An [FeIII34] Molecular Metal Oxide

• Published in: Angewandte Chemie International Edition Vol. 58; no. 47; pp. 16903 - 16906
• 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: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 18.11.2019; John Wiley and Sons Inc
• Edition: International ed. in English
• Subjects: Acetonitrile; Antiferromagnetism; Communication; Communications; Coupling (molecular); DFT calculations; FeIII cages; Ions; Iron oxides; magnetic behaviour; Metal oxides; Metals; molecular metal oxides; Oxides; Polyoxometallates; Pyridines; spin frustration; molecular metal oxides; magnetic behaviour; DFT calculations; spin frustration; FeIII cages
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.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: An [Fe34] molecular metal oxide consists of an [Fe4] tetrahedron encapsulated in a [Fe18] truncated tetrahedron, face‐capped by four [Fe3] triangles, and is characterised by alternate layers of tetrahedral and octahedral Fe ions linked by oxide and hydroxide anions.