An [FeIII34] Molecular Metal Oxide

• Published in: Angewandte Chemie 2019-11, Vol.131 (47), p.17059-17062
• Main Authors: Dearle, Alice E., Cutler, Daniel J., Fraser, Hector W. L., Sanz, Sergio, Lee, Edward, Dey, Sourav, Diaz‐Ortega, Ismael F., Nichol, Gary S., Nojiri, Hiroyuki, Evangelisti, Marco, Rajaraman, Gopalan, Schnack, Jürgen, Cronin, Leroy, Brechin, Euan K.
• Format: Article
• Language: English
• Subjects: Acetonitrile; Antiferromagnetism; Chemistry; Coupling (molecular); DFT-Rechnungen; FeIII-Käfige; Ions; Iron oxides; Magnetisches Verhalten; Metal oxides; Metals; Molekulare Metalloxide; Oxides; Polyoxometallates; Pyridines; Spinfrustration
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.201911003

The dissolution of anhydrous iron bromide in a mixture of pyridine and acetonitrile, in the presence of an organic amine, results in the formation of an [Fe34] metal oxide molecule, structurally characterised by alternate layers of tetrahedral and octahedral FeIII ions connected by oxide and hydroxide ions. The outer shell of the complex is capped by a combination of pyridine molecules and bromide ions. Magnetic data, measured at temperatures as low as 0.4 K and fields up to 35 T, reveal competing antiferromagnetic exchange interactions; DFT calculations showing that the magnitudes of the coupling constants are highly dependent on both the Fe‐O‐Fe angles and Fe−O distances. The simplicity of the synthetic methodology, and the structural similarity between [Fe34], bulk iron oxides, previous FeIII–oxo cages, and polyoxometalates (POMs), hints that much larger molecular FeIII oxides can be made. Fe Maiden: Ein molekulares [Fe34]‐Metalloxid besteht aus einem [Fe4]‐Tetraeder, das in einem gekappten [Fe18]‐Tetraeder verkapselt ist, auf dessen Flächen sich vier [Fe3]‐Dreiecke anordnen. Die Struktur enthält abwechselnde Schichten von tetraedrischen und oktaedrischen Fe‐Ionen, die über Oxid‐ und Hydroxidanionen verknüpft sind.