Assembly of Discrete, One-, Two-, and Three-Dimensional Silver(I) Supramolecular Complexes Containing Encapsulated Acetylide Dianion with Nitrogen-Donor Spacers

The first successful attempt to construct supramolecular entities via incorporation of bifunctional exodentate ligands into the silver acetylide system is reported. Coordination assembly with nitrogen-donor spacers led to the formation of five distinct supramolecular complexes, namely [(Ag2C2)(AgCF3CC)2)4(pyz)2]n (1), [(Ag2C2)2(AgCF3C02)io(CF3C02)4(DabcoH)4(H20)i.5]-H20 (2), [(Ag2C2)(AgCF3C02)4(CF3C02)(bpaH)]n (3), [(Ag2C2)(AgCF3C02)8(bpa)4]n (4), and [(Ag2C2)2(AgCF3C02)1o(bppz)2(H20)]n (5) (pyz = pyrazine; Dabco = 1,4-diazabicyclo[2.2.2]octane; bpa = 1,2bis(4-pyridyl)ethane; bppz = 2,3-bis(2-pyridyl)pyrazine). Complex 1 is a three-dimensional framework composed of silver columns cross-linked by pyrazine bridges, whereas 2 contains a discrete supermolecule whose core is a Agi4 double cage that is completely surrounded by trifluoroacetate, aqua, and terminal monoprotonated Dabco ligands. Complex 3 has a branched-tree architecture with one terminal of the bpa ligand attached to the silver backbone and the other exposed and protonated. In 4, neutral decanuclear [(Ag2C2)(AgCF3CC)2)8] units are interlinked by bpa spacers adopting both gauche and anti conformations to generate a layer structure. Another two-dimensional network was formed with bppz serving as an angular bridging ligand in 5, in which the building unit is a silver quadruple cage containing 24 silver atoms.