Silver(I)−Organic Networks Assembled with Propargyl-Functionalized Di- and Trihydroxybenzenes

A series of four new ligands bearing terminal ethynide moieties attached via pendant arms to a benzene skeleton have been used in the syntheses of four silver(I) complexes: [(Ag2L1)2·(AgCF3CO2)10·(CH3CN)2·(H2O)4·(μ2-H2O)2]·(AgBF4) (1), [(Ag2L2)·(AgCF3CO2)7·(CH3CN)·(H2O)] (2), {[(Ag2L3)·(AgCF3CO2)10·(CH3CN)6·(H2O)2·(OH)2]·(H2O)} (3), and [(Ag3L4)2·(AgCF3CO2)13·(CH3CN)5·(H2O)] (4) (H2L1 = 1,2-bis(prop-2-ynyloxy)benzene, H2L2 = 1,3-bis(prop-2-ynyloxy)benzene, H2L3 = 1,4-bis(prop-2-ynyloxy)benzene, H3L4 = 1,2,3-tris(prop-2-ynyloxy)benzene). In these compounds, the invariable appearance of the μ4- and μ5-ligation modes of the ethynide moiety affirms the general utility of the silver−ethynide supramolecular synthon Agn⊂CCCH2OC6H4OCH2CC⊃Agn (n = 4, 5) in coordination network assembly. Additionally, several conventional and unconventional silver−ethynyl, argentophilic, hydrogen-bonding, silver−aromatic, and π−π interactions play an important role in stabilizing their framework structures. In 1, Ag15 aggregates are fused together by argentophilic interaction to yield thick silver rods, which are further linked through interchain hydrogen bonds into a 2D network. In 2, butterfly-shaped Ag4 baskets are fused into silver(I) columns, which are further associated by external Ag(CF3COO)2 units and argentophilic interactions to give a metal−organic sheet; adjacent layers are then linked into a 3D metal−organic framework through face-to-face aromatic π−π interactions. In 3, Ag6−phenyl ring−Ag6 structural units are interconnected by a pair of μ4-η2,η2 trifluoroacetate groups to yield silver columns, which are further united by hydrogen bonds to give a 3D metal−organic network. Two kinds of silver rods in parallel orientation are bridged by three μ3-η1,η2 and one μ4-η2,η2 trifluoroacetate groups to generate a two-dimensional metal−organic network of 4, in which the trianion exhibits the unprecedented μ20-coordination mode.