A new oxamato-bridged heterotrinuclear Ni IICu IINi II complex with irregular spin state structure: Synthesis, spectroscopy, crystal structure and magnetism

Abstract

A new oxamato-bridged Ni IICu IINi II species, [Ni(tacn)(H 2O)] 2[μ-Cu(pba)](ClO 4) 2·6H 2O 1, (tacn=1,4,7-triazacyclononane; pba=1,3-propylenebis(oxamato)) has been synthesized and structurally as well as magnetically characterized. Complex 1 has a discrete trinuclear Ni IICu IINi II structure: Two nickel(II) ions are bridged by [Cu(pba)] 2− anion, macrocyclic ligand tacn works as terminal ligand of the nickel(II) center. The magnetic data of compound 1 was analyzed by means of H ̑ = − J ( S ̑ Ni 1 · S ̑ Cu + S ̑ Ni 2 · S ̑ Cu ) + D [ S ̑ z 2 − 1 / 3 S ( S + 1 ) ] + β [ g Ni ( S ̑ Ni 1 + S ̑ Ni 2 ) + g Cu S ̑ Cu ] H leading to g Cu=2.19, g Ni=2.18, J=−112.8 cm −1, D=±4.31 cm −1. The parameters are compared with the similar complexes and the irregular spin state structure of complex 1 is also described here.