The influence of the second and outer coordination spheres on Rh(diphosphine)2 CO2 hydrogenation catalysts

J. Timothy Bays, Nilusha Priyadarshani, Matthew S. Jeletic, Elliot B. Hulley, Deanna L. Miller, John Linehan, Wendy J. Shaw

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

A series of [Rh(PCH2XRCH2P)2]+ complexes was prepared to investigate second and outer coordination sphere effects on CO2 hydrogenation catalysis, where X is CH2 (dppp) or X-R is N-CH3, N-CH2COOH (glycine), N-CH2COOCH3 (Gly-OMe), or N-CH2C(O)N-CH(CH3)COOCH3 (GlyAla-OMe). All of these complexes were active for CO2 reduction to formate, with the N-CH3 derivative offering an 8-fold enhancement over the dppp derivative, which is consistent with increased electron density around the metal. Despite the increase in rate with the addition of the pendant nitrogen, the addition of electron withdrawing amino acids and dipeptides to the amine resulted in complexes with reductions in rate of 1 to 2 orders of magnitude, most consistent with a change in pKa of the pendant amine, resulting in lower activity. Collectively, the data suggest multiple contributions of the pendant amine in this catalytic system.

Original languageEnglish
Pages (from-to)3663-3670
Number of pages8
JournalACS Catalysis
Volume4
Issue number10
DOIs
Publication statusPublished - Oct 3 2014

Fingerprint

Hydrogenation
Amines
formic acid
Catalysts
Amino acids
Derivatives
Dipeptides
Glycine
Catalysis
Carrier concentration
Nitrogen
Metals
Amino Acids
Electrons

Keywords

  • amino acid catalysts
  • CO hydrogenation
  • homogeneous catalysis
  • in situ NMR
  • outer coordination sphere

ASJC Scopus subject areas

  • Catalysis

Cite this

Bays, J. T., Priyadarshani, N., Jeletic, M. S., Hulley, E. B., Miller, D. L., Linehan, J., & Shaw, W. J. (2014). The influence of the second and outer coordination spheres on Rh(diphosphine)2 CO2 hydrogenation catalysts. ACS Catalysis, 4(10), 3663-3670. https://doi.org/10.1021/cs5009199

The influence of the second and outer coordination spheres on Rh(diphosphine)2 CO2 hydrogenation catalysts. / Bays, J. Timothy; Priyadarshani, Nilusha; Jeletic, Matthew S.; Hulley, Elliot B.; Miller, Deanna L.; Linehan, John; Shaw, Wendy J.

In: ACS Catalysis, Vol. 4, No. 10, 03.10.2014, p. 3663-3670.

Research output: Contribution to journalArticle

Bays, JT, Priyadarshani, N, Jeletic, MS, Hulley, EB, Miller, DL, Linehan, J & Shaw, WJ 2014, 'The influence of the second and outer coordination spheres on Rh(diphosphine)2 CO2 hydrogenation catalysts', ACS Catalysis, vol. 4, no. 10, pp. 3663-3670. https://doi.org/10.1021/cs5009199
Bays, J. Timothy ; Priyadarshani, Nilusha ; Jeletic, Matthew S. ; Hulley, Elliot B. ; Miller, Deanna L. ; Linehan, John ; Shaw, Wendy J. / The influence of the second and outer coordination spheres on Rh(diphosphine)2 CO2 hydrogenation catalysts. In: ACS Catalysis. 2014 ; Vol. 4, No. 10. pp. 3663-3670.
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