Synthesis of zinc phthalocyanine derivatives with improved photophysicochemical properties in aqueous media

The synthesis, photophysical and photochemical properties of new peripherally (β) tetra-substituted thioquinoline Zn(II) (2) and quaternized thioquinoline Zn(II) phthalocyanines (3) and quaternized fluoro functional thiopyridine Zn(II) (5) are described for the first time. These complexes (2, 3 and 5) have been synthesized and characterized by elemental analysis, IR, 1H NMR spectroscopy and electronic spectroscopy. Complexes 2, 4 and 6 have good solubility in organic solvents such as CHCl3, DCM, DMSO, DMF, THF and toluene and are not aggregated in all solvents (except for 2 in DMSO) within a wide concentration range. Complexes 3 and 5 showed very good solubility in water as well as DMSO and DMF. General trends are described for singlet oxygen, photodegradation, fluorescence quantum yields, triplet quantum yields and triplet life times of these complexes in DMSO (2, 4 and 6) and water (3 and 5). Complex 3 gave a very large triplet quantum yield in aqueous media (ΦT = 0.8 in water plus Triton X-100) and a reasonable triplet lifetime of 110 μs. Photophysical and photochemical properties of the phthalocyanines complexes 2–6 are very useful for PDT.