Elimination of R-H from Iridium Acyl Hydrides without Loss of CO: Evidence for the Intervention of Metal Cation/Carbanion Pairs

Journal of the American Chemical Society

Volumn 126, Issue 11, 2004, Pages 3432-3433

  Cordaro, Joseph G ^a   Bergman, Robert G ^a  

^a UNIVERSITY OF CALIFORNIA   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

CARBANION; CARBON MONOXIDE; IRIDIUM; IRIDIUM ACYL HYDRIDE DERIVATIVE; METAL ION; UNCLASSIFIED DRUG;

ARTICLE; CALCULATION; CHEMICAL REACTION KINETICS; COMPLEX FORMATION; ELIMINATION REACTION; ENERGY; HYDROFORMYLATION; IONIZATION; METAL BINDING; MOLECULAR MODEL; REACTION OPTIMIZATION; STRUCTURE ANALYSIS; THERMODYNAMICS;

EID: 1642322905     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja031784u     Document Type: Article

References (19)

1. Morrison, J. A. Adv. Inorg. Chem. 1983, 27, 293.
2. Morrison, J. A. Adv. Organomet. Chem. 1993, 35, 211.
3. Treichel, P. M.; Stone, F. G. A. Adv. Organomet. Chem. 1964, 1, 143.
4. Paisner, S. N.; Burger, P.; Bergman, R. G. Organometallics 2000, 19, 2073.
5. Collman, J. P.; Hegedus, L. S.; Norton, J. R.; Finke, R. G. Principles and Applications of Organotransition Metal Chemistry; University Science Books: Mill Valley, California, 1987; Chapter 12.
6. 2, see Clark, H. C.; Manzer, L. E. J. Organomet. Chem. 1973, 59, 411. Group 12 bisperfluoroalkyl complexes of Zn, Cd, and Hg have also been used as a source of perfluoroalkyl anions (Burton, D. J.; Wiemers, D. M. J. Am. Chem. Soc. 1985, 107, 5014 and Eujen, R.; Hoge, B. J. Organomet. Chem. 1995, 503, C51).
7. 2, see Clark, H. C.; Manzer, L. E. J. Organomet. Chem. 1973, 59, 411. Group 12 bisperfluoroalkyl complexes of Zn, Cd, and Hg have also been used as a source of perfluoroalkyl anions (Burton, D. J.; Wiemers, D. M. J. Am. Chem. Soc. 1985, 107, 5014 and Eujen, R.; Hoge, B. J. Organomet. Chem. 1995, 503, C51).
8. 2, see Clark, H. C.; Manzer, L. E. J. Organomet. Chem. 1973, 59, 411. Group 12 bisperfluoroalkyl complexes of Zn, Cd, and Hg have also been used as a source of perfluoroalkyl anions (Burton, D. J.; Wiemers, D. M. J. Am. Chem. Soc. 1985, 107, 5014 and Eujen, R.; Hoge, B. J. Organomet. Chem. 1995, 503, C51).
9. 3F7](H) was also briefly mentioned. See Peterson, T. H.; Golden, J. T.; Bergman, R. G. Organometallics 1999, 18, 2005.
10. A fluoroalkyl carbanion/metal cation pair has been reported in W and Mo chemistry. See Hughes, R. P.; Maddock, S. M.; Guzei, I. A.; Liable-Sands, L. M. ; Rheingold, A. L. J. Am. Chem. Soc. 2001, 123, 3279.
11. 3 did not affect the observed rate of reaction.
12. No aldehyde elimination was ever observed. Classical reductive elimination reactions of Ir(III) alkyl or aryl hydride compounds typically require much higher reaction temperatures. See Buchanan, J. M.; Stryker, J. M.; Bergman, R. G. J. Am. Chem. Soc. 1986, 108, 1537.
13. See Supporting Information for details.
14. For related experiments, see ref 8 and references therein.
15. Blanksby, S. J.; Ellison, G. B. Acc. Chem. Res. 2003, 36, 255.
16. See Supporting Information for details on the formation of 15.
17. Energies are reported relative to 1 and include zero-point vibrational energies (ZPE) and Gibbs free energy corrections at 298.15 K and 1 atm in the gas phase. See the Supporting Information and Figure S-2 for computational details.
18. Although the gas-phase calculated energy of TS-1 is high, it is a reasonable activation energy for a heterolytic bond-breaking process in the absence of solvent. Preliminary solvent-inclusive DFT calculations indicate that TS-1 is significantly lowered in energy relative to TS-2 or TS-3.
19. NBO, 5.0; Theoretical Chemistry Institute, University of Wisconsin, Madison, Wisconsin, 2001.