Synthesis of Palladium 10 Isocorrole as a Photosensitizer for Photodynamic Therapy

• Elizabeth Bodio, Chemistry, University of Delaware

• Joel Rosenthal, Chemistry and Biochemistry, University of Delaware

Photodynamic therapy (PDT) is a cancer treatment option that destroys cancerous cells and tumors through photoinduced sensitization of singlet oxygen. To enhance the efficacy of PDT, an ideal photosensitizer should yield a high amount of singlet oxygen and strongly absorb light within the phototherapeutic region (between 650 to 900 nm), however current commercial photosensitizers do not absorb strongly within the phototherapeutic region. The Rosenthal Lab has synthesized a nontraditional tetrapyrrole, titled the 10,10-dimethylbiladiene (DMBil), which has been metalated to generate M[DMBil]. Previous research done by the Rosenthal has proved that metalation with Palladium to create the Pd[DMBil] has the highest singlet oxygen yield compared to any other metalated species due to the heavy atom effect, but lacks strong absorbance bands within the phototherapeutic region. Ring closure of the biladiene to the isocorrole using an iodine(III) reagent successfully red-shifted the absorbance profile to approximately 850 nm, but required bromination at the 2- and 18 carbon positions which other Metalated isocorrole closures did not require. Pending removal of the bromines on the Pd[DMICBr2] using n-BuLi would provide a compound for direct comparison to the other metalated isocorroles.