Arene Ruthenium Complexes as Versatile Catalysts in Water in both Transfer Hydrogenation of Ketones and Oxidation of Alcohols. Selective Deuterium Labeling of rac-1-Phenylethanol

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• 作者：Cristina Aliende ; Mercedes P茅rez-Manrique ; F茅lix A. Jal贸n ; Blanca R. Manzano ; Ana M. Rodrı ; ́ ; guez ; Gustavo Espino
• 刊名：Organometallics
• 出版年：2012
• 出版时间：September 10, 2012
• 年：2012
• 卷：31
• 期：17
• 页码：6106-6123
• 全文大小：737K
• 年卷期：v.31,no.17(September 10, 2012)
• ISSN：1520-6041

文摘

The preparation of three series of arene Ru(II) half-sandwich compounds with the functional ligand 4,4鈥?dimethoxy-2,2鈥?bipyridine (dmobpy) is described. The new cationic derivatives have the general formula [(畏⁶-arene)RuCl(魏²-N,N-dmobpy)]X (arene = benzene, X = Cl^{鈥?/sup> ([1]Cl), BF₄鈥?/sup> ([1][BF₄]), TsO鈥?/sup> ([1]TsO), PF₆鈥?/sup> ([1][PF₆]); arene = p-cymene (p-cym), X = Cl鈥?/sup> ([2]Cl), BF₄鈥?/sup> ([2][BF₄]), TsO鈥?/sup> ([2]TsO), PF₆鈥?/sup> ([2][PF₆]); arene = 2-phenoxy-1-ethanol (phoxet), X = Cl鈥?/sup> ([3]Cl), BF₄鈥?/sup> ([3][BF₄]), TsO鈥?/sup> ([3]TsO), PF₆鈥?/sup> ([3][PF₆])). The structures of [1]Cl, [1]TsO, [2]TsO, [2][BF₄], and [2][PF₆] were determined by X-ray crystallography. All of the complexes except the PF₆鈥?/sup> salts were water-soluble, and they behaved as active catalysts in two different processes: the transfer hydrogenation of water-soluble and -insoluble ketones to the corresponding alcohols, using HCOONa as the hydrogen source at pH 4, and the oxidation of rac-1-phenylethanol to acetophenone with tBuOOH at pH 7, both in aqueous solution. For the transfer hydrogenation with p-cymene complexes the aqua, formato, and hydride species were detected by means of 1H NMR experiments in D₂O. It was found that the cationic hydrido complex was [(畏6-p-cymene)RuD(dmobpy)]+. The reversible and pH-dependent formation of the hydroxo derivative was also observed. When the catalytic transfer hydrogenation was performed in D₂O, the 1-phenylethanol obtained was selectively deuterated at the benzylic carbon. Mechanistic proposals are also included.}