Cubic assembly of a geometrically frustrated {Fe12} spin cluster.

We describe an S(4)-symmetric {Fe(12)} spin cluster [Fe(12)O(4)(OH)(2)(L)(4)(OAc)(8)][Cl](2) {H(4)L = (HOCH(2)CH(2))(2)NCH(2)CH(2)N(CH(2)CH(2)OH)(2)} where the iron(III) centres describe a squashed hexagonal antiprism. The clusters pack into a large cubic cell with circular cavities, lined by weak C-H···O interactions, and a unit cell volume of over 60,000 Å(3) containing large solvent accessible voids. The core of the cluster is stable in solution, as confirmed by electrospray mass spectrometry. The cluster possesses a non-trivial, frustrated S = 0 ground state, due to the presence of multiple competing antiferromagnetic interactions. The finite temperature Lanczos method has been employed to calculate the temperature dependent magnetic properties of an analogous dodecanuclear S(i) = 3/2 model spin system, in order to reduce the very large Hilbert space. Three archetypal models with two independent exchange coupling parameters have been employed that render a low temperature feature possible, as seen in the χ vs. T plot for the {Fe(12)} spin cluster.

Access to an unusual Fe9 core topology from the initial use of tricine in iron(III) cluster chemistry.

We describe an enneanuclear Fe(III) complex with an unusual boat-shaped core topology and an S=11/2 ground state, assembled using the ligands tricine {N-(2-hydroxy-1,1-bis(hydroxymethyl)ethyl)glycine, H(4)L} and 2-phenoxybenzoate.

Bis-tris propane as a new polydentate linker in the synthesis of iron(III) and manganese(II/III) complexes.

We describe the synthesis, structure, and magnetic properties of two new complexes, one decanuclear iron(III) cluster and one hexanuclear mixed-valence manganese(II/III) cluster, where the previously unexplored polydentate ligand Bis-tris propane {(CH2OH)3CNH(CH2)3NHC(CH2OH)3} is used to link small cluster fragments into high-nuclearity complexes.