Synthesis, Structure, and Magnetic Properties of Three Chiral Sodium‐Centered Polynuclear Copper(II) Clusters with L ‐Alanine

By controlling the reactant proportion, three sodium‐centered polynuclear octahedral copper(II)–amino acid clusters, [Na⊂{Cu 6 (Ala) 8 (H 2 O)(ClO 4 )}] · 4ClO 4 · 4H 2 O ( 1 ), Na[Na⊂{Cu 6 (Ala) 8 (ClO 4 )}] 2 · 9ClO 4 · 8H 2 O ( 2 ), and [Na⊂{Cu 5 (Ala) 6 (H 2 O) 3 }] n · 5 n (ClO 4 ) · 3 n (H 2 O) ( 3 ) (Ala = L ‐alanine), were synthesized. The structures were characterized by X‐ray structure analysis. The structure of 1 can be described as an octahedron formed with six copper atoms in which four Cu(Ala) 2 ligands bridge two axial copper ions and capture one Na + in the center of the cage and that of 2 as an octahedral dimer that is linked by two carboxylate oxygen atoms. Complex 3 is a chain composed of incomplete octahedron [NaCu 5 ] units linked together by two carboxylate oxygen atoms. The magnetic susceptibility measurements indicate that all three clusters are ferromagnetic overall, although the intercluster interactions may be antiferromagnetic. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)