DEPENDENCE OF TAUTOMERISM ON SUBSTITUENT TYPE IN o-HYDROXY SCHIFF BASES
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Tarih
2019
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Soc Chemists Technologists Madeconia
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Quantum computational methods were used to elucidate the structures of the o-hydroxy Schiff bases with different substituents. It is possible for a Schiff base to have different tautomeric structures depending on intramolecular proton transfer from the phenolic oxygen atom to the nitrogen atom. Proton transfer results in two tautomeric structures known as the phenol-imine and keto-amine forms. To explain the substituent effect on the proton transfer process in five o-hydroxy-Schiff bases, possible geometric structures in gas phase were optimized using density functional theory (DFT) at the B3LYP/6-311G(d,p) level. To describe tautomerism including intramolecular proton transfer, potential energy surface (PES) scans were performed starting from the optimized geometry of the phenol-imine form. HOMA indices were calculated in order to estimate pi-electron delocalization. In addition, the substituent effect on the tautomerization rate was examined using Hammett substituent constants and calculating the activation energies.
Açıklama
Anahtar Kelimeler
Schiff base, tautomerism, phenol-imine, keto-amine, DFT, PES
Kaynak
Macedonian Journal of Chemistry and Chemical Engineering
WoS Q Değeri
Q3
Scopus Q Değeri
Q3
Cilt
38
Sayı
1
