Acta Phys. -Chim. Sin. ›› 2016, Vol. 32 ›› Issue (7): 1691-1698.doi: 10.3866/PKU.WHXB201604061

• ARTICLE • Previous Articles     Next Articles

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
  • 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)


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