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Two planarized analogues of the prototypical Blatter radical (1), peri‐annulated1_Sand1_O, are demonstrated and provide a new platform for molecular and supramolecular engineering, and for tuning electronic and magnetic properties of the radical. Planarization of1results in bathochromic shift to the near‐IR region, greater spin delocalization, and anodic shift of the reduction potential only for1_S. Magnetization studies revealed nearly ideal paramagnetic behavior at high temperatures for both radicals1_Sand1_Owith one‐dimensional ferromagnetic interaction in the former (2J=14.4 cm⁻¹) and antiferromagnetic interactions in1_Oat low temperatures.

Formal nickelate(−I) complexes bearing Group 13 metalloligands (M=Al and Ga) were isolated. These 17 e⁻complexes were synthesized by one‐electron reduction of the corresponding Ni⁰→M^IIIprecursors, and were investigated by single‐crystal X‐ray diffraction, EPR spectroscopy, and quantum chemical calculations. Collectively, the experimental and computational data support: 1) the strengthening of the Ni−M bond upon one‐electron reduction, and 2) the delocalization of the unpaired spin across the Ni and M atoms. An intriguing electronic configuration is revealed where three valence electrons occupy two σ‐type bonding interactions: Ni(3d)²→M and σ‐(Ni−M)¹. The latter is an unusual Ni−M σ‐bonding molecular orbital that comprises primarily the Ni 4p_zand M np_z/ns atomic orbitals.

Formal nickelate(−I) complexes bearing Group 13 metalloligands (M=Al and Ga) were isolated. These 17 e⁻complexes were synthesized by one‐electron reduction of the corresponding Ni⁰→M^IIIprecursors, and were investigated by single‐crystal X‐ray diffraction, EPR spectroscopy, and quantum chemical calculations. Collectively, the experimental and computational data support: 1) the strengthening of the Ni−M bond upon one‐electron reduction, and 2) the delocalization of the unpaired spin across the Ni and M atoms. An intriguing electronic configuration is revealed where three valence electrons occupy two σ‐type bonding interactions: Ni(3d)²→M and σ‐(Ni−M)¹. The latter is an unusual Ni−M σ‐bonding molecular orbital that comprises primarily the Ni 4p_zand M np_z/ns atomic orbitals.

Oxoiron(IV) units are often implicated as intermediates in the catalytic cycles of non‐heme iron oxygenases and oxidases. The most reactive synthetic analogues of these intermediates are supported by tetradentate tripodal ligands withN‐methylbenzimidazole or quinoline donors, but their instability precludes structural characterization. Herein we report crystal structures of two [Fe^IV(O)(L)]²⁺complexes supported by pentadentate ligands incorporating these heterocycles, which show longer average Fe–N distances than the complex with only pyridine donors. These longer distances correlate linearly with log k₂′ values for O‐ and H‐atom transfer rates, suggesting that weakening the ligand field increases the electrophilicity of the Fe=O center. The sterically bulkier quinoline donors are also found to tilt the Fe=O unit away from a linear N‐Fe=O arrangement by 10°.