NiII‐LnIII Heterometallic Complexes as Single‐Molecule Magnets

Abstract

This article deals with the synthesis, structural characterization, and magnetic studies of heterometallic NiII/LnIII complexes. The article begins with an introduction on the phenomenon of single‐molecule magnetism and various types of molecular complexes that can function as molecular magnets. Among such complexes, 3d/4f combinations have been studied considerably, although examples involving NiII are considerably fewer than those involving ions like MnIII. In this article, we discuss how NiII can be profitably used to construct molecular magnets by describing features that allow this ion to exhibit magnetic anisotropy. Several examples of NiII/4f complexes drawn from the literature and our own work are described. In most of these complexes, NiII is six‐coordinate in a distorted octahedral geometry, while in one example NiII is four‐coordinate in a square‐planar geometry. The various ligands involved in assembling such diverse complexes are also discussed. In each case the magnetic properties of the complexes, including some SMM properties in particular, are discussed. In view of the isotropic nature of the GdIII ion with seven unpaired f electrons, some NiII/GdIII complexes possessing interesting magnetocaloric properties are also included.