Ruthenium Complex Catalysts Supported by a Bis(trifluoromethyl)pyrazolyl鈥揚yridyl-Based NNN Ligand for Transfer Hydrogenation of Ketones

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• 作者：Wangming Du ; Qingfu Wang ; Liandi Wang ; Zhengkun Yu
• 刊名：Organometallics
• 出版年：2014
• 出版时间：February 24, 2014
• 年：2014
• 卷：33
• 期：4
• 页码：974-982
• 全文大小：603K
• 年卷期：v.33,no.4(February 24, 2014)
• ISSN：1520-6041

文摘

Ru(III) and Ru(II) complexes bearing a tridentate 2-(3鈥?5鈥?dimethylpyrazol-1鈥?yl)-6-(3鈥?5鈥?bis(trifluoromethyl)pyrazol-1鈥?yl)pyridine or 2-(benzimidazol-2鈥?yl)-6-(3鈥?5鈥?bis(trifluoromethyl)pyrazol-1鈥?yl)pyridine ligand were synthesized and applied to the transfer hydrogenation of ketones. The Ru(II) complex was structurally confirmed by the X-ray crystallographic analysis and achieved up to 2150 turnover numbers and final TOFs up to 29700 h^鈥? in the transfer hydrogenation of ketones. The benzimidazolyl moiety with an unprotected NH functionality in the ligand exhibited an enhancement effect on the catalytic activity of its RuCl₃ complex in the ketone reduction reactions, reaching a final TOF value up to 35640 h^鈥?. The controlled experiments have revealed that the compatibility of the trifluoromethylated pyrazolyl and unprotected benzimidazolyl is crucial for the establishment of the highly active catalytic system.