Photophysical properties of anthracenylmethyloxycarbonylmethylsulfanyl- phthalocyanines

Metal-free and metallophthalocyanine compounds with four 9-anthracenylmethyl ester of thioglycolic acid groups have been prepared via esterification of related carboxy-terminated derivatives of phthalocyanines with anthracene-9-methanol. In order to justify the esterification reaction, UV-vis spectra have been used as an efficient tool: in addition to the usual Q and B bands of phthalocyanine moieties, the presence of anthracene groups was proven with their strong absorptions in the range of 340-380 nm. Aggregation tendency of the newly prepared Pcs has been investigated in the concentration range of 1.0-5.0 × 10^-6 M. The influence of the substituents and the metal ions on the spectroscopic and photophysical properties of the Pcs has been investigated. The energy transfer to phthalocyanine core and radiative decays of the anthracene emission and phthalocyanine core were examined. The lower energy transfer efficiency is probably due to the saturated linker moiety and lack of spectral overlap between phthalocyanine core and anthracene units.