Photophysical properties of catechol axially substituted tetra-α-(pentyloxy) titanium (Ⅳ) phthalocyanine

摘要

Metal phthalocyanines (MPcs) have been found to be a promising photosensitizers for photodynamic therapy (PDT) of cancers and non-cancer diseases. Nevertheless, phthalocyanines are substantially limited in clinical applications owing to their poor solubility, aggregation and insufficient selectivity for cancer cells. Catechol is an important pharmaceutical intermediate, playing important in vivo biological activity in medicine. Using catechol (pyrocatechin) as axial ligands, utilizing of the pharmaceutical effect of catechins, could improve the bioavailability, and achieve synergistic therapeutic effect in PDT. To address these issues, a novel catechol axially substituted tetra-α-(pentyloxy) titanium(Ⅳ) (TiPc(OC_5H_(11))4-Catechol) was synthesized. The structure of TiPc(OC_5H_(11))_4-Catechol was characterized by elemental analysis, IR, ~1HNMR and MS methods. The photophysical properties of TiPc(OC_5H_(11))_4 and TiPc(OC_5H_(11))_4-Catechol have been studied by UV/Vis and steady-state fluorescence spectra. After being axially substituted with catechin groups, no obviously intensity and position of maximum wavelength in Q-band of TiPc(OC_5H_(11))_4 and TiPc(OC_5H_(11))_4-Catechol were observed. The fluorescence intensity of TiPc(OC_5H_(11))_4 was stronger than that of TiPc(OC_5H_(11))_4-Catechol, but the fluorescence lifetime of TiPc(OC_5H_(11))_4-Catechol was longer than that of TiPc(OC_5H_(11))_4. TiPc(OC_5H_(11))_4-Catechol may be considered as a promising photosensitizer for PDT.