Thioglucose-linked Pd(II)dipyrrinates: Synthesis and photodynamic studies against breast cancer cells

A series of Pd(II) complexes of dipyrrin ligands have been synthesized, having thioglucose and oligoethylene glycol (OEG) units at the C-8 positions. All the complexes were characterized by NMR, IR and Mass spectrometry. The deprotection of the acetyl groups of the thioglucose unit also prepared the water-soluble derivatives. Four Pd(II)dipyrrinates were examined for cytotoxicity levels in the triple-negative breast cancer cells (TNBC) under dark and light conditions. The water-soluble Pd(II)dipyrrinates displayed very good phototoxicity with IC<inf>50</inf> values between 10 to 1 μM. All four complexes were found to be non-toxic to cancer cells in dark conditions. Additionally, Pd(II)dipyrrinates were cell-permeable and showed bright red emission in the cytoplasm of TNBC cells, suggesting their potential application as photosensitizers in photodynamic therapy for cancer.