Crystal structures of [Cu2(bpy)2(H2O)(OH)2(SO4)] • 4H2O and [Cu(bpy)(H2O)2]SO4 with bpy=2,2′-bipyridine

Two sulfato Cu-II complexes [Cu-2(bpy)(2)(H2O)(OH)(2)(SO4)].4H(2)O (1) and [Cu(bpy)(H2O)(2)]SO4 (2) were synthesized and structurally characterized by single crystal X-ray diffraction. Complex 1 consists of the asymmetric dinuclear [Cu-2(bpy)(2)(H2O)(OH)(2)(SO4)] complex molecules and hydrogen bonded H2O mol- ecules. Within the dinuclear molecules, the Cu atoms are in square pyramidal geometries, where the equatorial sites are occupied by two N atoms of one bpy ligand and two O atoms of different mu(2)-OH groups and the apical position by one aqua ligand or one sulfato group. Through intermolecular O-H...O and C-H...O hydrogen bonds and intermolecular pi-pi stacking interactions, the dinuclear complex molecules are assembled into layers, between which the hydrogen bonded H2O molecules are located. The Cu atoms in 2 are octahedrally coordinated by two N atoms of one bpy ligand and four O atoms of two H2O molecules and two sulfato groups with the sulfato O atoms at the trans positions and are bridged by sulfato groups into (1)(infinity)[Cu(bpy)(H2O)(2)(SO4)(2/2)] chains. Through the interchain pi-pi stacking interactions and interchain C-H...O hydrogen bonds, the resulting chains are assembled into bi-chains, which are further interlinked into layers by O-H...O hydrogen bonds between adjacent bichains.