Ag(I) and Cu(II) Discrete and Polymeric Complexes Based on Single- and Double-Armed Oxadiazole-Bridging Organic Clips

Four new oxadiazole-bridging ligands (L1−L4) were designed and synthesized by the reaction of 2,5-bis(2-hydroxyphenyl)-1,3,4-oxadiazole with isonicotinoyl chloride and nicotinoyl chloride, respectively. L1 and L3 are
unsymmetric single-armed ligands (4- or 3-pyridinecarboxylate arm), and L2 and L4 are symmetric double-armed
ligands (4- or 3-pyridinecarboxylate arms). Nine new complexes, [Ag(L1)]PF6·CH3OH (1), [Ag(L1)]ClO4·CH3OH
(2), Cu(L2)(NO3)2·2(CH2Cl2) (3), [Cu(L2)2](ClO4)2·2(CH2CCl2) (4), Cu(L2)Cl2 (5), [Cu4(L3)2(H2O)2](L3)4(ClO4)4 (6),
[Ag(L4)(C2H5OH)]ClO4 (7), [Ag(L4)(C2H5OH)]BF4 (8), and [Ag(L4)(CH3OH)]SO3CF3 (9), were isolated from the solution
reactions based on these four new ligands, respectively. L1, L2, and L3 act as convergent ligands and bind metal
ions into discrete molecular complexes. In contrast, L4 exhibits a divergent spacer to link metal ions into one-dimensional coordination polymers. New coordination compounds were fully characterized by infrared spectroscopy,
elemental analysis, and single-crystal X-ray diffraction. In addition, the luminescent and electrical conductive properties
of these new compounds were investigated.