SYNTHESIS AND MOLECULAR STRUCTURE OF TETRA-3-(4-CYCLOHEXYLPHENOXY)PHTHALOCYANINE ALUMINUM CHLORIDE COMPLEX

Abstract

This work is devoted to the synthesis and study of the molecular structure of the tetra-3-(4-cyclohexylphenoxy)phthalocyanine aluminum chloride complex. The synthesis of tetra-3-(4-cyclohexylphenoxy)phthalocyanine aluminum chloride was carried out by the "nitrile" method. The complex was purified by M60 silica gel column chromatography, eluting with the chromophore. IR-spectroscopy and mass-spectrometry (MALDI-TOF) were used for the identification of the obtained compound. The electronic absorption spectrum was obtained in tetrahydrofurane and interpreted by quantum-chemical calculations in TDDFT approximation. The conformational search was performed utilizing the CREST program and GFN2-xTB approximation, followed by DFT calculations of the “single-point” energies of the found conformations. For each configuration, "single-point" energy calculations were carried out in the B3LYP-D3/dgdzvp approximation and the most energetically favorable structure was identified. It has been established that the most energetically favorable structure of the tetra-3-(4-cyclohexylphenoxy)phthalocyanine aluminum chloride molecule is characterized by a helical mutual arrangement of bulky substituents on the same side of the macrocyclic plane. The interpretation of the electronic absorption spectrum was made on the basis of TDDFT calculations in the B3LYP-D3/def2-TZVP and CAM-B3LYP/def2-TZVP approximations with and without solvent (tetrahydrofuran, THF) within the C-PCM continuum solvation model. For both approximations, taking into account the solvent leads to a shift of the long-wavelength absorption maximum by 25–33 nm towards the experimental value (704 nm). The best agreement with experiment is achieved with the [PCM] CAM-B3LYP/def2-TZVP method.The simulated electronic spectrum is compared with the previously obtained spectra for complexes of Al(Cl) with tetrabenzoporphyrin (ClAlTBP) and tetrapyrazinoporphyrazine (ClAlTPyzPA).