{Co^III₂Dy^III₂} single molecule magnet with two resolved thermal activated magnetization relaxation pathways at zero field

Abstract

The new complex [Co(III)2Dy(III)2(OMe)2(teaH)2(Piv)6] in the {Co(III)2Dy(III)2} family, shows two well resolved thermal activated magnetization relaxation pathways under AC experiments in zero DC field. Fitted crystal field parameters suggest that the origin of these two pathways relies on two different excited mJ sub-levels.

Exploring the Slow Relaxation of the Magnetization in CoIII‐Decorated {DyIII2} Units

“…The expected M saturation value for a completely aligned sample of a Dy III ion along the main quantization axis must equal g J m J for an isolated ground mJ doublet state. In the previous studies of compound 2 , a saturation value of 20 Nβ was observed, which is in agreement with the expected saturation value for a completely oriented sample along the main quantization axis for mJ =±15/2 with g J =4/3. This was a definitive evidence of an mJ =±15/2 ground state doublet.…”

“…This behavior supports the idea of crystallites field alignment and also suggests a crystal field mainly stabilizing higher values of mJ . We have already observed this behavior for the previously reported magnetic data of compound 2 …”

“…Reactions performed in acetonitrile with the addition of triethylamine as a base for deprotonation of the teaH 3 ligand, affords the compound [Co III 2 Dy III 2 (OCH 3 ) 2 (teaH) 2 (Piv) 6 ]. This compound appears particularly interesting regarding its magnetization relaxation dynamic properties . Hence, we decided to further explore the reaction of [Co 2 (μ‐H 2 O)(Piv) 4 (HPiv) 4 ] with Dy III nitrate in the presence of the teaH 3 ligand.…”

“…The asymmetric unit of the monoclinic C 2 c cell consist of half of the molecule due to the presence of a C 2 rotation axis, which makes both coordination spheres of the Dy III crystallographically equivalent (Figure ). The metal core displays a syn – syn butterfly‐like arrangement in contrast to compound 2 , [Co III 2 Dy III 2 ], where the arrangement is a syn – anti one …”

“…We are now reporting a new member of this family, that is, [Co III 4 Dy III 2 (OH) 2 (teaH) 2 (tea) 2 (Piv) 6 ] ( 1 ), where the local environment of the Dy III is affected through remote decoration of the butterfly {Co III 2 Dy III 2 } core with additional close‐shell Co III ions. We are presenting a detailed magnetic study focused on the dynamic properties and making the comparison of this new {Co III 4 Dy III 2 } core with the closely related [Co III 2 Ln III 2 (OCH 3 ) 2 (teaH) 2 (Piv) 6 ] ( 2 ) previously reported …”