Syntheses and crystal structures of manganese(II), cadmium(II), cobalt(II), and zinc(II) complexes with 4-pyridyl dithioether ligands

The reactions of three structurally related flexible pyridyl dithioether ligands, 1,2-bis(4-pyridylthio)ethane (L-1), 1,3-bis(4-pyridylthio)propane (L-2), and 1,5-bis(4-pyridylthio)pentane (L-3), with Mn(ClO4)(2)(.)6H(2)O, Cd(ClO4)(2)(.)6H(2)O, Co(ClO4)(2)(.)6H(2)O, and Zn(ClO4)(2)(.)6H(2)O led to the formation of four new complexes: {[Mn(L-1)(2)(H2O)(2)]-(L-1)(2)(ClO4)(2)(CHCl3)(2)}(infinity) (1), {[Cd(L-2)(2)(H2O)(2)](ClO4)(2)(H2O)(3)}(infinity) (2), {[Co(L-3)(2)(H2O)(2)](ClO4)(2)(H2O)(3)}(2) (3), and {[Zn(L-3)(2)(H2O)(2)]-(ClO4)(2)(H2O)(3)}(2) (4), which have been characterized by elemental analyses, IR spectroscopy, and X-ray crystallography. Single-crystal X-ray analyses show that complex 1 is a unique one-dimensional chain containing cage unit, 2 is a double-stranded chain structure, and 3 and 4 are binuclear cage molecules. In the complexes, all the ligands adopt N,N-bidentate bridging coordination mode using the two pyridyl nitrogens to coordinate to metal centers. In complexes 1 and 2, the uncoordinated sulfur atoms show interchain weak (SS)-S-... interactions, by which two 1-D chains are linked to two different 2-D supramolecular networks. Additional weak C-(HO)-O-... hydrogen bonds further connect complex 1 into a 3-D supramolecular architecture. These (SS)-S-... contacts and C-(HO)-O-... hydrogen bonds also help to stabilize the crystal structures of these complexes.