Substituent Effect on the Catalytic Activity of Ruthenium(II) Complexes Bearing a Pyridyl-Supported Pyrazolyl-Imidazolyl Ligand for Transfer Hydrogenation of Ketones

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• 作者：Huining Chai ; Tingting Liu ; Qingfu Wang ; Zhengkun Yu
• 刊名：Organometallics
• 出版年：2015
• 出版时间：November 9, 2015
• 年：2015
• 卷：34
• 期：21
• 页码：5278-5284
• 全文大小：517K
• ISSN：1520-6041

文摘

Air- and moisture-stable ruthenium(II) complexes bearing a multisubstituted pyrazolyl-imidazolyl-pyridine ligand were synthesized and structurally characterized by NMR and X-ray single-crystal crystallographic analyses. The substituents on the imidazolyl moiety of the NNN ligand exhibited a remarkable impact on the catalytic activity of the corresponding Ru(II) complexes for transfer hydrogenation of ketones in refluxing 2-propanol, following the order NHTs > Me > H > NO₂, to tune the catalytic activity. The highest final TOF value of 345鈥?00 h^鈥? was reached by means of 0.05 mol % of the Ru(II)-NHTs-substituted NNN complex as the catalyst. The corresponding structurally confirmed RuH complexes are proposed as the catalytically active species.