Digital back off for computer controlled flash spectrometers

Tuning thermodynamic driving force and electronic coupling through structural modifications of a carotene (C) porphyrin (P) fullerene (C60) molecular triad has permitted control of five electron and energy transfer rate constants and two excited state lifetimes in order to prepare a high‐energy charge‐separated state by photoinduced electron transfer with a quantum yield of essentially unity (≥96%). Excitation of the porphyrin moiety of C–P–C60 is followed by a combination of photoinduced electron transfer to give C–P·+–C60·− and singlet–singlet energy transfer to yield C–P–1C60. The fullerene excited state accepts an electron from the porphyrin to also generate C–P·+–C60·−. Overall, this initial state is formed with a quantum yield of 0.97. Charge shift from the carotenoid to yield C·+–P–C60·− is at least 60 times faster than recombination of C–P·+–C60·−, leading to the overall quantum yield near unity for the final state. Formation of a similar charge‐separated species from the zinc analog of the triad with a yield of 40% is also observed. Charge recombination of C·+–P–C60·− in 2‐methyltetrahydrofuran yields the carotenoid triplet state, rather than the ground state. Comparison of the results for this triad with those for related triads with different structural features provides information concerning the effects of driving force and electronic coupling on each of the electron transfer steps.

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“…The pulse width was ϳ5 ns, and the repetition rate was 10 Hz. The detection portion of the spectrometer has been described elsewhere (51).…”

Section: Methodsmentioning

confidence: 99%

Driving Force and Electronic Coupling Effects on Photoinduced Electron Transfer in a Fullerene-based Molecular Triad¶

Bahr

Kuciauskas

Liddell

et al. 2007

Photochemistry and Photobiology

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“…The detection portion of the spectrometer has been described. 47 The femtosecond transient absorption apparatus consisted of a kilohertz pulsed laser source and a pump-probe optical setup, as previously described. 15,48 To determine the number of lifetime components in the transient absorption data, singular value decomposition analysis was performed and decayassociated spectra derived, as previously described.…”

Section: Experimental Instrumental Techniquesmentioning

confidence: 99%

Photoinduced electron transfer in π-extended tetrathiafulvalene–porphyrin–fullerene triad molecules

et al. 2002

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“…The transient absorbance was measured by means of a diode detector equipped with 10-nm bandpass interference filters. The detection portion of the spectrometer has been described elsewhere [51].…”

Section: Experimental Partmentioning

confidence: 99%

Photoinduced Electron Transfer in Tetrathiafulvalene−Porphyrin−Fullerene Molecular Triads

Liddell

Kodis

Garza

et al. 2001

HCA

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Digital back off for computer controlled flash spectrometers

Cited by 34 publications

References 5 publications

Driving Force and Electronic Coupling Effects on Photoinduced Electron Transfer in a Fullerene-based Molecular Triad¶

Driving Force and Electronic Coupling Effects on Photoinduced Electron Transfer in a Fullerene-based Molecular Triad¶

Photoinduced electron transfer in π-extended tetrathiafulvalene–porphyrin–fullerene triad molecules

Photoinduced Electron Transfer in Tetrathiafulvalene−Porphyrin−Fullerene Molecular Triads

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