Cobaltocenium substituents as electron acceptors in photosynthetic model dyads

Lauck, Maximilian; Förster, Christoph; Gehrig, Dominik; Heinze, Katja

doi:10.1016/j.jorganchem.2017.02.026

Cited by 6 publications

(8 citation statements)

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“…29,30,35 The molecular design of our compounds (Scheme 1a) is such that about 2.0 eV are stored (in CH 3 CN) in the nal CSS aer absorption of a single visible photon (energies of the photons used for excitation, 2.6 to 3.0 eV). A comparison with CSS energies of other triads revealed that the stored energy typically amounts to about 1.5 eV upon visible light excitation, [9][10][11][12]36 and in two recent CSS studies stored energies between 1.7 and 1.8 eV were declared as highly energetic. 4,5 Recently, we reported on the distance dependence of thermal charge recombination in the compounds from Scheme 1a in comparison to two series of other molecular triads.…”

Section: Introductionmentioning

confidence: 99%

Quantitative insights into charge-separated states from one- and two-pulse laser experiments relevant for artificial photosynthesis

2019

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Section: Introductionmentioning

confidence: 99%

Quantitative insights into charge-separated states from one- and two-pulse laser experiments relevant for artificial photosynthesis

2019

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“…Electron-poor metallocenes such as Cp 2 Ti(CCR) 2 or [Cp 2 Co] + (Cc + ) , were successfully incorporated as electron acceptors in CT systems. Compared to the ubiquitous Fc/Fc + couple, the Cc/Cc + couple has been less often employed in CT and PET schemes. ,, This underdeveloped attention is certainly due to the more difficult and less established substitution chemistry of Cc + . Only in the last years have the groups of Bildstein and Heck put forward reliable routes toward important Cc + key building blocks, such as [Cc-Br] + , [Cc-NO 2 ] + , [Cc-N 3 ] + , [Cc-COOH] + , or [Cc-NH 2 ] + . , …”

Section: Introductionmentioning

confidence: 99%

N-Cobaltocenium Amide as Reactive Nucleophilic Reagent for Donor–Acceptor Bimetallocenes

2017

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Deprotonation of the aminocobaltocenium ion [Cc-NH2]+ ([H-1] + ) generates the nucleophilic imine CcNH (1). Reaction of 1 with acid chlorides R–COCl (R = Ph, Fc, and Cc+) yields the reference amide [Ph-CO-NH-Cc]+ (2 + ) and the amide-linked hetero- and homobimetallocenes [Fc-CO-NH-Cc]+ (3 + ) and [Cc-CO-NH-Cc]2+ (4 2+ ), respectively. Cation–anion interactions of charged amides 2 + –4 2+ in the solid state and in solution are probed by single crystal X-ray diffraction and NMR and IR spectroscopy. Intramolecular metal–metal interactions in donor–acceptor heterobimetallocene 3 + and in mixed-valent homobimetallocene 4 + (prepared electrochemically) are discussed within the Marcus–Hush framework aided by spectroelectrochemical experiments and time-dependent density functional theory calculations.

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“…Cobaltoceniumi ons [7] or gold(III) porphyrins [8][9][10] (Scheme 1a) constitute ac lass of artificial cationic electron acceptors.…”

Section: Introductionmentioning

confidence: 99%

“…Ferrocene, carotenoid polyenes, and zinc(II) porphyrins represent typical electron‐donor entities whereas quinones, (natural acceptors) or fullerenes,,– act as electron acceptors. Cobaltocenium ions or gold(III) porphyrins (Scheme a) constitute a class of artificial cationic electron acceptors.…”

Section: Introductionmentioning

confidence: 99%

Gold(II) Porphyrins in Photoinduced Electron Transfer Reactions

Preiß

Päpcke

Burkhardt

et al. 2019

Chemistry A European J

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In the context of solar‐to‐chemical energy conversion, inspired by natural photosynthesis, the synthesis, electrochemical properties and photoinduced electron‐transfer processes of three novel zinc(II)‐gold(III) bis(porphyrin) dyads [ZnII(P)–AuIII(P)]+ are presented (P: tetraaryl porphyrin). Time‐resolved spectroscopic studies indicated ultrafast dynamics (kET1 >1010 s−1) after visible‐light excitation, which finally yielded a charge‐shifted state [ZnII(P⋅+)–AuII(P)]+ featuring a gold(II) center. The lifetime of this excited state is quite long due to a comparably slow charge recombination (kBET2 ≈3×108 s−1). The [ZnII(P⋅+)–AuII(P)]+ charge‐shifted state is reductively quenched by amines in bimolecular reactions, yielding the neutral zinc(II)–gold(II) bis(porphyrin) ZnII(P)–AuII(P). The electronic nature of this key gold(II) intermediate, prepared by chemical or photochemical reduction, is elucidated by UV/Vis, X‐band EPR, gold L3‐edge X‐ray absorption near edge structure (XANES) and paramagnetic 1H NMR spectroscopy as well as by quantum chemical calculations. Finally, the gold(II) site in ZnII(P)–AuII(P) is thermodynamically and kinetically competent to reduce an aryl azide to the corresponding aryl amine, paving the way to catalytic applications of gold(III) porphyrins in photoredox catalysis involving the gold(III/II) redox couple.

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Cobaltocenium substituents as electron acceptors in photosynthetic model dyads

Cited by 6 publications

References 55 publications

Quantitative insights into charge-separated states from one- and two-pulse laser experiments relevant for artificial photosynthesis

Quantitative insights into charge-separated states from one- and two-pulse laser experiments relevant for artificial photosynthesis

N-Cobaltocenium Amide as Reactive Nucleophilic Reagent for Donor–Acceptor Bimetallocenes

Gold(II) Porphyrins in Photoinduced Electron Transfer Reactions

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