Sulphonated phthalocyanines as effective oxidation photocatalysts for visible and UV light regions

Attention was paid to the synthesis, chemical modification (sulphonation), characterisation and practical catalytic utilisation of metal free phthalocyanine and a series of phthalocyanines (PHCs) with Zn, Al, Si, Co, Ni, Cu and Ti central atoms. These organometallic compounds are referred to as highly active species due to their ability to produce singlet oxygen upon energy absorption. Photocatalytic efficiency of the prepared PHCs was tested in a model oxidation of 4-chlorophenol under illumination with visible and UV light in agreement with location of their distinctive absorption bands in both these regions. It was shown that different types of phthalocyanines revealed very different photocatalytic activities and only those with a long life-time of the excited triplet states (ZnPHC, SiPHC, AlPHC) effectively interacted with molecular oxygen to form the reactive singlet oxygen. The indispensable role of constant pH (∼10) was also clarified in separate experiments. Determined values of quantum yields for reactions carried out in the UV region were always higher than for reactions induced by the visible light.

Attention was paid to the synthesis, chemical modification (sulphonation), characterisation and practical catalytic utilisation of metal free phthalocyanine and a series of phthalocyanines (PHCs) with Zn, Al, Si, Co, Ni, Cu and Ti central atoms in a model oxidation of 4-chlorophenol under illumination with visible and UV light.Figure optionsDownload as PowerPoint slide