[CrIII8NiII6]n+ Heterometallic Coordination Cubes.

Three new heterometallic [CrIII 8NiII 6] coordination cubes of formulae [CrIII 8NiII 6L24(H2O)12](NO3)12 (1), [CrIII 8NiII 6L24(MeCN)7(H2O)5](ClO4)12 (2), and [CrIII 8NiII 6L24Cl12] (3) (where HL = 1-(4-pyridyl)butane-1,3-dione), were synthesised using the paramagnetic metalloligand [CrIIIL3] and the corresponding NiII salt. The magnetic skeleton of each capsule describes a face-centred cube in which the eight CrIII and six NiII ions occupy the eight vertices and six faces of the structure, respectively. Direct current magnetic susceptibility measurements on (1) reveal weak ferromagnetic interactions between the CrIII and NiII ions, with J Cr-Ni = + 0.045 cm−1. EPR spectra are consistent with weak exchange, being dominated by the zero-field splitting of the CrIII ions. Excluding wheel-like structures, examples of large heterometallic clusters containing both CrIII and NiII ions are rather rare, and we demonstrate that the use of metalloligands with predictable bonding modes allows for a modular approach to building families of related polymetallic complexes. Compounds (1)–(3) join the previously published, structurally related family of [MIII 8MII 6] cubes, where MIII = Cr, Fe and MII = Cu, Co, Mn, Pd.