One- and Two-Electron Reduced 1,2-Diketone Ligands in [Cr<sup>III</sup>(L<sup>•</sup>)<sub>3</sub>] (<i>S</i> = 0) and Na<sub>2</sub>(Et<sub>2</sub>O)<sub>2</sub>[V<sup>IV</sup>(L<sup>Red</sup>)<sub>3</sub>] (<i>S</i> = <sup>1</sup>/<sub>2</sub>)
作者:Geoffrey H. Spikes、Stephen Sproules、Eckhard Bill、Thomas Weyhermüller、Karl Wieghardt
DOI:10.1021/ic801122m
日期:2008.12.1
and two electrons generating a monoanion, [V(L)3]1-, and a neutral species, [V(L)3]0, respectively. DFT calculations atthe B3LYP level show that the one-electron oxidized product contains an octahedral VIV ion coupled antiferromagnetically to one monoanionic ligand pi-radical [VIV(L*)(LRed)2]1- (S ) 0). In contrast, the two-electron oxidized product contains a VIII ion coupled antiferromagnetically
One- and Two-Electron Reduced 1,2-Diketone Ligands in [Zn<sup>II</sup>(L<sup>•</sup>)<sub>2</sub>(Et<sub>2</sub>O)], [Co<sup>II</sup>(L<sup>•</sup>)<sub>2</sub>(Et<sub>2</sub>O)], and Na<sub>2</sub>(Et<sub>2</sub>O)<sub>4</sub>[Co<sup>II</sup>(L<sup>Red</sup>)<sub>2</sub>]
作者:Geoffrey H. Spikes、Carsten Milsmann、Eckhard Bill、Thomas Weyhermüller、Karl Wieghardt
DOI:10.1021/ic801470p
日期:2008.12.15
The reaction of 1,2-diketone bis(2,6-diisopropylphenyl)glyoxal (L-Ox) with ZnCl2 or COCl2 (ratio 2:1) in dry diethyl ether with 2 equiv of sodium (per transition-metal ion) afforded the neutral complexes [Zn-II(L-center dot)(2)(Et2O)] (1) and [Co-II(L-center dot)(2)(Et2O)] (2), which were characterized by X-ray crystallography, magnetochemistry, IR, electron paramagnetic resonance, and UV-vis spectroscopy. When 4 equiv of sodium were added, complex Na-2(Et2O)(4)[Co-II(L-Red)(2)[ (4) was isolated, which included some crystals of a minor (<2%) product Na(Et2O)(2)[Co-III(L-Red)(2)] (3). (L-center dot)(-) represents the T-radical monoanion of the 1,2-diketone, and (L-Red)(2-) is its enediolate(2-) analogue. The electronic structures of 1, 2, and 4 have been elucidated by spectroscopy, and results are corroborated by broken-symmetry density functional theory calculations using the B3LYP functional. 1 possesses an S = 0 ground state with an excited triplet state that is 130 cm(-1) higher in energy; 2 and 4 have an S = 1/2 ground state. These complexes corroborate the notion that acyclic 1,2-diketones are redox noninnocent ligands.
Transition-Metal Complexes with Singly Reduced 1,2-Diketone Radical Ligands
作者:Geoffrey H. Spikes、Eckhard Bill、Thomas Weyhermüller、Karl Wieghardt
DOI:10.1002/anie.200705410
日期:2008.4.7
Unusual mixed valent FeIIIFeII complex (St = 3/2) stabilised by a reduced bulky 1,2-diketone
作者:Geoffrey H. Spikes、Eckhard Bill、Thomas Weyhermüller、Karl Wieghardt
DOI:10.1039/b713062g
日期:——
The reduction of the bulky 1,2-diketone bis(2,6-diisopropylphenyl)glyoxal (1) and FeBr2 with 1.5 equivalents of Na results in a Class 2 mixed valent H.S. FeII L.S. FeIII complex (2) with two five-coordinate Fe centres which are antiferromagnetically exchange-coupled to give a total spin St = 3/2 ground state and an St = 5/2 excited state that are separated by about 25 cm−1 (for ΔJ
≈ 5J)
用 1.5 等量的 Na 还原笨重的 1,2-二酮双(2,6-二异丙基苯基)乙二醛(1)和 FeBr2,可得到 2 级混合价 H.S. FeII L.S. FeIII 复合物(2),其中有两个五配位的 Fe 中心,它们通过反铁磁交换耦合产生一个总自旋 St = 3/2 基态和一个 St = 5/2 激发态,两者相距约 25 cm-1 (ΔJ≈5J)。