Ligand-Enhanced Electron Transfer from Zinc Tetraphenylporphyrin to Pyridine-Based Anthraquinone

Abstract

Enhancements of axial ligands on the electron transfer from excited zinc tetraphenylporphyrin (ZnTPP) to pyridine-based anthraquinone (AQPy) were studied in CH₂Cl₂ solution at room temperature by UV-visible, fluorescence and fluorescence decay methods. The change in fluorescence lifetime and fluorescence intensity of ZnTPP was found to depend on the formation of the axial ligation with pyridine-based electron acceptor, from 1.70 to 0.16 ns and 18 %, respectively. The intramolecular electron transfer rate constants (k_c) values between ZnTPP-AEAQPy were obtained by calculating (k_c = 5.7 × 10⁹ s^-1). Pyridine/phene-based anthraquinone derivatives were synthesized and characterized by ¹H NMR, IR and ESI-MS.