METALLOPHTHALOCYANINES AS PHOTODYNAMIC SENSITIZERS FOR TREATMENT OF PATHOGENIC BACTERIA. SYNTHESIS AND SINGLET OXYGEN FORMATION

Methylpyridyloxy-substituted phthalocyanine complexes. of zinc, aluminium, gallium and indium were prepared to be studied as photodynamic sensitizers for inactivation of oral pathogenic bacteria. The complexes of Ga(III) and In(III) are used for the first time in photodynamic processes. The absorbance parameters of the metallophthalocyanines of gallium and indium as new compounds were examined in solvents with increasing polarity. All studied phthalocyanines are water-soluble, but only complexes of Ga(III) are non-aggregated in water. Long-wavelength absorption of the Q-bands (673-679 nm) with high molar extinction coefficients (> 10(5) mol(-1) cm(-1)), which is typical of the highly conjugated heterocyclic macromolecules were determined. The photooxidation. of singlet oxygen scavenger 1,3-diphenylisobenzofuran that indicates a singlet oxygen formation in a model system was applied to evaluate the studied phthalocyanines as photosensitizers. The data showed a linear dependence of the size of coordinated metal ion on the magnitude of singlet oxygen quantum yield for all studied metallophthalocyanines in order: Al(III) < In(III) < Ga(III) < Zn(II) as was detected by optical transmittance.