The effect of Er(III) on the thermal behavior of azo (–N=N–) and azomethinic (–CH=N–) chromophores

This paper reports the investigation of the thermal stability of a series of new complexes with azo and azomethinic chromophores of the type Er(HL)₂(H₂O)₂](HO); ((B) H₂L: o,o’-dihydroxy-azobenzene (A); (D) H₂L: N-(2-hydroxy-1-naphthalidene)aminophenol (C); (F) H₂L: N-(2-hydroxy-1-naphthalidene)anthranilic acid (E)). The complexes thermal behaviour steps were investigated and comparatively presented with those of corresponding ligand. The thermal transformations are complex processes according to TG and DTG curves including phenol elimination, oxidative condensation and thermolysis processes. The final product of complexes decomposition is Er₂O₃.