Optical properties studies on metal–ligand bonding of novel quinoline azodyes thin films

Copper(II) complexes of (4-alkylphenylazo)-5-sulfo-8-hydroxyquinoline, [Cu(Ln)2], are synthesized and characterized with various experimental techniques. Optical properties and spectral behavior of the complexes [Cu(Ln)2] also investigated using spectrophotometric measurements of transmissivity and reflectivity at normal incident light in the wavelength range 200–2500 nm. The values of dispersion parameters Eo, Ed, ɛL, ɛ∞ and N/m* are calculated according to the single oscillator model. The values of the fundamental and onset energy gaps, Eg and Eg∗ are calculated and found to be in the range 2.48–3.51 eV and 1.8–3.01 eV, respectively; depending on the substituent. The thermal properties of the complexes were investigated using TGA. It is found that the change of substituent affects the thermal properties of complexes.

Graphical abstractPlot of the absorption coefficient, α, as a function of the incident photon energy, hν, for [Cu(Ln)2] thin films.Figure optionsDownload full-size imageDownload as PowerPoint slide