Microwave-Assisted Synthesis of Some Metal-Free Phthalocyanine Derivatives and a Comparison with Conventional Methods of their Synthesis

Synthesis of metal-free 2,9(10),16(17),23(24)-tetra(3,5-dimethylphenoxy) phthalocyanine, 2,9(10),16(17), 23(24)-tetra(4-tert-butylphenoxy) phthalocyanine, and 2,9(10),16(17),23(24)-tetra(3,5-di-tert-butyl-4-hydroxyphenyl) phthalocyanine was carried out via microwave irradiation. Furthermore, pentanol and lithium were used for the first time in the synthesis of metal-free phthalocyanine under microwave irradiation as a solvent and a base-catalyst, respectively. The microwave irradiation experiments were performed in a MARS5 with a CEM XP-1500 vessel. In addition, these compounds were obtained with conventional heating procedures to compare them with those obtained with microwave irradiation. The compounds were characterized by elemental and spectroscopic analysis, including UV-Vis, H-1 NMR, FT-IR, and MALDI-TOF mass data. In particular, both methods were compared in terms of reaction parameters and product yields. In addition, we first performed the synthesis of phthalonitriles as an initial material at room temperature, which is a slight modi. cation of that reported in the literature.