Thermally stable water insoluble azo-azomethine dyes: Synthesis, characterization and solvatochromic properties

Six new water insoluble azo-azomethine dyes have been synthesized via condensation reaction of α,α′-bis(o-aminophenylthio)-1,2-xylene with substituted azo-coupled salicylaldehyde. The condensation reaction provides the expected bis-iminated azo-azomethine dyes in good yields, ranging from 59% to 90%. The dyes have been characterized by IR, UV–Vis and 1H NMR spectroscopic methods as well as elemental analysis. The thermal behavior of the prepared dyes has been determined using thermogravimetry technique. Furthermore, the effect of various organic solvents with different polarities on the UV–Vis spectra of the dyes has been also studied.

Graphical abstractNew thermally stable bis-iminated water insoluble azo-azomethine dyes were synthesized via condensation reaction of α,α′-bis(o-aminophenylthio)-1,2-xylene with substituted azo-coupled salicylaldehyde. The effect of various organic solvents with different polarities on the UV–Vis spectra of the dyes has been investigated.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► New bisiminated water insoluble azo-azomethine dyes have synthesized. ► Solvatochromic properties of the dyes in various organic solvents has been investigated. ► Thermal behavior of the prepared dyes has been reported.