Acta Phys. -Chim. Sin. ›› 1989, Vol. 5 ›› Issue (02): 135-140.doi: 10.3866/PKU.WHXB19890202

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ESR STUDY ON THE FREE RADICAL INTERMEDIATES FORMED DURING THE PHOTOLYSIS OF METHYL PHENYLDIAZONIUM SALTS AND THEIR CROWN ETHER COMPLEXES

Liu Yang; Xu Guangzhi; Zhao Yaoxing; Sun Xiangyu   

  1. Institute of Chemistry; Academia Sinica; Beijing, Graduate School; Beijing
  • Received:1988-01-22 Revised:1988-12-05 Published:1989-04-15
  • Contact: Liu Yang

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Abstract:

Active free radicals formed by the photolysis of methyl substitute phenyldiazonium and their crown ether complexes have been studied by current spin trapps nitrosodurene (ND) and phenyl-t-butyl nitrone (PBN). The ESR results reveal that the methyl substituted phenyl produced therein can be easily trapped by ND and PBN.
The hyperfine splitting caused by hyperconjugation interaction of proton in substituted methyl group can be obtained from ESR spectra and their splitting constants are approximately equal to those caused by polarizing couple interaction between unpaired electron and protons in the same ring position, that is to say, a (p-H)≈a(p-CH_3); a(o-H)≈a(o-CH_3); a(m-H)≈a(m-CH_3).
For the different ring position, the constants a(H) are in the order of
a(p=h)≈a(o-H)>a(m-H)