A Study on the Ability of Metal Naphthalocyanines for Photo-Generating Singlet Oxygen

The abilities of a series metal naphthalocyanines for photo-generating singlet oxygen （¹O₂） were studied. The results showed that the abilities of producing ¹O₂ by the metal naphthalocyanines with different central ions were decreased in the order of f ZnNc＞＞NiNc＞CoNc;ZnNc （OC₄H₉）₈＞＞ClMnNc （OC₄H₉）₈＞FeNc （OC₄H₉）₈＞NiNe （OC₄H₉）₈＞CuNc （OC₄H₉）₈＞CoNc（OC₄H₉）₈, It is indicated that their abilities of photo-gemerating ¹O₂ are obviously different when the central ions of sensitizers have got different electron structure. The sensitizers having got the central ions with dosed shell, such as Zn（Ⅱ） 3d¹⁰ ZnNc, ZnNc（OC₄H₉）₈, their abilities of photo-generating ¹O₂ are stronger. However, the sensitizers having got the central ions with open shell, such as Mn（Ⅲ） 3d⁴, Fe（Ⅱ） 3d⁶, Co（Ⅱ） 3d⁷, Ni（Ⅱ） 3d⁸ and Cu（Ⅱ） 3d⁹;ClMnNc（OC₄H₉）₈, CoNc（OC₄H₉）₈, NiNc（OC₄H₉）₈ and CuNc（OC₄H₉）₈, their ability of photo-generating ¹O₂ is weaker. And the abilities of producing ¹O₂ by the naphthalocyanines with different substituents on the Nc ring were decreased in the order off ZnNcS₄＞ZnNcBr₄＞ZnNc＞ZnNc （OC₄H₉）₈. It is indicated that their abilities of photo-generating ¹O₂ are different when the naphthalocyanines have got different substitutents. The sensitiers having got sulfonic group orbromo substitnents, their abilities of photo-generating ¹O₂ are increased. The sensitzers having got alkoxyl substituents, their abilities of photo-generating ¹O₂ decreased to a certain extent.
The effect of naphthalocyanines concentration, such as ZnNcS₄, on the monomer:dimer ratio and the ability of producing ¹O₂ was researched. The results showed that the equilibrium between monomer and dimer of ZnNcS₄ moves toward forming monomer with the dilution of ZnNcS₄. concentration, and the ability of ZnNcS₄. for photo -generating ¹O₂ was increased.