Radical Superexchange in Semiquinone Complexes Containing Diamagnetic Metal Ions. 3,6-Di-tert-butyl-1,2-semiquinoate Complexes of Zinc(II), Cobalt(III), Gallium(III), and Aluminum(III)

Oxidation by Oxygen and Sulfur of Tin(IV) Derivatives Containing a Redox‐Active o‐Amidophenolate Ligand

“…The EPR spectrum stays unchanged in character over the temperature interval 220–300 K. In the NIR spectrum, the low‐energy band at λ =1800 nm can be assigned to a spin‐ and dipole‐allowed LLCT (ligand‐to‐ligand charge transition) between the MOs of o ‐iminoquinone ligands. Such transitions are usual for mixed‐valence transition‐metal complexes containing o ‐quinoid ligands in different redox states,7 but attempts to observe this transition for similar non‐transition‐metal derivatives were unsuccessful 7c. These spectral features have led us to propose the formation of an [Sn(ap)(isq)Ph] derivative 4 (Scheme ).…”

Electronic Structures of the Electron Transfer Series [M(bpy)3]n, [M(tpy)2]n, and [Fe(tbpy)3]n (M = Fe, Ru; n = 3+, 2+, 1+, 0, 1–): A Mössbauer Spectroscopic and DFT Study

“…Unfortunately, these monocationic complexes have yet to be characterized by X-ray crystallography, which could resolve the matter. [31] As the above [Al(bpy · ) 3 ] 0 and [Sc(bpy · ) 3 ] 0 complexes have not been structurally characterized, we have optimized their structures by DFT (vide supra) and calculated their radical-radical coupling constants, using the Yamaguchi approach, [32] to be J Al,calcd. Whereas DFT calculations for the former Cr III complex gave an optimized geometry with inequivalent bpy ligands, the tpy ligands in the latter were calculated to be equivalent.…”

Transition metal complexes with bulky 4,6-di-tert-butyl-N-aryl(alkyl)-o-iminobenzoquinonato ligands: Structure, EPR and magnetism

“…The mononuclear tris-ligand octahedral cobalt complex Co(3,6-DBSQ) 3 is formed in the case of 3,6-tert-butyl-obenzoquinone 3,6-DBBQ [80]. The Co-O, C-O and C-C bond distances of the chelate rings allow us to interpret this complex as a tris-semiquinonato cobalt(III) complex.…”