Individual control of singlet lifetime and triplet yield in halogen-substituted coumarin derivatives

Oberhofer, K.; Musheghyan, Mikayel; Wegscheider, Sebastian; Wörle, Martin; Iglev, Eleonora D; Nikolova, Rositca D.; Kienberger, Reinhard; Petkov, Petko St.; Iglev, Hristo

doi:10.1039/d0ra05737a

Cited by 7 publications

(6 citation statements)

References 49 publications

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“…The absorption and emission spectra of several compounds ( CM-1—CM-12 , Table 1 ), varying the substituent in position C-6 of the coumarin ring were calculated. Based on previous investigations in our group, coumarins bearing substituents in position C-6 [ 33 ] and C-7 [ 34 ] exhibit good fluorescent properties. The model compounds phenyl and aryl groups were chosen to enlarge the conjugated system, connected to the coumarin fragment.…”

Section: Resultsmentioning

confidence: 99%

Efficient Synthesis of Fluorescent Coumarins and Phosphorous-Containing Coumarin-Type Heterocycles via Palladium Catalyzed Cross-Coupling Reactions

Lyapchev

Koleva

et al. 2022

Molecules

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Quantum-chemical calculations on the spectral properties of some aryl substituted 3-phosphonocoumarins were performed, and the effect of the substituents in the aryl moiety was evaluated. The structures possessing promising fluorescent properties were successfully synthesized via Suzuki and Sonogashira cross-coupling. The synthetic protocol was also applied for the phosphorous chemoisomer of 3-phosphonocoumarin, 1,2-benzoxaphosphorin, and their carboxylate analogues. The optical properties of the arylated and alkynylated products were experimentally determined. The obtained quantum-chemical and experimental results give the possibility for a fine tuning of the optical properties of phosphorous-containing coumarin systems by altering the substituent at its C-6 position.

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Section: Resultsmentioning

confidence: 99%

Efficient Synthesis of Fluorescent Coumarins and Phosphorous-Containing Coumarin-Type Heterocycles via Palladium Catalyzed Cross-Coupling Reactions

Lyapchev

Koleva

et al. 2022

Molecules

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“…Although they overestimate the transition energies, MAD is in the admissible range of 0.2-0.3 eV. The performance of the range-separated functional CAM-B3LYP is the worst in our case, although it has been recommended for the calculation of electronic charge transfer transitions [65,67,68]. In Gaussian 16, HFS stands for the Slater exchange.…”

Section: Modelling Spectroscopic Propertiesmentioning

confidence: 87%

“…Altho they overestimate the transition energies, MAD is in the admissible range of 0.2-0. The performance of the range-separated functional CAM-B3LYP is the worst in our although it has been recommended for the calculation of electronic charge transfer tr tions [65,67,68]. The deviation in the theoretically calculated absorption energies from the experimentally observed values for the electronic transitions (in eV) can be seen in Figure 4.…”

Section: Modelling Spectroscopic Propertiesmentioning

confidence: 97%

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Theoretical Modeling of Absorption and Fluorescent Characteristics of Cyanine Dyes

et al. 2022

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The rational design of cyanine dyes for the fine-tuning of their photophysical properties undoubtedly requires theoretical considerations for understanding and predicting their absorption and fluorescence characteristics. The present study aims to assess the applicability and accuracy of several DFT functionals for calculating the absorption and fluorescence maxima of monomethine cyanine dyes. Ten DFT functionals and different basis sets were examined to select the proper theoretical model for calculating the electronic transitions of eight representative molecules from this class of compounds. The self-aggregation of the dyes was also considered. The pure exchange functionals (M06L, HFS, HFB, B97D) combined with the triple-zeta basis set 6-311+G(2d,p) showed the best performance during the theoretical estimation of the absorption and fluorescent characteristics of cyanine dyes.

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“…Looking forward, several rational design motives can thus be proposed to improve triplet yield in dimethylxylindein thin films by incorporating heterocyclic nitrogen or thionation to provide nonbonding lone pairs and enhance SOC. ,, The heavy-atom effect through halogen substitution has also been used to enhance triplet formation, , though these electron-withdrawing substituents may facilitate CT formation and have other effects . We note it is interesting that dimethylxylindein in DCM shows pronounced triplet state formation without heterocyclic nitrogen or thionation, and envision these substitutions at strategic atomic sites of the organic molecular framework could further boost the triplet yield in DCM and result in appreciable triplet states in thin films.…”

Section: Discussionmentioning

confidence: 99%

Ultrafast Triplet State Formation in a Methylated Fungi-Derived Pigment: Toward Rational Molecular Design for Sustainable Optoelectronics

et al. 2021

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Organic triplet-generating materials have prolonged excited-state lifetimes that could enhance photocatalysis, light-emitting diodes, and versatile optoelectronics. Dimethylxylindein, a methylated derivative of a naturally sourced electronic material, xylindein, generates detectable triplet states upon photoexcitation in solution. Femtosecond transient absorption measurements of dimethylxylindein demonstrate that bluer excitation wavelengths enhance the intersystem crossing (ISC) in dichloromethane (DCM), which reduces the photostability compared to robust xylindein. No appreciable triplet states are generated in the more polar ethanol or thin films. The methoxy groups open two ISC pathways: one ultrafast (∼140 fs) and one slower (∼20 ps), the latter process enhanced by nonplanar structural motions that promote spin−orbit coupling over the chromophore ring-conjugated framework. Tunable femtosecond stimulated Raman spectroscopy (FSRS) and systematic quantum calculations characterize a light-induced charge-transfer state that becomes more stabilized in polar solvents like ethanol to quench ISC. In thin films, though the stabilized charge-transfer state on ultrafast timescales may promote photosensitivity, the triplet yield could be boosted via rational design strategies, including thionation and implementation of heterocyclic nitrogen, to broaden the sustainable optoelectronic applications of xylindein derivatives.

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Individual control of singlet lifetime and triplet yield in halogen-substituted coumarin derivatives

Abstract: The photophysical properties of three 3-diethylphosphonocoumarin derivatives are studied by transient absorption spectroscopy and DFT calculations.

Cited by 7 publications

References 49 publications

Efficient Synthesis of Fluorescent Coumarins and Phosphorous-Containing Coumarin-Type Heterocycles via Palladium Catalyzed Cross-Coupling Reactions

Efficient Synthesis of Fluorescent Coumarins and Phosphorous-Containing Coumarin-Type Heterocycles via Palladium Catalyzed Cross-Coupling Reactions

Theoretical Modeling of Absorption and Fluorescent Characteristics of Cyanine Dyes

Ultrafast Triplet State Formation in a Methylated Fungi-Derived Pigment: Toward Rational Molecular Design for Sustainable Optoelectronics

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