Cooperative catalysis of a trinuclear ruthenium(II) complex in transfer hydrogenation of ketones by formic acid

• 小島, 隆彦

• Yano, Yuichi

• Kojima, Takahiko

• Fukuzumi, Shunichi

Abstract

A novel TPA derivative (TPA = tris(2-pyridylmethyl)amine) having two 1,10-phenanthroline (phen) moieties via amide linkage was synthesized and this ligand reacted with [Ru(hmb)Cl2]2 (hmb: hexamethylbenzene) to give a trinuclear Ru(II) complex, [RuCl(TPA-{phenRuCl(hmb)}2-H+)](PF6)2 (1-Cl), in a moderate yield. The complex involves a deprotonated and oxygen-coordinated amide linkage, which exhibits reversible protonation–deprotonation equilibrium. The chlorido complex was converted to be an aqua complex, [Ru(H2O)(TPA-{phenRu(H2O)2(hmb)}2-H+)](SO4)5/2 (1-H2O), by the reaction of 1-Cl with Ag2SO4 in H2O. Transfer hydrogenation of ketones was examined by using 1-Cl as a catalyst and HCOONa as a hydride source in H2O/CH3OH (1:1 v/v) at 50 °C under Ar. The time-course of the transfer hydrogenation of cyclohexanone to give cyclohexanol revealed that 1-Cl showed a cooperative effect on the catalytic reactivity as compared with that of mononuclear [RuCl(hmb)(phen)] (3-Cl) and [RuCl((1-Naph)2-TPA)]PF6 in H2O/CH3OH (1:2 v/v) under the same conditions. The detailed kinetic study has revealed that the catalytic transfer hydrogenation proceeds via the formato complex, which interacts with a substrate rather than via the hydrido complex. The two Ru centers placed at close proximity in 1-H2O enhanced the interaction of the formato complex with a substrate, resulting in an increase in the catalytic reactivity as compared with the mononuclear complex.

Journal

• Inorganica chimica acta

  Inorganica chimica acta 374 (1), 104-111, 2011-08

  Elsevier B.V.

Keywords

• Materials Chemistry
• Inorganic Chemistry
• Physical and Theoretical Chemistry

Details

• CRID: 1050001202618105728
• NII Article ID: 120007130794
• NII Book ID: AA11530191
• ISSN: 00201693
• DOI: 10.1016/j.ica.2011.01.100
• HANDLE: 2241/113753
• Web Site: https://tsukuba.repo.nii.ac.jp/records/24937
• Web Site: https://api.elsevier.com/content/article/PII:S0020169311001320?httpAccept=text/xml
• Web Site: https://api.elsevier.com/content/article/PII:S0020169311001320?httpAccept=text/plain
• Text Lang: en
• Article Type: journal article
• Data Source:
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