Catalysis of Alkene Epoxidation by a Series of Gallium(III) Complexes with Neutral N-Donor Ligands
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- 作者：Wenchan Jiang ; John D. Gorden ; Christian R. Goldsmith
- 刊名：Inorganic Chemistry
- 出版年：2013
- 出版时间：May 20, 2013
- 年：2013
- 卷：52
- 期：10
- 页码：5814-5823
- 全文大小：429K
- 年卷期：v.52,no.10(May 20, 2013)
- ISSN：1520-510X
文摘
Six gallium(III) complexes with N-donor ligands were synthesized to study the mechanism of GaIII-catalyzed olefin epoxidation. These include 2:1 ligand/metal complexes with the bidentate ligands ethylenediamine, 5-nitro-1,10-phenanthroline, and 5-amino-1,10-phenanthroline, as well as 1:1 ligand/metal complexes with the tetradentate N,N鈥?bis(2-pyridylmethyl)-1,2-ethanediamine, the potentially pentadentate N,N,N鈥?tris(2-pyridylmethyl)-1,2-ethanediamine, and the potentially hexadentate N,N,N鈥?N鈥?tetrakis(2-pyridylmethyl)-1,2-ethanediamine. In solution, each of the three pyridylamine ligands appears to coordinate to the GaIII through four donor atoms. The six complexes were tested for their ability to catalyze the epoxidation of alkenes by peracetic acid. Although the complexes with relatively electron-poor phenanthroline derivatives display faster initial reactivity, the gallium(III) complexes with the polydentate pyridylamine ligands appear to be more robust, with less noticeable decreases in their catalytic activity over time. The more highly chelating trispicen and tpen are associated with markedly decreased activity.