Bulky-substituted phthalodinitriles and cobalt and copper phthalocyanines based on them: synthesis, thermal analysis and spectroscopic properties

Abstract

By the nucleophilic substitution of the nitro group in 4-nitrophthalononitrile for the residues of alkoxy-substituted phenols, the synthesis of alkoxyphenoxyphthalonitriles was carried out. By template condensation of the substituted phthalonitriles obtained with copper and cobalt acetates at 200 °C, the corresponding phthalocyaninates were obtained. The conditions for the isolation and purification of the complexes synthesized were selected. The stability of substituted phthalonitriles and phthalocyaninates synthesized based on them regarding to heating in an argon–oxygen medium was evaluated (1:1 ratio). It was found the compounds obtained are thermally stable, and the destruction of phthalocyanines begins at lower temperatures compared to the corresponding phthalonitriles. For the complexes synthesized, the spectroscopic properties in organic solvents and concentrated sulfuric acid were studied. The influence of the nature of the substituent, metal complexing agent and solvent on the nature of the spectroscopic curves and the position of the main absorption band of phthalocyanine complexes has been established. It is noted passing from polar aprotic solvents to nonpolar ones, a shift of the maximum of the Q absorption band for the studied macrocycles was observed. Electronic absorption spectra in sulfuric acid show a significant bathochromic shift of the absorption band. An increase in the length of the alkyl substituent practically was found not to affect the position of the absorption maximum. Passing from complexes with Co(II) to Cu(II), a bathochromic shift of the absorption maximum was observed.