Indexed by:期刊论文

Date of Publication:2013-09-28

Journal:JOURNAL OF MATERIALS CHEMISTRY C

Included Journals:SCIE、EI、Scopus

Volume:1

Issue:30

Page Number:4577-4589

ISSN No.:2050-7526

Abstract:Two Ru(II) polyimine complexes containing a boron-dipyrromethene (Bodipy) chromophore were prepared. The two complexes are different in the linker which connects the Bodipy part and the Ru(II) coordination centre. The Bodipy core and the Ru(II) centre are in p-conjugation in Ru-1, whereas in Ru-2 the Bodipy part is linked in a non-conjugated way to the Ru(II) centre. Ru(bpy)(3)[PF6](2) (Ru-3) was used as a reference complex. Both Ru-1 and Ru-2 show strong absorption in the visible region (epsilon = 65 200 M-1 cm(-1) at 528 nm for Ru-1 and epsilon = 76 700 M-1 cm(-1) at 499 nm for Ru-2). The fluorescence of the Bodipy ligands was almost completely quenched in Ru-1 and Ru-2. Ru-1 shows room temperature phosphorescence of the Bodipy chromophore, as well as the residual fluorescence of the Bodipy ligand. Ru-2 shows only the residual fluorescence of the Bodipy ligand. A long-lived Bodipy-localized triplet excited state was observed for both Ru-1 and Ru-2 upon visible light excitation (tau(T) is up to 279.7 mu s, the longest T-1 state lifetime observed for the Bodipy moiety in the transition metal complex). Application of the complexes in triplet-triplet-annihilation upconversion and singlet oxygen (O-1(2))-mediated photo-oxidation proved that Ru-1 is more efficient (e.g. singlet oxygen quantum yield Phi(Delta) = 0.93) as a triplet photosensitizer than Ru-2 (Phi(Delta) = 0.64). Therefore, direct connection of the pi-core of the Bodipy chromophore to the coordination centre, i.e. by establishing pi-conjugation between the visible light-harvesting chromophore and the metal coordination centre is essential to enhance the effective visible light-harvesting of the Ru(II) complexes.