The effect of chlorine and fluorine substitutions on tuning the ionization potential of benzoate-bridged paddlewheel diruthenium(II, II) complexes
The effect of chlorine and fluorine substitutions on tuning the ionization potential of benzoate-bridged paddlewheel diruthenium(II, II) complexes
复制标题
DOI：
10.1039/c5dt00505a
复制
发表时间：
2015-01-01
影响因子：
4
通讯作者：
Miyasaka, Hitoshi
中科院分区：
文献类型：
--
作者：
Kosaka, Wataru;Itoh, Masahisa;Miyasaka, Hitoshi
合成了一系列带有各种氯取代苯甲酸酯配体（Cl系列）的叶轮二钌（II，II）配合物作为四氢呋喃（THF）加合物[Ru-2（ClxPhCO2）（4）（THF）（2）]；其中 ClxPhCO2- = 邻氯苯甲酸酯，o-Cl；间氯苯甲酸酯，m-Cl；对氯苯甲酸酯，p-Cl； 2,3-二氯苯甲酸酯，2,3-Cl-2； 2,4-二氯苯甲酸酯，2,4-Cl-2； 2,5-二氯苯甲酸酯，2,5-Cl-2； 2,6-二氯苯甲酸酯，2,6-Cl-2； 3,4-二氯苯甲酸酯，3,4-Cl-2； 3,4-二氯苯甲酸酯，3,5-Cl-2； 2,3,4-三氯苯甲酸酯,2,3,4-Cl-3; 2,3,5-三氯苯甲酸酯，2,3,5-Cl-3； 2,4,5-三氯苯甲酸酯，2,4,5-Cl-3； 3,4,5-三氯苯甲酸酯，3,4,5-Cl-3； 2,3,4,5-四氯苯甲酸酯，2,3,4,5-Cl-4。该Cl系列和先前合成的F系列以及四种新的氟取代衍生物[Ru-2(FxPhCO2)(4)(THF)(2)]（其中FxPhCO(2)(-) = 2,3-二氟苯甲酸酯，2,3-F-2；2,4-二氟苯甲酸酯，2,4-F-2；2,5-二氟苯甲酸酯，2,5-F-2； 2,3,5-三氟苯甲酸酯（2,3,5-F-3）的固态结构、磁性能和电化学进行了实验表征。通过使用氯或氟原子调节苯甲酸酯配体的取代基，[Ru-2(II,II)]/[Ru-2(II,III)](+) 的氧化还原电位 (E-1/2) 在 -40 mV 至 360 mV 的宽电位范围内变化（相对于 THF 中的 Ag/Ag+）。这取决于 (i) 邻位取代基的数量，即非、单和二邻位取代基团，以及邻位 -Cl 和 -F 取代的准哈米特参数（sigma(o) = -0.272 和 -0.217，分别）和 (ii) 每个基团的一般哈米特常数 sigma(m) 和 sigma(p)。基于固态结构原子坐标计算的HOMO能级受到Cl-和F-取代以及溶液中氧化还原电位的强烈影响，这强调了邻位取代基在能级中的空间贡献，给出了E-HOMO < 0.3 eV的偏差
A series of paddlewheel diruthenium(II, II) complexes with various chlorine-substituted benzoate ligands (Cl-series) was synthesized as tetrahydrofuran (THF) adducts [Ru-2(ClxPhCO2)(4)(THF)(2)]; where ClxPhCO2- = o-chlorobenzoate, o-Cl; m-chlorobenzoate, m-Cl; p-chlorobenzoate, p-Cl; 2,3-dichlorobenzoate, 2,3-Cl-2; 2,4-dichlorobenzoate, 2,4-Cl-2; 2,5-dichlorobenzoate, 2,5-Cl-2; 2,6-dichlorobenzoate, 2,6-Cl-2; 3,4-dichlorobenzoate, 3,4-Cl-2; 3,4-dichlorobenzoate, 3,5-Cl-2; 2,3,4-trichlorobenzoate,2,3,4-Cl-3; 2,3,5-trichlorobenzoate, 2,3,5-Cl-3; 2,4,5-trichlorobenzoate, 2,4,5-Cl-3; 3,4,5-trichlorobenzoate, 3,4,5-Cl-3; 2,3,4,5-tetrachlorobenzoate, 2,3,4,5-Cl-4. This Cl-series and the previously synthesized F-series together with four new fluorine-substituted derivatives, [Ru-2(FxPhCO2)(4)(THF)(2)] (where FxPhCO(2)(-) = 2,3-difluorobenzoate, 2,3-F-2; 2,4-difluorobenzoate, 2,4-F-2; 2,5-difluorobenzoate, 2,5-F-2; 2,3,5-trifluorobenzoate, 2,3,5-F-3), were experimentally characterized with respect to solid-state structure, magnetic properties and electrochemistry. By tuning the substituents of the benzoate ligands using chlorine or fluorine atoms, the redox potential (E-1/2) for [Ru-2(II,II)]/[Ru-2(II,III)](+) varied over a wide range of potentials from -40 mV to 360 mV (vs. Ag/Ag+ in THF). This was dependent on (i) the number of ortho-substituents, i.e. non-, mono- and di-o-substituted groups, with quasi-Hammett parameters for ortho-Cl and -F substitutions (sigma(o) = -0.272 and -0.217, respectively) and (ii) the general Hammett constants, sigma(m) and sigma(p), for each group. The HOMO energy level calculated on the basis of the atomic coordinates of the solid-state structure was strongly affected by Cl- and F-substitutions as well as the redox potential in solution, which emphasizes the steric contribution of ortho-substituents in the energy level giving a deviation of E-HOMO < 0.3 eV and