Intramolecular Proton Transfer Equilibrium in Salicylidene- and Naphthalene-based Tetraimine Schiff Bases


Ozdemir Gungor Ö.

GAZI UNIVERSITY JOURNAL OF SCIENCE, vol.30, no.1, pp.191-214, 2017 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 30 Issue: 1
  • Publication Date: 2017
  • Journal Name: GAZI UNIVERSITY JOURNAL OF SCIENCE
  • Journal Indexes: Emerging Sources Citation Index, Scopus
  • Page Numbers: pp.191-214
  • Keywords: Tetraimines, Schiff bases, Tautomerism, Structure effect, Solvent effect, SOLID-STATE, SPECTROSCOPIC PROPERTIES, DFT CALCULATIONS, HYDROGEN-BOND, IN-VITRO, COMPLEXES, TAUTOMERISM, NMR, ANTIBACTERIAL, PHOTOCHROMISM

Abstract

In this work, two nitro-Schiff bases were synthesized by condensation reaction of 4-nitrobenzaldehyde with p-phenylenediamine and 3-amino-2-naphthol in 2: 1 and 1: 1 ratios, respectively. Then, the reduction of nitro group to amino group with sodium dithionite and forming the new imine bond by adding aldehyde, as salicylaldehyde, 2-hydroxy-1-naphthaldehyde or terephthaldehyde, asymmetric tetraimine Schiff bases (L-1, L-2, L-3) were prepared. Tetraimines have been characterized by elemental analysis, FT-IR, H-1/C-13 NMR, UVVis, and mass spectroscopy techniques in order to study the structure effect on the phenol-keto tautomerism. Solvent, acid and base effects on the tautomeric equilibrium have been also investigated by using UV-Vis spectra.