Syntheses, crystal structures and electron paramagnetic resonance studies of CoII- and MnII-coordination polymers with the twisted ligand di(4-pyridyl)disulfide in double bridge fashion

Four coordination polymers, {[Co2(4-DPSS)4(DMF)4](ClO4)4}n (1), {[Mn2(4-DPSS)4(DMF)4](ClO4)4}n (2), {[Co(4-DPSS)2(H2O)(NO3)]NO3·3H2O}n (3) and [Co(4-DPSS)2(NCS)2]n (4) were synthesized by reaction between the cobalt (II) and manganese (II) salts (perchlorate, thiocyanate and nitrate) and the flexible ligand di(4-pyridyl)disulfide (4-DPSS). All the compounds presented repeated rhomboidal structures in which the di(4-pyridyl)disulfide ligands coordinate the metal centers in a double bridged fashion. The crystal packing of these coordination polymers reveals that, in all cases, weak interactions such as classical and non-classical hydrogen bonds, as well as S⋯S interactions, connect the polymeric chains to increase the dimensionality of the network. Low-temperature electron paramagnetic resonance (EPR) measurements on powdered samples show that the transition-metal ions, Co (II) and Mn (II) ions, are in the high spin states S = 3/2 and 5/2, respectively.