cis,fac-[Ir((13)CO)2I3((13)CH3)]AsPh4 | 681445-91-0

• 英文名称: cis,fac-[Ir((13)CO)2I3((13)CH3)]AsPh4
• CAS: 681445-91-0
• 化学式: C₂₄H₂₀As*C₃H₃I₃IrO₂
• 分子量: 1030.3
• InChiKey: VDVIHMIIDKQEMJ-UUZVFGBJSA-K

计算性质

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

• 作为反应物：
  描述：

  cis,fac-[Ir((13)CO)2I3((13)CH3)]AsPh4 以 not given 为溶剂， 生成 [(Ir((13)CO)I2(μ-I)((13)CH3))2][AsPh4]2
  参考文献：
  名称：

  [Ir（CO）2 I 3 Me] -的反应性顺式异构体的鉴定：与铱催化的甲醇羰基化反应机理的关系

  摘要：

  CO从顺式，fac- [Ir（CO）2 I 3 Me] -（1a）上热解得到碘化物桥联的二聚体[{Ir（CO）I 2（μ-I）Me} 2 ] 2-，其中在晶体学上表征为其Ph 4 As +盐。用CO此二聚体发生反应在环境温度下，得到乙酰复杂反式，聚体-的[Ir（CO）2我3（COME）] - 。在该反应中的中间体是先前未观察到的顺式，聚体-的[Ir（CO）2I 3 Me] -（1b），其通过IR和NMR光谱表征。1b的羰基化比顺式，fac异构体1a的羰基化要快得多（在25°C下t 1/ 2〜1分钟），也比中性三羰基[Ir（CO）3 I 2 Me]要快。观察结果表明，羰基配体的相对位置比其数量对反应性的影响更大，并且当将CO配体反式放置在迁移的甲基上时，CO的插入会特别加速。DFT计算表明，Ir-CO键的反式转化为甲基合约的值为1b接近甲基迁移的过渡态，促进了从Ir到旁观者CO配体的更强的π

  DOI：

  10.1021/ic8017858
• 作为产物：
  描述：

  碘甲烷-13C 、 以 neat (no solvent) 为溶剂， 生成 cis,fac-[Ir((13)CO)2I3((13)CH3)]AsPh4
  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