Hexanuclear, Heterometallic, Ni₃Ln₃ Complexes Possessing O‑Capped Homo- and Heterometallic Structural Subunits: SMM Behavior of the Dysprosium Analogue

The reaction of hetero donor chelating mannich base ligand 6,6′-{(2-(dimethylamino)­ethylazanediyl)­bis­(methylene)}­bis­(2-methoxy-4-methylphenol) with Ni­(ClO₄)₂·6H₂O and lanthanide­(III) salts [Dy­(III) (1); Tb­(III) (2); Gd (III) (3); Ho­(III) (4); and Er­(III) (5)] in the presence of triethylamine and pivalic acid afforded a series of heterometallic hexanuclear Ni­(II)–Ln­(III) coordination compounds, [Ni₃Ln₃(μ₃-O)­(μ₃-OH)₃(L)₃­(μ-OOCCMe₃)₃]·(ClO₄)·wCH₃CN·xCH₂Cl₂·yCH₃OH·zH₂O [for 1, w = 8, x = 3, y = 0, z = 5.5; for 2, w = 0, x = 5, y = 0, z = 6.5; for 3, w = 15, x = 18, y = 3, z = 7.5; for 4, w = 15, x = 20, y = 6, z = 9.5; and for 5, w = 0, x = 3, y = 2, z = 3]. The molecular structure of these complexes reveals the presence of a monocationic hexanuclear derivative containing one perchlorate counteranion. The asymmetric unit of each of the hexanuclear derivatives comprises the dinuclear motif [NiLn­(L)­(μ₃-O)­(μ₃-OH)­(μ-Piv)]. The cation contains three interlinked O-capped clusters: one Ln^III₃O and three Ni^IILn^III₂O. Each of the lanthanide centers is eight- coordinated (distorted trigonal-dodecahedron), while the nickel centers are hexacoordinate (distorted octahedral). The study of the magnetic properties of all compounds are reported and suggests single molecule magnet behavior for the Dy­(III) derivative (1).