物理化学学报 >> 2016, Vol. 32 >> Issue (7): 1691-1698.doi: 10.3866/PKU.WHXB201604061

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取代基效应对二取代二苯基硝酮还原电位的影响

罗青青,曹朝暾,曹晨忠*()   

  • 收稿日期:2015-12-14 发布日期:2016-07-08
  • 通讯作者: 曹晨忠 E-mail:czcao@hnust.edu.cn
  • 基金资助:
    国家自然科学基金(21272063);湖南省教育厅科研项目(14C0466);湖南省自然科学基金(14JJ3112)

Effects of Substituents on Reduction Potentials of Disubstituted N-Phenyl-α-phenylnitrones

Qing-Qing LUO,Chao-Tun CAO,Chen-Zhong CAO*()   

  • Received:2015-12-14 Published:2016-07-08
  • Contact: Chen-Zhong CAO E-mail:czcao@hnust.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(21272063);Scientific Research Fund of Hunan ProvincialEducation Department, China(14C0466);Natural Science Foundation of Hunan Province, China(14JJ3112)

摘要:

合成了36种二取代二苯基硝酮XArCH=N(O)ArY (简称XPNY)化合物,研究了取代基效应对其还原电位(Ered)的影响,并系统对比了XPNY与XArCH=NArY (简称XBAY)和XArC(Me)=NArY (简称XPEAY)还原电位的差异。研究结果表明:XPNY的Ered与C=N键的13C NMR化学位移δC(C=N)没有线性关系;XPNY、XBAY和XPEAY三类化合物的Ered之间没有线性关系,表现出不同的变化规律;X基团的激发态取代基效应和间位基团位置指示变量对化合物XPEAY和XBAY的Ered都有贡献,而对化合物XPNY的Ered贡献都很小,可忽略;Y基团的激发态取代基效应对化合物XPNY的Ered有一定贡献,而对化合物XPEAY和XBAY的Ered贡献很小,可忽略;XBAY和XPNY的母体有近似的还原电位,而XPEAY的母体其还原电位更低,一般而言,X-Y基团对相同时,XPEAY化合物更难被还原。

关键词: 二苯基硝酮, 取代基效应, 化学位移, 还原电位, 激发态取代基参数, 指示变量

Abstract:

Thirty-six samples of disubstituted N-Phenyl-α-phenylnitrones, XArCH=N(O)ArY (XPNY), were synthesized. The effects of their substituents on their reduction potentials (Ered) were investigated by systematically comparing the Ered differences for XPNY versus XArCH = NArY (XBAY) and XPNY versus XArC(Me)=NArY (XPEAY). The results show the following: there is no linear relationship between the Ered values and 13C NMR chemical shifts, δC(C=N), of the C=N bridging bond for XPNY; there are no linear relationships among the Ered values for XPNY versus XBAY and XPNY versus XPEAY, i.e., their Ered values show their own specific regular changes; the excited-state substituent effect of X and the indicating parameter of the metaposition group make important contributions to the Ered values of XPEAY and XBAY, but have little effect on Ered of XPNY; the excited-state substituent effect of the Y group contributes to the XPNY Ered, but rarely contributes to the Ered values of XPEAY and XBAY, and can be ignored; the parents of XBAY and XPNY have similar reduction potentials, but the reduction potential of the parent of XPEAY is lower than those of XBAY and XPNY. In general, XPEAY is more difficult to be reduced than XBAY or XPNY, for these three types of compound with X-Y group couples.

Key words: N-Phenyl-α-phenylnitrone, Substituent effect, Chemical shift, Reduction potential, Excited-state substituent parameter, Indicating parameter

MSC2000: 

  • O646