Self-Assembly of Coordination Polymers from AgX (X = SbF₆^-, PF₆^-, and CF₃SO₃^-) and Oxadiazole-Containing Ligands

The coordination chemistry of the oxadiazole-containing rigid bidentate ligands 2,5-bis(4-pyridyl)-1,3,4-oxadiazole (L1), 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (L2), and 2,5-bis(3-aminophenyl)-1,3,4-oxadiazole (L3) with inorganic Ag(I) salts has been investigated. Four new coordination polymers (1, 2, 3, and 5) and one new bimetallic macrocyclic supramolecular complex (4) were synthesized from solution reactions of L1−L3 with inorganic Ag(I) salts, respectively. Compounds {[Ag(L1)]SbF6}n (1) (1, monoclinic, P21/c, a = 6.6846(4) Å, b = 27.1113(15) Å, c = 8.6802(5) Å, β = 94.1080(10)°, Z = 4) and {[Ag(L1)]PF6}n (2) (2, monoclinic, P21/c, a = 6.6753(3) Å, b = 27.2824(14) Å, c = 8.2932(4) Å, β = 94.6030(10)°, Z = 4) were obtained from the reactions of L1 with AgSbF6 and AgPF6 in a CH2Cl2/CH3OH mixed solvent system, respectively. Compounds 1 and 2 are isostructural and feature a novel two-dimensional zeolite-like net with two different individual rings. {[Ag(L2)]SbF6}n (3) (3, monoclinic, P21/c, a = 5.5677(3) Å, b = 17.3378(9) Å, c = 15.6640(8) Å, β = 94.4100(10)°, Z = 2) and [Ag2(L2)2](SbF6)2 (4) (4, triclinic, P1̄, a = 8.7221(5) Å, b = 9.2008(6) Å, c = 10.7686(7) Å, α = 70.6270(10)°, β = 75.7670(10)°, γ = 73.7560(10)°, Z = 1) were obtained from one-pot reaction of L2 with AgSbF6 in a CH2Cl2/CH3OH mixed solvent system. Compound 3 features a one-dimensional chain pattern, while compound 4 adopts a novel bimetallic macrocyclic structural motif which consists of Ag2(L2)2 ringlike units (crystallographic dimensions, 8.06 × 7.42 Å2). {[Ag(L3)]SO3CF3}n (5) is generated from L3 and AgSO3CF3 in a CH2Cl2/CH3OH mixed solvent system and crystallizes in the unusual space group Pbcn, with a = 9.8861(5) Å, b = 20.2580(10) Å, c = 17.5517(8) Å, Z = 8. It adopts novel two-dimensional sheets that are cross-linked to each other by strong interlayer N−H···O hydrogen bonding interactions into a novel H-bonded three-dimensional network.