Novel metal-free, metallophthalocyanines and their quaternized derivatives: Synthesis, spectroscopic characterization and catalytic activity of cobalt phthalocyanine in 4-nitrophenol oxidation

Abstract

Novel metal-free, Zn and Co phthalocyanines substituted with four 4-[4-((E)-{[4-(dimethylamino)phenyl]imino}methyl)phenoxy] substituents at peripheral positions have been synthesized. Quaternization of the dimethylamino functionality produced quaternized cationic metal-free, Zn and Co phthalocyanines which were soluble in DMF, DMSO and pyridine. The aggregation behavior of these compounds was investigated in different concentrations of chloroform for the metal-free, Zn and Co phthalocyanines, and DMF for the quaternized metal-free, Zn and Co phthalocyanines. The effect of solvents on the absorption spectra was studied in various organic solvents. Cobalt phthalocyanine complex 6 was tested as a catalyst for the oxidation of 4-nitrophenol with different oxidants, such as tert-butylhydroperoxide (TBHP), m-chloroperoxybenzoic acid (m-CPBA) and hydrogen peroxide (H2O2), in organic solvent. The novel compounds were characterized using IR, 1H NMR, 13C NMR, UV–Vis, MS spectral data and elemental analysis.