| Abstract
| - Treatment of [Ir2(μ-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(μ-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(μ-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.
- Examples of an oxidative addition of a C(sp3)−H bond to iridium are provided by the reactions of 1-benzyl-2-imidazolyldiphenylphosphine (Ph2PBnIm) with [Ir2(μ-Cl)2(coe)4] and [IrCl(Ph2PPy)2]. Evidence is given for a remote activation of the C−H bond and for the active species undergoing this reaction.
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