TY - JOUR
T1 - The monoanionic π-radical redox state of α-iminoketones in bis(ligand)metal complexes of nickel and cobalt
AU - Lu, Connie C.
AU - Bill, Eckhard
AU - Weyhermüller, Thomas
AU - Bothe, Eberhard
AU - Wieghardt, Karl
PY - 2007/9/17
Y1 - 2007/9/17
N2 - The electronic structures of nickel and cobalt centers coordinated by two α-iminoketone ligands have been elucidated using density functional theory calculations and a host of physical methods such as X-ray crystallography, cyclic voltammetry, UV-vis spectroscopy, electron paramagnetic resonance spectroscopy, and magnetic susceptibility measurements. In principle, α-iminoketone ligands can exist in three oxidation levels: the closed-shell neutral form (L)0, the closed-shell dianion (L red)2-, and the open-shell monoanion (L •)-. Herein, the monoanionic π-radical form (L•)- of α-iminoketones is characterized in the compounds [(L•)2Ni] (1) and [(L•) 2Co] (3), where (L•)- is the one-electron-reduced form of the neutral ligand (t-Bu)N=CH-C(Ph)=O. The metal centers in 1 and 3 are divalent, high-spin, and coupled antiferromagnetically to two ligand π radicals. These bis(ligand)metal complexes can be chemically oxidized by two electrons to give the dications [trans-(L)2Ni(CH 3CN)2](PF6)2 (2) and [trans-(L) 2Co(CH3-CN)2](PF6)2 (4), wherein the ligands are in the neutral form.
AB - The electronic structures of nickel and cobalt centers coordinated by two α-iminoketone ligands have been elucidated using density functional theory calculations and a host of physical methods such as X-ray crystallography, cyclic voltammetry, UV-vis spectroscopy, electron paramagnetic resonance spectroscopy, and magnetic susceptibility measurements. In principle, α-iminoketone ligands can exist in three oxidation levels: the closed-shell neutral form (L)0, the closed-shell dianion (L red)2-, and the open-shell monoanion (L •)-. Herein, the monoanionic π-radical form (L•)- of α-iminoketones is characterized in the compounds [(L•)2Ni] (1) and [(L•) 2Co] (3), where (L•)- is the one-electron-reduced form of the neutral ligand (t-Bu)N=CH-C(Ph)=O. The metal centers in 1 and 3 are divalent, high-spin, and coupled antiferromagnetically to two ligand π radicals. These bis(ligand)metal complexes can be chemically oxidized by two electrons to give the dications [trans-(L)2Ni(CH 3CN)2](PF6)2 (2) and [trans-(L) 2Co(CH3-CN)2](PF6)2 (4), wherein the ligands are in the neutral form.
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U2 - 10.1021/ic7008094
DO - 10.1021/ic7008094
M3 - Article
C2 - 17715916
AN - SCOPUS:34948860046
VL - 46
SP - 7880
EP - 7889
JO - Inorganic Chemistry
JF - Inorganic Chemistry
SN - 0020-1669
IS - 19
ER -