A capped trigonal prismatic cobalt(ii) complex as a structural archetype for single-ion magnets.

ABSTRACT

Two mononuclear, seven-coordinate Co(ii) and Fe(ii) complexes [CoII(BPA-TPA)](BF4)2 (1-Co) and [FeII(BPA-TPA)](ClO4)2 (2-Fe) with a capped trigonal prismatic coordination geometry have been synthesized from the pentapyridyldiamine (BPA-TPA) ligand. 1-Co exhibits easy plane anisotropy in which slow magnetic relaxation is observed under a 1.0 kOe dc field. It is the first example of a single-ion magnet (SIM) of a 3d transition metal ion with a capped trigonal prismatic configuration. 2-Fe is not a SIM at 1.8 K.