| 51994-85-5

• CAS: 51994-85-5
• 化学式: C₁₉H₂₀N₂O₆W
• 分子量: 556.228
• InChiKey: BQECFNYFGLXTLQ-UHFFFAOYSA-N

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：

  三乙烯二胺 、 pentacarbonyl(methoxyphenylmethylene)tungsten(0) 以 乙腈 为溶剂， 生成
  参考文献：
  名称：

  过渡金属卡宾化学。4. DABCO与MeCN中的Fischer卡宾配合物的亲核连接。

  摘要：

  DABCO（1,4-二氮杂双环[2.2.2]辛烷）与（CO）（5）Cr = C（XR）C（6）H（4）Z（X报道了在25摄氏度的干燥MeCN中的O和S）。对于具有（CO）（5）Cr = C（OMe）C（6）H（4）Z（10-Cr-Z）和（CO ）（5）Cr = C（SMe）C（6）H（4）Z（11-Cr-Z）。在50％MeCN-50％H（2）O（v / v）中10-Cr-Z和11-Cr-Z与CH（CN）（2）（-）反应的rho值可与目前的反应。DABCO与10-Cr-Z的反应与（n-Bu）（3）P与（CO）（5）W = C（OMe）C（6）H（5）-Z的反应更紧密相关（23）也提供了rho值2.22。与相应的硫代甲基衍生物相比，更高的rho值和因此更高的甲氧基碳烯配合物的反应性符合先前观察到的醇盐离子的模式，OH（-），胺和硫醇盐离子亲核试剂，合理的解释来自对取代基的影响，不仅考虑过渡态，

  DOI：

  10.1021/ic050349t

文献信息

• Physical Organic Chemistry of Transition Metal Carbene Complexes. 4. Kinetics and Equilibria of Methoxide Ion Addition to [Methoxy(phenyl)carbene]pentacarbonylchromium(0) and [Methoxy(phenyl)carbene]pentacarbonyltungsten(0)
  作者：Claude F. Bernasconi、Francis X. Flores、Joseph R. Gandler、Aquiles E. Leyes

  DOI：10.1021/om00018a011

  日期：1994.6

  A stopped-flow kinetic study of the reversible addition of methoxide ion to [methoxy(phenyl)-carbenelpentacarbonylchromium(0) (2-Cr) and [methoxy(phenyl)carbene]pentacarbonyltungsten-(0) (2-W) in methanol at 25-degrees-C is reported. The reaction was investigated by approaching the equilibrium (eq 1) from either side; due to the rapid decomposition of the adduct, the reaction in the reverse direction had to be measured in a sequential stopped-flow apparatus a few milliseconds after the adduct had been generated. Evidence that the observed reaction refers to the formation of (CO)5--C(Ph) (OCH3)2 (M = Cr, W) includes a comparison of the absorption spectrum of (CO)5W--C(Ph)(OCH3)2 with that of the ylide derived from 2-W and DABCO, low-temperature IR of the adducts, and demonstration of CH3O/CD3O exchange on the same time scale as the kinetic experiments. The following rate and equilibrium constants were obtained: k1 = 77.1 M-1 s-1, k-, = 1.10 s-1, and K1 = 70.1 M-1 for 2-Cr and k1 = 186 M-1, s-1, k-1 = 1.68 s-1, and K1 = 111 M-1 for 2-W. Approximate intrinsic rate constants (k0 = k1 = k-1 when K1 = 1) were calculated from the experimental rate constants. The k0 values are substantially lower than those estimated for the addition of methoxide ion to methyl benzoate. This is consistent with significant charge delocalization in the methoxide ion adducts of the metal carbene complexes. Rate constants, k-1BH, for general acid catalyzed methoxide ion loss from the adducts by phenol and 3,5-dichlorophenol were also determined. They allow an estimate of a Bronsted a value on the order of 0.9, suggesting a transition state in which proton transfer from the catalyst to the incipient methoxide ion is well advanced. The near-independence of K, on the metal contrasts with the strong metal dependence (Cr vs W) of the pK(a) values of (eta5-C5H5)M(CO)3H-type hydrido complexes and supports Norton's view that the acidity of these hydrido complexes is not governed by the stabilization of the negative charge in the respective anions.