Polynuclear Nickel(II) Complexes: Preparation and Magnetic Properties of NiII4, NiII5, and NiII6 Species with Ligands containing O∩X∩O (X = S, Se or N) Donor Atoms

Abstract

AbstractA family of bisphenol‐containing ligands with XO2 donor atoms, where X = S, Se, or N, yields [NiII]4 (1) and (2), [NiII]5 (3), and [NiII]6 (4) complexes. Complex 2, 3, and 4 have been structurally characterised by X‐ray diffraction. The compounds were characterised spectroscopically and by variable‐temperature (2−295 K), variable‐field (1, 4, and 7 T) magnetic susceptibility measurements. Analysis of the magnetic data shows predominant ferromagnetic interactions between the nickel centres (SNi = 1) indicating “high‐spin” ground states for 1, 2, and 3, whereas complex 4 shows antiferromagnetic interactions. A plot of J vs. Ni−O−Ni angles for all structurally characterised Ni4O4 cubane cores, including 2, irrespective of their symmetry, shows a large variation of J values within a small range of Ni−O−Ni angles. A simple two‐J model was found to be adequate to describe the magnetic properties of the hexanuclear complex, 4. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)