- 作者: Raafat M. Issa, Abdalla M. Khedr* and Helen Rizk
- 作者服務機構: Chemistry Department, Faculty of Science, Tanta University, Tanta, Egypt
- 中文摘要:
By condensing 2-aminobenzothiazole with 2-hydroxy-1-naphthaldehyde, 2-hydroxybenzaldehyde,
4-methoxybenzaldehyde, 4-hydroxybenzal-dehyde, benzaldehyde and 4-dimethylaminobenzaldehyde,
and five Schiff bases Ia-Ie are prepared. Also, two Schiff bases IIa and IIb are prepared by condensation of
2-amino-3-hydroxypyridine with 2-hydroxy-1-naphthaldehyde and 2-hydroxybenzaldehyde. The 1H
NMR, IR and UV/Vis spectra of these seven Schiff bases are investigated. The signals of the 1H NMR
spectra as well as the important bands in the IR spectra are considered and discussed in relation to molecular
structure. The UV/Vis absorption bands in ethanol are assigned to the corresponding electronic transitions
and the electronic absorption spectra of Schiff bases Ib and IIb are studied in organic solvents of different
polarities. The UV/Vis absorption spectra of 2-amino-3-hydroxypyridine Schiff bases IIa and IIb
are investigated in buffer solutions of different pH values containing 5% (v/v) methanol, and the results
are utilized for the determination of pKa and △G* of the ionization of the phenolic OH-groups. The fluorescence
spectra of IIa and IIb are studied in organic solvents of different polarities.
The obtained spectral results are confirmed by somemolecular calculations using the atom super position
and electron delocalization molecular orbital theory for the Schiff base IIb. - 英文摘要: --
- 中文關鍵字: 2-Aminobenzothiazole; 2-Amino-3-hydroxypyridine; Benzaldehyde derivatives; Schiff bases; Spectral studies; Molecular orbital calculations.
- 英文關鍵字: --