Tetra-, tetradeca- and octadecametallic clusters of Mn.

Reaction of equimolar amounts of MnBr·4HO and HL ((3,5-dimethyl-1-pyrazol-1-yl)methanol) in a basic MeCN solution leads to the formation of [MnII4(L)Br(HO)] (1), whose metallic skeleton is a [MnII4] tetrahedron and cluster core a [MnII4(μ-O)] cubane. Replacing MnBr·4HO with Mn(OCMe)·4HO affords [MnIII2MnII12O(L)(OAc)] (2) which is best described as a series of edge-sharing [Mn] tetrahedra that have self-assembled into a linear array in which each [Mn] pair is 'twisted' with respect to its neighbours in a corkscrew-like manner. Employment of the triangle MnIII3O(OAc)(py) as a reactant instead of a Mn salt results in the formation of [MnIII14MnII4O(L)(HL)(OAc)(HO)] (3) whose core is comprised of three vertex-sharing [MnIII4] butterflies flanked on either side by one [MnIII4] cubane and one [MnIII2MnII2] tetrahedron. Dc magnetic susceptibility and magnetisation measurements of polycrystalline samples of 1-3 reveal the predominance of antiferromagnetic exchange interactions. For [Mn] (1) this leads to a diamagnetic ground state, while for [Mn] (3) competing exchange interactions result in Single-Molecule Magnet (SMM) behaviour with = 22 K.