Particle Formation during Oxidation Catalysis with Cp* Iridium Complexes

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• 作者：Ulrich Hintermair ; Sara M. Hashmi ; Menachem Elimelech ; Robert H. Crabtree
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：June 13, 2012
• 年：2012
• 卷：134
• 期：23
• 页码：9785-9795
• 全文大小：698K
• 年卷期：v.134,no.23(June 13, 2012)
• ISSN：1520-5126

文摘

Real-time monitoring of light scattering and UV鈥搗is profiles of four different Cp*Ir^III precursors under various conditions give insight into nanoparticle formation during oxidation catalysis with NaIO₄ as primary oxidant. Complexes bearing chelate ligands such as 2,2鈥?bipyridine, 2-phenylpyridine, or 2-(2鈥?pyridyl)-2-propanolate were found to be highly resistant toward particle formation, and oxidation catalysis with these compounds is thus believed to be molecular in nature under our conditions. Even with the less stable hydroxo/aqua complex [Cp*₂Ir₂(渭-OH)₃]OH, nanoparticle formation strongly depended on the exact conditions and elapsed time. Test experiments on the isolated particles and comparison of UV鈥搗is data with light scattering profiles revealed that the formation of a deep purple-blue color (580 nm) is not indicative of particle formation during oxidation catalysis with molecular iridium precursors as suggested previously.