Family of Mixed 3d–4f Dimeric 14-Metallacrown‑5 Compounds: Syntheses, Structures, and Magnetic Properties

An
isomorphous family of mixed 3d–4f dodenuclear aggregates,
{[MnIII8Ln4(Clshi)8(OAc)6(μ3-OCH3)2(μ3-O)2(CH3OH)12(H2O)2]·4CH3OH·xH2O)} (where Ln = EuIII (1), GdIII (2), TbIII (3), and
DyIII (4); ClshiH3 = 5-chlorosalicylhydroxamic
acid; x = 5 for 1 and 3; x = 6 for 2; x =
2 for 4), were synthesized and characterized. They were
obtained from the reaction of ClshiH3 with Mn­(OAc)2·4H2O and Ln­(NO3)3·6H2O. These isomorphous mixed 3d–4f compounds represent
a family of novel structures with lanthanide ions in the metallacrown
(MC) ring. Each dodecanuclear aggregate contains two offset stacked
14-MC-5 units with M–N–O–M–N–O–Ln–O–N–M–O–N–M
connectivity to capture one LnIII ion in the core of each
MC. Two 14-MC-5 units are connected through O ions with four Mn ions
and six O atoms arranged in a double Mn4O6 cubane.
Magnetic measurement indicates that antiferromagnetic interactions
are present between the metal ions. The DyIII analogue
with high anisotropy and large spin shows slow magnetization relaxation
at a direct-current field of 2 kOe.