A Heteroleptic Palladium(II) Complex Containing a Bidentate Carbene/Amido Ligand and 3-(Trifluoromethyl)-5-(2-pyridyl)pyrazolate: Fast Catalyst Activation in the Heck Coupling Reaction

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• 作者：Ming-Han Sie ; Yuan-Hsin Hsieh ; Yi-Hua Tsai ; Jia-Rong Wu ; Shih-Jung Chen ; P. Vijaya Kumar ; Jenn-Huei Lii ; Hon Man Lee
• 刊名：Organometallics
• 出版年：2010
• 出版时间：December 13, 2010
• 年：2010
• 卷：29
• 期：23
• 页码：6473-6481
• 全文大小：983K
• 年卷期：v.29,no.23(December 13, 2010)
• ISSN：1520-6041

文摘

A multicomponent reaction between PdCl₂, fppzH, and [LH¹H²]Cl in the presence of K₂CO₃ (L = bidentate amido/carbene; fppzH = 3-(trifluoromethyl)-5-(2-pyridyl)pyrazole) allows the preparation of PdL(fppz) in good yield. The analogous platinum complex, however, needs to be prepared by a two-step procedure. The new palladium(II) and platinum(II) complexes were characterized by 1D and 2D NMR spectroscopy, X-ray crystallography, electrospray ionization mass spectrometry, and elemental analyses. X-ray photoelectron spectroscopy indicates the high electron richness of the palladium atoms in PdL(fppz). These palladium complexes are efficient in catalyzing Heck coupling reactions with challenging aryl halide substrates. The catalyst activation in PdL(fppz) is significantly faster than that in cis-PdL₂. A mere 0.5 mol % of palladium loading is enough to afford a 82% yield of coupled product from 4-chloroanisole and styrene in 24 h.