Probing the influence of molecular symmetry on the magnetic anisotropy of octahedral cobalt(II) complexes

摘要

We herein report on the synthetic, structural, magnetic, and computational studies of six air-stable mononuclear Co(II) complexes with distorted octahedral geometry from PyBox type ligands. Magnetic and theoretical studies reveal that these complexes all exhibit field-induced type single-molecule magnet behaviour and a large energy splitting between the ground and first excited Kramers doublets. Dynamic magnetic property analysis shows that the Raman relaxation process is the predominant process in all six compounds. For complexes 1, 2, 3, 5, and 6, the contribution of the direct process also existed. Importantly, the axial zero-field splitting parameter D in this series varies from positive to negative with the increased distortion of the octahedral geometry for the Co(II) center, indicating that the fine-tuning of the molecular symmetry is an effective approach to manipulate the magnetic anisotropy in SIMs.