Photoinduced intramolecular electron transfer in covalently linked porphyrin–triptycene–(bis)quinone diads and triads

Korth, Olaf; Wiehe, Arno; Kurreck, H.; Röder, Beate

doi:10.1016/s0301-0104(99)00111-1

Cited by 22 publications

(16 citation statements)

References 14 publications

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“…The access to the inverted region of the Marcus curve and the derived total reorganization energies λ R (0.66–0.79 eV) for photoinduced electron transfer are of great value, since for the first time these are established for acetylene‐derived non‐planar push–pull chromophores as electron acceptors in D–A conjugates. The values for λ R are remarkably small compared to other artificial model acceptors (0.8–1.4 eV), and compete with those seen for fullerene‐based systems . Taking the aforementioned into account, smaller λ R combine faster charge separation and slower charge recombination for our push–pull derived systems.…”

Section: Resultsmentioning

confidence: 64%

Porphyrin Donor and Tunable Push–Pull Acceptor Conjugates—Experimental Investigation of Marcus Theory

Reekie

Sekita

Urner

et al. 2017

Chemistry A European J

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We report on a series of electron donor-acceptor conjugates incorporating a Zn -porphyrin-based electron donor and a variety of non-conjugated rigid linkers connecting to push-pull chromophores as electron acceptors. The electron acceptors comprize multicyanobutadienes or extended tetracyanoquinodimethane analogues with first reduction potentials ranging from -1.67 to -0.23 V vs. Fc /Fc in CH Cl , which are accessible through a final-step cycloaddition-retroelectrocyclization (CA-RE) reaction. Characterization of the conjugates includes electrochemistry, spectroelectrochemistry, DFT calculations, and photophysical measurements in a range of solvents. The collected data allows for the construction of multiple Marcus curves that consider electron-acceptor strength, linker length, and solvent, with data points extending well into the inverted region. The enhancement of electron-vibration couplings, resulting from the rigid spacers and, in particular, multicyano-groups in the conformationally highly fixed push-pull acceptor chromophores affects the charge-recombination kinetics in the inverted region drastically.

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Section: Resultsmentioning

confidence: 64%

Porphyrin Donor and Tunable Push–Pull Acceptor Conjugates—Experimental Investigation of Marcus Theory

Reekie

Sekita

Urner

et al. 2017

Chemistry A European J

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“…In all solvents, AQ-(H 2 ) 2 decay curves are fitted with a triexponential expression and the major component has shorter lifetime which is attributed to the deactivation (quenching) of the excited porphyrin by anthraquinone . The other two lifetime components are assigned either to an unquenched decay or decay of the porphyrin–hydroquinone generated by porphyrin-sensitized photoreduction and different conformers of the molecule with flexible linker in solution state. , On the other hand, AQ-(Zn) 2 decay curves are fitting into a three-exponential expression composed of one major (see Table , shorter lifetime) component and two minor components (shorter and longer lifetime). From this data, the shorter lifetimes with higher amplitude and longer lifetime components have the same origin as in AQ-(H 2 ) 2 , but the additional shorter lifetime component may be due to the noncovalent interaction of the oxygen lone pair of electrons (anthraquinone) with zinc metal present in other porphyrin of AQ-(Zn) 2 .…”

Section: Results and Discussionmentioning

confidence: 99%

Bis(porphyrin)–Anthraquinone Triads: Synthesis, Spectroscopy, and Photochemistry

et al. 2013

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Molecular triads based on bis(porphyrin)-anthraquinone having azomethine bridge at the pyrrole-β position have been designed and synthesized. Both free-base AQ-(H2)2 and zinc AQ-(Zn)2 triads are characterized by elemental analysis, MALDI-MS, (1)H NMR, UV-visible, and fluorescence spectroscopy (steady-state and time-resolved) as well as electrochemical method. The absorption spectra of both Soret and Q-bands of the triads are red-shifted by 12-20 nm with respect to their monomer units. The study supported by theoretical calculations manifests that there exists a negligible electronic communication in the ground state between the donor porphyrin and acceptor anthraquinone of these triads. However, interestingly, both the triads exhibit significant fluorescence emission quenching (51-92%) of the porphyrin emission compared to their monomeric units. The emission quenching is attributed to the excited-state intramolecular photoinduced electron transfer from porphyrins to anthraquinone. The electron-transfer rates (kET) of these triads are found in the range 1.0 × 10(8) to 7.7 × 10(9) s(-1) and are found to be solvent dependent.

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“…As acceptors different groups such as quinones [109][110][111][112][113][114][115][116], 7,7,8,8-tetracyanoquinodimethane (TCNQ) [117], pyromellitic diimide [118], and others [119,120] were utilized. As acceptors different groups such as quinones [109][110][111][112][113][114][115][116], 7,7,8,8-tetracyanoquinodimethane (TCNQ) [117], pyromellitic diimide [118], and others [119,120] were utilized.…”

Section: [Nn]paracyclophane Quinhydronesmentioning

confidence: 99%

UV/Vis Spectra of Cyclophanes

Rademacher

2004

Modern Cyclophane Chemistry

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Photoinduced intramolecular electron transfer in covalently linked porphyrin–triptycene–(bis)quinone diads and triads

Cited by 22 publications

References 14 publications

Porphyrin Donor and Tunable Push–Pull Acceptor Conjugates—Experimental Investigation of Marcus Theory

Porphyrin Donor and Tunable Push–Pull Acceptor Conjugates—Experimental Investigation of Marcus Theory

Bis(porphyrin)–Anthraquinone Triads: Synthesis, Spectroscopy, and Photochemistry

UV/Vis Spectra of Cyclophanes

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