Functional zinc(II) phthalocyanines bearing Schiff base complexes as oxidation catalysts for bleaching systems

Abstract

Oxidation catalysis is used to increase the performance of hydrogen peroxide in laundry bleach applications. Bleach catalysts provide cost‐effective, energy‐saving and environmentally friendly bleach systems yielding perfect stain removal at lower temperatures. This comparative study is based on the synthesis of bis[bis(salicylhydrazonephenoxy)manganese(III)] phthalocyaninatozinc(II) (2), bis[bis(salicylhydrazonephenoxy)cobalt(III)] phthalocyaninatozinc(II) (3) and bis[bis(salicylhydrazonephenoxy)iron(III)] phthalocyaninatozinc(II) (4) as tri‐nuclear complexes consisting of two Schiff base complexes substituting a zinc phthalocyanine. Complexion on the periphery to obtain complexes 2, 3, 4 was performed through the reaction of a Schiff base‐substituted phthalocyanine using MnCl2⋅4H2O, CoCl2⋅6H2O or FeCl3⋅6H2O salts in basic condition in dimethylformamide. Fourier transform infrared, 1H NMR, 13C NMR, UV–visible, inductively coupled plasma optical emission and mass spectra were applied to characterize the prepared compounds. The bleach performances of the three phthalocyanine compounds 2, 3, 4 were examined by the degradation of morin as hydrophilic dye. The degradation progress in the presence of catalysts 2, 3, 4/H2O2 combination in aqueous solution was investigated using an online spectrophotometric method. It was found that the catalysts 2, 3, 4 exhibited better bleaching performance at 25 °C than tetraactylethylethylenediamine as bleach activator used in powder detergent formulations for stain removal. Copyright © 2015 John Wiley & Sons, Ltd.