Enhancement of magnetic anisotropy in a Mn–Bi heterobimetallic complex

Abstract

A novel MnBi heterobimetallic complex, featuring the closest MnBi interaction for a paramagnetic molecular species, exhibits unusually large axial zero-field splitting. We attribute this enhancement to the proximity of Mn to a heavy main group element, namely, bismuth.

Exchange Coupling in Binuclear Manganese and Cobalt Complexes with the Tetraimido Sulfate Anion [S(NtBu)4]2–

“…Recent examples display cyanate bridging between Mn II and Fe III 6 or W V 7 as well as oxo bridges between Mn III and Dy III8 and Mn II and Bi III . 9 Heterobimetallic ligand-induced synergies are not limited to manganese but are also triggered by, e.g., Co II , 10 Ni II , 11 and Fe II . 3 However, little is known about less traditional ligands containing heavier maingroup elements.…”

“…They are indeed particularly attractive probes for observing enhancement of the magnetic anisotropy. 9 The target compound 1 was synthesized from the donor-stabilized dilithium tetraimidosulfate [(THF) 4 Li 2 (NtBu) 4 S] and 2 equiv of MnCl 2 , both dissolved in THF at ambient temperature (Scheme 1). Direct crystallization of the reaction mixture at 34 °C yielded orange crystals suitable for X-ray structure analysis in 67% yield.…”

Enhancing Steric Hindrance via Ligand Design in Dysprosium Complexes: From Induced Slow Relaxation to Zero-Field Single-Molecule Magnet Properties

“…33,34 Currently, it seems that the experimental exploration of further cyclopentadienyl substitutions is stalling. New strategies to include heavier 35,36 and softer main group elements 15,37,38 still mostly rely on p-block substituted cyclopentadienyl ligands for lanthanide-based SMMs. 39−43 Since the obtained f-element containing complexes do not necessarily show better SMM performances, investigation of ligands, whose design is further away from cyclopentadienyl derivatives, seems a challenging yet promising alternative.…”

“…These parameters depend on the relaxation time of the magnetization and on the energy barrier U . While the latter is difficult to apprehend, ligand tuning and engineering highly influence the magnetic anisotropy of a molecule and, therefore, may directly impact the magnitude of the energy barrier to spin reversal. − Indeed, magnetic anisotropy has been demonstrated to be a key factor in SMM design in the past decade. − Since the discovery of lanthanide-based single-molecule magnets in 2003, , it appears that lanthanides are the most suitable candidates to generate highly anisotropic complexes with promising magnetic abilities . This is due to their large magnetic moment and their huge intrinsic anisotropy stemming from a strong spin–orbit coupling .…”

“…Even more challenging is to find ligands that may induce better magnetic performances, for example by entirely suppressing alternative relaxation processes such as Raman relaxations and underbarrier quantum tunneling of the magnetization (QTM). , Currently, it seems that the experimental exploration of further cyclopentadienyl substitutions is stalling. New strategies to include heavier , and softer main group elements ,, still mostly rely on p-block substituted cyclopentadienyl ligands for lanthanide-based SMMs. − Since the obtained f-element containing complexes do not necessarily show better SMM performances, investigation of ligands, whose design is further away from cyclopentadienyl derivatives, seems a challenging yet promising alternative. ,, Notably, the large family of SN ligands − provides a versatile and Galore tunable platform toward the design of SMMs. , The extreme flexibility of sulfur coupled with the hardness of the nitrogen donor atoms offers a promising compromise for obtaining an appropriate environment around the paramagnetic center, as demonstrated recently. , It further allows a fine-tuning of the SN ligands toward a well-controlled synthesis of novel mono- and multinuclear SMMs. Starting from selected SN ligands, we recently obtained binuclear systems with antiferromagnetically coupled manganese and cobalt centers .…”