Diamagnetic-paramagnetic conversion of tris(2-pyridylthio)methylcopper(III) through a structural change from trigonal bipyramidal to octahedral.
Diamagnetic-paramagnetic conversion of tris(2-pyridylthio)methylcopper(III) through a structural change from trigonal bipyramidal to octahedral.
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DOI：
10.1002/anie.200603127
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发表时间：
2006-11
影响因子：
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通讯作者：
R. Santo;Riichi Miyamoto;R. Tanaka;T. Nishioka;Kazunobu Sato;K. Toyota;M. Obata;S. Yano;I. Kinoshita;A. Ichimura;T. Takui
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文献类型：
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作者：
R. Santo;Riichi Miyamoto;R. Tanaka;T. Nishioka;Kazunobu Sato;K. Toyota;M. Obata;S. Yano;I. Kinoshita;A. Ichimura;T. Takui
7611安吉2006，45，7611-7614 2006 Wiley-VCH Verlag GmbH & Co. KGaA，魏因海姆，仍然只有少数几个结构表征的CuIII络合物的例子，[3]其中大多数具有正方形平面结构。CuIII状态被强配位体稳定，其络合物已被分离为羧酸盐，[4]硫醇盐，[5]去质子化酰胺，[6]氨基甲酸盐，[7]和N-混乱卟啉。[8]通过卟啉环上的π-离域效应和外围氮原子的质子化-去质子化作用，稳定了N-混乱卟啉中的Cu 2 + C（sp2）键. [8]非平面的CuIII配合物是罕见的，只有少数结构已被报道，[3]即四方锥[Cu（PhCO 2）2-（吡啶）2Cl][9]和八面体部分在CoIIICuIIICoIII杂金属簇中由1，4，7-三（4-叔丁基-2-硫代苄基）-1，4，7-三氮杂环壬烷桥接。[10]在这里，我们报告的三角双锥（TBP）结构的铜III配合物的合成和电子性质。这是第一次报告的TBP铜III复合物，已在结构上和光谱定义良好。我们还报告了抗磁-顺磁转换的CuIII配合物，伴随着从trigonalbipyramidal到八面体结构的变化。本文报道了一种新的配合物[Cu Ⅱ（tptm）X]（tptm=三（2-吡啶硫基）甲酰胺; X= F，Cl，Br，I），它具有一个新的Cu Ⅱ-C（sp3）键和一个tbp结构。[11]这些配合物显示出高度可逆的单电子氧化过程，在约+0.1 V处，相对于二茂铁/二茂铁的氧化还原电位Eo '（Fc+/Fc），在CH 2 Cl 2中。[11a]这些电化学结果表明，一个电子氧化的配合物保留其TBP结构在铜III状态，密度泛函理论（DFT）计算预测。[11a][CuII（tptm）Cl]（1）与1当量的[CeIV（NH 4）2（NO3）6]在KPF 6存在下氧化生成稳定的配合物[CuIII（tptm）Cl] PF 6（2-PF 6）。该复合物的晶体结构如图1所示。2-PF 6的不对称单元含有一个独立的配位阳离子。1晶体的不对称单元中有四个独立的络合物分子。它们具有类似的结构，由于晶体堆积，键参数只有很小的偏差（参见所选键长和键角的支持信息）。[12]配合物1和2都具有畸变相对较小的tbp几何形状。化合物2中的Cu 2 + Cl键长比化合物1中的短0.05-0.06。氧化后，Cu 3 N的键长也从2.074（7）-2.142（7）in 1收缩到2.028（3）-2.074（3）in 2。虽然化合物1和2中的Cu 2 + C键长在实验误差范围内相同（分别为2.005（9）-2.020（7）和2.038（4）），但由于化合物2中铜离子的离子半径较小，因此化合物2中的Cu 2 + Cl键和Cu 2 + N键比化合物1中的短。这些结果表明，配合物2含有铜（III）离子，而不是氧化的配体部分。通过密度泛函理论计算，得到了Cu原子周围的键长。[13]1在二氯甲烷中的电子光谱在385和529 nm处有两个最大吸收（ε= 1.98 × 103和1.46 × 103 mJ/cm ↑ [-1]），而2的光谱在351、463和550 nm处有三个最大吸收（ε= 2.52 × 103、4.37 × 103和5.24 × 103 mJ/cm ↑ [-1];图2）。2的摩尔吸收系数大于1在这个区域，因为存在的CuIII原子，它接受来自配体的电荷的空dz 2轨道。这一结果也表明，配合物2含有CuIII（参见支持信息）。[14个]
7611 Angew. Chem. Int. Ed. 2006, 45, 7611–7614 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim there are still only a few examples of structurally characterized CuIII complexes,[3] most of which have a square-planar structure. The CuIII state is stabilized by strong coordinating ligands, and its complexes have been isolated as carboxylates,[4] thiolates,[5] deprotonated amides,[6] carbamates,[7] and N-confused porphyrins.[8] The CuÀC (sp2) bonds in the N-confused porphyrins are stabilized by the π-delocalization effect in the porphyrin ring aided by protonation–deprotonation of the peripheral nitrogen atoms.[8] Nonplanar CuIII complexes are rare, and only a few structures have been reported,[3] namely square-pyramidal[Cu (PhCO2) 2-(pyridine) 2Cl][9] and an octahedral moiety in a CoIIICuIIICoIII heterometallic cluster bridged by 1, 4, 7-tris (4-tert-butyl-2-sulfidobenzyl)-1, 4, 7-triazacyclononane.[10] Herein, we report the synthesis and electronic properties of a CuIII complex with a trigonal-bipyramidal (tbp) structure. This is the first report of a tbp CuIII complex that has been structurally and spectroscopically well defined. We also report the diamagnetic–paramagnetic conversion of the CuIII complex which accompanies a change from a trigonalbipyramidal to an octahedral structure. We have reported the complexes [CuII (tptm) X](tptm= tris (2-pyridylthio) methanide; X= F, Cl, Br, I), which have a novel CuIIÀC (sp3) bond and a tbp structure.[11] These complexes show a highly reversible one-electron oxidation process at around+ 0.1 V versus the redox potential of ferrocenium/ferrocene, Eo’(Fc+/Fc), in CH2Cl2.[11a] These electrochemical results suggested that the one-electron-oxidized complexes retain their tbp structures in the CuIII state, as predicted by density functional theory (DFT) calculations.[11a] The oxidation of [CuII (tptm) Cl](1) with one equivalent of [CeIV (NH4) 2 (NO3) 6] in the presence of KPF6 produces the stable complex [CuIII (tptm) Cl] PF6(2-PF6), which was crystallized from CH2Cl2/cyclohexane. The crystal structure of this complex is shown in Figure 1. The asymmetric unit of 2-PF6 contains an independent complex cation. There are four independent complex molecules in the asymmetric unit of the crystal of 1. These have a similar structure, with only small deviations of the bond parameters due to the crystal packing (See Supporting Information for selected bond lengths and angles).[12] Both complexes 1 and 2 have a tbp geometry with relatively little distortion. The CuÀ Cl bond lengths in 2 are 0.05–0.06 shorter than those in 1. The CuÀN bond lengths also shrink, from 2.074 (7)–2.142 (7) in 1 to 2.028 (3)–2.074 (3) in 2, upon oxidation. Although the CuÀC bond lengths in 1 and 2 are identical within the experimental error (2.005 (9)–2.020 (7) and 2.038 (4) respectively), complex 2 has shorter CuÀCl and CuÀN bonds than those in 1 owing to the smaller ionic radius of the copper ion in 2. These results suggest that complex 2 contains a copper (III) ion rather than an oxidized ligand moiety. The experimental bond lengths around the Cu atom could be reproduced by DFT calculations.[13] The electronic spectrum of 1 in CH2Cl2 has two absorption maxima at 385 and 529nm (ε= 1.98 103 and 1.46 103 mÀ1 cmÀ1), while the spectrum of 2 has three maxima at 351, 463, and 550nm (ε= 2.52 103, 4.37 103, and 5.24 103 mÀ1 cmÀ1; Figure 2). The molar absorption coefficients of 2 are larger than those of 1 in this region because of the presence of the vacant dz2 orbital of the CuIII atom, which accepts charge from the ligands. This result also suggests that complex 2 contains CuIII (see Supporting Information).[14]