• Diamagnetic susceptibilities of some substituted anisoles and thioanisoles. Evidence for steric enhancement of resonance

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    • Keywords

       

      Diamagnetic susceptibilities; 4-nitroanisoles; 4-nitrothioanisoles; 4-methoxy-acetophenones; steric enhancement of resonance; steric inhibition of resonance

    • Abstract

       

      Evidence for steric enhancement of resonance in some benzene derivatives is obtained from their diamagnetic susceptibilities. Conjugative interaction of substituents in the benzene ring results in a decrease in diamagnetic susceptibility. For 2-methyl-4-nitroanisole and 2-halogeno-4-nitroanisoles the observed diamagnetic susceptibilities are significantly lower than the expected value, indicating that the 2-substituent in these compounds enhances the resonance interaction of the 1,4-substituents. Interestingly, the diamagnetic susceptibility data also show steric inhibition of resonance in 2,6-disubstituted-4-nitroanisoles. 2-Methyl-4-nitrothioanisole seems to exhibit a behaviour similar to that of its oxygen analogue, though the evidence for steric enhancement of resonance in this case is not beyond doubt. 2,6-Dimethyl-4-nitrothioanisole, however, convincingly shows the expected steric inhibition of resonance. The diamagnetic susceptibilities of 3-substituted-4-methoxyacetophenones also furnish further evidence for steric enhancement of resonance.

    • Author Affiliations

       

      V Baliah1 2 J Judith Diana Jeyanthy1

      1. Department of Chemistry, Annamalai University, Annamalainagar - 608 002, India
      2. 79, 3rd Cross Road, Venkatanagar, Pondicherry - 605 011, India
    • Dates

       
  • Journal of Chemical Sciences | News

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