Catalytic Four-Electron Oxidation of Water via Intramolecular Coupling of the Oxo Ligands of Bis(ruthenium-bipyridine) Complex
Catalytic Four-Electron Oxidation of Water via Intramolecular Coupling of the Oxo Ligands of Bis(ruthenium-bipyridine) Complex
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双(钌-联吡啶)配合物的氧配体分子内偶联催化水的四电子氧化
DOI：
10.1002/chem.201102236
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
K.Tanaka
中科院分区：
文献类型：
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作者：
T.Wada;H.Ohtsu;K.Tanaka
制备了由 1, 8-双 (2, 2′: 6′, 2′′-三联吡啶-4′-基) 蒽 (btpyan)、Ru2 (μ-Cl)(bpy) 2 (btpyan)(BF4) 3 (1 (BF4) 3; bpy= 2, 2′-联吡啶)桥接的双(钌-联吡啶)络合物。 1 (BF4) 3 在 pH 1.0 水中的循环伏安图显示两个可逆 RuII、RuII 3+/RuII、RuIII 4+ 和 RuII、RuIII 4+/RuIII、RuIII 5+ 氧化还原对，分别为 E1/2 (1)=+ 0.61 和 E1/2 (2)=+ 0.80 V（相对于 Ag/AgCl），以及不可逆在 E=+ 1.2 V 附近出现阳极峰值，随后由于水的氧化而产生强阳极电流。在 pH 2.6 的水中（用 H3PO4/NaH2PO4 缓冲），在 E=+ 1.60 V 下控制电位电解 1 3+ 离子，催化产生分子氧。在 E=+ 1.40 V 下电解 H216O 中的 1 3+ 离子后，所得溶液立即在 ̃ν= 442 和 824 cm-1 处显示两个共振拉曼谱带。当在 H218O 中进行相同的电解时，这些谱带分别移动到 ̃ν= 426 和 780 cm−1。在H 2 16 O和H 2 18 O中使用CeIV物质对1 3+ 离子的化学氧化也表现出相同的共振拉曼光谱。观测到的同位素频移（Δ̃ν= 16 和 44 cm−1）分别完全符合基于 Ru O 和 O O 伸缩模式计算的同位素频移。首次成功鉴定出水氧化中的金属OO金属伸缩带，表明在O2析出之前阶段的氧-氧键是通过源自1 3+ 离子的两个Ru-氧代基团的分子内偶联形成的。
A bis (ruthenium–bipyridine) complex bridged by 1, 8‐bis (2, 2′: 6′, 2′′‐terpyrid‐4′‐yl) anthracene (btpyan), Ru2 (μ‐Cl)(bpy) 2 (btpyan)(BF4) 3 (1 (BF4) 3; bpy= 2, 2′‐bipyridine), was prepared. The cyclic voltammogram of 1 (BF4) 3 in water at pH 1.0 displayed two reversible RuII, RuII 3+/RuII, RuIII 4+ and RuII, RuIII 4+/RuIII, RuIII 5+ redox couples at E1/2 (1)=+ 0.61 and E1/2 (2)=+ 0.80 V (vs. Ag/AgCl), respectively, and an irreversible anodic peak at around E=+ 1.2 V followed by a strong anodic currents as a result of the oxidation of water. The controlled potential electrolysis of 1 3+ ions at E=+ 1.60 V in water at pH 2.6 (buffered with H3PO4/NaH2PO4) catalytically evolved dioxygen. Immediately after the electrolysis of the 1 3+ ion in H216O at E=+ 1.40 V, the resultant solution displayed two resonance Raman bands at ̃ν= 442 and 824 cm‐1. These bands shifted to ̃ν= 426 and 780 cm− 1, respectively, when the same electrolysis was conducted in H218O. The chemical oxidation of the 1 3+ ion by using a CeIV species in H216O and H218O also exhibited the same resonance Raman spectra. The observed isotope frequency shifts (Δ ̃ν= 16 and 44 cm− 1) fully fit the calculated ones based on the Ru O and O O stretching modes, respectively. The first successful identification of the metal O O metal stretching band in the oxidation of water indicates that the oxygen–oxygen bond at the stage prior to the evolution of O2 is formed through the intramolecular coupling of two Ru–oxo groups derived from the 1 3+ ion.