In this paper, we elucidated the synthesis, characterization, and investigation of catalytic activity studies of new metallophthalocyanines 4 and 5 as the catalyst for phenolic compounds oxidation by trying different types of oxygen sources. The structural characterization of the products was made by a combination of elemental analysis, FT-IR, LC-MS/MS (for phthalonitrile derivative 3), MALDI-TOF mass spectral data (for metallophthalocyanines 4–7), UV–vis spectroscopy (for metallophthalocyanines 4–7), ¹H NMR and ¹³C NMR spectroscopies (for compounds 3 and 6). The synthetic routes for the (trans-3,7-dimethyl-2,6-octadien-1-ol) substituted phthalonitrile derivative 3 and corresponding metallophthalocyanines 4–7 are outlined in Scheme 1. The MPc complexes 4–7 were synthesized via cyclotetramerization of compound 3 in the presence of the corresponding anhydrous metal salts (CoCl₂ for 4, CuCl₂ for 5, Zn(CH₃COO)₂ for 6 and MnCl₂ for 7) in dry n-pentanol as solvent and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as strong base at reflux temperature under nitrogen gas. Phthalocyanines and their metal complexes, in general, display poor solubility in most of the organic solvents, however, the synthesized metallophthalocyanine complexes 4–7 were highly soluble in common organic solvents because of the introduction of the methyl groups on alkyl chains of peripheral arms. The catalytic activity of compounds 4 and 5 was evaluated for the oxidation of phenolic compounds such as 4-nitrophenol, o-chlorophenol, 2,3-dichlorophenol, and p-methoxyphenol. CoPc 4 displayed good catalytic performance with a full oxidation of 4-nitrophenol into the corresponding benzoquinone and hydroquinone with the highest TON and TOF values within 3 h.

In this work, 2,3-dichlorophenoxy substituted cobalt and iron phthalocyanines have been synthesized and used as efficient catalysts for aerobic oxidation of nitrophenols. Co(II) and Fe(II) phthalocyanines have been characterized by IR, ¹H NMR, ¹³C NMR, UV–vis, and mass spectroscopies. tert-butyl hydroperoxide (TBHP), m-chloroperoxybenzoic acid, hydrogen peroxide, and air oxygen have been used as oxygen source. These catalysts offered the highest activity on 4-nitrophenol oxidation in 3 h. In order to achieve the best reaction conditions, oxidant ratio, temperature, and oxidant type have been investigated with different nitrophenols in 3 h.

Research on substituted phenol degradations has received substantial attention. In this work, effective Co(II) and Cu(II) phthalocyanine complexes as catalysts were studied in order to degrade toxic phenols to harmless products. The effect of various process parameters such as initial concentration of phenol, catalyst, oxygen sources and temperature on the degradation reaction was investigated to achieve maximum degradation efficiency. The catalytic activities of Co(II) and Cu(II) phthalocyanines were evaluated for oxidation of phenolic compounds such as p-nitrophenol, o-chlorophenol, 2,3-dichlorophenol and m-methoxyphenol. Co(II) phthalocyanine displayed good catalytic performance in degradation of 2,3-dichlorophenol to 2,3-dichlorobenzaldehyde and 2,3-dichloro-1,4-benzoquinone with the highest TON and TOF values within 3 h at 50 °C. The fate of catalyst during the degradation process was followed by UV-Vis spectroscopy.