Syntheses, spectroscopic and structural characterizations and metal ion binding properties of Schiff bases derived from 4′-aminobenzo-15-crown-5

A series of benzyloxybenzaldehyde derivatives (1–4) were synthesized by the reactions of 4-(bromomethyl)benzonitrile with 4-hydroxy-3-methoxybenzaldehyde (vanillin), 2-hydroxy-3-methoxybenzaldehyde (o-vanillin), 2-hydroxy-4-methoxybenzaldehyde and 2-hydroxy-5-methoxybenzaldehyde. Condensation reactions among the new benzyloxybenzaldehyde derivatives (1–4) with 4′-aminobenzo-15-crown-5 yielded the new Schiff base compounds (5–8). Sodium complexes (5a–8a) and potassium complexes (5b–8b) were prepared with NaClO4 and KI, respectively. All of these synthesized compounds were characterized on the basis of FT-IR, 1H and 13C NMR, mass spectrometry and elemental analyses data. The solid state structures of compounds 8 and 5a were determined by X-ray crystallography. The extraction abilities of compounds 5–8 were also evaluated in CH2Cl2 by using several main group and transition metal picrates, such as Na+, K+, Pb2+, Cr3+, Ni2+, Cu2+ and Zn2+.

A series of benzyloxybenzaldehyde derivatives 1–4 have been synthesized. Condensation reactions among the new benzyloxybenzaldehydes (1–4) with 4′-aminobenzo-15-crown-5 yielded the new Schiff bases 5–8. Sodium complexes (5a–8a) and potassium complexes (5b–8b) have been prepared. The solid state structures of compounds 8 and 5a were determined by X-ray crystallography. The extraction ability of compounds 5–8 were also evaluated in CH2Cl2 by using several metal picrates, such as Na+, K+, Cr3+, Ni2+, Cu2+, Zn2+ and Pb2+.Figure optionsDownload as PowerPoint slideHighlights
► A series of benzyloxybenzaldehydes, new crown ether Schiff bases and Na+ and K+ complexes have been synthesized.
► The solid state structures of crown ether and Na+ complex were determined by X-ray crystallography.
► The extraction abilities of crown ethers were studied by using Na+, K+, Pb2+, Cr3+, Ni2+, Cu2+ and Zn2+ picrates.