• Electronic structure of spin-mixed iron(III) porphyrins: A proton magnetic resonance study

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      https://www.ias.ac.in/article/fulltext/jcsc/095/01-02/0189-0205

    • Keywords

       

      Proton magnetic resonance; perchlorato iron(III) porphyrins; spin state mixing; crystal field calculations ofIPS; electronic structure in solution

    • Abstract

       

      The proton magnetic resonance studies on the perchlorato iron(III) porphyrins in solution have been described. The isotropic proton shifts in these complexes show anomalous temperature dependence, consistent with its unusual properties in solid state. TheNMR data have been analysed on the basis of a crystal field theory which includes lower asymmetric field and spin-orbit interaction. The analysis brings out that the ground state of the ferric ion in these porphyrin complexes exhibits the novel spin-mixed behaviour with spin-mixing betweenS = 3/2 andS = 5/2. The ground state is predominantly a spin quartet with the spin sextet being a very close lying excited state. Such a spin situation and spin-mixing have been speculated for the ferric ion in some ferricytochromec’. The present paper also highlights that the isotropic proton shift is very sensitive to the electronic structure of the metal ion and hence can be used to determine the electronic structure of the metal ion in heme systemsin solution.

    • Author Affiliations

       

      L B Dugad1 V R Marathe1 Samaresh Mitra1

      1. Chemical Physics Group, Tata Institute of Fundamental Research, Colaba, Bombay - 400005, India
    • Dates

       
  • Journal of Chemical Sciences | News

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