Reactions of Phosphine Ligands with Iridium Complexes Leading to C(sp3)-H Bond Activation
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- 作者：Cristina Tejel ; Miguel A. Ciriano ; Sonia Jimé ; nez ; Luis A. Oro ; Claudia Graiff ; and Antonio Tiripicchio
- 刊名：Organometallics
- 出版年：2005
- 出版时间：March 14, 2005
- 年：2005
- 卷：24
- 期：6
- 页码：1105 - 1111
- 全文大小：154K
- 年卷期：v.24,no.6(March 14, 2005)
- ISSN：1520-6041
文摘
Treatment of [Ir2(
-Cl)2(coe)4] (coe = cyclooctene) with the short-bite bifunctional N,P-donor ligand 1-benzyl-2-imidazolyldiphenylphosphine (Ph2PBnIm) resulted in the oxidativeaddition of the C(sp3)-H bond from the benzyl group to the metal to give [IrHCl{Ph2P(CHPh)Im}(Ph2PBnIm)] (1), fully characterized by an X-ray study. The related ligand2-pyridyldiphenylphosphine (Ph2PPy) reacted with [Ir2(-Cl)2(coe)4] to give the mononucleariridium(I) complex [IrCl(Ph2PPy)2] (2), which showed P,N-chelating and P-coordinatedligands. Addition of Ph2PBnIm to 2 produced the replacement of the P-coordinated Ph2PPyligand along with the benzyl C-H bond addition to iridium to give [IrHCl{Ph2P(CHPh)Im}(Ph2PPy)]. This result indicates that mononuclear complexes of the type [IrCl(Ph2PBnIm)(L)] (L = P,N-chelating ligand) are the active species undergoing the C-H bond activationreaction. A related C-H bond activation process of the methylene group of dppm occurs inthe reaction of [Ir2(-Cl)2(coe)4] with dppm in toluene to give the hydrido complex with onedeprotonated dppm ligand [IrHCl(Ph2PCHPPh2)(dppm)] (4). On the other hand, the hydridemigrates to the methanide carbon in 4 on dissolving the complex in CD2Cl2 to establish anequilibrium with [IrCl(dppm)2] without H/D exchange. Protonating agents such as HBF4·Et2Oand water reacted with complex 4 easily to give [IrHCl(dppm)2]X (X = BF4, OH). Themononuclear complex 2 was found to be highly reactive. Reactions of 2 with O2, H2, anddichloromethane gave the complexes [IrCl(O2)(Ph2PPy)2], [IrCl(H)2(Ph2PPy)2], and [IrCl2(CH2Cl)(Ph2PPy)2], respectively.
-Cl)2(coe)4] (coe = cyclooctene) with the short-bite bifunctional N,P-donor ligand 1-benzyl-2-imidazolyldiphenylphosphine (Ph2PBnIm) resulted in the oxidativeaddition of the C(sp3)-H bond from the benzyl group to the metal to give [IrHCl{Ph2P(CHPh)Im}(Ph2PBnIm)] (1), fully characterized by an X-ray study. The related ligand2-pyridyldiphenylphosphine (Ph2PPy) reacted with [Ir2(-Cl)2(coe)4] to give the mononucleariridium(I) complex [IrCl(Ph2PPy)2] (2), which showed P,N-chelating and P-coordinatedligands. Addition of Ph2PBnIm to 2 produced the replacement of the P-coordinated Ph2PPyligand along with the benzyl C-H bond addition to iridium to give [IrHCl{Ph2P(CHPh)Im}(Ph2PPy)]. This result indicates that mononuclear complexes of the type [IrCl(Ph2PBnIm)(L)] (L = P,N-chelating ligand) are the active species undergoing the C-H bond activationreaction. A related C-H bond activation process of the methylene group of dppm occurs inthe reaction of [Ir2(-Cl)2(coe)4] with dppm in toluene to give the hydrido complex with onedeprotonated dppm ligand [IrHCl(Ph2PCHPPh2)(dppm)] (4). On the other hand, the hydridemigrates to the methanide carbon in 4 on dissolving the complex in CD2Cl2 to establish anequilibrium with [IrCl(dppm)2] without H/D exchange. Protonating agents such as HBF4·Et2Oand water reacted with complex 4 easily to give [IrHCl(dppm)2]X (X = BF4, OH). Themononuclear complex 2 was found to be highly reactive. Reactions of 2 with O2, H2, anddichloromethane gave the complexes [IrCl(O2)(Ph2PPy)2], [IrCl(H)2(Ph2PPy)2], and [IrCl2(CH2Cl)(Ph2PPy)2], respectively.