Assessment of the Electronic Factors Determining the Thermodynamics of "oxidative Addition" of C-H and N-H Bonds to Ir(I) Complexes

David Y. Wang, Yuriy Choliy, Michael C. Haibach, John F. Hartwig, Karsten Krogh-Jespersen, Alan S. Goldman

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

A study of electronic factors governing the thermodynamics of C-H and N-H bond addition to Ir(I) complexes was conducted. DFT calculations were performed on an extensive series of trans-(PH3)2IrXL complexes (L = NH3 and CO; X = various monodentate ligands) to parametrize the relative σ- and π-donating/withdrawing properties of the various ligands, X. Computed energies of oxidative addition of methane to a series of three- and four-coordinate Ir(I) complexes bearing an ancillary ligand, X, were correlated with the resulting (σX, πX) parameter set. Regression analysis indicates that the thermodynamics of addition of methane to trans-(PH3)2IrX are generally strongly disfavored by increased σ-donation from the ligand X, in contradiction to widely held views on oxidative addition. The trend for oxidative addition of methane to four-coordinate Ir(I) was closely related to that observed for the three-coordinate complexes, albeit slightly more complicated. The computational analysis was found to be consistent with the rates of reductive elimination of benzene from a series of isoelectronic Ir(III) phenyl hydride complexes, measured experimentally in this work and previously reported. Extending the analysis of ancillary ligand energetic effects to the oxidative addition of ammonia to three-coordinate Ir(I) complexes leads to the conclusion that increasing σ-donation by X also disfavors oxidative addition of N-H bonds to trans-(PH3)2IrX. However, coordination of NH3 to the Ir(I) center is disfavored even more strongly by increasing σ-donation by X, which explains why the few documented examples of H-NH2 oxidative addition to transition metals involve complexes with strongly σ-donating ligands situated trans to the site of addition. An orbital-based rationale for the observed results is presented.

Original languageEnglish
Pages (from-to)149-163
Number of pages15
JournalJournal of the American Chemical Society
Volume138
Issue number1
DOIs
Publication statusPublished - Jan 13 2016

Fingerprint

Thermodynamics
Ligands
Methane
Bearings (structural)
Coordination Complexes
Carbon Monoxide
Metal complexes
Benzene
Ammonia
Discrete Fourier transforms
Regression analysis
Hydrides
Transition metals
Regression Analysis

ASJC Scopus subject areas

  • Chemistry(all)
  • Catalysis
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

Assessment of the Electronic Factors Determining the Thermodynamics of "oxidative Addition" of C-H and N-H Bonds to Ir(I) Complexes. / Wang, David Y.; Choliy, Yuriy; Haibach, Michael C.; Hartwig, John F.; Krogh-Jespersen, Karsten; Goldman, Alan S.

In: Journal of the American Chemical Society, Vol. 138, No. 1, 13.01.2016, p. 149-163.

Research output: Contribution to journalArticle

Wang, David Y. ; Choliy, Yuriy ; Haibach, Michael C. ; Hartwig, John F. ; Krogh-Jespersen, Karsten ; Goldman, Alan S. / Assessment of the Electronic Factors Determining the Thermodynamics of "oxidative Addition" of C-H and N-H Bonds to Ir(I) Complexes. In: Journal of the American Chemical Society. 2016 ; Vol. 138, No. 1. pp. 149-163.
@article{779bd75d66ee4a42b4a285b313d66795,
title = "Assessment of the Electronic Factors Determining the Thermodynamics of {"}oxidative Addition{"} of C-H and N-H Bonds to Ir(I) Complexes",
abstract = "A study of electronic factors governing the thermodynamics of C-H and N-H bond addition to Ir(I) complexes was conducted. DFT calculations were performed on an extensive series of trans-(PH3)2IrXL complexes (L = NH3 and CO; X = various monodentate ligands) to parametrize the relative σ- and π-donating/withdrawing properties of the various ligands, X. Computed energies of oxidative addition of methane to a series of three- and four-coordinate Ir(I) complexes bearing an ancillary ligand, X, were correlated with the resulting (σX, πX) parameter set. Regression analysis indicates that the thermodynamics of addition of methane to trans-(PH3)2IrX are generally strongly disfavored by increased σ-donation from the ligand X, in contradiction to widely held views on oxidative addition. The trend for oxidative addition of methane to four-coordinate Ir(I) was closely related to that observed for the three-coordinate complexes, albeit slightly more complicated. The computational analysis was found to be consistent with the rates of reductive elimination of benzene from a series of isoelectronic Ir(III) phenyl hydride complexes, measured experimentally in this work and previously reported. Extending the analysis of ancillary ligand energetic effects to the oxidative addition of ammonia to three-coordinate Ir(I) complexes leads to the conclusion that increasing σ-donation by X also disfavors oxidative addition of N-H bonds to trans-(PH3)2IrX. However, coordination of NH3 to the Ir(I) center is disfavored even more strongly by increasing σ-donation by X, which explains why the few documented examples of H-NH2 oxidative addition to transition metals involve complexes with strongly σ-donating ligands situated trans to the site of addition. An orbital-based rationale for the observed results is presented.",
author = "Wang, {David Y.} and Yuriy Choliy and Haibach, {Michael C.} and Hartwig, {John F.} and Karsten Krogh-Jespersen and Goldman, {Alan S.}",
year = "2016",
month = "1",
day = "13",
doi = "10.1021/jacs.5b09522",
language = "English",
volume = "138",
pages = "149--163",
journal = "Journal of the American Chemical Society",
issn = "0002-7863",
publisher = "American Chemical Society",
number = "1",

}

TY - JOUR

T1 - Assessment of the Electronic Factors Determining the Thermodynamics of "oxidative Addition" of C-H and N-H Bonds to Ir(I) Complexes

AU - Wang, David Y.

AU - Choliy, Yuriy

AU - Haibach, Michael C.

AU - Hartwig, John F.

AU - Krogh-Jespersen, Karsten

AU - Goldman, Alan S.

PY - 2016/1/13

Y1 - 2016/1/13

N2 - A study of electronic factors governing the thermodynamics of C-H and N-H bond addition to Ir(I) complexes was conducted. DFT calculations were performed on an extensive series of trans-(PH3)2IrXL complexes (L = NH3 and CO; X = various monodentate ligands) to parametrize the relative σ- and π-donating/withdrawing properties of the various ligands, X. Computed energies of oxidative addition of methane to a series of three- and four-coordinate Ir(I) complexes bearing an ancillary ligand, X, were correlated with the resulting (σX, πX) parameter set. Regression analysis indicates that the thermodynamics of addition of methane to trans-(PH3)2IrX are generally strongly disfavored by increased σ-donation from the ligand X, in contradiction to widely held views on oxidative addition. The trend for oxidative addition of methane to four-coordinate Ir(I) was closely related to that observed for the three-coordinate complexes, albeit slightly more complicated. The computational analysis was found to be consistent with the rates of reductive elimination of benzene from a series of isoelectronic Ir(III) phenyl hydride complexes, measured experimentally in this work and previously reported. Extending the analysis of ancillary ligand energetic effects to the oxidative addition of ammonia to three-coordinate Ir(I) complexes leads to the conclusion that increasing σ-donation by X also disfavors oxidative addition of N-H bonds to trans-(PH3)2IrX. However, coordination of NH3 to the Ir(I) center is disfavored even more strongly by increasing σ-donation by X, which explains why the few documented examples of H-NH2 oxidative addition to transition metals involve complexes with strongly σ-donating ligands situated trans to the site of addition. An orbital-based rationale for the observed results is presented.

AB - A study of electronic factors governing the thermodynamics of C-H and N-H bond addition to Ir(I) complexes was conducted. DFT calculations were performed on an extensive series of trans-(PH3)2IrXL complexes (L = NH3 and CO; X = various monodentate ligands) to parametrize the relative σ- and π-donating/withdrawing properties of the various ligands, X. Computed energies of oxidative addition of methane to a series of three- and four-coordinate Ir(I) complexes bearing an ancillary ligand, X, were correlated with the resulting (σX, πX) parameter set. Regression analysis indicates that the thermodynamics of addition of methane to trans-(PH3)2IrX are generally strongly disfavored by increased σ-donation from the ligand X, in contradiction to widely held views on oxidative addition. The trend for oxidative addition of methane to four-coordinate Ir(I) was closely related to that observed for the three-coordinate complexes, albeit slightly more complicated. The computational analysis was found to be consistent with the rates of reductive elimination of benzene from a series of isoelectronic Ir(III) phenyl hydride complexes, measured experimentally in this work and previously reported. Extending the analysis of ancillary ligand energetic effects to the oxidative addition of ammonia to three-coordinate Ir(I) complexes leads to the conclusion that increasing σ-donation by X also disfavors oxidative addition of N-H bonds to trans-(PH3)2IrX. However, coordination of NH3 to the Ir(I) center is disfavored even more strongly by increasing σ-donation by X, which explains why the few documented examples of H-NH2 oxidative addition to transition metals involve complexes with strongly σ-donating ligands situated trans to the site of addition. An orbital-based rationale for the observed results is presented.

UR - http://www.scopus.com/inward/record.url?scp=84954323277&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84954323277&partnerID=8YFLogxK

U2 - 10.1021/jacs.5b09522

DO - 10.1021/jacs.5b09522

M3 - Article

AN - SCOPUS:84954323277

VL - 138

SP - 149

EP - 163

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 1

ER -