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 [Ni^II₆Ln^III₃] 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 (<b>1</b>·5.75MeCN·2Et₂O·1.5H₂O), [Ni₆Dy₃(OH)₆(HL)₆(NO₃)₃]·2MeCN·2.7Et₂O·2.4H₂O (<b>2</b>·2MeCN·2.7Et₂O·2.4H₂O), and [Ni₆Er₃(OH)₆(HL)₆(NO₃)₃]·5.75MeCN·2Et₂O·1.5H₂O (<b>3</b>·5.75MeCN·2Et₂O·1.5H₂O). The structure of all three clusters describes a [Ln^III₃] triangle capping a [Ni^II₆] trigonal prism. Direct current magnetic susceptibility studies in the 5–300 K range for complexes <b>1</b>–<b>3</b> reveal the different nature of the magnetic interactions within the clusters: dominant antiferromagnetic exchange interactions for the Dy^III and Er^III analogues and dominant ferromagnetic interactions for the Gd^III example. Alternating current magnetic susceptibility measurements under zero external dc field displayed fully formed temperature- and frequency-dependent out-of-phase peaks for the [Ni^II₆Dy^III₃] analogue, establishing its single molecule magnetism behavior with <i>U</i>_eff = 24 K