Cubane [CuII4] cluster as a precursor for the preparation of a mixed-valent [CuII12CuI2] core.

Current interests in the chemistry of high-nuclearity transition-metal complexes draw from their utility in the emerging science of nanomaterials, as models for the multimetal active sites of metal-storage proteins, and as single molecule magnets (SMMs). In addition, such super-sized molecules often show a variety of supramolecular interactions. The “self-assembly” process of generating a high-nuclearity cluster from a monoor dimeric precursor generally involves low-dentate organic ligands. Using a pentadentate Schiff base, N,N’-(2-hydroxypropane-1,3-diyl)bis(acetylacetoneimine) (H3L), we have been successful in isolating a discrete tetranuclear copper(ii) cubane cluster [{Cu(HL)}4] (1) which, unlike other clusters, has four pendant arms with eight donor sites (four imine nitrogen atoms and four hydroxy groups) available for binding to additional metal ions. Complex 1, as a “molecular octopus”, is a new precursor for high nuclearity copper clusters. This complex on reaction with copper(ii) perchlorate in presence of KOH forms an octanuclear copper(ii) species