Improved singlet oxygen generation in rhenium(I) complexes functionalized with a pyridinyl selenoether ligand

The synthesis, characterization, electrochemical and photophysical properties of three novel polypyridine rhenium(I) complexes coordinated to an organoselenide ligand, 4-(phenylseleno)-pyridine (PhSepy), structurally related ligands, fac-[Re(CO)3(NN)(PhSepy)]+ NN = 1,10-phenanthroline (phen), 4,7-diphenyl-1,10-phenanthroline (ph2phen) pyrazino[2,3-f]-1,10-phenanthroline (dpq), are reported. In addition, their ability act as a photosensitizer agent for the generation singlet oxygen was investigated. Cyclic differential pulse voltammetry experiments showed overlap redox waves characteristic ligand Re(I) complex. This finding is consistent with strong contribution pyridine-based on HOMO levels investigated complexes, further supported by quantum mechanical calculations. Moreover, lowest energy band observed in absorption spectra also influenced combination usual MLCTRe→NN transition ligand-to-ligand charge transfer (LLCT) one. typical emission this class compounds ascribed 3MLCTRe→NN, excellent yields (ΦΔ 0.65–070). Remarkably, these significantly larger (15–29%) than those non-functionalized pyridyl revealing significant agent. Therefore, we envisage work be interest engaged development optoelectronic applications.