Ferromagnetic Ni(II) discs.

A family of planar disc-like hexa-, octa- and decametallic NiII complexes exhibit dominant ferromagnetic exchange. The deca- and octametallic clusters [NiII10(tmp)2(N3)8(acac)6(MeOH)6] (1, H3tmp=1,1,1-tris(hydroxymethyl)propane; acac=acetylacetonate) and [NiII8(thme)2(O2CPh)4(Cl)6(MeCN)6(H2O)2] (2, H3thme=1,1,1-tris(hydroxymethyl)ethane) represent rare examples of NiII-based single-molecule magnets, and [NiII10] (1) possesses the largest barrier to magnetisation reversal of any NiII single-molecule magnet to date.