期刊
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
卷 136, 期 40, 页码 14015-14018出版社
AMER CHEMICAL SOC
DOI: 10.1021/ja5084078
关键词
-
资金
- NSF [CHE-0911610]
- NSF MRI-R2 grant [CHE-0958205]
- ONR [N00014-13-1-0864]
A tetra-nickel-containing polyoxotungstate, Na6K4[Ni-4(H2O)(2)(PW9O34)(2)]center dot 32H(2)O (Na6K4-Ni4P2), has been synthesized in high yield and systematically characterized. The X-ray crystal structure confirms that a tetra-nickel cluster core [Ni4O14] is sandwiched by two trivacant, heptadentate [PW9O34]9--POM ligands. When coupled with (4,4'-di-tert-butyl-2,2'-dipyridyl)-bis(2-phenylpyridine(1H))-iridium(III) hexafluorophosphate [Ir(ppy)(2)(dtbbpy)][PF6] as photosensitizer and triethanolamine (TEOA) as sacrificial electron donor, the noble-metal-free complex Ni4P(2) works as an efficient and robust molecular catalyst for H-2 production upon visible light irradiation. Under minimally optimized conditions, Ni4P2 catalyzes H-2 production over 1 week and achieves a turnover number (TON) of as high as 6500 with almost no loss in activity. Mechanistic studies (emission quenching, time-resolved fluorescence decay, and transient absorption spectroscopy) confirm that, under visible light irradiation, the excited state [Ir(ppy)(2)(dtbbpy)](+)* can be both oxidatively and reductively quenched by Ni4P2 and TEOA, respectively. Extensive stability studies (e.g., UV-vis absorption, FT-IR, mercury-poison test, dynamic light scattering (DLS) and transmission electron microscopy (TEM)) provide very strong evidence that Ni4P2 catalyst remains homogeneous and intact under turnover conditions.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据