Visible Light-Driven Hydrogen Production from Aqueous Protons Catalyzed by Molecular Cobaloxime Catalysts
Visible Light-Driven Hydrogen Production from Aqueous Protons Catalyzed by Molecular Cobaloxime Catalysts
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DOI：
10.1021/ic900389z
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发表时间：
2009-06-01
影响因子：
4.6
通讯作者：
Eisenberg, Richard
中科院分区：
文献类型：
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作者：
Du, Pingwu;Schneider, Jacob;Eisenberg, Richard
一系列钴肟配合物-([Co(dmgH)(2)pyCl] (1)、[Co(dmgH)(2)(4-COOMe-py)Cl] (2)、[Co(dmgH)(2)(4-Me2N-py)Cl] (3)、[Co(dmgH)(dmgH(2))Cl-2] (4)、 [Co(dmgH)(2)(py)(2)](PF6) (5)、[Co(dmgH)(2)(P(n-Bu)(3))Cl] (6) 和 [Co (dmgBF(2))(2)(OH2)(2)] (7)，其中 dmgH = 二甲基乙二肟单阴离子，dmgH(2) = 二甲基乙二肟，dmgBF(2) =合成并研究了（二氟硼基）二甲基乙肟酸阴离子和 py = 吡啶，作为在乙腈水溶液中含有 Pt 三联吡啶基乙炔发色团和三乙醇胺 (TEOA) 作为牺牲供体的体系光生成氢的分子催化剂。所有钴肟配合物 1-7 都能够猝灭 Pt(II) 发色团的发光。 [Pt(ttpy)(C CPh)]ClO4 (C1) (ttpy = 4'-p-tolyterpyridine) 是最有效的析氢电子受体，它为 C1 提供了最快的发光猝灭速率常数 1.7 x 10(9) M-1 s(-1)。析氢速率取决于许多因素，包括催化剂的稳定性、质子的驱动力。例如，当 TEOA 浓度增加时，H-2 光生成速率更快，诱导期更短，进行胶体钴实验和汞测试以验证系统是均匀的，并且在光解过程中不会发生原位生成的胶体颗粒的催化作用。 MeCN/水混合物（24:1 v/v，总计 25 mL）中的发色团 C1 (1.1 x 10(-5) M)、TEOA (0.27 M) 和催化剂复合物 1 (2.0 x 10(-4) M)；该系统在 lambda > 410 nm 的光解仅 10 小时后就产生了类似于 2150 次转换的 H-2。
A series of cobaloxime complexes-([Co(dmgH)(2)pyCl] (1), [Co(dmgH)(2)(4-COOMe-py)Cl] (2), [Co(dmgH)(2)(4-Me2N-py)Cl] (3), [Co(dmgH)(dmgH(2))Cl-2] (4), [Co(dmgH)(2)(py)(2)](PF6) (5), [Co(dmgH)(2)(P(n-Bu)(3))Cl] (6), and [Co (dmgBF(2))(2)(OH2)(2)] (7), where dmgH = dimethylglyoximate monoanion, dmgH(2) = dimethylglyoxime, dmgBF(2) = (difluoroboryl)dimethylglyoximate anion, and py = pyridine-were synthesized and studied as molecular catalysts for the photogeneration of hydrogen from systems containing a Pt terpyridyl acetylide chromophore and triethanolamine (TEOA) as a sacrificial donor in aqueous acetonitrile. All cobaloxime complexes 1-7 are able to quench the luminescence of the Pt(II) chromophore [Pt(ttpy)(C CPh)]ClO4 (C1) (ttpy = 4'-p-tolyterpyridine). The most effective electron acceptor for hydrogen evolution is found to be complex 2, which provides the fastest luminescence quenching rate constant for C1 of 1.7 x 10(9) M-1 s(-1). The rate of hydrogen evolution depends on many factors, including the stability of the catalysts, the driving force for proton reduction, the relative and absolute concentrations of system components (TEOA, Co molecular catalyst, and sensitizer), and the ratio of MeCN/water in the reaction medium. For example, when the concentration of TEOA increases, the rate of H-2 photogeneration is faster and the induction period is shorter. Colloidal cobalt experiments and mercury tests were run to verify that the system is homogeneous and that catalysis does not occur from in situ generated colloidal particles during photolysis. The most effective system examined to date consists of the chromophore C1 (1.1 x 10(-5) M), TEOA (0.27 M), and catalyst complex 1 (2.0 x 10(-4) M) in a MeCN/water mixture (24:1 v/v, total 25 mL); this system has produced similar to 2150 turnovers of H-2 after only 10 h of photolysis with lambda > 410 nm.