Structure, Magnetism and Theory of a Family of Nonanuclear Cu^II₅Ln^III₄–Triethanolamine Clusters Displaying Single‐Molecule Magnet Behaviour

Abstract

Synthesis, crystal structures and magnetic studies are reported for four new heterometallic Cu(II)-Ln(III) clusters. The reaction of Cu(NO(3))(2)·3H(2)O with triethanolamine (teaH(3)), pivalic acid, triethylamine and Ln(NO(3))(3)·6H(2)O (Ln=Gd, Tb, Dy and Ho) results in the formation of four isostructural nonanuclear complexes of general formula [Cu(II)(5)Ln(III)(4)O(2)(teaH)(4){O(2)CC(CH(3))(3)}(2)(NO(3))(4)(OMe)(4)]·2MeOH·2Et(2)O [Ln=Gd (1), Tb (2), Dy (3) and Ho (4)]. The metal core of each cluster is made up of four face- and vertex-sharing tetrahedral units. Solid-state DC magnetic susceptibility studies reveal competing anti- and ferromagnetic interactions within each cluster leading to large-spin ground states for 1-4. Solid-state AC magnetic susceptibility studies show frequency-dependent out-of-phase (χ''(M)) signals for 2-4 below 4 K, suggestive of single-molecule magnet behaviour. Ab initio calculations on one of the anisotropic examples (3) provided a rare set of J values for Dy-Cu and Cu-Cu exchange interactions (Dy-Dy zero), some ferro- and some antiferromagnetic in character, that explain its magnetic behaviour.

Molecular Nanomagnets and Related Phenomena

“…21a). These results open the way to the possibility of 360 L. Bogani To make the discussion complete, in panel (h), we show analogous dependencies but in the case when the field lies along the medium axis y. 21 for the structures).…”

Heterometallic 3d–4f single-molecule magnets

“…48 There 49 Two papers report 3d-Er SMMs 62,63 and there are eight 3d-Ho SMMs. 34,57,[64][65][66][67][68]69 All of them display very small energy barriers and no reported blocking temperatures. Some of these are part of families of SMMs, where usually the Dy and Tb analogues display better SMM properties.…”

Crystal structure of the salt bis(triethanolamine-κ4N,O,O′,O′′)cadmium bis[2-(2-oxo-2,3-dihydro-1,3-benzothiazol-3-yl)acetate]

“…The interaction of metal ions with TEA results in the formation of complexes in which TEA demonstrates monodentate (Kumar et al, 2014), bidentate (Kapteijn et al, 1997;Long et al, 2004), tridentate (Gao et al, 2004;Ucar et al, 2004;Krabbes et al, 1999;Haukka et al, 2005;Yeşilel et al, 2004;Mirskova et al, 2013) or tetradentate binding modes (Zaitsev et al, 2014;Kazak et al, 2003;Yilmaz et al, 2004;Rickard et al, 1999;Maestri & Brown, 2004;Kovbasyuk et al, 2001;Tudor et al, 2001). In some complexes, TEA has bridging properties (Langley et al, 2011;Atria et al, 2015;Wittick et al, 2006;Sharma et al, 2014;Yang et al, 2014;Funes et al, 2014). In addition, there are metal complexes known in which TEA molecules are uncoordinating (Ilyukhin et al, 2013;Manos et al, 2012).…”