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)(AgCF3CO2)4(pyz)2]n (1), [(Ag2C2)2(AgCF3CO2)10(CF3CO2)4(DabcoH)4(H2O)1.5]·H2O (2), [(Ag2C2)(AgCF3CO2)4(CF3CO2)(bpaH)]n (3), [(Ag2C2)(AgCF3CO2)8(bpa)4]n (4),
and [(Ag2C2)2(AgCF3CO2)10(bppz)2(H2O)]n (5) (pyz = pyrazine; Dabco = 1,4-diazabicyclo[2.2.2]octane; bpa = 1,2-bis(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
Ag14 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)(AgCF3CO2)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.