Synthesis, characterization and spectroscopic properties of new azo dyes derived from aniline derivatives based on acetylacetone and azo-metal (II) complexes and singular value decomposition (SVD) investigation

Four new azo-dyes, 3-phenyl azopentane-2,4-dion (L-A), 3-(4-nitro phenyl azo)-pentane-2,4-dion (L-P), 3-(2-nitro phenyl azo)-pentane-2,4-dion (L-o) and 4-(1-acetyle-2-oxo-propyl azo)-benzene sulfonate sodium (L-S), were synthesized from aniline, 4-nitroaniline, 2-nitroaniline and sulfanilic acid with acetylacetone, respectively. Reaction of these new dyes with acetate salts of copper(II), nickel(II) and cobalt(II) in molar ratios of 1:2 were carried out to produce azo metal (II) complexes with the general stoichiometry; CuL2, CoL2 and NiL3 in complexes. Structure of azo dyes was characterized using FT-IR, H-1 NMR, C-13 NMR, UV-Visible and also the corresponding metal (II) complex were characterized by FT IR, UV-Visible and CHN and XRD analysis techniques. Elemental analysis and spectral data indicated that the dye as a ligand with two teeth, N and 0, acts as a bidentate ligand. Differences in absorption maxima of azo ligands compared to those corresponding complexes were also studied. Also, in this work, singular value decomposition (SVD) as a chemometric method was used to determine the Cu(II), Co(II) and Ni(II) complexes with the mentioned ligands in methanol by UV-Vis spectrophotometry. SVD method confirmed the formation of CuL2, CoL2 and NiL3 complexes.