Unprecedented multistability in dodecanuclear complex compound observed by Mössbauer spectroscopy

The precursors [Fe(III)(5XL)Cl] (5XLH2 = 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)5Fe(II)-CN-Co(III)(CN)5]6− to yield star-shaped dodecanuclear clusters, [(5XLFe(III)-NC)5Fe(II)-CN-Co(III)(CN-Fe(III)5XL)5]Cl4. 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 Mössbauer spectroscopy, i.e. multiple electronic transitions, while the S-star remains in the high-spin state.

Graphical abstractThe pentadentate ligand precursors [Fe(III)LCl] yield in synthesis with the bridging unit [(NC)5Fe(II)-CN-Co(III)(CN)5]6− a star-shaped dodecanuclear compound. They are high-spin systems with 50 unpaired electrons at room temperature. Some of them change sequentially between multiple electronical states on cooling while light irradiation favours a concerted reaction mechanism.Figure optionsDownload full-size imageDownload as PowerPoint slide