Unprecedented multistability in dodecanuclear complex compound observed by Mossbauer spectroscopy

The precursors [Fe(III)(L-5x)Cl] ((LH2)-L-5x = N,N'-bis(1-hydroxy-2-benzyliden)-1,6-diamino-3-X-hexane, X = N,S) are high-spin (S = 5/2) complexes. This precursors are combined with the bridging unit [(NC)(5)Fe(II)-CN-Co(III)(CN)(5)](6-) to yield star-shaped dodecanuclear clusters, [((LFe)-L-5x(III)-NC)(5)Fe(II)-CN-Co(III)(CN-Fe(III)L-5x)(5)]Cl-4. The star-shaped compounds are high-spin systems at room temperature. On cooling to 20 K some of the iron(III) centers in the N-star switch to the low-spin state as proven by Mossbauer spectroscopy, i.e. multiple electronic transitions, while the S-star remains in the high-spin state. (c) 2006 Elsevier Ltd. All rights reserved.