Assembly of Silver-Organic Frameworks and Discrete Molecules Containing Embedded 1,3-Butadiyne-1,4-diide with Ancillary Heteroaromatic N‑Donor Ligands

Six new silver­(I) double salts containing embedded 1,3-butadiyne-1,4-diide
(C42–) and various types of ancillary
heteroaromatic N-donor ligands, namely [{(Ag2C4)0.5(AgNO3)3(L1)}·H2O]n (1; L1 = 3-chloropyridine),
[(Ag2C4)2(AgCF3CO2)9(L1)7(H2O)]n (2; L1 = 3-chloropyridine), [(Ag2C4)2(AgCF3CO2)9(L2)7(H2O)]n (3; L2 = 3-bromopyridine), [{(Ag2C4)­(AgCF3CO2)5(L3)1.5(H2O)2}·H2O]n (4; L3 = 2-methylpyrazine), [(Ag2C4)­(AgCF3CO2)6(L4)6] (5; L4 = 2-cyanopyridine), and [(Ag2C4)­(AgCF3CO2)10(L5)8] (6; L5 = imidazole) have been synthesized and characterized
by X-ray crystallography. Complex 1 exhibits a two-dimensional
coordination network in which the basic building unit is a [Ag4C4Ag4] aggregate. Isomorphous complexes 2 and 3 feature a composite-chain structure with
trifluoroacetate and halogen-substituted pyridine ligands surrounding
a columnar silver backbone. Complex 4 is a three-dimensional
coordination framework composed of silver columns cross-linked by
external silver atoms and 2-methylpyrazine bridges. Complex 5 contains two nearly identical discrete supramolecular clusters,
each with its [Ag4C4Ag4] core stabilized
by four bridging 2-cyanopyridine ligands and three peripheral trifluoroacetates
at each terminal. Complex 6 is composed of somewhat similar
but larger discrete supramolecules, with its [Ag4C4Ag4] core stabilized by trifluoroacetate as well
as both inner and peripheral bis­(imidazole)silver units.