Structure, magnetic properties and electronic structure of a nickel(II) complex with redox-active 6-(8-quinolylamino)-2,4-bis(tert-butyl)phenol

Insensitivity of Magnetic Coupling to Ligand Substitution in a Series of Tetraoxolene Radical-Bridged Fe2Complexes

“…Because the overlap between this ligand-based π orbital and Fe-based t 2g orbitals predominantly determines the magnitude of the exchange coupling in these compounds, the nature of the bridging ligand substituents should have minimal effect. Moreover, analysis of spin density distributions in related mono- and dinuclear transition-metal complexes featuring terminal or bridging semiquinone, iminosemiquinone, and diiminosemiquinone radical ligands and Fe III , Co III , Ni II , Ru II , and Pt II metal centers of different geometries reveals similar insignificant contribution from the substituents at 3- and 6-positions on the quinoid ring to the total spin density . This suggests that the minimal influence of the ring-bound substituents on magnetic coupling strength may not be limited to tetraoxolene-bridged Fe II 2 complexes, as observed in 2-R , but could generally apply to metal-semiquinoid compounds.…”

Nickel(II) Complex of a Hexadentate Ligand with Two o-Iminosemiquinonato(1−) π-Radical Units and Its Monocation and Dication

“…To the best of our knowledge, 1 provides the first example of an air-stable six-coordinate Ni II complex of two O , N -coordinated o -iminosemiquinonate­(1−) π-radicals, supported by a hexadentate ligand. The only other example is the Ni II complex of bis­(tridentate) ligand 6-(8-quinolylamino)-2,4-bis­( tert -butyl)­phenol …”

Assigning Ligand Redox Levels in Complexes of 2-Aminophenolates: Structural Signatures

“…A set of three square-planar Pd II complexes (22, 62, and 85) with an invariant metal–ligand coordination environment, where 2-aminophenolate ligands are present in (L •– , L •– ), (L 0 , L 0 ), and (L •– , L 0 ) redox levels, respectively, have been reported. Complexes 1 – 15 , with square-planar, distorted-octahedral, and capped-octahedral geometry, where ligands are coordinated in the L 2– redox level, have been reported. ,− A sizable number of complexes, 16 – 59 , with distorted-tetrahedral, square-planar, and octahedral geometry have also been reported, where ligands are coordinated in the L •– redox level. ,,,,,− The PPh 3 -bound complexes 5 with 2-aminophenolate in the L 2– redox level and 38 in the L •– redox level provided examples of proof-of-concept of hemilability. , The distorted-tetrahedral 47 and 48 are the first examples of radical-bound high-spin hs-Co II and hs-Ni II . Complexes 56 – 59 of the composition [Co III (L •– ) 2 X] (X = monodentate anionic ligand) with five-coordinate geometry, where ligands are coordinated in the L •– redox level, have also been reported. ,− Four/six-coordinate complexes 60 – 66 with ligands in the L 0 redox level have also been reported. ,,,,,, Notably, using a tridentate and a hexadentate ligand, complexes have also been synthesized with two coordinated ligands in two different redox levels (tridentate), 89 , or two arms in two different redox levels (hexadentate), 91 .…”