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 language | English |
|---|---|
| Pages (from-to) | 4714-4715 |
| Number of pages | 2 |
| Journal | Journal of the American Chemical Society |
| Volume | 125 |
| Issue number | 16 |
| DOIs | |
| Publication status | Published - Apr 23 2003 |
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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 journal › Article
}
TY - JOUR
T1 - Selective ortho C-H activation of haloarenes by an Ir(I) system
AU - Ben-Ari, Eyal
AU - Gandelman, Mark
AU - Rozenberg, Haim
AU - Shimon, Linda J W
AU - Milstein, David
PY - 2003/4/23
Y1 - 2003/4/23
N2 - 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.
AB - 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.
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U2 - 10.1021/ja028362p
DO - 10.1021/ja028362p
M3 - Article
VL - 125
SP - 4714
EP - 4715
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 16
ER -