[(Cr8Ni6II)-Ni-III](n+) Heterometallic Coordination Cubes

Three new heterometallic [(Cr8Ni6II)-Ni-III] coordination cubes of formulae [(Cr8Ni6L24)-Ni-III-L-II(H2O)(12)](NO3)(12) (1), [(Cr8Ni6L24)-Ni-III-L-II(MeCN)(7)(H2O)(5)](ClO4)(12) (2), and [(Cr8Ni6L24Cl12)-Ni-III-L-II] (3) (where HL = 1-(4-pyridyl)butane-1,3-dione), were synthesised using the paramagnetic metalloligand [(CrL3)-L-III] and the corresponding Ni-II salt. The magnetic skeleton of each capsule describes a face-centred cube in which the eight Cr-III and six Ni-II 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 Cr-III and Ni-II 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 Cr-III ions. Excluding wheel-like structures, examples of large heterometallic clusters containing both Cr-III and Ni-II 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 [(M8M6II)-M-III] cubes, where M-III = Cr, Fe and M-II = Cu, Co, Mn, Pd.

Automated summary

Three new heterometallic coordination cubes have been synthesized using a paramagnetic metalloligand and corresponding Ni-II salt, showing weak ferromagnetic interactions between Cr-III and Ni-II ions. These compounds expand the structurally related family of heterometallic cubes containing Cr-III and Ni-II ions, demonstrating a modular approach to building related polymetallic complexes.