Fig. 2. (A) Construction and optimized structure of Pd2L2 complex 4 from a PDI-based ligand 3via a spontaneous deprotonation self-assembly process. (B) and (E) The UV-Vis absorption spectra in DMSO and H2O solution and (C) and (F) the excitation and emission spectra of ligand 1, metallacycle 2, ligand 3 and complex 4 in DMSO (c = 2.5 × 10−5 M). (D) and (G) Measurement of 1O2 generation efficiency via decrease in absorption maxima of DPBF at 418 nm versus irradiation time in the presence of metallacycle 2 and complex 4 with the inset showing plots for the absorption decays of DPBF (150 μM) (for 2: ln(A0/At) versus time, where y = 0.0174x, R2: 0.999; for 4: ln(A0/At) versus time, where y = 0.0193x, R2: 0.997).
