Design and synthesis of a dinucleating ligand system with varying terminal donor functions that provides no bridging donor and its application to the synthesis of a series of Fe(III)-μ-O-Fe(III) complexes.

Based on a rational ligand design for stabilizing high-valent {Fe(μ-O)2Fe} cores, a new family of dinucleating bis(tetradentate) ligands with varying terminal donor functions has been developed: redox-inert biomimetic carboxylates in H4julia, pyridines in susan, and phenolates in H4hilde(Me2). Based on a retrosynthetic analysis, the ligands were synthesized and used for the preparation of their diferric complexes [(julia){Fe(OH2)(μ-O)Fe(OH2)}]·6H2O, [(julia){Fe(OH2)(μ-O)Fe(OH2)}]·7H2O, [(julia){Fe(DMSO)(μ-O)Fe(DMSO)}]·3DMSO, [(hilde(Me2)){Fe(μ-O)Fe}]·CH2Cl2, [(hilde(Me2)){FeCl}2]·2CH2Cl2, [(susan){FeCl(μ-O)FeCl}]Cl2·2H2O, [(susan){FeCl(μ-O)FeCl0.75(OCH3)0.

Highly oxidized diiron complexes: generation, spectroscopy, and stabilities.

Oxidation of the diferric complex [LFe(III)OFe(III)L] to the monoradical complex [LFe(III)OFe(III)L ](+) and the diradical complex [L Fe(III)OFe(III)L ](2+) is followed by a decay into monomeric complexes including a highly reactive putative [LFe(IV)[double bond, length as m-dash]O] complex.