Nanosized Chiral [Mn6Ln2] Clusters Modeled by Enantiomeric Schiff Base Derivatives: Synthesis, Crystal Structures, and Magnetic Properties

Two enantiomeric pairs of new 3d–4f heterometallic clusters have been built from two enantiomer Schiff base derivatives, labeled as R -/ S -H 2 L, in situ obtained from the condensation reactions with o -vanillin and R -/ S -2-phenylglycinol. The formulas of the series clusters are [Mn 6 Ln 2 (μ 3 -OH) 4 (μ 4 -O)(Ac) 4 (H 2 O) 2 ( R -L) 6 ]·NO 3 ·OH (Ln = Dy ( 1R ), Gd ( 2R )), [Mn 6 Ln 2 (μ 3 -OH) 4 (μ 4 -O)(Ac) 4 (H 2 O) 2 ( S -L) 6 ]·NO 3 ·OH (Ln = Dy ( 1S ), Gd ( 2S )), whose crystal structures and magnetic properties have been characterized. Structural analysis indicated that the above clusters consisted of a [Mn 6 Ln 2 ] core, featuring a sandwich configuration. The results of magnetic measurements showed the presence of slow magnetic relaxation with the effective energy barrier of 14.85 K in two Dy derivatives under the condition of zero-dc field, while the significant magnetocaloric effect of Gd analogues was found in a wide temperature range.