Photophysical Properties of the Ground and Triplet State of Four Multiphenylated [70]Fullerene Compounds

Bensasson, René V.; Schwell, Martin; Fanti, M.; Wachter, Norbert K.; Lopez, Jaime O.; Janot, Jean‐Marc; Birkett, P. R.; Land, Edward J.; Leach, Sydney; Seta, P.; Taylor, Roger; Zerbetto, Francesco

doi:10.1002/1439-7641(20010216)2:2<109::aid-cphc109>3.0.co;2-x

Cited by 14 publications

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“…[45] The quantum yield of singlet oxygen sensitization (F D ) and of fullerene triplet formation (F T ) are found to be identical for C 60 , for its closed-cage [46] and open-cage [47] derivatives, as well as for higher fullerenes like C 70 [48] and C 76 . The excited 1 O 2 * state deactivates to the ground state, giving rise to a characteristic IR emission band centered at l = 1268 nm.…”

Section: Triplet Behaviormentioning

confidence: 98%

Structure‐Dependent Photoinduced Electron Transfer in Fullerodendrimers with Light‐Harvesting Oligophenylenevinylene Terminals

Armaroli

Accorsi

Clifford

et al. 2006

Chemistry An Asian Journal

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Oligophenylenevinylene (OPV)-terminated phenylenevinylene dendrons G1-G4 with one, two, four, and eight "side-arms", respectively, were prepared and attached to C60 by a 1,3-dipolar cycloaddition of azomethine ylides generated in situ from dendritic aldehydes and N-methylglycine. The relative electronic absorption of the OPV moiety increases progressively along the fullerodendrimer family C60G1-C60G4, reaching a 99:1 ratio for C60G4 (antenna effect). UV/Vis and near-IR luminescence and transient absorption spectroscopy was used to elucidate photoinduced energy and electron transfer in C60G1-C60G4 as a function of OPV moiety size and solvent polarity (toluene, dichloromethane, benzonitrile), taking into account the fact that the free-energy change for electron transfer is the same along the series owing to the invariability of the donor-acceptor couple. Regardless of solvent, all the fullerodendrimers exhibit ultrafast OPV-->C60 singlet energy transfer. In CH2Cl2, the OPV-->C60 electron transfer from the lowest fullerene singlet level ((1)C60*) is slightly exergonic (deltaG(CS) approximately = 0.07 eV), but is observed, to an increasing extent, only in the largest systems C60G2-C60G4 with lower activation barriers for electron transfer. This effect has been related to a decrease of the reorganization energy upon enlargement of the molecular architecture. Structural factors are also at the origin of an unprecedented OPV-->C60 electron transfer observed for C60G3 and C60G4 in apolar toluene, whereas in benzonitrile, electron transfer occurs in all cases. Monitoring of the lowest fullerene triplet state by sensitized singlet oxygen luminescence and transient absorption spectroscopy shows that this level is populated through intersystem crossing and is not involved in photoinduced electron transfer.

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Section: Triplet Behaviormentioning

confidence: 98%

Structure‐Dependent Photoinduced Electron Transfer in Fullerodendrimers with Light‐Harvesting Oligophenylenevinylene Terminals

Armaroli

Accorsi

Clifford

et al. 2006

Chemistry An Asian Journal

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show abstract

“…The excited 1 O 2 * state deactivates to the ground state giving rise to a characteristic IR emission band centred at l ~1268 nm. 48 The quantum yield of singlet oxygen sensitization (W D ) and of fullerene triplet formation (W T ) are found to be identical for C 60 , for its closed cage 49 or open cage 50 derivatives as well as for higher fullerenes like C 70 51 and C 76 . 52 Therefore the determination of W D (derived by recording the sensitized IR emission of 1 O 2 *) can be taken as an indirect evaluation of W T for all fullerenes.…”

Section: Photophysical Propertiesmentioning

confidence: 98%