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Front Cover: A Tetrapodal Penta-Carbene Ligand and Iron(III) Complex (Eur. J. Inorg. Keywords: Carbene ligands; Iron; Magnetic properties; Structure elucidation; Tetrapodal pentadentate complexes EN Carbene ligands Iron Magnetic properties Structure elucidation Tetrapodal pentadentate complexes 1 1 1 07/18/23 20230713 NES 230713 B The Front Cover b shows selected tetrapodal-pentadentate "butterflies" taking flight. Carbene ligands, Iron, Magnetic properties, Structure elucidation, Tetrapodal pentadentate complexes. [Extracted from the article]

The chemistry of diiron complexes has seen a recent renaissance, due to the prominent role played by the element iron in the development of sustainable synthetic processes and the cooperative effects provided by two metal centers working in concert, that is a concept amazingly exploited by Nature. Aminoalkylidyne derivatives of [Fe2Cp2(CO)4] are a convenient scaffold to grow organic fragments; in particular, the facile removal of one CO ligand opens the doors to the unconventional assembly of molecules/ions, affording unusual structural motifs. In particular, vinyliminium complexes result from carbyne–alkyne coupling and offers the opportunity for a great variety of selective derivatization pathways, including addition of nucleophiles, access to substituted ferrocenes, deprotonation and reduction processes, and trapping of small molecules. [ABSTRACT FROM AUTHOR]

For the first time, the potential of noble-metal-free iron-based photosensitizers for photocatalytic water reduction by using homo- and heteroleptic carbene complexes was proven. The development of a facile synthesis route for such carbene complexes was delineated. The complexes were investigated by UV/Vis and fluorescence spectroscopy, DFT calcula-tions, cyclic voltammetry, and X-ray absorption spectroscopy. Their catalytic performance was compared to that of established noble-metal-containing photosensitizers such as [Ir(ppy)2(bpy)][PF6] (Hppy = 2-phenylpyridine, bpy = 2,2'-bipyridine). [ABSTRACT FROM AUTHOR]

Noble-metal-derived functional materials have played indispensable roles in the reduction of dye under aqueous conditions; however, their cost and separation are great limitations on their wider practical applications. Therefore, an alternative preparation of comparable materials with low cost and good ease of separation is required. Herein magnetic microspheres (i.e., Fe3O4/Cu) were synthesized through a green single-step solvothermal method for the first time with ethylene glycol serving as reductant and reaction media. The prepared materials were characterized by means of powder Xray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, energy- dispersive X-ray spectrometry, a vibrating sample magnetometer, and so forth. Additionally, by employing the reduction of 4-nitrophenol to 4-aminophenol as a model reaction, the effects of preparation time and the initial dosage of Cu(NO3)2 on the rate constant of the catalytic reduction reaction were systematically investigated. Moreover, the obtained hybrid nanocatalysts were also applied to reduce and degrade common organic dyes (rhodamine B and methylene blue) in the presence of NaBH4. Quite significantly, it was shown that it could catalytically degrade different organic dyes with excellent catalytic performance and high stability in recycled reactions up to five times. More interestingly, the material can be easily separated from the catalytic system for further use. [ABSTRACT FROM AUTHOR]

The reduction of the compound [Fe2(CO)4(κ2-dmpe){μ-(SCH2)2NBn}] [dmpe = 1,2-bis(dimethylphosphino)ethane], which is considered as an FeI-FeI model of the [2Fe]H subsite of [Fe-Fe]H2ases with a rotated conformation in the solid state, was investigated by cyclic voltammetry. Under reductive conditions, [Fe2(CO)4(κ2-dmpe){μ-(SCH2)2NBn}] undergoes electron-transfer-catalyzed isomerization to afford an isomer featuring a bridging diphosphine [Fe2(CO)4(μ-dmpe){μ-(SCH2)2NBn}]. Comparison of the crystallographic structures of the two isomers affords unique and direct experimental evidence that dissymmetrical coordination of the chelate ligand is required to promote the rotated conformation at one iron atom in this compound. DFT calculations were performed to rationalize this isomerization process and the slightly distorted structure of [Fe2(CO)4(μ-dmpe){μ-(SCH2)2NBn}]. The symmetrization of the coordination sphere results in the disruption of the agostic interaction that stabilized the rotated isomer. [ABSTRACT FROM AUTHOR]

The five-membered electron-transfer series [M(bpy)3] n and [M(tpy)2] n (M = Fe, Ru; bpy = 2,2′-bipyridine, tpy = 2,2′:6′,2″-terpyridine) and [Fe(tbpy)3] n (tbpy = 4,4′-di- tert-butyl-2,2′-bipyridine; n = 3+, 2+, 1+, 0, 1-) have been investigated and the electronic structure of the so called 'low-valent' complexes ( n = 1+, 0, 1-) have been established by a combination of electro- and magnetochemistry, electron paramagnetic resonance (EPR) and Mössbauer spectroscopy, X-ray crystallography, and DFT calculations. These complexes are accessed by reduction of the d6 S = 0 dicationic starting materials [M(bpy)3]2+ and [M(tpy)2]2+ (M = Fe, Ru) and [Fe(tbpy)3]2+. The monocations [M(bpy ·)(bpy0)2]1+ ( S = 1/2) and [M(tpy ·)(tpy0)]1+ ( S = 1/2) (M = FeII, RuII) also contain a low-spin (t2g)6 divalent metal center, plus a single radical monoanion (bpy ·)1- or (tpy ·)1-, and two or one neutral (bpy0) or (tpy0) ligands, respectively. The unpaired electron resides in a ligand π* orbital. The neutral complexes [FeII(bpy ·)2(bpy0)]0 and [RuII(tpy ·)2]0 were found, by DFT calculations, to possess an S = 1 ground state that is attained by weak intramolecular ferromagnetic coupling between two ligand radical anions and a singlet excited state ( S = 0). In contrast, the neutral species [RuII(bpy ·)2(bpy0)]0 possesses an S = 0 ground state. The metal centers of these neutral complexes retain a low-spin (t2g)6 configuration. Remarkably, the corresponding neutral complex [FeII(tpy ·)2]0 contains high-spin FeII ( SFe = 2). Strong intramolecular antiferromagnetic metal-radical coupling yields an experimentally observed S = 1 ground state. The monoanions [MII(bpy ·)3]1- (M = Fe, Ru) are composed of a low-spin metal ion [Fe, Ru; (t2g)6; SM = 0] and three (bpy ·)1- radical anions. [ABSTRACT FROM AUTHOR]