1364487-79-5Relevant academic research and scientific papers
Bis(diethylphosphino)methane as a bridging ligand in complexes of Ir 2, Rh2, and IrRh: Geminal C-H activation of α-olefins
Slaney, Michael E.,Anderson, D. Jason,Ferguson, Michael J.,McDonald, Robert,Cowie, Martin
, p. 2286 - 2301 (2012/05/20)
Bis(diethylphosphino)methane (depm, Et2PCH2PEt 2) is used as a new bridging ligand for the syntheses of a series of diiridium, dirhodium, and iridium/rhodium complexes, starting from trans-[MM′Cl2(CO)2(depm)2] (M = M′ = Ir (1); M = M′ = Rh (11); M = Ir, M′ = Rh (19)). The reduction of all three chloro compounds in aqueous KOH under an atmosphere of CO produces the neutral tricarbonyl complexes [MM′(CO)3(depm)2] (M = M′ = Ir (2); M = M′ = Rh (12); M = Ir, M′ = Rh (20)). Protonation of these tricarbonyl complexes by triflic acid (HOTf) or Brookhart's acid (HBArF4) yields the hydride-bridged tricarbonyl complexes [MM′(CO)3(μ-H)(depm)2][X] (M = M′ = Ir (9); M = M′ = Rh (16); M = Ir, M′ = Rh (25); X = SO 3CF3 or B(3,5-(CF3)2C 6H3)4). Reaction of 2 with methyl triflate yields the methylene/hydride product [Ir2(H)(CO)3(μ- CH2)(depm)2][OTf] (4), while the same reaction with the dirhodium analogue (12) produces the methyl complex [Rh2(CH 3)(CO)3(depm)2][OTf] (14) at below -20 °C, which upon warming to above -20 °C results in migratory insertion to yield an acetyl-bridged species, [Rh2(CO)2(μ-C(CH 3)O)(depm)2][OTf] (14a). The analogous Rh/Ir species(20) reacts with methyl triflate to give the methyl-tricarbonyl product [IrRh(CH 3)(CO)3(depm)2][OTf] (22). Removal of a carbonyl from 4 and 22 yields [MIr(CH3)(CO)2(depm) 2][OTf] (M = Ir (5); M = Rh (23)), which are highly susceptible to hydrolysis; however the dirhodium species 14 and 14a are not susceptible to CO loss under the conditions investigated. The reaction of [Ir2(CO) 3(μ-H)(depm)2][BArF4] (9) with a number of α-olefins results in double C-H bond activation of the geminal hydrogens to give the vinylidene-bridged trihydride products of the form [Ir2(H)2(CO)2(μ-H)(μ-C=CRR′)(depm) 2][BArF4].
