Acta Phys. -Chim. Sin. ›› 1995, Vol. 11 ›› Issue (04): 325-330.doi: 10.3866/PKU.WHXB19950408

• ARTICLE • Previous Articles     Next Articles

ESR Studies for the Photoinduced Electron Transfer of the Phthalocyanine-Paraquat Systems

Chen De-Wen, Wang Hai, Zhou Jian-Wei, Yang Yu-Kun, Xu Guang-Zhi   

  1. The State Key Laboratory for Structural Chemistry of Unstable and Stable Species,Institute of Chemistry,Academia Sinica,Beijing 100080
  • Received:1994-04-04 Revised:1994-07-23 Published:1995-04-15
  • Contact: Chen De-Wen

Abstract:

Photoinduced electron transfer of metal-phthalocyanine MPc (M=Zn, Mg, Fe, Co, Cu) dispersions in the presence of electron acceptors such as paraquat (4,4’-[-1,4-phenylene-]-Bis-[-N-alkyl(oraryl)-2,6-(diphenyl-]-pyridinium perchlorates, i.e. PQ2+) has been studied by means of ESR spectroscopy. The results show that, when irradiated with visible light, electron in valence band (VB) of photoconductor can be excited to conduction band (CB) to form an electron-hole pair and the electron may transfer from CB to PQ2+ to produce a radical cation PQ, then a weak ESR signal was observed. As in the presence of cationic surfactant Chloro-Tetradecyl-Pridium, as well as of hole-quencher TEA or EDTA, the strength of ESR signal can be enhanced by 5~6 times as much or more. While in the presence of oxygen in the system, the signal of PQ+ radical disappeared and superoxide radical anion O2- was detected. It is obvious that the existence of oxygen might seriously hinder the process of photoinduced electron transfer.

Key words: Phthalocyanine, Paraquat, Electron transfer, ESR