Synthesis, Photophysical and Photochemical Properties of Poly(oxyethylene)‐Substituted Phthalocyaninato Oxotitanium(IV) Complexes

Abstract The synthesis, photophysical and photochemical properties of tetra‐ and chlorotetrapoly(oxyethylene)‐substituted oxotitanium(IV) phthalocyanines are reported for the first time. The new compounds were characterized by elemental analysis, IR, 1 H and 13 C NMR spectroscopy, electronic spectroscopy and mass spectra. These complexes showed monomeric behaviour in solution. General trends are described for photodegredation, singlet oxygen, triplet state and fluorescence quantum yields, and triplet and fluorescence lifetimes of these compounds in dimethyl sulfoxide (DMSO). Photophysical and photochemical properties of phthalocyanine complexes are very useful for PDT applications. The complexes showed high triplet quantum yields and triplet lifetimes in DMSO. The singlet oxygen quantum yields ( Φ Δ ), which give an indication of the potential of the complexes as photosensitizers in applications where singlet oxygen is required (Type II mechanism), were 0.72 and 0.78 for 3a and 5a , respectively. Thus, these complexes show potential as Type II photosensitizers. These complexes were also quenched by benzoquinone for fluorescence quenching studies.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)