Magnetic Anisotropy of a High-Spin Octanuclear Nickel(II) Complex with a <i>meso</i>-Helicate Core

The octanickel(II) cluster 2b has been synthesized from the novel ferromagnetically coupled dinickel(II) metallacryptand 1b assembled from the m-phenylene-bis(oxamate) ligand. Complex 2b exhibits a dimer-of-tetramers structure, with two oxamate-bridged propeller-shaped tetranuclear units connected through three meta-substituted phenylenediamidate bridges, giving a metallacryptand core of the meso-helicate type. Complex 2b behaves as a ferromagnetically coupled dimer of two S = 2 NiII4 units with appreciable magnetic anisotropy.