Issue 2, 2015

Dehydrogenation of formic acid by Ir–bisMETAMORPhos complexes: experimental and computational insight into the role of a cooperative ligand

Abstract

The synthesis and tautomeric nature of three xanthene-based bisMETAMORPhos ligands (La–Lc) is reported. Coordination of these bis(sulfonamidophosphines) to Ir(acac)(cod) initially leads to the formation of IrI(LH) species (1a), which convert via formal oxidative addition of the ligand to IrIII(L) monohydride complexes 2a–c. The rate for this step strongly depends on the ligand employed. IrIII complexes 2a–c were applied in the base-free dehydrogenation of formic acid, reaching turnover frequencies of 3090, 877 and 1791 h−1, respectively. The dual role of the ligand in the mechanism of the dehydrogenation reaction was studied by 1H and 31P NMR spectroscopy and DFT calculations. Besides functioning as an internal base, bisMETAMORPhos also assists in the pre-assembly of formic acid within the Ir-coordination sphere and aids in stabilizing the rate-determining transition state through hydrogen-bonding.

Graphical abstract: Dehydrogenation of formic acid by Ir–bisMETAMORPhos complexes: experimental and computational insight into the role of a cooperative ligand

Supplementary files

Article information

Article type
Edge Article
Submitted
22 Aug 2014
Accepted
21 Oct 2014
First published
22 Oct 2014
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2015,6, 1027-1034

Author version available

Dehydrogenation of formic acid by Ir–bisMETAMORPhos complexes: experimental and computational insight into the role of a cooperative ligand

S. Oldenhof, M. Lutz, B. de Bruin, J. Ivar van der Vlugt and J. N. H. Reek, Chem. Sci., 2015, 6, 1027 DOI: 10.1039/C4SC02555E

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements