物理化学学报 >> 1990, Vol. 6 >> Issue (06): 720-724.doi: 10.3866/PKU.WHXB19900616

研究论文 上一篇    下一篇

对苯二胺和N-取代衍生物正离子自由基的共振喇曼光谱研究

孙凯; 徐广智   

  1. 动态与稳态结构国家开放实验室, 中国科学院化学研究所, 北京
  • 收稿日期:1989-03-07 修回日期:1990-06-14 发布日期:1990-12-15
  • 通讯作者: 徐广智

RESONANCE RAMAN SPECTROSCOPIC STUDIES OF THE CATIONIC RADICALS OF p-PHENYLENEDIAMINE AND ITS N-SUBSTITUTED DERIVATIVES

Sun Kai; Xu Guang-Zhi   

  1. National Laboratory for Structural Chemistry of Unstable and Stable Species; Institute of Chmeistry; Academia Sinica; Beijing
  • Received:1989-03-07 Revised:1990-06-14 Published:1990-12-15
  • Contact: Xu Guang-Zhi

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摘要： 本文中报道了对苯二胺和四种N-烷基取代衍生物正离子自由基的共振喇曼光谱, 揭示了自由基是具有明显C=C和C=N双键性质的半醌式结构, N原子上给电子基团的取代引起上述化学键振动峰低频移动, 反映出结构一端N上有烷基的自由基中与取代基直接相连的N原子失去一个p电子带正电荷, 并吸引环上的π电子形成一定程度C=N双键. 共振喇曼光谱随激发光波长的变化表明, 自由基的两个可见电子吸收带分别主要产生于环结构的π→π*和包含N原子结构的n→π*电子跃迁。

Abstract: The resonance Raman spectra of the cationic radicals of p-phenylenediamine and its N-substituted derivatives (N-methyl, N,N-dimethyl, N,N-diethyl and N,N'-dimethyl) are reported. The spectra reveal that the radicals have a half-quinoid structure with obvious C=C and C=N double bond characteristics. The resonance Raman bands at about 1635 cm~(-1) and 1410 cm~(-1) which are caused respectively by the C=C and C=N double bonds shift to lower frequencies when methyls or ethyls are bonded to the N atom as the substituting groups are bonded directly is lost in the radicals and a partial C=N double bond is formed between this N atom and the ring C atom as the π electrons are attracted by the positive charge. The two visible absorption bands are assigned based on the changes of the resonance Ranman spectra with the alternation of the wavelength of the excitation.