Selective ortho C-H activation of haloarenes by an Ir(I) system

Eyal Ben-Ari, Mark Gandelman, Haim Rozenberg, Linda J W Shimon, David Milstein

Research output: Contribution to journalArticle

105 Citations (Scopus)

Abstract

The cationic PNP-Ir(I)(cyclooctene) complex 1 (PNP = 2,6-bis-(di-tert-butyl phosphino methyl)pyridine) reacts with benzene at 25 °C to quantitatively yield the crystallographically characterized, square pyramidal, iridium phenyl hydride complex cis-(PNP)Ir(Ph)(H), 2, in which the hydride is trans to the vacant coordination site. The cationic complex 2 is stable to heating at 100 °C, in sharp contrast to the previously reported unstable neutral, isoelectronic (PCP)Ir(H)(Ph) (PCP = η3-2,6-(tBu2PCH2)2C6H3). Heating of 2 at 50 °C with other arenes results in arene exchange. Complex 1 activates C-H bonds of chloro- and bromobenzene with no C-halide oxidative addition being observed. Selective ortho C-H activation takes place, the process being directed by halogen coordination and being thermodynamically and kinetically favorable. The meta- and para-C-H activation products are formed at a slower rate than the ortho isomer and are converted to it. NMR data and an X-ray crystallographic study of the ortho-activated chlorobenzene complex, which was obtained as the only product upon heating of 1 with chlorobenzene at 60 °C, show that the chloro substituent is coordinated to the metal center.

Original languageEnglish
Pages (from-to)4714-4715
Number of pages2
JournalJournal of the American Chemical Society
Volume125
Issue number16
DOIs
Publication statusPublished - Apr 23 2003

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Heating
Chemical activation
Hydrides
Iridium
Halogens
Benzene
Isomers
Pyridine
Metals
Nuclear magnetic resonance
X-Rays
X rays
Hydrogen
chlorobenzene
pyridine
bromobenzene

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Selective ortho C-H activation of haloarenes by an Ir(I) system. / Ben-Ari, Eyal; Gandelman, Mark; Rozenberg, Haim; Shimon, Linda J W; Milstein, David.

In: Journal of the American Chemical Society, Vol. 125, No. 16, 23.04.2003, p. 4714-4715.

Research output: Contribution to journalArticle

Ben-Ari, Eyal ; Gandelman, Mark ; Rozenberg, Haim ; Shimon, Linda J W ; Milstein, David. / Selective ortho C-H activation of haloarenes by an Ir(I) system. In: Journal of the American Chemical Society. 2003 ; Vol. 125, No. 16. pp. 4714-4715.
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