Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstraße 34-36, D-14195, Berlin, Germany.
Dalton Trans. 2014 Mar 21;43(11):4437-50. doi: 10.1039/c3dt52898g.
The compounds Ru(bpy)2(L(1))2 (1(ClO4)2), Ru(bpy)2(L(2))2 (2(ClO4)2), Ru(bpy)2(L(3))2 (3(ClO4)2), Ru(bpy)2(L(4))2 (4(ClO4)2), Ru(bpy)2(L(5))2 (5(ClO4)2), and Ru(bpy)2(L(6))2 6(ClO4)2 (bpy = 2,2'-bipyridine, L(1) = 1-(4-isopropyl-phenyl)-4-(2-pyridyl)-1,2,3-triazole, L(2) = 1-(4-butoxy-phenyl)-4-(2-pyridyl)-1,2,3-triazole, L(3) = 1-(2-trifluoromethyl-phenyl)-4-(2-pyridyl)-1,2,3-triazole, L(4) = 4,4'-bis-{1-(2,6-diisopropyl-phenyl)}-1,2,3-triazole, L(5) = 4,4'-bis-{(1-phenyl)}-1,2,3-triazole, L(6) = 4,4'-bis-{1-(2-trifluoromethyl-phenyl)}-1,2,3-triazole) were synthesized from Ru(bpy)2(EtOH)22 and the corresponding "click"-derived pyridyl-triazole or bis-triazole ligands, and characterized by (1)H-NMR spectroscopy, elemental analysis, mass spectrometry and X-ray crystallography. Structural analysis showed a distorted octahedral coordination environment about the Ru(II) centers, and shorter Ru-N(triazole) bond distances compared to Ru-N(pyridine) distances in complexes of mixed-donor ligands. All the complexes were subjected to cyclic voltammetric studies, and the results were compared to the well-known Ru(bpy)3 compound. The oxidation and reduction potentials were found to be largely uninfluenced by ligand changes, with all the investigated complexes showing their oxidation and reduction steps at rather similar potentials. A combined UV-vis-NIR and EPR spectroelectrochemical investigation, together with DFT calculations, was used to determine the site of electron transfer in these complexes. These results provided insights into their electronic structures in the various investigated redox states, showed subtle differences in the spectroscopic signatures of these complexes despite their similar electrochemical properties, and provided clues to the unperturbed redox potentials in these complexes with respect to ligand substitutions. The reduced forms of the complexes display structured absorption bands in the NIR region. Additionally, we also present new synthetic routes for the ligands presented here using Cu-abnormal carbene catalysts.
该化合物Ru(bpy)2(L(1))2(1(ClO4)2)、Ru(bpy)2(L(2))2(2(ClO4)2)、Ru(bpy)2(L(3))2(3(ClO4)2)、Ru(bpy)2(L(4))2(4(ClO4)2)、Ru(bpy)2(L(5))2(5(ClO4)2)和Ru(bpy)2(L(6))2(6(ClO4)2)(bpy=2,2'-联吡啶，L(1)=1-(4-异丙基苯基)-4-(2-吡啶基)-1,2,3-三唑，L(2)=1-(4-丁氧基苯基)-4-(2-吡啶基)-1,2,3-三唑，L(3)=1-(2-三氟甲基苯基)-4-(2-吡啶基)-1,2,3-三唑，L(4)=4,4'-双-{1-(2,6-二异丙基苯基)-}1,2,3-三唑，L(5)=4,4'-双-{(1-苯基)-}1,2,3-三唑，L(6)=4,4'-双-{1-(2-三氟甲基苯基)-}1,2,3-三唑)是由Ru(bpy)2(EtOH)22和相应的“点击”衍生的吡啶三唑或双三唑配体合成的，并通过(1)H-NMR 光谱、元素分析、质谱和 X 射线晶体学进行了表征。结构分析表明，Ru(II)中心的配位环境为扭曲的八面体，与混合供体配体配合物中的 Ru-N(三唑)键距离相比，Ru-N(吡啶)键距离较短。所有配合物均进行了循环伏安研究，并将结果与知名的Ru(bpy)3化合物进行了比较。发现配体变化对氧化还原电位的影响不大，所有研究的配合物在相当相似的电位下显示其氧化还原步骤。结合紫外可见近红外和电子顺磁共振光谱电化学研究以及密度泛函理论计算，确定了这些配合物中电子转移的位置。这些结果深入了解了它们在各种研究氧化还原态下的电子结构，尽管它们具有相似的电化学性质，但在这些配合物的光谱特征上显示出细微差异，并为这些配合物在配体取代方面不受干扰的氧化还原电位提供了线索。配合物的还原形式在近红外区域显示出结构化的吸收带。此外，我们还提出了使用 Cu-异常卡宾催化剂的这些配体的新合成路线。
