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An air and moisture tolerant iminotrihydroquinoline-ruthenium(ii) catalyst for the transfer hydrogenation of ketones.

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journal contribution
posted on 25.07.2018, 14:11 by Jiaoyan Li, Yingmiao Ma, Zheng Wang, Qingbin Liu, Gregory A. Solan, Yanping Ma, Wen-Hua Sun
Reaction of 8-amino-5,6,7,8-tetrahydroquinoline with RuCl2(PPh3)3 at room temperature affords the ruthenium(ii) chelate (8-NH2-C9H10N)RuCl2(PPh3)2 (E), in which the two triphenylphosphine ligands are disposed mutually cis. By contrast, when the reaction is performed at reflux ligand oxidation/dehydrogenation occurs along with cis-trans reorganization of the triphenylphosphines to form the 8-imino-5,6,7-trihydroquinoline-ruthenium(ii) complex, (8-NH-C9H9N)RuCl2(PPh3)2 (F). Complex F can also be obtained in higher yield by heating a solution of E alone to reflux. Comparison of their molecular structures highlights the superior binding properties of the bidentate imine ligand in F over its amine-containing counterpart in E. Both complexes are highly effective in the transfer hydrogenation of a wide range of alkyl-, aryl- and cycloalkyl-containing ketones affording their corresponding secondary alcohols with loadings of as low as 0.1 mol%. Significantly, F can deliver excellent conversions even in bench quality 2-propanol in reaction vessels open to the air, whereas the catalytic efficiency of E is diminished by the presence of air but only operates efficiently under inert conditions.

Funding

This work is supported by the National Natural Science Foundation of China (No. 21476060, and U1362204) and the Nature Science Foundation of Hebei Province (No. B2014205049), China. G. A. S. thanks the Chinese Academy of Sciences for a President’s International Fellowship for Visiting Scientists.

History

Citation

Dalton Transactions, 2018, 47 (26), pp. 8738-8745

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Chemistry

Version

AM (Accepted Manuscript)

Published in

Dalton Transactions

Publisher

Royal Society of Chemistry

issn

1477-9226

eissn

1477-9234

Acceptance date

11/06/2018

Copyright date

2018

Available date

12/06/2019

Publisher version

http://pubs.rsc.org/en/Content/ArticleLanding/2018/DT/C8DT01919C#!divAbstract

Notes

Electronic supplementary information (ESI) available: Figures, tables, and giving NMR spectra of the new complexes and a selected substrate. CCDC 1586459 for E, 1586458 for F. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c8dt01919c;The file associated with this record is under embargo until 12 months after publication, in accordance with the publisher's self-archiving policy. The full text may be available through the publisher links provided above.

Language

en

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