Novel non-peripheral mercaptopyridine-substituted mono- and double-decker lutetium() phthalocyanines: synthesis, photophysicochemical and electrochemical properties

In this study, novel non-peripheral tetra-mercaptopyridine-substituted mono- and double-decker phthalocyanines ( LuPc and LuPc 2 ) containing lutetium( iii ) as a rare earth metal were synthesized and characterized using different spectroscopic techniques. ESR and electrochemical analyses were performed to support the sandwich structure of LuPc 2 . The g factor was determined to be 2.00039 and the characteristic first reduction couple at 0.29 V indicated a reduction of the radical Pc ring of LuPc 2 . In addition, the UV-Vis-NIR spectra of LuPc 2 in neutral, reduced, and oxidized states demonstrate its intrinsic π-radical nature in CHCl 3 . The photophysicochemical properties of LuPc and LuPc 2 were investigated in DMSO. It was found that mono-phthalocyanine ( LuPc ) is a more effective photosensitizer than double-decker ( LuPc 2 ) and metal-free ( H 2 Pc ) phthalocyanines based on a comparison of their photophysical and photochemical properties. The singlet oxygen quantum yields ( Φ Δ ) of the synthesized LuPc and LuPc 2 compounds were calculated to be 0.57 and 0.14, respectively, and the obtained results were compared with H 2 Pc ( Φ Δ = 0.04). Also, electrochemical measurements were performed to estimate their redox potentials and the results indicated the important electrochemical performance of double-decker phthalocyanine ( LuPc 2 ). Novel non-peripheral tetra-mercaptopyridine-substituted mono- and double-decker lutetium( iii ) phthalocyanines were synthesized and their photophysicochemical and electrochemical properties were investigated.