Kapre Ruta R, Bothe Eberhard, Weyhermüller Thomas, George Serena Debeer, Muresan Nicoleta, Wieghardt Karl
Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany.
Inorg Chem. 2007 Sep 17;46(19):7827-39. doi: 10.1021/ic7008607. Epub 2007 Aug 23.
From the reaction mixture of 3,6-di-tert-butylcatechol, H2[3,6L(cat)], [CrCl3(thf)3], and NEt3 in CH3CN in the presence of air, the neutral complex [CrIII(3,6L*(sq))3] (S = 0) (1) was isolated. Reduction of 1 with [Co(Cp)2] in CH2Cl2 yielded microcrystals of [Co(Cp)2][CrIII(3,6L*(sq))2(3,6L(cat))] (S = 1/2) (2) where (3,6L*(sq)(1-) is the pi-radical monoanionic o-semiquinonate of the catecholate dianion (3,6Lcat)(2-). Electrochemistry demonstrated that both species are members of the electron-transfer series [Cr(3,6LO,O)]z (z = 0, 1-, 2-, 3-). The corresponding tris(benzo-1,2-dithiolato)chromium complex [N(n-Bu)4][CrIII(3,5LS,S)2(3,5LS,S)] (S = 1/2) (3) has also been isolated; (3,5LS,S)(2-) represents the closed-shell dianion 3,5-di-tert-butylbenzene-1,2-dithiolate(2-), and (3,5LS,S)(1-) is its monoanionic pi radical. Complex 3 is a member of the electron-transfer series [Cr(3,5L(S,S))3]z (z = 0, 1-, 2-, 3-). It is shown by Cr K-edge and S K-edge X-ray absorption, UV-vis, and EPR spectroscopies, as well as X-ray crystallography, of 1 and 3 that the oxidation state of the central Cr ion in each member of both electron-transfer series remains the same (+III) and that all redox processes are ligand-based. These experimental results have been corroborated by broken symmetry density functional theoretical calculations by using the B3LYP functional.
在空气存在下，于乙腈中由3,6 - 二叔丁基邻苯二酚、H₂[3,6L(cat)]、[CrCl₃(thf)₃]和三乙胺的反应混合物中，分离得到中性配合物[CrIII(3,6L*(sq))₃] (S = 0) (1)。在二氯甲烷中用[Co(Cp)₂]还原1得到[Co(Cp)₂][CrIII(3,6L*(sq))₂(3,6L(cat))] (S = 1/2) (2)的微晶，其中(3,6L*(sq)(1-)是儿茶酚二阴离子(3,6Lcat)(2-)的π - 自由基单阴离子邻半醌。电化学表明这两种物质都是电子转移系列[Cr(3,6LO,O)]z (z = 0, 1-, 2-, 3-)的成员。相应的三(苯并 - 1,2 - 二硫醇根)铬配合物[N(n - Bu)₄][CrIII(3,5LS,S)₂(3,5LS,S)] (S = 1/2) (3)也已被分离出来；(3,5LS,S)(2-)代表闭壳二阴离子3,5 - 二叔丁基苯 - 1,2 - 二硫醇根(2-)，(3,5LS,S)(1-)是其单阴离子π自由基。配合物3是电子转移系列[Cr(3,5L(S,S))₃]z (z = 0, 1-, 2-, 3-)的成员。通过对1和3进行Cr K边和S K边X射线吸收、紫外 - 可见光谱以及电子顺磁共振光谱分析，以及X射线晶体学分析表明，两个电子转移系列中每个成员的中心Cr离子的氧化态保持相同(+III)，并且所有氧化还原过程都是基于配体的。这些实验结果已通过使用B3LYP泛函的破缺对称性密度泛函理论计算得到证实。
