Differently substituted phthalocyanines: Comparison of calculated energy levels, singlet oxygen quantum yields, photo-oxidative stabilities, photocatalytic and catalytic activities

Zinc(II) and cobalt(II) phthalocyanines bearing different electron-donating or -withdrawing substituents were prepared. The following properties of these phthalocyanines were investigated: singlet oxygen quantum yields, photo-oxidative stabilities, photocatalytic activities (photooxidation of (S)-(−)-citronellol) and catalytic activities (oxidation of 2-mercaptoethanol). Furthermore, the positions of HOMO/LUMO energy levels of the ground state (S0), first excited singlet state (S1) and first excited triplet state (T1) were calculated. Relationships between HOMO energy levels of S0 and photodecompositions, photocatalytic activities and photo-decompositions, and catalytic activities and HOMO energy levels of S0 were found. Singlet oxygen quantum yields of the different metallophthalocyanines are around 0.55 and independent from the calculated triplet energies.