Hexafluorbenzolkation

• 分子结构分类: 有机化合物 - 有机卤素化合物 - 乙烯基卤化物
• 英文名称: Hexafluorbenzolkation
• 英文别名: 1,2,3,4,5,6-hexafluorocyclohexa-1,3-diene
• 化学式: C₆HF₆
• 分子量: 187.064
• InChiKey: VGUVEADJXYVVQN-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  3.14
• 重原子数：
  12.0
• 可旋转键数：
  0.0
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.17
• 拓扑面积：
  0.0
• 氢给体数：
  0.0
• 氢受体数：
  0.0

反应信息

• 作为反应物：
  描述：

  Hexafluorbenzolkation 在 methane 、 二氧化硫 作用下， 以 gas 为溶剂， 270.0 ℃ 、1.07 kPa 条件下， 生成 六氟苯
  参考文献：
  名称：

  迈向绝对气相质子亲和度标度的进展

  摘要：

  已经检查了大约 80 对碱基的质子转移平衡常数的温度依赖性，这些碱基的质子亲和力范围从 N 2 到叔丁胺。这些数据为制定修订后的气相质子亲和度标度提供了基础，该标度现在似乎具有坚实的基础。获得了与质子亲和力的外观能测定以及从头算计算值的极好一致性。这项工作的一个重要发现是，叔丁基阳离子的 ΔH fo 值必须显着高于 Traeger 表观能测量得出的值，后者是异丁烯质子亲和性分配的基础，这是一个重要的参考点。质子亲和力量表

  DOI：

  10.1021/ja00070a033
• 作为产物：
  描述：

  六氟苯 在 methane 、 SO₂H⁺ 作用下， 以 gas 为溶剂， 270.0 ℃ 、1.07 kPa 条件下， 生成 Hexafluorbenzolkation
  参考文献：
  名称：

  迈向绝对气相质子亲和度标度的进展

  摘要：

  已经检查了大约 80 对碱基的质子转移平衡常数的温度依赖性，这些碱基的质子亲和力范围从 N 2 到叔丁胺。这些数据为制定修订后的气相质子亲和度标度提供了基础，该标度现在似乎具有坚实的基础。获得了与质子亲和力的外观能测定以及从头算计算值的极好一致性。这项工作的一个重要发现是，叔丁基阳离子的 ΔH fo 值必须显着高于 Traeger 表观能测量得出的值，后者是异丁烯质子亲和性分配的基础，这是一个重要的参考点。质子亲和力量表

  DOI：

  10.1021/ja00070a033

文献信息

• Combined Experimental and Theoretical Study of the Protonation of Polyfluorobenzenes [C6H6-nFn] (n=0-6)
  作者：J. E. Szulejko、J. Hrušák、T. B. McMahon

  DOI：10.1002/(sici)1096-9888(199705)32:5<494::aid-jms508>3.0.co;2-y

  日期：1997.5

  In a recent high-pressure mass spectrometric revision to the gas-phase basicity scale (J. E. Szulejko and T. B. McMahon, J. Am. Chem, Soc. 115, 7839 (1993)), it was observed that the proton affinity for hexafluorobenzene was 24 kcal mol(-1) (1 kcal = 4.184 kJ) lower than the accepted National Institute of Science and Technology (NIST) database value of 177.7 kcal mol(-1) (S. G. Lias et al., J. Phys. Chem. Ref. Data 17, Suppl. 1 (1988)). Furthermore, the proton affinities for most other polyfluorobenzenes were also found to differ substantially from the NIST values, For many of the polyfluorobenzenes large protonation entropy changes were noted, which were substantially greater than then those expected from rotational symmetry number changes alone, In vies of these observations, MP2/6-31G(**)//HF/6-31G(**) ab initio calculations sere undertaken to investigate further the proton affinity and entropy changes with respect to the degree of fluorine substitution. The present proton affinity variations found for the polyfluorobenzenes (hexaflorobenzene excepted) can be interpreted with the aid of the ab initio results in terms of a simple additivity scheme. Each fluorine substituent para, meta, ortho or ipso to the ring protonation site will induce an incremental proton affinity change with respect to benzene of 1.5, -7.0, -1.5 and -19.0 kcal mol(-1), respectively, This additivity scheme can also be used to rationalize the re-evaluated proton affinities for the polymethylbenzenes and m- and o-fluorotoluenes. The corresponding methyl increments are 7.5, 5.5, 25 and 1.0 kcal mol(-1) for para, meta, ortho and ipso protonation respectively, From the present ab initio statistical thermodynamic analysis of the various protonation entropy components, it was concluded that the low-frequency vibrations are almost exclusively responsible for the large excess entropy changes observed experimentally. Ab initio calculated barriers for 1,2 proton shifts in arenium species available in the literature are concluded to be too large to allow the existence of a so-called dynamic proton. Large excess protonation entropies are noted from the literature for polymethylbenzenes, naphthalene and 1-methylnaphthalene. (C) 1997 by John Wiley & Sons, Ltd.
• Progress toward an absolute gas-phase proton affinity scale
  作者：J. E. Szulejko、T. B. McMahon

  DOI：10.1021/ja00070a033

  日期：1993.8

  The temperature dependence of the proton transfer equilibrium constants for approximately 80 pairs of bases ranging in proton affinity from N 2 to tert-butylamine has been examined. These data provide the basis for formulation of a revised gas-phase proton affinity scale which now appears to have a firm basis. Excellent agreement with appearance energy determinations of proton affinities as well as

  已经检查了大约 80 对碱基的质子转移平衡常数的温度依赖性，这些碱基的质子亲和力范围从 N 2 到叔丁胺。这些数据为制定修订后的气相质子亲和度标度提供了基础，该标度现在似乎具有坚实的基础。获得了与质子亲和力的外观能测定以及从头算计算值的极好一致性。这项工作的一个重要发现是，叔丁基阳离子的 ΔH fo 值必须显着高于 Traeger 表观能测量得出的值，后者是异丁烯质子亲和性分配的基础，这是一个重要的参考点。质子亲和力量表