AM1 and PM3 study of the protonation tautomerization and valence tautomerization of some 4-substituted imidazoles

Ogretir C., Yarligan S.

THEOCHEM-JOURNAL OF MOLECULAR STRUCTURE, cilt.425, sa.3, ss.249-254, 1998 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 425 Sayı: 3
  • Basım Tarihi: 1998
  • Doi Numarası: 10.1016/s0166-1280(97)00168-1
  • Dergi Adı: THEOCHEM-JOURNAL OF MOLECULAR STRUCTURE
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.249-254
  • Eskişehir Osmangazi Üniversitesi Adresli: Hayır

Özet

The gas-phase geometries, relative stabilities, ionization potentials and proton affinities of the different tautomers of some 4-substituted imidazoles and their N-methyl derivatives were calculated with full geometry optimization. The predominance of the a (i.e. 1H-form) form with an electron-acceptor group at the 4-position over the b (i.e. 3H-form) form and the predominance of the b (i.e. 3H-form) form with an electron-donor group at the 4-position over the a (i.e. 1H-form) form were confirmed. A correlation between experimentally obtained acidity constants, pK(a), and calculated proton affinities was detected. (C) 1998 Elsevier Science B.V.