Enneanuclear [Ni₆Ln₃] Cages: [Ln^III₃] Triangles Capping [Ni^II₆] Trigonal Prisms Including a [Ni₆Dy₃] Single-Molecule Magnet

The use of (2-(β-naphthalideneamino)-2-hydroxymethyl-1-propanol) ligand, H3L, in Ni/Ln chemistry has led to the isolation of three new isostructural [NiII6LnIII3] metallic cages. More specifically, the reaction of Ni­(ClO4)2·6H2O, the corresponding lanthanide nitrate salt, and H3L in MeCN, under solvothermal conditions in the presence of NEt3, led to the isolation of three complexes with the formulas [Ni6Gd3(OH)6(HL)6(NO3)3]·5.75MeCN·2Et2O·1.5H2O (1·5.75MeCN·2Et2O·1.5H2O), [Ni6Dy3(OH)6(HL)6(NO3)3]·2MeCN·2.7Et2O·2.4H2O (2·2MeCN·2.7Et2O·2.4H2O), and [Ni6Er3(OH)6(HL)6(NO3)3]·5.75MeCN·2Et2O·1.5H2O (3·5.75MeCN·2Et2O·1.5H2O). The structure of all three clusters describes a [LnIII3] triangle capping a [NiII6] trigonal prism. Direct current magnetic susceptibility studies in the 5–300 K range for complexes 1–3 reveal the different nature of the magnetic interactions within the clusters: dominant antiferromagnetic exchange interactions for the DyIII and ErIII analogues and dominant ferromagnetic interactions for the GdIII example. Alternating current magnetic susceptibility measurements under zero external dc field displayed fully formed temperature- and frequency-dependent out-of-phase peaks for the [NiII6DyIII3] analogue, establishing its single molecule magnetism behavior with Ueff = 24 K.