ESIPT mechanism of triple emission with hydroxy-oxadiazole compound in DMSO: A theoretical reconsideration

Guo, Meilin; Li, Qi; Lu, Yan; Wan, Yongfeng; Zhu, Ling; Li, Bo; Yin, Hao; Shi, Ying

doi:10.1016/j.saa.2023.122937

Cited by 4 publications

(1 citation statement)

References 55 publications

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“…Due to the large variety of emissive excited states, the emission of ESIPT-capable molecules is sensitive to various stimuli. − The breaking of the intramolecular hydrogen bond due to the interaction of the ESIPT site of the molecule with other molecules or ions or due to deprotonation causes strong changes in the luminescence response of ESIPT-capable molecules. The protonation of ESIPT-capable molecules can proceed at the hydrogen bond-accepting atom switching the ESIPT reaction off or at other heteroatoms leading to modulating ESIPT and ESIPT-coupled luminescence. − Binding metal ions by ESIPT dyes which is accompanied by the deprotonation in most cases (only rare examples of ESIPT-capable metal complexes are known) ,,− also results in strong changes of emission. − This sensitivity allows one to switch the emission of ESIPT-capable molecules between various emission mechanisms and makes them a multivariate platform for the design of stimuli-responsive emissive materials, probes, and sensors.…”

Section: Introductionmentioning

confidence: 99%

Complexes on the Base of a Proton Transfer Capable Pyrimidine Derivative: How Protonation and Deprotonation Switch Emission Mechanisms

Shekhovtsov,

Vorob’eva,

Nikolaenkova

et al. 2023

Inorg. Chem.

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A rare example of pyrimidine-based ESIPT-capable compounds, 2-(2-hydroxyphenyl)-4-(1H-pyrazol-1-yl)-6-methylpyrimidine (HL H ), was synthesized (ESIPT�excited state intramolecular proton transfer). Its reactions with zinc(II) salts under basic or acidic conditions afforded a dinuclear [Zn 2 L H 2 Cl 2 ] complex and an ionic (H 2 L H ) 4 [ZnCl 4 ] 2 • 3H 2 O solid. Another ionic solid, (H 2 L H )Br, was obtained from the solution of HL H acidified with HBr. In both ionic solids, the H + ion protonates the same pyrimidinic N atom that accepts the O−H•••N intramolecular hydrogen bond in the structure of free HL H , which breaks this hydrogen bond and switches off ESIPT in these compounds. This series of compounds which includes neutral HL H molecules and ionic (L H ) − and (H 2 L H ) + species allowed us to elucidate the impact of protonation and coordination coupled deprotonation of HL H on the photoluminescence response and on altering the emission mechanism. The neutral HL H compound exhibits yellow emission as a result of the coexistence of two radiative decay channels: (i) T 1 → S 0 phosphorescence of the enol form and (ii) anti-Kasha S 2 → S 0 fluorescence of the keto form, which if feasible due to the large S 2 −S 1 energy gap. However, owing to the efficient nonradiative decay through an energetically favorable conical intersection, the photoluminescence quantum yield of HL H is low. Protonation or deprotonation of the HL H ligand results in the significant blue-shift of the emission bands by more than 100 nm and boosts the quantum efficiency up to ca. 20% in the case ofand (H 2 L H )Br have the same (H 2 L H ) + cation in the structures, their emission properties differ significantly, whereas (H 2 L H )Br shows dual emission associated with two radiative decay channels: (i) S 1 → S 0 fluorescence and (ii) T 1 → S 0 phosphorescence, (H 2 L H ) 4 [ZnCl 4 ] 2 •3H 2 O exhibits only fluorescence. This difference in the emission properties can be associated with the external heavy atom effect in (H 2 L H )Br, which leads to faster intersystem crossing in this compound. Finally, a huge increase in the intensity of the phosphorescence of (H 2 L H )Br on cooling leads to pronounced luminescence thermochromism (violet emission at 300 K, sky-blue emission at 77 K).

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Section: Introductionmentioning

confidence: 99%

Complexes on the Base of a Proton Transfer Capable Pyrimidine Derivative: How Protonation and Deprotonation Switch Emission Mechanisms

Shekhovtsov,

Vorob’eva,

Nikolaenkova

et al. 2023

Inorg. Chem.

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Effect of different substituted groups on excited state intramolecular proton transfer of BOHMB

Song,

Wang

2024

J Chinese Chemical Soc

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The photophysical features of 3‐(benzo[d]oxazol‐2‐yl)‐2‐hydroxy‐5‐methoxy benzaldehyde (BOHMB) were investigated through experimental (J. Phys. Chem. A 2019, 123, 10,246–10,253) and theoretical (Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2022, 266, 120,406) methods. However, the effect of substituent groups on the excited state proton transfer process has not been studied. In this work, the excited state intramolecular proton transfer (ESIPT) dynamics and photophysical properties of BOHMB with different substituent groups were investigated by density‐functional theory (DFT) and time‐dependent DFT (TDDFT) methods at CAM‐B3LYP/6‐311G(d,p) level. The primary parameters related to hydrogen bonding and infrared vibration frequency were obtained to understand the ESIPT properties of BOHMB derivatives. The results indicate that the excited‐state intramolecular hydrogen bond (ESIHB) strengthening behaviors, and the intramolecular hydrogen bond O1–H2···O3 for 1a in the S1 state is the strongest among BOHMB derivatives. From the calculated potential energy curves, it can be inferred that the substitution and position of NH2 and NO2 groups will regulate the excited‐state energy barrier and thus affect the ESIPT process. The molecular absorption peak and fluorescence peak are affected by different substituting groups and different positions.

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Deepening insights of AIE plus TICT activated fluorescent sensor mechanism in probe molecule DPA-CI

Zhang,

Gao,

et al. 2024

Chemical Physics Letters

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ESIPT mechanism of triple emission with hydroxy-oxadiazole compound in DMSO: A theoretical reconsideration

Cited by 4 publications

References 55 publications

Complexes on the Base of a Proton Transfer Capable Pyrimidine Derivative: How Protonation and Deprotonation Switch Emission Mechanisms

Complexes on the Base of a Proton Transfer Capable Pyrimidine Derivative: How Protonation and Deprotonation Switch Emission Mechanisms

Effect of different substituted groups on excited state intramolecular proton transfer of BOHMB

Deepening insights of AIE plus TICT activated fluorescent sensor mechanism in probe molecule DPA-CI

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