Syntheses of near infrared absorbed phthalocyanines to utilize photosensitizers

Abstract

Phthalocyanines have become of major interest as functional colorants for various applications. In order to use various applications especially photosensitizers, the absorption maxima called Q-band of phthalocyanines are required to be shifted to the near infrared region. Substituted phthalocyanine analog alkylbenzopiridoporphyrazins, especially zinc bis(1,4-didecylbenzo)-bis(3,4-pyrido)porphyrazine, and toroidal-shaped phthalocyanines having aminoamine dendric side chains such as toroidal zinc poly(aminoamine)phthalocyanine dendrons were synthesized. Phthalocyanines of two types reportedly use photosensitizers for photodynamic therapy of cancer. The respective efficacies of photodynamic therapy of cancer for zinc bis(1,4-didecylbenzo)-bis(3,4-pyrido)porphyrazine and its regioisomers were estimated using laser-flash photolysis. The capability of using photodynamic therapy for toroidal zinc poly(aminoamine)phthalocyanine dendrons was assessed using a cancer cell culture. Both phthalocyanines were suitable for the use as a photosensitizer as photodynamic therapy of cancer. Then, non-peripheral thioaryl substituted phthalocyanines, 1,4,8,11,15,18,22,25-octakis(thioaryl)phthalocyanines, such as 1,4,8,11,15,18,22,25-octakis(thiophenylmethyl)phthalocyanines, 1,4,8,11,15,18,22,25-octakis(thiophenylmethoxy)phthalocyanines, and 1,4,8,11,15,18,22,25-octakis(thiophenyl tert-butyl)phthalocyanines were also synthesized in order to develop next- generation photovoltaic cells and/or dye-sensitized solar cells. Non-peripheral substituted 1,4,8,11,15,18,22,25-octakis(thioaryl)phthalocyanines exhibited a Q-band in the near infrared region. Electrochemical measurements were performed on the above-mentioned 1,4,8,11,15,18,22,25-octakis(thioaryl)phthalocyanines described above to examine their electron transfer abilities and electrochemical mechanisms. The compounds 1,4,8,11,15,18,22,25-octakis(thioaryl)phthalocyanines are anticipated to be appropriate materials for use in the next generation of photovoltaic cells.