物理化学学报 >> 2017, Vol. 33 >> Issue (4): 729-735.doi: 10.3866/PKU.WHXB201611291

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间位基团激发态取代基常数的扩展及应用

朱倩,曹朝暾,曹晨忠*()   

  • 收稿日期:2016-10-13 发布日期:2017-03-23
  • 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);国家自然科学基金(21672058);湖南省教育厅科研项目(14C0466);国家自然科学基金(湖南省自然科学基金)

Extension and Application of Excited-State Constants of meta-Substituents

Qian ZHU,Chao-Tun CAO,Chen-Zhong CAO*()   

  • Received:2016-10-13 Published:2017-03-23
  • Contact: Chen-Zhong CAO E-mail:czcao@hnust.edu.cn
  • Supported by:
    The project was supported by the National Natural Science Foundation of China(21272063);The project was supported by the National Natural Science Foundation of China(21672058);Scientific Research Fund of Hunan Provincial Education Department, China(14C0466);Natural Science Foundation of Hunan Province, China(湖南省自然科学基金)

摘要:

合成了七个系列含间位取代基X的二苯乙烯m-XArCH=CHArY-p(简称m-XSBY-p),其中X为NO2、I、CHCH2、Ph、Et、NMe2和CCH。在无水乙醇中测定它们的紫外(UV)吸收光谱,得到紫外吸收最大波长λmax(nm)。对λmax的波数Vmax(cm-1)进行定量相关,采用曲线拟合方法,得到上述7个间位基团的激发态取代基常数σCC(mex。将对位基团和间位基团的σCCex与Hammett常数σ进行对比,表明σCCex与σ分别表达取代基不同的电子效应。另外,合成了含上述间位基团的二芳基希夫碱(10个)和二苯乙烯(14个),用所得σCC(mex预测它们的λmax,并用实验测定它们的λmax,结果表明预测值与实验值相吻合,验证了所得σCC(mex常数的可靠性。收集了225个化合物(涉及二取代苯及二苯乙烯)的Vmax,建立了一个统一的定量方程来表达这些化合物Vmax的变化规律。

关键词: 激发态常数, 间位基团, 紫外吸收光谱, 二苯乙烯, 二芳基希夫碱

Abstract:

Seven series of 3, 4'-disubstituted stilbenes were synthesized, with meta-substituents X (m-XSBYp) including: NO2, I, CHCH2, Ph, Et, NMe2, and CCH (m-XSBY-p). The longest wavelength maximum λmax (nm) in ultraviolet absorption spectra of the compounds were measured. A quantitative correlation analysis was performed in terms of energy, the Vmax (cm-1) for 3, 4'-disubstituted stilbenes. The excited-state substituent constants σCC (m)exof the seven meta-substituents were determined by curve-fitting. The constants σCCexof the metaand para-substituents were compared with their Hammett constants σ. The results indicated that σCCexand σ express the substituent electrostatic effects in the excited-and ground-states, respectively. In addition, 10 samples of aryl Schiff bases and 14 samples of 3, 3'-disubstituted stilbenes with meta-substituents X were synthesized, and their λmax, pred. were predicated based on the obtained constants σCC (m)ex. These results showed that the λmax, pred. values agreed well with the experimental values, and confirmed the reliability of the obtained σCC (m)exvalues. We also collected Vmax values of 225 samples of disubstituted stilbenes and disubstituted benzenes and established a general quantitative equation to express the change regularity of their Vmax.

Key words: Excited-state substituent constant, meta-Substituent, Ultraviolet absorption spectrum, Stilbene, Aryl Schiff base

MSC2000: 

  • O641