C-H Bond Activation by Unsymmetrical 2-(N-Arylimino)pyrrolide Pt Complexes: Geometric Effects on Reactivity

Journal of the American Chemical Society

Volumn 125, Issue 42, 2003, Pages 12674-12675

  Iverson, Carl N ^a   Carter, Charles A G ^a   Baker, R Tom ^a   Scollard, John D ^b   Labinger, Jay A ^b   Bercaw, John E ^b  

^a LOS ALAMOS NATIONAL LABORATORY   (United States)

^b CALIFORNIA INSTITUTE OF TECHNOLOGY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

LIGAND; METHANE; PLATINUM COMPLEX; PYRROLE DERIVATIVE;

AQUEOUS SOLUTION; ARTICLE; CHEMICAL BOND; COMPLEX FORMATION; ISOMERISM; OXIDATION; THERMODYNAMICS; X RAY CRYSTALLOGRAPHY;

EID: 0142040731     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja036511d     Document Type: Article

References (35)

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18. Several reports relating C-H bond activation chemistry of neutral platinum-methyl complexes utilizing monoanionic bi- or tridentate ligands have recently appeared: (a) Wick, D. D.; Goldberg, K. I. J. Am. Chem. Soc. 1997, 119, 10235.
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27. The cis:trans ratio of the products is 1:1 for 2a and 1:4 for 2b. We arbitrarily label the geometries cis and trans according to the relationship of the anionic (methyl or phenyl) group and the pyrrolide arm of the chelating ligand.
28. 2 (51 Hz vs 58 Hz), for cis (Me cis to pyrrolide) versus trans isomers, respectively.
29. Synthetic details, full NMR spectroscopic characterization of all new compounds, and X-ray crystallographic results are presented in the Supporting Information.
30. Hydrocarbon substitution of labile ligands in C-H bond activation studies has been observed previously. See, for example, refs 3b, 3e, and 7a.
31. See, for example: Tobe, M. L.; Burgess, J. Inorganic Reaction Mechanisms; Addison-Wesley Longman: New York, 1999; pp 101-103
32. 6 results only in the activation of benzene solvent, and we do not observe trans-2 in the reaction solution. However, given the difference in qualitative rates, it is possible that cis-2 isomerizes to trans-2 and then undergoes C-H bond activation.
33. Pt-H = 24 Hz. This is the lowest value observed for this coupling, however, and another possibility may be an H-bonding interaction with the sulfur.
34. 2 decreases the amount of methane deuteration, increases the amount of trans-2 formed, and slows the rate of the reaction.
35. Similar exchange has been observed in a related system: Fekl, U.; Goldberg, K. I. J. Am. Chem. Soc. 2002, 124, 6804-6805.