New Highly Charged Iron(III) Metal–Organic Cube Stabilized by a Bulky Amine

[Image: see text] In this work, we report a new octanuclear cluster based on Fe(III) and the ligand 1H-imidazole-4,5-dicarboxylic acid, [Et(3)NH](12)[Fe(8)(IDC)(12)]·10DMF·13H(2)O (1), with a metal core containing eight Fe(III) connected by only one type of organic ligand. A peak at 573 m/z in the mass spectra of the compound suggests the adduct species {[Fe(8)(IDC)(12)]+8H}(4–). By X-ray photoelectron spectroscopy, the oxidation state of the iron cation was confirmed to be 3+, also identifying the presence of a quaternary nitrogen species, which act as a countercation of the anionic metal core [Fe(8)(IDC)(12)](12–). Mössbauer spectra recorded at different temperatures show an isomer shift and quadrupole splitting parameters that confirm the existence of only Fe(III)-HS in the structure of 1. X-ray analysis reveals that compound 1 crystallizes in the orthorhombic system space group Ibam, confirming a molecular cluster structure with an almost regular cube as geometry, with the Fe(III) atoms located at the corners of the cube and connected by μ-1κ(2)N,O:2κ(2)N′,O‴-IDC(3–) bridges. Additionally, the magnetic measurements reveal a weak antiferromagnetic coupling in the Fe(8)(III) coordination cluster (J = −3.8 cm(–1)). To the best of our knowledge, 1 is the first member of the family of cubes assembled with 1H-imidazole-4,5-dicarboxylic acid and Fe(III) cation, exhibiting high pH stability over a broad pH range, making it an ideal candidate for the design of supramolecular structures and metal–organic frameworks.