Synthesis, photophysical, photochemical and electrochemical properties of crown ether bearing coumarin substituted phthalocyanines

Zinc (II), cobalt (II) and copper (II) phthalocyanines substituted at the peripheral (complexes 5, 6 and 7) and non-peripheral (complexes 8, 9 and 10) positions with 7,8-(15-crown-5)-3-(4-oxyphenyl)coumarin groups have been prepared and characterized. The photophysical and photochemical properties of zinc (II) Pc complexes (5 and 8) were also described. The singlet oxygen quantum yields (0.54 for 5, 0.65 for 8) are indicating the potential of the complexes as photosensitizers in applications of PDT. The redox processes of the complexes were identified by voltammetry and in situ spectroelectrochemistry. Alpha and beta-substituted complexes displayed metal- and/or phthalocyanine ring-based redox processes. It was found that the kind of substitution affects the redox processes of the phthalocyanine complexes considerably, due to the difference in their aggregation behaviors. (C) 2011 Elsevier B. V. All rights reserved.