The equilibrium between the iso and the normal forms of 9-nitrofluorene

  • K. D. Nenitzescu
  • I. G. Dinulescu
Organic and Biological Chemistry


  1. 1.

    A series of bromometric titrations of solution of iso-9-nitrofluorene in ethanol, dioxane and benzene was run.

  2. 2.

    The iso-form is thermodynamically more stable in the crystalline form than is the normal form; equilibria are established in solution in which the content of the normal form is greater with lower polarity of the solvent. The normal form of 9-nitrofluorene cannot be isolated since it disproportionates forming 1,2-dinitro1,2-dibiphenylene-ethane and fluorenone oxime. This reaction occurs at a lower rate than the reaction of formation of the normal form from the iso-form. Consequently, temporarily large concentrations of the normal form exist in solution and these were established by a chemical route.

  3. 3.

    The greater stability of the iso-form of 9-nitrofluorene is determined by the tendency of the cyclopentadiene ring to form an aromatic sextet by attracting electron pairs from the nitro group.



Benzene Titration Normal Form Dioxane Oxime 
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Copyright information

© Consultants Bureau Inc. 1959

Authors and Affiliations

  • K. D. Nenitzescu
    • 1
  • I. G. Dinulescu
    • 1
  1. 1.Division of Chemical Research of the Academy of Rumanian Peoples RepublicRumania

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