Regioselective Synthesis of Directly Connected BODIPY Dimers through Oxidative Coupling of α-Amino-Substituted BODIPYs

Organic Letters, Год журнала: 2023, Номер 25(27), С. 5055 - 5060

Опубликована: Июль 2, 2023

A family of directly β,β-linked BODIPY dimers with amino groups at α-positions were regioselectively prepared by the oxidative coupling reaction α-amino-substituted BODIPYs. The structure one representative dimer was elucidated X-ray diffraction analysis, showing its twisted orientation two units a dihedral angle 49°. Comparing corresponding monomers, these showed red-shifted absorptions and emissions along efficient intersystem crossing, giving ΦΔ 43% for 4b in toluene, indicating potential use as heavy-atom-free photosensitizers.

Язык: Английский

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Excimer Formation Driven by Excited-State Structural Relaxation in a Covalent Aminonaphthalimide Dimer

The Journal of Physical Chemistry Letters, Год журнала: 2024, Номер 15(5), С. 1469 - 1476

Опубликована: Янв. 31, 2024

Strongly coupled excimer formation from interchromophoric charge transfer driven by the ultrafast excited-state structural dynamics of a 5,5′-linked 4-amino-1,8-naphthalimide covalent homodimer was investigated transient spectroscopy and chemical calculations. Theoretical calculations indicate that relaxation associated with dihedral motion leads to significantly enhanced (CT) coupling, which favors an excimer-like symmetry-broken CT state. The state in dimer are identified via absorption fluorescence spectroscopy. following photoexcitation occurs tens picoseconds stabilizes strongly highly polar solvents further stabilize enhance character, enable efficient electron excitation energy transport molecular aggregates.

Язык: Английский

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Modulating the Charge Transfer Coupling in Boron-Dipyrromethene Homodimers by π-Bridge Units

The Journal of Physical Chemistry B, Год журнала: 2025, Номер unknown

Опубликована: Март 19, 2025

To mimic the excitation energy conversion mechanisms observed in natural light-harvesting systems, we have extensively investigated photoinduced symmetry-breaking charge separations (SBCSs) various multichromophoric model systems been investigated. However, designing capable of simultaneously achieving ultrafast and complete SBCS remains a significant challenge. In this study, employed benzene, thiophene, furan as π-bridges to develop series boron dipyrromethene (BODIPY) homodimers. Spectral analysis, together with an estimation π-bridge-dependent transfer (CT) coupling using fragment difference method, reveals that π-bridge units different electron-donating abilities can effectively modulate CT between chromophores. Notably, furan-based π-bridge, exhibiting most pronounced character, facilitates (SBCT), i.e., excimer formation time constant about 12 ps weak polar toluene. Furthermore, dramatic increase rate was highly acetonitrile, improving from 60.4 for benzene-bridged homodimer 2.9 furan-bridged counterpart. These findings underscore potential tuning photophysical properties covalent molecular aggregates by optimizing such specific applications organic photovoltaics photocatalysis.

Язык: Английский

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Spin–orbit charge-transfer intersystem crossing in heavy-atom-free orthogonal covalent boron-dipyrromethene heterodimers

Physical Chemistry Chemical Physics, Год журнала: 2023, Номер 25(36), С. 24386 - 24394

Опубликована: Янв. 1, 2023

Boron-dipyrromethene (BODIPY) derivatives are prospective organic-based triplet photosensitizers. Since the generation yield of parent BODIPY is low, heavy atoms widely used to improve yield. However, dimerization BODIPYs can also significantly their ability produce triplets. Through a comparative study formation dynamics two heavy-atom-free orthogonal covalent heterodimers that differ in dihedral angles, we have demonstrated mechanism spin-orbit charge-transfer intersystem crossing (SOCT-ISC) promotes solution. Different from general understanding SOCT-ISC, heterodimer with smaller angle and low structural rigidity showed better due (a) stronger inter-chromophoric interaction heterodimer, which promoted solvent-stabilized (CT) state, (b) more favorable energy level alignment sizeable coupling strength, (c) balance between stabilized singlet CT state limited direct charge recombination ground weakly polar solvent. The complete spectral characterization clarified SOCT-ISC important factors affecting heterodimers.

Язык: Английский

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Ultrafast Photoinduced Dynamics of Styryl-Substituted BODIPY Dyes and Their Aggregates

The Journal of Physical Chemistry C, Год журнала: 2024, Номер 128(30), С. 12762 - 12774

Опубликована: Июль 23, 2024

Язык: Английский

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Stimulated Resonance Raman and Excited-State Dynamics in an Excitonically Coupled Bodipy Dimer: A Test for TD-DFT and the Polarizable Continuum Model

The Journal of Physical Chemistry A, Год журнала: 2023, Номер 127(34), С. 7156 - 7167

Опубликована: Авг. 18, 2023

Bodipy is one of the most versatile and studied functional dyes due to its myriad applications tunable spectral properties. One strategies adjust their properties formation dimers oligomers whose differ significantly from corresponding monomer. Recently, we have developed a novel strategy for synthesizing α,α-ethylene-bridged dimers; however, excited-state dynamics was heretofore unknown. This work presents ultrafast α,α-ethylene-bridge dimer monomeric parent. The dimer's steady-state absorption fluorescence suggest Coulombic interaction between units' transition dipole moments (TDMs), forming what often termed "J-dimer". were using molecular excitonic theory time-dependent density (TD-DFT). We chose M06 exchange-correlation (XCF) based on ability reproduce experimental oscillator strength resonance Raman spectra. Ultrafast laser spectroscopy reveals symmetry-breaking charge separation (SB-CS) in polar solvents subsequent population charge-separated ion-pair state. rate falls into normal regime, while recombination inverted regime. Conversely, nonpolar solvents, thermodynamically not feasible. In contrast, monomer's shows no dependence solvent polarity. Furthermore, found evidence significant structural rearrangement upon photoexcitation, regardless deactivation pathway. After an extensive analysis electronic transitions, concluded that fluctuations local environment around create asymmetry drives stabilizes separation. sheds light charge-transfer process this new set systems how can be modeled by combining experiment theory.

Язык: Английский

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NIR-absorbing and emitting α,α-nitrogen-bridged BODIPY dimers with strong excitonic coupling

Chemical Communications, Год журнала: 2024, Номер 60(38), С. 5054 - 5057

Опубликована: Янв. 1, 2024

Three new distinct NIR α,α-NH-bridged BODIPY dimers were prepared by a direct nucleophilic substitution reaction. The synergistic effects of the nitrogen bridges and strong excitonic coupling between each unit play major roles in enhancing delocalization an electron spin over entire dimers.

Язык: Английский

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Near‐IR Emissive B–N Lewis Pair‐Functionalized Anthracenes via Selective LUMO Extension in Conjugated Dimer and Polymer

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(45)

Опубликована: Июль 8, 2024

Abstract Acenes are attractive as building blocks for low gap organic materials with applications, example, in light emitting diodes, solar cells, bioimaging and diagnostics. Previously, we have shown that modification of dipyridylanthracene via B–N Lewis pair fusion (BDPA) strongly redshifts the emission, while facilitating self‐sensitized reactivity toward O 2 to reversibly generate corresponding endoperoxides. Herein, report on further expansion π‐system BDPA a vinyl‐substituted monomer, vinylene‐bridged dimer, polymer an average 20 chromophores. The extension π‐conjugation results largely reduced band gaps 1.8 eV dimer 1.7 polymer, latter giving rise NIR emission maximum at 731 nm appreciable quantum yield 7 %. Electrochemical computational studies reveal efficient delocalization lowest unoccupied molecular orbital (LUMO) along pyridyl‐anthracene‐pyridyl axis, which effective electronic communication between units, selectively lowers LUMO, ultimately narrows gap. Time‐resolved transient absorption (TA) measurements offer insights into pertinent photophysical processes. Extension also slows down formation endoperoxides, significantly accelerating thermal release singlet oxygen regenerate parent acenes.

Язык: Английский

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Essential challenges and new opportunities in the investigation of excited state structure and dynamics for complex systems

Scientia Sinica Chimica, Год журнала: 2024, Номер 54(12), С. 2348 - 2360

Опубликована: Июль 25, 2024

Язык: Английский

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Solvent Effects on Spin–Orbit Charge-Transfer Intersystem Crossing in Aryl-Substituted Boron-dipyrromethene Donor–Acceptor Dyads

The Journal of Physical Chemistry B, Год журнала: 2024, Номер unknown

Опубликована: Сен. 12, 2024

In heavy-atom-free organic molecules, the rate of triplet generation through charge recombination, as dictated by El-Sayed rule, can be enhanced 10

Язык: Английский

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