Improved Photophysical and Photochemical Properties of Thiopheneethoxy Substituted Metallophthalocyanines on Immobilization onto Gold‐speckled Silica Nanoparticles

This work reports on the synthesis of tetrakis‐[(thiophineethoxy) phthalocyaninato] indium(II) chloride (3). The photophysical behavior of complex 3 was compared to that of the Zn derivative (tetrakis‐[(thiophineethoxy) phthalocyaninato] zinc(II) (complex 2)). The compounds were interacted with gold‐speckled silica (GSS) nanoparticles via Au–S self assembly to afford the conjugates (2–GSS and 3–GSS). The photophysicochemical behavior of the compounds and their conjugates were assessed. The conjugates afforded a decrease in fluorescence quantum yields and lifetimes with improved triplet and singlet oxygen quantum yields in comparison with complexes 2 and 3 alone. The complexes and their conjugates could serve as good candidates for photodynamic therapy. Tetrakis‐[(thiophineethoxy) phthalocyaninato]indium(II) chloride is conjugated to gold‐speckled silica nanoparticles via Au–S bond with improved triplet and singlet oxygen quantum yields.