Protecting the triplet excited state in sterically congested platinum porphyrin

Platinum tetrakis(2,4,6-triethylphenyl) porphyrin (Pt-1) was synthesized and its structural (X-ray), electrochemical and photophysical properties were fully characterized. Comparative studies of Pt-1 and its unsubstituted analog PtTPP show the effect of sterically congesting ortho-substituents on the dynamics of the triplet excited states. Lowered quenching rates by 3-4 times were observed for Pt-1 vs. PtTPP in the presence of oxygen and perylene, and in concentration (self)-quenching experiments.