INTRAMOLECULAR PROTON TRANSFER EQUILIBRIUM IN SALICYLIDENE- AND NAPHTHALENE-BASED TETRAIMINE SCHIFF BASES

Özlem Özdemir Güngör
1.131 248

Abstract


In this work, two nitro-Schiff bases were synthesized by condensation reaction of 4-nitro-benzaldehyde with p-phenylenediamine and 3-amino-2-naphthol in 2:1 and 1:1 ratios, respectively. Then, asymmetric tetraimine Schiff bases (L-1, L-2, L-3) were prepared by the reduction of nitro group to amino group with sodium dithionite and adding aldehyde, such as salicylaldehyde, 2-hydroxy-1-naphthaldehyde or terephthaldehyde. Tetraimines have been characterized by elemental analysis, FT-IR, 1H/13C NMR, UV–vis, 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.


Keywords


Tetraimines; Schiff bases; Tautomerism; Structure effect; Solvent effect

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References


Aleksander Filarowski

Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie st., 50-383 Wrocław, Poland

Tel.: +48 71 3757229; fax: +48 71 3282348

aleksander.filarowski@chem.uni.wroc.pl

(Ortho-hydroxy aryl and heterocyclic Schiff bases, Tautomeric equilibrium, Intramolecular hydrogen bond)

Çiğdem Albayrak

Sinop University, Faculty of Arts and Sciences, Department of Chemistry, 57000 Sinop, Turkey

Tel.: +90 368 2715532; fax: +90 368 2715530

calbayrak@sinop.edu.tr

(Proton tautomerism is experimentally and theoretically investigated.)

Halil Berber

Anadolu University, Faculty of Science, Chemistry Department, 26470 Eskişehir, Turkey

Tel.: +90 222 335 05 80x4827; fax: +90 222 320 49 10.

hlberber@anadolu.edu.tr

(The tautomerisms of all of the Schiff bases compounds were determined in DMSO, CHCl3, C2H5OH and C6H12 solvents and in both acidic and basic media using the UV–vis spectrophotometric method).