Isomers of β-substituted di and tri-nitrotetraphenylporphyrins and their copper(II) derivatives: Structure, optical and electrochemical redox properties

  • S Dahal
  • V Krishnan
  • M Nethaji
Inorganic And Analytical


Controlled nitration ofmeso-tetraphenylporphyrinatocopper(II) using fuming nitric acid leads to the formation of different β-substituted nitro derivatives. Five isomers of dinitro and three isomers of trinitrotetraphenylporphyrins have been isolated and characterised using FAB/MS,1H NMR, UV-VIS and IR spectroscopies. The single crystal X-ray data on the copper(II) derivative of one of the isomers of trinitrotetraphenylporphyrin revealed ‘saddle’ conformation of the porphyrin core resulting from the nitro group substitution at theβ-pyrrole carbons. The electrochemical redox behaviour of the free-base porphyrins and their copper(II) derivatives revealed that successive substitution of nitro groups at the pyrrole carbons shifts the one-electron ring oxidations anodically while the ring reduction occurs at a less cathodic potential relative to the unsubstituted porphyrin. The isomer specific shifts in the redox potentials bear a direct relationship with the relative energy levels of HOMO/LUMO obtained from AM1 calculations.


Isomers di and trinitrotetraphenylporphyrins ring-redox potentials crystal structure trinitrotetraphenylporphyrinatocopper(II) 


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Copyright information

© Indian Academy of Sciences 1998

Authors and Affiliations

  • S Dahal
    • 1
  • V Krishnan
    • 1
  • M Nethaji
    • 1
  1. 1.Department of Inorganic and Physical ChemistryIndian Institute of ScienceBangaloreIndia

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