Magnetic "Molecular Oligomers" Based on Decametallic Supertetrahedra: A Giant Mn49 Cuboctahedron and its Mn25Na4 Fragment.

Two nanosized Mn49 and Mn25Na4 clusters based on analogues of the high-spin (S=22) [Mn(III)6Mn(II)4(μ4-O)4](18+) supertetrahedral core are reported. Mn49 and Mn25Na4 complexes consist of eight and four decametallic supertetrahedral subunits, respectively, display high virtual symmetry (O(h)), and are unique examples of clusters based on a large number of tightly linked high nuclearity magnetic units. The complexes also have large spin ground-state values (Mn49: S=61/2; Mn25Na4: S=51/2) with the Mn49  cluster displaying single-molecule magnet (SMM) behavior and being the second largest reported homometallic SMM.