Synthesis, characterization and dyeing properties of copper(II), nickel(II) and cobalt(III) complexes of 2-pyridylmethylene-1-amino-2-naphthol

Abstract

Synthetic methods for the preparation of the heterocyclic ligand 2-pyridylmethylene-1-amino-2-naphthol (PMAN) and its complexes with copper(II), nickel(II) and cobalt(III) are described. The structure of the ligand and of its metal complexes has been investigated by IR, UV/VIS and mass spectroscopy, and by elemental analysis. It has been found that the azomethine compound PMAN behaves as a tridentate ligand which forms various types of complexes. The Cu(II)-PMAN complex tends to form a chelate of ML type and with perchlorate as an anion. The Ni(II)-PMAN complex forms an ML 2 type of neutral complex, while the Co(III)-PMAN complex has the same ML 2 stoichiometry, but with perchlorate as an anion. The dyestuffs have been used for wool dyeing under a controlled dyeing process. Parameters such as the optimal dyeing temperature, exhaustion with time and fixing on fabrics under acidic conditions have been determined.