Abstract
We recently reported that 2-(phospholanylmethyl)-6-(2-phosphaethenyl)pyridine (PPEP) with a 2,4,6-tri-tert-butylphenyl group (Mes∗) as steric protection of the PC bond serves as a noninnocent ligand on Ir(I), leading to extremely high reactivity toward metal-ligand cooperative activation of ammonia and acetonitrile. The high reactivity is largely due to the strong accepting properties of the PC bond. However, PPEP had a stability problem that provokes the loss of the PC bond on other transition metals, including Rh(I), and restricts its utilization. This paper describes the synthesis of Eind-PPEP protected by an octaethyl-s-hydrindacen-4-yl group (Eind) instead of Mes∗. The fused-ring bulky Eind group successfully prevents the loss of the PC bond and enables us to compare the reactivity of Rh(I) and Ir(I) complexes toward ammonia. The complex K[RhCl(Eind-PPEP∗)], bearing a dearomatized Eind-PPEP∗ ligand, undergoes simple ligand displacement to give [Rh(NH3)(Eind-PPEP∗)], whereas the iridium analogue K[IrCl(Eind-PPEP∗)] causes N-H bond cleavage to form [Ir(NH2)(Eind-PPEP)]. DFT calculations indicate a thermodynamic cause of the metal-dependent product change.
| Original language | English |
|---|---|
| Pages (from-to) | 1526-1533 |
| Number of pages | 8 |
| Journal | Organometallics |
| Volume | 35 |
| Issue number | 10 |
| DOIs | |
| Publication status | Published - May 23 2016 |
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All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry
Cite this
Unsymmetrical pnp-pincer type phosphaalkene ligands protected by a fused-ring bulky eind group : Synthesis and applications to rh(i) and ir(i) complexes. / Taguchi, Hiro Omi; Sasaki, Daichi; Takeuchi, Katsuhiko; Tsujimoto, Shota; Matsuo, Tsukasa; Tanaka, Hiromasa; Yoshizawa, Kazunari; Ozawa, Fumiyuki.
In: Organometallics, Vol. 35, No. 10, 23.05.2016, p. 1526-1533.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Unsymmetrical pnp-pincer type phosphaalkene ligands protected by a fused-ring bulky eind group
T2 - Synthesis and applications to rh(i) and ir(i) complexes
AU - Taguchi, Hiro Omi
AU - Sasaki, Daichi
AU - Takeuchi, Katsuhiko
AU - Tsujimoto, Shota
AU - Matsuo, Tsukasa
AU - Tanaka, Hiromasa
AU - Yoshizawa, Kazunari
AU - Ozawa, Fumiyuki
PY - 2016/5/23
Y1 - 2016/5/23
N2 - We recently reported that 2-(phospholanylmethyl)-6-(2-phosphaethenyl)pyridine (PPEP) with a 2,4,6-tri-tert-butylphenyl group (Mes∗) as steric protection of the PC bond serves as a noninnocent ligand on Ir(I), leading to extremely high reactivity toward metal-ligand cooperative activation of ammonia and acetonitrile. The high reactivity is largely due to the strong accepting properties of the PC bond. However, PPEP had a stability problem that provokes the loss of the PC bond on other transition metals, including Rh(I), and restricts its utilization. This paper describes the synthesis of Eind-PPEP protected by an octaethyl-s-hydrindacen-4-yl group (Eind) instead of Mes∗. The fused-ring bulky Eind group successfully prevents the loss of the PC bond and enables us to compare the reactivity of Rh(I) and Ir(I) complexes toward ammonia. The complex K[RhCl(Eind-PPEP∗)], bearing a dearomatized Eind-PPEP∗ ligand, undergoes simple ligand displacement to give [Rh(NH3)(Eind-PPEP∗)], whereas the iridium analogue K[IrCl(Eind-PPEP∗)] causes N-H bond cleavage to form [Ir(NH2)(Eind-PPEP)]. DFT calculations indicate a thermodynamic cause of the metal-dependent product change.
AB - We recently reported that 2-(phospholanylmethyl)-6-(2-phosphaethenyl)pyridine (PPEP) with a 2,4,6-tri-tert-butylphenyl group (Mes∗) as steric protection of the PC bond serves as a noninnocent ligand on Ir(I), leading to extremely high reactivity toward metal-ligand cooperative activation of ammonia and acetonitrile. The high reactivity is largely due to the strong accepting properties of the PC bond. However, PPEP had a stability problem that provokes the loss of the PC bond on other transition metals, including Rh(I), and restricts its utilization. This paper describes the synthesis of Eind-PPEP protected by an octaethyl-s-hydrindacen-4-yl group (Eind) instead of Mes∗. The fused-ring bulky Eind group successfully prevents the loss of the PC bond and enables us to compare the reactivity of Rh(I) and Ir(I) complexes toward ammonia. The complex K[RhCl(Eind-PPEP∗)], bearing a dearomatized Eind-PPEP∗ ligand, undergoes simple ligand displacement to give [Rh(NH3)(Eind-PPEP∗)], whereas the iridium analogue K[IrCl(Eind-PPEP∗)] causes N-H bond cleavage to form [Ir(NH2)(Eind-PPEP)]. DFT calculations indicate a thermodynamic cause of the metal-dependent product change.
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U2 - 10.1021/acs.organomet.6b00113
DO - 10.1021/acs.organomet.6b00113
M3 - Article
VL - 35
SP - 1526
EP - 1533
JO - Organometallics
JF - Organometallics
SN - 0276-7333
IS - 10
ER -