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CtBu)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 Ln (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.