One-dimensional cobalt(ii) coordination polymer featuring single-ion-magnet-type field-induced slow magnetic relaxation

Abstract

Organizing magnetically discrete 3d transition metal ions, which behave as single-ion magnet (SIM) units, in a coordination network is a promising approach to design novel single-molecule magnets (SMMs). Herein a Co(II)-based compound of formula [Co(3-Hppt)₂(adip)(H₂O)₂]·2H₂O (1), has been prepared and structurally analyzed by single-crystal X-ray crystallography. The structure of the title compound consists of well-isolated one-dimensional chains of Co(II) ions where the octahedral metal atoms are spatially separated from each other by adipic acid bridges (Co⋯Co = 11.197 Å). The resulting compound presents a negative uniaxial anisotropy parameter (D = −33.9 cm⁻¹) by the analysis of the direct current magnetic data, which is further probed by ab initio calculations. Alternating-current magnetic susceptibility experiments on 1 exhibit field-induced double magnetic relaxation processes with an anisotropic energy barrier of 38.8 K resulting from the single-ion anisotropy of the individual Co(II) ions.