Synthesis and aggregation behavior of zinc phthalocyanines substituted with bulky naphthoxy and phenylazonaphthoxy groups: An experimental and theoretical study

• Zinc (II) phthalocyanines bearing bulky groups were prepared and characterized.
• Aggregation properties of these compounds were investigated in THF.
• Aggregation is limited with the solvent rather than bulky side groups.
• DFT-D is necessary to describe the interactions between phthalocyanines.

Zinc (II) phthalocyanines, bearing peripherally β-naphthol and ({1-[(Z or E)-phenylazo]-2-naphthyl}oxy) have been synthesized and characterized. Aggregation properties of these compounds were investigated in different concentration ranges. The molecular orbital properties and ultraviolet–visible spectra of these phthalocyanines were studied using density functional and time-dependent density functional theories. The computed electronic spectra are in good agreement with the experimental data. Moreover, dimerization of these phthalocyanine complexes in solvent (tetrahydrofuran) medium was investigated by counterpoise corrected interaction energy calculations employing dispersion corrected Becke's 1997 hybrid functional with valence triple-zeta basis set. These calculations revealed that aggregation in these complexes are prevented due to the strong solvent–phthalocyanine interactions and this finding was supported by our experiments.

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