A Coordination Polymer of Nickel(II) Based on a Pentadentate N, S, and O Donor Ligand

The synthesis, structural characterization, and electrochemical properties of a Ni^II complex derived from the template reaction of N,N‘-bis(2-mercaptoethyl)-1,5-diazacyclooctane nickel(II), Ni-1, with ICH₂CO₂Na are described. Blue N-(3-thiabutyl)-N‘-(3-thiapentanoate)-1,5-diazacyclooctanenickel(II)iodide, [(tbtp-daco)Ni][I], [5]I, contains Ni^II in an octahedral environment with N₂S₂O₂ donor atoms; one oxygen is from an adjacent [(tbtp-daco)Ni] ion and has the same distance to Ni^II as the intramolecular oxygen, resulting in a coordination polymer. Complex [5]I·H₂O, C₁₃H₂₇N₂O₃S₂NiI, crystallizes in the orthorhombic space group Pbca with a = 10.898(3), b = 18.103(5), c = 19.020(5), and Z = 8. The extent to which the polymer is retained in solution is counterion dependent, which influences redox properties (accessibility of Ni^I and Ni^III).