Excited state intramolecular proton transfer process in benzazole fluorophores tailored by polymeric matrix: A combined theoretical and experimental study

Berbigier, Jônatas Faleiro; Duarte, Luís Gustavo Teixeira Alves; Perez, Janaína Mendez; Mendes, Rodrigo A.; Zapp, Eduardo; Atvars, Teresa Dib Zambon; Dal-Bó, Alexandre Gonçalves; Rodembusch, Fabiano Severo

doi:10.1016/j.molliq.2019.111710

Cited by 13 publications

(5 citation statements)

References 60 publications

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“…ESIPT fluorescence is observed in aromatic cores presenting a 5- or 6-membered H-bonded ring in the ground state and relies on a photoinduced tautomerization between the excited normal (N*) and tautomeric species (T*), corresponding, in the majority of cases, to phenol (E*) and keto (K*). Many beneficial characteristics arise from this specific excited-state dynamics, that is, large Stokes shifts, enhanced photostability, strong solid-state emission, and environment-sensitive optical properties, owing to an easily perturbed proton transfer . Over the years, a large structural variety of ESIPT emitters, including 2-(2′-hydroxyphenyl)benzazoles (HBX), triazolo[1,5- a ]pyrimidines, or amino-benzoquinolines among many others, have been reported.…”

Section: Introductionmentioning

confidence: 99%

Dual Solution-/Solid-State Emissive Excited-State Intramolecular Proton Transfer (ESIPT) Dyes: A Combined Experimental and Theoretical Approach

et al. 2021

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Excited-state intramolecular proton transfer (ESIPT) dyes typically show strong solid-state emission, but faint fluorescence intensity is observed in the solution state owing to detrimental molecular motions. This article investigates the influence of direct (hetero)arylation on the optical properties of 2-(2′-hydroxyphenyl)benzoxazole ESIPT emitters. The synthesis of two series of ESIPT emitters bearing substituted neutral or charged aryl, thiophene, or pyridine rings is reported herein along with full photophysical studies in solution and solid states, demonstrating the dual solution-/solid-state emission behavior. Depending on the nature of substitution, several excited-state dynamics are observed: quantitative or partially frustrated ESIPT process or deprotonation of the excited species. Protonation studies revealed that pyridine substitution triggered a strong increase of quantum yield in the solution state for the protonated species owing to favorable quinoidal stabilization. These attractive features led to the development of a second series of dyes with alkyl or aryl pyridinium moieties showing strong tunable solution/solid fluorescence intensity. For each series, ab initio calculations helped rationalize and ascertain their behavior in the excited state and the nature of the emission observed by the experimental results.

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Section: Introductionmentioning

confidence: 99%

Dual Solution-/Solid-State Emissive Excited-State Intramolecular Proton Transfer (ESIPT) Dyes: A Combined Experimental and Theoretical Approach

et al. 2021

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“…Jae Kyong Kim et al [27] designed a fluorescent turn-on H 2 S probe BT-ITC with 2-(2-aminophenyl) benzothiazole (BTC-NH 2 ) as the ESIPT chromophore. Although the Stokes shift in this article is not very large, it can help prove the existence of ESIPT process based on past experience [28][29][30][31]. The reaction of 2-aminothiophenol with 2-aminobenzoic acid produced the compound BTC-NH 2 [32].…”

Section: Introductionmentioning

confidence: 80%

Study on ESIPT process of fluorescence probe BT-ITC for detecting H₂S in DMF/H₂O mixed solution

Ma,

2024

Phys. Scr.

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A probe molecule named BT-ITC with an isothiocyanate group was synthesized and evaluated for its H2S sensing ability based on the excited state intramolecular proton transfer (ESIPT) process [1]. The BT-ITC molecule has a large Stokes shift, short response time, and low detection limit. The end result of the reaction between the molecules BT-ITC and H2S is the BTC-NH2 molecule. The hydrogen bond of the Enol structure BTC-NH2 molecule in excited-state (S1 state) is strengthened, compared to the ground-state (S0 state). The calculated absorption and fluorescence spectra were in good agreement with the experimental values. The frontier molecule orbitals (FMOs), the potential energy curve (PEC), and scatter plots of reduced density gradient (RDG) were calculated. According to aforementioned, it was discovered that the charges of BTC-NH2 molecule were rearranged via an electron transition brought on by photoexcitation. This changes the acidity and alkaline of the proton donor and acceptor, and thus promotes the ESIPT process.

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“…Benzazole heterocycles, aromatic compounds with a benzene-azole ring fusion, play a crucial role in heterocyclic compounds, forming benzoxazoles, benzimidazoles, benzothiazoles, or benzoselenazoles [43]. These compounds, which contain diverse heteroatoms, are fundamental building blocks in medicinal chemistry for synthesizing biologically active molecules [44][45][46][47] and photoactive polymeric materials [48][49][50][51][52][53]. Regarding ESIPT and benzazoles, hydroxyphenylbenzazoles, which can undergo proton transfer in the excited state, exist predominantly as enol (E) species in the ground state (Figure 1) [28].…”

Section: Introductionmentioning

confidence: 99%

Solid-State Luminescence with a Large Stokes Shift in Starch Functionalized with Low-Content ESIPT Dye

Colonetti,

da Luz,

Rodembusch

2024

Colorants

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Herein, we present the preparation of solid-state photoactive starches with a large Stokes shift, along with the resulting materials. In this investigation, 2-(2′-hydroxyphenyl)benzazole derivatives responsive to intramolecular proton transfer in the excited state (ESIPT) were covalently bonded to the polymeric structure of starch through a reaction involving an isothiocyanate group and the hydroxyl groups of starch. These compounds exhibit absorption at approximately 350 nm, which is related to fully spin- and symmetry-allowed π → π* electronic transitions, and solid-state fluorescence at approximately 500 nm, which features a significant separation between the absorption and emission maxima (~9000 cm−1). Due to the minimal use of fluorophores in functionalized starch preparation, this modification does not affect the original properties of the starch. Finally, photoactive starch-based films with significantly high transparency were successfully produced.

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Excited state intramolecular proton transfer process in benzazole fluorophores tailored by polymeric matrix: A combined theoretical and experimental study

Cited by 13 publications

References 60 publications

Dual Solution-/Solid-State Emissive Excited-State Intramolecular Proton Transfer (ESIPT) Dyes: A Combined Experimental and Theoretical Approach

Dual Solution-/Solid-State Emissive Excited-State Intramolecular Proton Transfer (ESIPT) Dyes: A Combined Experimental and Theoretical Approach

Study on ESIPT process of fluorescence probe BT-ITC for detecting H₂S in DMF/H₂O mixed solution

Solid-State Luminescence with a Large Stokes Shift in Starch Functionalized with Low-Content ESIPT Dye

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Excited state intramolecular proton transfer process in benzazole fluorophores tailored by polymeric matrix: A combined theoretical and experimental study

Cited by 13 publications

References 60 publications

Dual Solution-/Solid-State Emissive Excited-State Intramolecular Proton Transfer (ESIPT) Dyes: A Combined Experimental and Theoretical Approach

Dual Solution-/Solid-State Emissive Excited-State Intramolecular Proton Transfer (ESIPT) Dyes: A Combined Experimental and Theoretical Approach

Study on ESIPT process of fluorescence probe BT-ITC for detecting H2S in DMF/H2O mixed solution

Solid-State Luminescence with a Large Stokes Shift in Starch Functionalized with Low-Content ESIPT Dye

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Study on ESIPT process of fluorescence probe BT-ITC for detecting H₂S in DMF/H₂O mixed solution