A series of metal (Cr(III), Fe(III), Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)) complexes with 4-[(Z-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-
yl]-1-methyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one were prepared by azo coupling of diazotised 4-aminoantipyrine with 4-hydroxy-6-
methyl-2-pyranone. The free ligand and its metal complexes were fully characterized on the basis of elemental analyses and 1H NMR, FTIR
and UV-Visible spectroscopy. The keto-enol tautomer azo ligand [HL] was a mixture of E and Z isomers as suggested by 1H NMR and FTIR spectroscopy. The chelating properties of the new azo ligand were studied towards Cr(III), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) ions,
and the spectral data revealed that the nitrogen and oxygen atoms of –N=N-, C=O and –OH groups participated in bonding with the metal
ions. The study of NMR, IR and electronic spectra indicated an octahedral structure for all metal complexes except zinc(II) complex,
which has the tetrahedral structure.
Key words: Azo dyes derived from 4-hydroxy-6-methyl-2-pyranone; transition metal complexes; synthesis.
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