| 259794-32-6

• CAS: 259794-32-6
• 化学式: C₃H₃I₃IrO₂*C₂₄H₂₀As
• 分子量: 1028.32
• InChiKey: VDVIHMIIDKQEMJ-YMDFMEFFSA-K

计算性质

• 辛醇/水分配系数(LogP)：
  None
• 重原子数：
  None
• 可旋转键数：
  None
• 环数：
  None
• sp3杂化的碳原子比例：
  None
• 拓扑面积：
  None
• 氢给体数：
  None
• 氢受体数：
  None

反应信息

• 作为产物：
  描述：

  碘甲烷-13C 、 Ph₄As[Ir(CO)₂I₂] 以 neat (no solvent) 为溶剂， 生成
  参考文献：
  名称：

  Promotion of Iridium-Catalyzed Methanol Carbonylation:  Mechanistic Studies of the Cativa Process

  摘要：

  The iridium/iodide-catalyzed carbonylation of methanol to acetic acid is promoted by carbonyl complexes of W, Re, Ru, and Os and simple iodides of Zn, Cd, Hg, Ga, and In. Iodide salts (Lil and Bu4NI) are catalyst poisons. In situ IR spectroscopy shows that the catalyst resting state (at H2O levels greater than or equal to 5% w/w) is fac,cis-[Ir(CO)(2)I3Me](-), 2. The stoichiometric carbonylation of 2 into [Ir(CO)(2)I-3(COMe)]-, 6, is accelerated by substoichiometric amounts of neutral promoter species (e.g., [Ru(CO)(3)I-2)(2), [Ru(CO)(2)I-2](n), InI3, GaI3, and ZnI2). The rate increase is approximately proportional to promoter concentration for promoter: Ir ratios of 0-0.2. By contrast anionic Ru complexes (e.g., [Ru(CO)(3)I-3](-), [Ru(CO)(2)I-4](2-)) do not promote carbonylation of 2 and BU4NI is an inhibitor. Mechanistic studies indicate that the promoters accelerate carbonylation of 2 by abstracting an iodide ligand from the Ir center, allowing coordination of CO to give [Ir(CO)(3)I2Me], 4, identified by high-pressure IR and NMR spectroscopy. Migratory CO insertion is ca. 700 times faster for 4 than for 2 (85 degreesC, PhCI), representing a lowering of DeltaG(+/-) by 20 kJ mol(-1). Ab initio calculations support a more facile methyl migration in 4, the principal factor being decreased pi-back-donation to the carbonyl ligands compared to 2. The fac,cis isomer of [Ir(CO)(2)I-3(COMe)](-), 6a (as its Ph4As+ salt), was characterized by X-ray crystallography. A catalytic mechanism is proposed in which the promoter [M(CO)(m)I-n] (M = Ru, In; m = 3, 0; n = 2, 3) binds I- to form [M(CO)(m)In+1]-H3O+ and catalyzes the reaction HI(aq) + MeOAc --> Mel + HOAc. This moderates the concentration of HI(aq) and so facilitates catalytic turnover via neutral 4.

  DOI：

  10.1021/ja039464y