Synthesis, structural characterization and properties of Ag(I)-complexes based on double-armed 1,3,4-oxadiazole bridging ligands

Four semirigid symmetric double-armed oxadiazole bridging ligands L1-L4 were designed and synthesized in good yields by reactions of 2,5-bis(2-hydroxyphenyl)-1,3,4-oxadiazole and 2,5-bis(3-hydroxyphenyl)- 1,3,4-oxadiazole with 3-(bromomethyl) benzonitrile and 4-(bromomethyl)benzonitrile, respectively. The coordination chemistry of these four ligands with various Ag(I) salts has been investigated. Eleven discrete, one-and two-dimensional polymeric Ag(I) complexes (1-11) were prepared by solution reactions and characterized by infrared spectroscopy, elemental analysis, and single-crystal X-ray diffraction. Compared to our reported ligands of this type, L1-L4 are more flexible. The ligand conformation and polyatomic anion templating effect play a key role in determining the final supramolecular structures. Compound 6 contains 3D intersecting channels with different interior microenvironments. It can absorb two different types of guest molecules (benzene and THF) independently or take them up simultaneously from a mixture of two kinds of guests. Furthermore, it can completely separate THF/furan and benzene/toluene guest substrates in liquid phase, respectively.