Synthesis and physicochemical behaviour of aluminium trikis and tetrakis (diaquaplatinum) octacarboxyphthalocynine

The combination of chemotherapy and photodynamic therapy was investigated by the synthesis and characterisation of phthalocyanine conjugates with Pt complexes. The complexes synthesized are: hydroxoaluminum trikis(diaquaplatinum) octacarboxyphthalocyanine (OHAlOCPc(Pt)3) and hydroxoaluminum tetrakis(diaquaplatinum) octacarboxyphthalocyanine (OHAlOCPc(Pt)4). The platinated phthalocyanine complexes gave long triplet lifetimes of 577 and 526 μs for OHAlOCPc(Pt)3 and OHAlOCPc(Pt)4, respectively. The triplet quantum yields were found to be 0.45 for OHAlOCPc(Pt)3 and 0.57 OHAlOCPc(Pt)4 while the singlet oxygen quantum yields were found to be 0.38 and 0.48, respectively.

Hydroxoaluminum trikis(diaquaplatinum) octacarboxyphthalocyanine (OHAlOCPc(Pt)3) and hydroxoaluminum tetrakis(diaquaplatinum) octacarboxyphthalocyanine (OHAlOCPc(Pt)4) conjugates gave very long lifetimes. The conjugates aggregated and both X – ray diffraction and transmission electron microscope revealed their nanoparticle nature.Figure optionsDownload as PowerPoint slideHighlights
► Al octacarboxy phthalocyanines substituted with three or four Pt groups are synthesized.
► Both show improved triplet state and singlet oxygen quantum yields.
► Long triplet lifetimes are obtained for both.
► The conjugate containing four platinum groups showed two fluorescence lifetimes.