Synthesis and Spectral Investigation of Some New Crown Ether Ligands

Abstract

The new crown ether ligands (5-6) were synthesized by condensation
of 4' -formyl-5' -hydroxybenzo-15-crown-5 (4) with 2-
chloroaniline and 3-bromoaniline. The structure of these compounds
have been elucidated on the basis of elemental analyses, IR, ¹H,
¹³C NMR, and UV-Vis spectroscopic techniques. The UV-V is spectra
of the ligands (5-6) were studied in polar and non-polar solvents,
as well as in acidic and basic media. The results indicate that the
tautomeric equilibria (phenol-imine O—H·· N and keto-amine
O^... H—N forms) are present only in the EtOH solution. But in
other solvents (DMSO, CHCI₃, n-hexane), acidic and basic media
only the phenol-imino form is dominant.