Silver–Organic Frameworks Containing Ethynediide or Ethynide with Ancillary Oligo-α-sulfanylpyrazinyl and Dimethylsulfoxide Ligands

Five new silver­(I)–organic frameworks containing ethynediide or alkyl and aryl ethynide, together with newly designed oligo-α-sulfanylpyrazinyl ligands, namely, [(Ag₂C₂)₂­(AgCF₃COO)₁₁(L₁)­(μ₂-DMSO)₃­(DMSO)₅]·¹/₄H₂O (L₁ = 2,6-bis­(pyridin-2-ylthio)­pyrazine, 1), [(Ag₂C₂)₂­(AgCF₃COO)₁₁­(L₂)­(μ₂-DMSO)₅­(DMSO)₃]·¹/₄H₂O (L₂ = 2-(pyrazin-2-ylthio)-6-(pyridin-2-ylthio)­pyrazine, 2), [(AgCC^tBu)₂­(AgCF₃COO)₅(L₃)­(DMSO)₃­(H₂O)] (L₃ = 2,6-bis­(pyrazin-2-ylthio)­pyrazine, 3), [(AgCCPh)₄­(AgCF₃COO)₂(L₃)­(DMSO)₂]·DMSO·¹/₂H₂O (4), and [(AgCCC₆H₄Cl-3)₄­(AgCF₃COO)₂­(L₃)­(DMSO)]·H₂O (5), have been synthesized and characterized by X-ray crystallography. Isomorphous complexes 1 and 2 feature an infinite coordination chain composed of (C₂)₂Ag₁₅ clusters alternatively linked by L₁ or L₂ ligands; weak intermolecular C–H···F hydrogen bonding between adjacent infinite chains results in a three-dimensional supramolecular network. Complex 3 exhibits a coordination layer structure composed of (^tBuC₂)₂Ag₇ aggregates. Compounds 4 and 5 are nearly isostructural, each possessing a ladder-like chain with a centrosymmetric (arylC₂)₈Ag₁₂ cluster as its structure building unit. With the assistance of weak intermolecular hydrogen bonds, three-dimensional and two-dimensional supramolecular architectures were generated in 4 and 5, respectively. The diverse coordination modes of oligo-α-sulfanylpyrazinyl ligands L_n (n = 1, 2, 3) account for the variable framework dimensionalities observed for 1–5. Notably, complexes 3–5 provide the first examples of extended, conformationally flexible N-donor ancillary ligands incorporated into silver alkyl and aryl ethynide systems. In addition, complexes 1–5 display ligand-based photoluminescence.