Singlet oxygen photogeneration efficiencies of a series of phthalocyanines in well-defined spectral regions

Singlet oxygen generation efficiencies of three photoactive metal phthalocyanines (Pcs of Al, Si, Zn) were investigated. This was achieved by monitoring the photooxidation of 4-chlorophenol (4-CP) in aquatic, aquatic/alcoholic or D2O environments with atmospheric oxygen and photons emitted in well-defined spectral regions. Another test was based on using the singlet oxygen chemical quencher 9,10-dimethylanthracene (DMA) in dimethylformamide. These tests were carried out using advanced opto-chemical apparatus with a series of well-defined light filters corresponding to the absorption bands of the used Pcs. The photocatalytic efficiencies were evaluated in the form of quantum yield (Φ) values. Special attention was paid to link the achieved quantum yields to the absorption spectra of the phthalocyanine solutions. In addition, the aggregation of sulfonated phthalocyanines was studied in detail, as this phenomenon results in significant losses in photocatalytic activity.