高等学校化学学报

高等学校化学学报 ›› 1996, Vol. 17 ›› Issue (9): 1387.

• 论文 • 上一篇    下一篇

离子基碳-氧键断裂能量的研究(Ⅱ)──负离子基的键能

韩宝航, 还振威, 米江林, 王洪星, 程津培   

  1. 南开大学化学系, 天津, 300071
  • 收稿日期:1995-11-20 出版日期:1996-09-24 发布日期:1996-09-24
  • 通讯作者: 程津培
  • 作者简介:韩宝航,男,28岁,讲师.
  • 基金资助:

    国家自然科学基金;国家教育委员会基金

Studies on Enthalpies of Carbon Oxygen Bond Cleavage in Radical Ions(Ⅱ)──Bond Energies of Radical Anions

HAN Bao-Hang, HUAN Zhen-Wei, MI Jiang-Lin, WANG Hong-Xing, CHENG Jin-pei   

  1. Department of Chemistry, Nankai University, Tianjin, 300071
  • Received:1995-11-20 Online:1996-09-24 Published:1996-09-24

PDF (PC)

被引次数

3

摘要： 合成了3个系列芳香类含碳一氧键的化合物,用循环伏安法测定了相关的氧化还原电势,通过热力学循环首次估测了负离子基的碳-氧键的断裂能量(ΔHcleav[C-O]·-).结果表明:得到1个电子形成负离子基可以活化碳-氧键。这与具有相同结构的正离子基的情况是一致的,但其活化程度略小。相关分析表明:ΔHcleav[C-O]·-vs(ΔEred[C-O]+ΔpKa[HA])和ΔHcleav[C-O]·+vs.(ΔBDE-ΔEox[C-O])均呈线性。讨论了负离子基和正离子基及其母体化合物中键的特征,并与文献中有关的键能数据进行了比较。

关键词: 负离子基, 正离子基, 键裂解能, 碳&mdash, 氧键的活化

Abstract: Three series of fossil model compounds were synthesized and their oxidation and reduction potentials were determined by CVusing BAS-100Belectrochemical analyzer.Thermodynamic cycles have been developed to determine the enthalpies of the carbon─oxygen bond cleavage of the derived radical ions.It was found that the carbon─oxygen bond is similarly activated in a thermodynamic sense by introducing an electron to the system as what was observed previously in a structurally similar radical cation, except smaller in amplitude.The carbon─oxygen bond cleavages of radical ions are all exothermic or slightly endothermic, implying a low barrier for rupture of the sessile bond,This is important to fossil fuel industry for improving traditional coal gasification routine and selecting new fragmentation path.Correlation analysis shows that plots of △Heleav[C─O]·+vs.( △BDE─△Eox[C─O]) and △Heleav[C─O]·+vs.( △Ered[C─O]+△pKa[HA]) are linear.Bond properties in relation to their structural features for both radical ions and their parent molecules are discussed and are compared with the relevant bond energy data in literature.

Key words: Radical anion, Radical cation, Bond cleavage energy, Activation of carbon─oxygen bond

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