O (1), Ag₂C₂­·7AgCF₃CO₂­·(H₃O)­(CF₃CO₂)­·2­(bipyH₂)­(CF₃CO₂)₂­·3H₂O (2), 2Ag₂C₂­·8AgCF₃CO₂·6L¹ (L¹ = pyrazole) (3), Ag₂C₂­·4AgCF₃CO₂­·2L² (L² = 3,5-dimethylpyrazole) (4), Ag₂C₂­·4AgCF₃CO₂­·2L³ (L³ = 1,2,4-triazole) (5), Ag₂C₂­·10AgCF₃CO₂­·2L⁴ (L⁴ = 4,5-dihydro-3-(4-pyridinyl)-2H-benz­(g)-indazole) (6), and Ag₂C₂­·5AgCF₃CO₂­·2­(H₃O)­(CF₃CO₂)­·3­(AgL⁵₂)­(CF₃CO₂)­·2­(L⁵H)­(CF₃CO₂)­·2­(H₂O) (L⁵ = benzimidazole) (7) have been synthesized under hydrothermal conditions and characterized by single crystal X-ray analysis. Directed by N-donor ligands of different bulkiness and disposition of coordinating sites, various silver chain-type architectures (compounds 1 and 3–6) and discrete molecular structures (2 and 7) were assembled. In the case of 1 and 2, the influence of nonincorporated additive agents (NH₄)₂HPO₄ and H₂C₂O₄·H₂O on product formation was also investigated.