Synthesis, crystal structure and magnetic properties of an oxalato-bridged dinickel(II) complex containing a macrocyclic ligand

A new binuclear nickel(II) complex [Ni(mu-C2O4)(rac-cth)(2)] (ClO4)(2) [rac-cth=rac-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane] has been prepared and its structure determined. It consists of centrosymmetric [Ni(mu-C2O4)(rac-cth)(2)](2+) cations separated by perchlorate anions, with a centre of symmetry lying in the middle of the C-C bond of the bis-bidentate oxalate bridge. The tetraazamacrocycle adopts a folded conformation around the nickel atom, which is six coordinated in a distorted octahedral arrangement. Variable temperature magnetic susceptibility measurements (4-300 K) suggest a moderate intramolecular antiferromagnetic interaction between the metal ions (J= -34.0 cm(-1), g=2.07).Chemistry, Inorganic & NuclearSCI(E)12ARTICLE5527-5355