Potential Electron Transfer Complexes of the [M-O₄] Type: Synthesis and Properties of Complexes Derived from Pyrocatechol and Tetrachloropyrocatechol

Radical ligand-containing single-molecule magnets

“…Compared to nitronyl nitroxides, benzosemiquinonoid radicals contain much stronger oxygen donors, resulting in stronger magnetic exchange coupling with metal ions [114,115]. Additionally, the metal and benzosemiquinonoid radical orbitals are closer in energy, thus providing a more efficient exchange bias.…”

Transition‐Metal Complexes with Singly Reduced 1,2‐Diketone Radical Ligands

“…[2] For instance, there is the potential for stepwise oxidation to coordinated benzoquinone and stepwise reductions to catecholate ligands as well as reduction of the metal center. Owing to the extreme air-and moisture-sensitivity of these species some decomposition in solution was always observed.…”

“…[1,2] The unpairedelectron density in these radical-anion ligands is stabilized by delocalization over the aromatic p system. In contrast, no examples of the singly reduced form of a 1,2-diketone have been isolated even though 1,2-diketones are widely used in organic synthesis and are present in a number of bioactive compounds.…”

Reaction of a model siderophore with Ni(II), Co(II) and Zn(II) in aqueous solution: Kinetics and spectroscopy

“…Complexes of catecholates and semiquinones with Co(II), Ni(II) and Zn(II) have been extensively investigated [14][15][16][17][18][19], whereas transition metal complexes of catecholamides are restricted essentially to Fe(III) due to their relevance to the Parkinson disease mechanism [20][21][22].…”