Polychromatic femtosecond fluorescence studies of metal-polypyridine complexes in solution
Femtosecond-resolved broadband fluorescence studies are reported for[ M(bpy)(3)](2+) (M = Fe, Ru), RuN3 and RuN719 complexes in solution. We investigated the pump wavelength dependence of the fluorescence of aqueous [ Fe(bpy)(3)](2+) and the solvent and ligand dependence of the fluorescence of Ru-complexes excited at 400 nm. For all complexes, the (MLCT)-M-1 fluorescence appears at zero time delay with a mirror-like image with respect to the absorption. It decays in <= 30-45 fs due to intersystem crossing to the (MLCT)-M-3 states, but a longer lived component of similar to 190 fs additionally shows up in RuN719 and RuN3. No solvent effects are detected. The very early dynamics are characterized by internal conversion (IC) and intramolecular vibrational redistribution (IVR) processes on a time scale which we estimate to <= 10 fs using the (MLCT)-M-1 lifetime as an internal clock. (C) 2011 Elsevier B. V. All rights reserved.
Keywords: Metal-polypyridine complexes ; Ivr ; Internal conversion ; Intersystem crossing ; Ultrafast ; Fluorescence up-conversion ; Photoinduced Electron-Transfer ; Titanium-Dioxide Films ; Excited-State Dynamics ; Anatase Tio2 Film ; Ru-Dye Molecules ; Single-Crystal (Pf6)2 ; Nanocrystalline Tio2 ; Relaxation Dynamics ; Up-Conversion ; Solvent Dependence
Record created on 2012-02-23, modified on 2016-08-09