2026-04-17T19:01:33Zhttps://recercat.cat/oai/request

oai:recercat.cat:2445/1546192025-12-04T21:42:57Zcom_2072_1057col_2072_478917col_2072_478933

00925njm 22002777a 4500 dc Aravena Ponce, Daniel Alejandro author Venegas-Yazigi, Diego author Ruiz Sabín, Eliseo author 2020-04-01T08:24:18Z 2020-04-01T08:24:18Z 2016-07-04 2020-04-01T08:24:18Z Single-molecule magnet (SMM) properties of transition-metal complexes coordinated to lacunary polyoxo-metalates (POM) are studied by means of state of the art ab initio methodology. Three [M(gamma-SiW10O36)(2)] (M =Mn-III Fe-III, Co-II) complexes synthesized by Sato et al. (Chem. Commun. 2015, 51, 4081-4084) are analyzed in detail. SMM properties for the Coll and Mninnsystems can be rationalized due to the presence of low-energy excitations in the case of Co-II, which are much higher in energy in the case of Mn-II. The magnetic behavior of both cases is consistent with simple d-orbital splitting considerations. The case of the Fe-III complex is special, as it presents a sizable demagnetization barrier for a high-spin d(5) configuration, which should be magnetically isotropic. We conclude that a plausible explanation for this behavior is related to the presence of low-lying quartet and doublet states from the iron(III) center. This scenario is supported by ab initio ligand field analysis based on complete active space self-consistent field results, which picture a d-orbital splitting that resembles more a square-planar geometry than an octahedral one, stabilizing lower multiplicity states. This coordination environment is sustained by the rigidity of the POM ligand, which imposes a longer axial bond distance to the inner oxygen atom in comparison to the more external, equatorial donor atoms. Anisotropia Magnetisme Anisotropy Magnetism Single-molecule magnet properties of transition-metal ions encapsulated in lacunary polyoxometalates: a theoretical study