Synthesis and Spectroscopic Characterization of an Ethyl Isonicotinate-Coordinated RuPc for Photodynamic Therapy

Photodynamic therapy (PDT) uses light-activated photosensitizers to generate reactive oxygen species for cancer treatment. Herein, [RuPc(ethyl isonicotinate)₂] was synthesized via axial ligand substitution of [RuPc(4-pic)₂] and purified by silica gel chromatography. UV–VIS, FTIR, and 1H NMR analyses confirmed the proposed structure. The complex exhibited characteristic absorption bands at 315 and 625 nm and a singlet oxygen quantum yield (ΦΔ) of 0.43 using ZnPc as standard. These preliminary results indicate that ester-functionalized ruthenium phthalocyanines are promising candidates for further photophysical and biological evaluation as PDT photosensitizers