Synthesis, characterization and crystal structures of new MnII, FeII and AgI complexes with an angular dipyridyl ligand 2,5-bis(4-pyridyl)-1,3,4-oxadiazole

Three new metal–organic supramolecular complexes based on the linking unit 2,5-bis(4-pyridyl)-1,3,4-oxadiazole (L) and inorganic MnII, FeII, AgI salts have been prepared and structurally determined by single-crystal X-ray analysis. Using L to react with Mn(ClO4)2·6H2O yielded a mononuclear molecule, [Mn(L)2(H2O)2(CH3CN)2](ClO4)2(CH3CN)2 (1) (triclinic, P 2 1, a ¼ 8:790ð4Þ A ° , b ¼ 10:227ð4Þ A ° , c ¼ 23:255ð10Þ A° , a ¼ 89:371ð8Þ8; b ¼ 82:980ð8Þ8; g ¼ 88:621ð8Þ8; Z ¼ 2), in which the hydrogen bonding and p–p aromatic stacking interactions extend the complex molecules to result in a two-dimensional (2D) supramolecular network. Reaction of L and FeCl2·4H2O, in the presence of NH4SCN, afforded another mononuclear complex, [Fe(L)2(NSC)2(H2O)2] (2) (triclinic, P 2 1, a ¼ 7:985ð3Þ A ° , b ¼ 8:657ð3Þ A ° , c ¼ 11:334ð4Þ A ° , a ¼ 94:243ð6Þ8; b ¼ 109:989ð7Þ8; g ¼ 94:413ð7Þ8; Z ¼ 1). A 3D framework is observed through hydrogen bonds and p–p stacking co-affections between the complex molecules. Additionally, a 1D coordination polymer, [Ag2(L)2](BF4)2(CH3OH)0.5(H2O)0.5 (3) (triclinic, P 2 1, a ¼ 8:321ð3Þ A ° , b ¼ 13:926ð5Þ A ° , c ¼ 14:229ð5Þ A ° , a ¼ 70:801ð7Þ8; b ¼ 77:216ð7Þ8; g ¼ 81:299ð7Þ8; Z ¼ 2) was obtained when AgBF4 was used in the above reaction. The structure of 3 contains significant aromatic interactions, which bind the infinite chains together to form a 2D layer network. q 2004 Elsevier B.V. All rights reserved.