Intersystem crossing of perylene bisimide neutral, radical anion, and dianion derivatives compared <i>via</i> ultrafast spectroelectrochemistry

Heitmüller, Julia; Fröhlich, Rebecca; Renner, R.; Wuerthner, Frank; Brixner, Tobias

doi:10.1039/d2cp05602j

Cited by 3 publications

(1 citation statement)

References 83 publications

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“…They are usually small when both states have ππ* character in a planar molecule (El-Sayed rule [8,9] ). This has led to the proposal that twisting of a molecular πelectron system might enhance ISC, [10] which was also confirmed both theoretically and experimentally for various systems, [11][12][13][14][15][16][17][18][19][20][21] among them carbon nanotubes which exhibit an especially strong intramolecular curvature. [22][23][24] However, whereas in some cases a strong increase in the efficiency of ISC by twisting has been observed, other twisted molecules showed just the opposite effect, and it was pointed out that other factors also play an important role.…”

Section: Introductionmentioning

confidence: 82%

Enhanced Intersystem Crossing in a Thiohelicene

Bergwinkl,

Nuernberger,

Dick

et al. 2024

ChemPhotoChem

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The photophysics of a helicene derivative in which two benzene units are replaced by thiophene units (thiohelicene, 6H) was studied by steady state and transient absorption and emission spectroscopies covering time ranges from femtoseconds to minutes. Efficient intersystem crossing (ISC) to the triplet state was observed, by far exceeding that of the parent helicene and the corresponding oxo‐helicene. Quantum chemical calculations indicate that the helical distortion and the heavy atom effect of sulfur cooperate in promoting spin‐orbit coupling, and that the most efficient decay channel involved the T2 or even the T3 state. These insights can help in the design of more efficient triplet sensitizes for may applications.

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Section: Introductionmentioning

confidence: 82%

Enhanced Intersystem Crossing in a Thiohelicene

Bergwinkl,

Nuernberger,

Dick

et al. 2024

ChemPhotoChem

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Faster Excited-State Intramolecular Electron Transfer from Perylenediimide Dianion Compared to Its Radical Anion

Lu,

Honda,

Fujitsuka

2024

J. Phys. Chem. A

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The properties of the excited perylenediimide dianion (PDI 2− * ) and its intramolecular electron transfer (ET) behavior were examined using femtosecond laser flash photolysis on PDI 2− and PDI 2− -acceptor (A) dyads. Upon laser excitation, the dianion of PDI first generated a singlet (S 1 ) state, followed by a triplet (T 1 ) state. In all of the dyads, rate constants of the intramolecular ET from PDI 2− * (S 1 ) varied with the driving forces. Comparison of the PDI 2− * -A and PDI •− * -A dyad systems revealed higher rate constants for the ET from PDI 2− * than from PDI •− * , which can be attributed to the difference in electronic coupling for the ET. These findings elucidate the previously unexplored photoinduced ET characteristics of PDI 2− , thereby advancing the groundwork for photochemical studies of excited multi-ions and their applications in related materials.

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Dynamics of reduced perylene bisimide cyclophane redox species by ultrafast spectroelectrochemistry

Fröhlich,

Rühe,

Moos

et al. 2024

The Journal of Chemical Physics

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Charged molecules play essential roles in many natural and artificial functional processes, ranging from photosynthesis to photovoltaics to chemical reactions and more. It is often difficult to identify the optical dynamic properties of relevant redox species because they cannot be easily prepared, their spectra overlap, or they evolve on a femtosecond timescale. Here, we address these challenges by combining spectroelectrochemistry, ultrafast transient absorption spectroscopy, and suitable data analysis. We illustrate the method with the various redox species of a cyclophane composed of two perylene bisimide subunits. While singular-value decomposition is a well-established tool in the analysis of time-dependent spectra of a single molecular species, we here use it additionally to separate transient maps of individual redox species. This is relevant because at any specific applied electrochemical potential, several redox species coexist in the ensemble, and our procedure allows disentangling their spectroscopic response. In the second step, global analysis is then employed to retrieve the excited-state lifetimes and decay-associated difference spectra. Our approach is generally suitable for unraveling ultrafast dynamics in materials featuring charge-transfer processes.

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Intersystem crossing of perylene bisimide neutral, radical anion, and dianion derivatives compared via ultrafast spectroelectrochemistry

Abstract: Perylene bisimides are widely studied due to their various applications. Most research is carried out on neutral molecules but charged species are essential in the context of organic electronics and...

Cited by 3 publications

References 83 publications

Enhanced Intersystem Crossing in a Thiohelicene

Enhanced Intersystem Crossing in a Thiohelicene

Faster Excited-State Intramolecular Electron Transfer from Perylenediimide Dianion Compared to Its Radical Anion

Dynamics of reduced perylene bisimide cyclophane redox species by ultrafast spectroelectrochemistry

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