Influence of the Coordinated Transition Metal Ion on Magnetic Relaxation of Lanthanide Based Complexes with Imino Nitroxide Biradical Ligands.
Chemistry
; 28(65): e202202239, 2022 Nov 21.
Article
in En
| MEDLINE
| ID: mdl-35979914
ABSTRACT
In spite of achievement of a lot of Ln-radical SMMs, how to improve magnetic behavior of Ln-radical system remains challenging. Here, two series of Ln-radical complexes have successfully been built using an imino nitroxide biradical, namely, [Ln2 (hfac)6 (ImPhPyobis)2 ] (LnIII =Gd 1, Tb 2, Dy 3) and [Ln2 Cu2 (hfac)10 (ImPhPyobis)2 ] (LnIII =Gd 4, Dy 5; hfac=hexafluoroacetylacetonate and ImPhPyobis=5-(4-oxypyridinium-1-yl)-1,3-bis(1'-oxyl-4',4',5',5'-tetramethyl-4,5-hydro-1H-imidazol-2-yl)benzene). For these biradical-metal complexes, two imino nitroxide biradicals bind two Ln(III) ions via their oxygen atoms coming from 4-oxypyridinium units to produce a binuclear {Ln2 O2 } unit. Those imino nitroxide groups are free for complexes 1-3, however one of imino nitroxide groups of the biradical is ligated to the copper(II) ion for complexes 4 and 5. The distinct magnetic relaxation behaviors are observed for two Dy derivatives, as revealed by ac magnetic studies complex 3 presents one magnetic process with the effective energy barrier(Ueff ) of 74.0â
K while complex 5 exhibits dual relaxation processes with Ueff values for the fast- and slow-relaxation being 20.2â
K and 30.9â
K, respectively, which implies that the second coordination sphere of Dy ion plays a critical role for magnetic relaxation.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Chemistry
Journal subject:
QUIMICA
Year:
2022
Type:
Article
Affiliation country:
China