First μ3-oxalato-bridged cis and trans configurations nickel macrocyclic complex: Synthesis, structure and magnetic properties

A novel nickel macrocyclic complex {[Ni2(cyclam)2(μ3-C2O4)]}n · (ClO4)2 · H2O has been synthesized and structural characterized by single-crystal X-ray diffraction. The complex forms a chain-like one-dimensional structure linked through a novel μ3-oxalato-bridging mode, which has never been reported for nickel. The complex adopts both trans-III configuration with the R, R, S, S arrangement of the four chiral nitrogen centers and cis-V conformation with the R, R, R, R nitrogen configuration. Variable-temperature magnetic susceptibility studies indicate the existence of weak antiferromagnetic (zj = −1.07 cm−1) coupling.