Synthesis, singlet-oxygen photogeneration, two-photon absorption, photo-induced DNA cleavage and cytotoxic properties of an amphiphilic β-Schiff-base linked Ru(II) polypyridyl-porphyrin conjugate

A novel porphyrin-polypyridyl ruthenium(II) conjugate (TPP-Ru), in which the ruthenium(II) polypyridyl moiety is linked to the β-position of the tetraphenylporphyrin via a Schiff base linkage, has been synthesized and characterized by 1H NMR, HRMS and UV-visible spectroscopy. The relative singlet oxygen quantum yield and two-photon absorption cross-section of this conjugate, together with its photo-induced DNA cleavage and cytotoxic activities were measured. The results show that the amphiphilic ruthenium(II) polypyridyl-porphyrin conjugate is an effective DNA photocleavage agent, with potential application in one- and two-photon absorption anti-cancer photodynamic therapy.