Synthesis and spectroscopic characterization of asymmetric Schiff bases derived from 4'-formylbenzo-15-crown-5 containing recognition sites for alkali and transition metal guest cations

HAYVALI Z., Yardimci D.

TRANSITION METAL CHEMISTRY, cilt.33, sa.4, ss.421-429, 2008 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 33 Sayı: 4
  • Basım Tarihi: 2008
  • Doi Numarası: 10.1007/s11243-008-9060-4
  • Dergi Adı: TRANSITION METAL CHEMISTRY
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.421-429
  • Ankara Üniversitesi Adresli: Evet

Özet

Asymmetric salen-type Schiff base ligands have been synthesized via a stepwise approach. In the first step, mono-Schiff base compounds were prepared by condensation of salicylaldehyde, 2-hydroxy-3-methoxybenzaldehyde, 2-hydroxy-5-methoxybenzaldehyde and 2-hydroxy-1-naphthaldehyde with hydrazine hydrate. These compounds were then reacted with 4'-formylbenzo-15-crown-5 to prepare asymmetric ligands. H-1-NMR spectra indicate that the mono- and asymmetric bis-Schiff base compounds exist in both (E) and (Z) isomeric forms in CDCl3 solution. The asymmetric crown compounds form crystalline 1:1 (Na+:ligand) complexes with sodium perchlorate. Homo-metallic Ni(II) and Zn(II) complexes with 1:2 (metal:ligand) stoichiometries have also been synthesized. The results indicate that the Schiff base ligands coordinate through the azomethine nitrogen and phenolic oxygen.