A photosensitizer dinuclear ruthenium complex: intramolecular energy transfer to a covalently linked fullerene acceptor.
A fullerene derivative (5) in which a dinuclear ruthenium complex is covalently linked to a fulleropyrrolidine (FP) through a rigid spacer has been prepared through azomethine ylide cycloaddition to C60. Electrochemical and photophysical studies revealed that ground-state electronic interactions between the bimetallic ruthenium chromophore and the FP moiety are small. The absorption spectrum of 5 displays a metal-to-ligand charge transfer (MLCT) transition at about 620 nm in CH2Cl2 which is shifted by nearly 160 nm relative to that of a previously reported mononuclear dyad (8). The photophysical investigations have also shown that both in dichloromethane and acetonitrile the photoexcited MLCT state of dyad 5 transforms into the fullerene triplet excited state with a quantum yield of 0.19 and that, contrary to mononuclear dyad 8, electron transfer, if any under the applied conditions, is negligible relative to energy transfer.
Guldi
D M
DM
Radiation Laboratory, University of Notre Dame, USA. guldi.1@nd.edu
Maggini
M
M
Menna
E
E
Scorrano
G
G
Ceroni
P
P
Marcaccio
M
M
Paolucci
F
F
Roffia
S
S
D002244:Carbon; D004563:Electrochemistry; D004735:Energy Transfer; D037741:Fullerenes; D008665:Metalloporphyrins / Q000737:chemistry*; D015394:Molecular Structure; D010100:Oxygen / Q000737:chemistry; D010782:Photolysis; D017319:Photosensitizing Agents / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*; D026082:Singlet Oxygen; D013054:Spectrophotometry, Atomic; D013056:Spectrophotometry, Ultraviolet
D037741:Fullerenes; D008665:Metalloporphyrins; D017319:Photosensitizing Agents; D026082:Singlet Oxygen; D002244:Carbon; D012428:Ruthenium; C069837:fullerene C60; D010100:Oxygen