Mixed Valency in Quadruple Hydrogen-Bonded Dimers of Bis(biimidazolate)dirhodium Complexes
Mixed Valency in Quadruple Hydrogen-Bonded Dimers of Bis(biimidazolate)dirhodium Complexes
复制标题
DOI：
10.1021/ic502953b
复制
发表时间：
2015-03-02
影响因子：
4.6
通讯作者：
Ebihara, Masahiro
中科院分区：
文献类型：
--
作者：
Jin-Long;Matsuda, Yuki;Ebihara, Masahiro
与biimidazole Dirhodium复合物(H (2) bim)配体(Rh-2 (O2CR) (2) (H (2) bim) (2) Cl-2] (R = Bu ([1 cl(2)]),公关([2 cl (2)))), [Rh-2 (O2CBu) (2) (H (2) bim) (2)] (PF6) (2) ([1] (PF6) (2)), [Rh-2 (O2CBu) (2) (H (2) bim) (2) (PPh3) (2)] (PF6) (2) ([1 (PPh3) (2)] (PF6)(2)),和[Rh-2 (O2CPr) (2) (H (2) bim) (2) (PPh3) (2)] Cl-2 ([2 (PPh3) (2)] Cl-2)合成。双咪唑配合物的去质子化产生了双咪唑酸配合物的四重氢键二聚体[Rh-2(O2CR)(2)(Hbim)(2)(PPh3)(2)](2)](2) (R = Bu ([1'(PPh3)（2)](2)）和Pr ([2'（PPh3)(2)](2))）。Hbim配体之间的互补氢键不是共面的，因为一个镝配合物中的Hbim离子不是平行的（它们之间的二面角约为15度）。[1'(PPh3)(2)](2)的循环伏安图显示CH2Cl2中有两组连续的氧化波。单电子氧化产物[1'(PPh3)(2)](2)在电子能谱上没有价间电荷转移带，由于两个磷原子的存在，形成了轴对称的超精细结构ESR谱。这些观察结果表明，奇数电子定位在一个铱单位的s（RhRh）轨道上。理论计算表明，氧化配合物[Rh-2(O2CMe)(2)(bim)(2)(PMe3)(2)]（-）氢键与双咪唑配合物[Rh-2(O2CMe)(2)(H(2)bim)(2)(PMe3)(2)]（2+）是稳定的混价配合物。
Dirhodium complexes with biimidazole (H(2)bim) ligands [Rh-2(O2CR)(2)(H(2)bim)(2)Cl-2] (R = Bu ([1Cl(2)]), Pr ([2Cl(2)])), [Rh-2(O2CBu)(2)(H(2)bim)(2)](PF6)(2) ([1](PF6)(2)), [Rh-2(O2CBu)(2)(H(2)bim)(2)(PPh3)(2)](PF6)(2) ([1(PPh3)(2)](PF6)(2)), and [Rh-2(O2CPr)(2)(H(2)bim)(2)(PPh3)(2)]Cl-2 ([2(PPh3)(2)]Cl-2) have been synthesized. Deprotonation of the biimidazole complexes afforded the quadruply hydrogen-bonded dimers of the biimidazolate complexes [Rh-2(O2CR)(2)(Hbim)(2)(PPh3)(2)](2) (R = Bu ([1'(PPh3)(2)](2)) and Pr ([2'(PPh3)(2)](2))). Complementary hydrogen bonds between the Hbim ligands are not coplanar because the Hbim ions in one dirhodium complex are not parallel (the dihedral angle between them is ca. 15 degrees). A cyclic voltammogram of [1'(PPh3)(2)](2) shows two sets of two consecutive oxidation waves in CH2Cl2. The one-electron-oxidized species of [1'(PPh3)(2)](2) showed no intervalence charge-transfer band in the electronic spectrum and an axially symmetrical ESR spectrum with hyperfine structure because of two phosphorus atoms. These observations show that the odd electron is localized in a s(RhRh) orbital on one dirhodium unit. Theoretical calculations indicate that an oxidized complex [Rh-2(O2CMe)(2)(bim)(2)(PMe3)(2)](-) hydrogen bonded with a biimidazole complex [Rh-2(O2CMe)(2)(H(2)bim)(2)(PMe3)(2)](2+) was a stable mixed-valence complex.