In:
Chemistry – A European Journal, Wiley, Vol. 28, No. 65 ( 2022-11-21)
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, [Ln 2 (hfac) 6 (ImPhPyobis) 2 ] (Ln III =Gd 1 , Tb 2 , Dy 3 ) and [Ln 2 Cu 2 (hfac) 10 (ImPhPyobis) 2 ] (Ln III =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‐1 H ‐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 {Ln 2 O 2 } 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( U eff ) of 74.0 K while complex 5 exhibits dual relaxation processes with U eff values for the fast‐ and slow‐relaxation being 20.2 K and 30.9 K, respectively, which implies that the second coordination sphere of Dy ion plays a critical role for magnetic relaxation.
Type of Medium:
Online Resource
ISSN:
0947-6539
,
1521-3765
DOI:
10.1002/chem.202202239
Language:
English
Publisher:
Wiley
Publication Date:
2022
detail.hit.zdb_id:
1478547-X
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