Fe3joner

Fe3joner is a term used in iron-chemistry discussions to denote trinuclear iron ion clusters. In the present context, a Fe3joner cluster is a motif consisting of three iron centers bound by μ-oxo, μ-hydroxo, or organic bridging ligands, forming a compact core with an overall positive charge. The oxidation states of the iron centers can vary, with common forms including Fe(III)3 or mixed Fe(II)/Fe(III) configurations. Fe3joner clusters are studied as models for cooperative metal-atom effects and for understanding electron transfer in multimetal systems.

Structure and bonding: The three iron atoms typically adopt a near-planar or edge-sharing geometry, held together by bridging ligands that enforce short Fe–O–Fe pathways. Ligand environments range from simple carboxylates to bulky polydentate donors; the exact coordination geometry influences redox properties and spin states. Magnetic coupling between centers often yields complex magnetic behavior, including low net magnetization in antiferromagnetic arrangements.

Preparation and occurrence: Fe3joner motifs are reported in coordination-chemistry experiments using iron(II) precursors and multidentate ligands, sometimes formed by controlled oxidation or by assembly on oxide or sulfide supports. They can also appear as transient intermediates in catalytic cycles or as surface motifs on iron oxide nanoparticles.

Properties and applications: Fe3joner clusters exhibit characteristic electronic transitions and variable spin states, with properties tunable by ligand choice. They are of interest as simplified models of biological trinuclear iron centers and as potential catalysts for small-molecule activation or redox processes. Practical use remains primarily in research settings.

See also: triiron cluster, ferric chemistry, iron-oxide surfaces, coordination chemistry.