The effect of ring aromaticity on ESIPT behavior and photophysical properties of 2-(2′-hydroxyphenyl)- 4-chloromethylthiazole derivatives: A TD-DFT study

Su, Shenyang; Liang, Xiuning; Fang, Hua

doi:10.1016/j.molliq.2021.116517

Cited by 22 publications

(5 citation statements)

References 63 publications

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“…. N) is to 180 • , the more stable the IHB [54][55][56]. For AE-OH-Phos, from the S 0 state to S 1 state (Table 1), the shortening of the O 2 -H 2 , the elongation of H 2 .…”

Section: Intramolecular Hydrogen Bondmentioning

confidence: 99%

Theoretical Investigation on the ESIPT Process and Detection Mechanism for Dual-Proton Type Fluorescent Probe

Cao

Sun

et al. 2022

IJMS

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Recently, a new fluorescent probeAE-Phoswas reported to detect the activity of alkaline phosphatases (ALP) in different living cell lines. Here, we present an in-depth computational analysis of the mechanism and source of the fluorescence of the AE-Phos probe. There is an intermediate product (AE-OH-Phos) in the experiment as well as a different configuration of products that may emit fluorescence. It is essential to investigate the origin of fluorescence and the detection mechanism of the probe, which could help us eliminate the interference of other substances (including an intermediate product and possible isomers) on fluorescence during the experiment. According to the change of geometric parameters and Infrared spectra, we deduce that the dual intramolecular hydrogen bonds of salicylaldehyde azine (SA) were enhanced at the excited state, while AE-OH-Phos was attenuated. Considering the complex ESIPT behavior of the dual proton-type probe, the potential energy surfaces were further discussed. It can be concluded that the single proton transfer structure of SA (SA-SPT) is the most stable form. Both the concerted double proton transfer process and stepwise single proton transfer process of SA were forbidden. The fluorescence for SA was 438 nm, while that of SA-SPT was 521 nm, which agrees with the experimentally measured fluorescence wavelength (536 nm). The conclusion that single proton transfer occurs in SA is once again verified. In addition, the distribution of electron-hole and relative index was analyzed to investigate the intrinsic mechanism for the fluorescence quenching of the probe and the intermediate product. The identification of the origin of fluorescence sheds light on the design and use of dual-proton type fluorescent probes in the future.

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“…. N) is to 180 • , the more stable the IHB [54][55][56]. For AE-OH-Phos, from the S 0 state to S 1 state (Table 1), the shortening of the O 2 -H 2 , the elongation of H 2 .…”

Section: Intramolecular Hydrogen Bondmentioning

confidence: 99%

Theoretical Investigation on the ESIPT Process and Detection Mechanism for Dual-Proton Type Fluorescent Probe

Cao

Sun

et al. 2022

IJMS

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“…To our knowledge, the TOP dyes are currently the sole examples of “giga” Stokes shift fluorophores that do not follow a TICT mechanism. , As such, these compounds represent a new lead for the development of novel “giga” Stokes shift fluorophores. It should be noted that the excited-state aromaticity reversal observed for TOP dyes has also been invoked in the past for excited-state proton transfer reactions. − In addition, aromaticity reversal in an electronic excited state has also been invoked to explain aggregation-induced emission and the fluorescence of macromolecular structures. , Clearly, the influence of Baird’s rule on the photophysics of conjugated fluorophores is a topic that merits further study.…”

Section: Discussionmentioning

confidence: 99%

Beyond “Mega”: Origin of the “Giga” Stokes Shift for Triazolopyridiniums

2022

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Over the past decade, fluorophores that exhibit "mega" Stokes shifts, defined to be Stokes shifts of greater than 100 nm, have gained considerable attention due to their potential technological applications. A subset of these fluorophores have Stokes shifts of at least 10,000 cm −1 , for whom we suggest the moniker "giga" Stokes shift. The majority of "giga" Stokes shifts reported in the literature arise from the twisted intramolecular charge transfer mechanism, but this mechanism does not fit empirical characterization of triazolopyridinium (TOP). This observation inspired a density functional theory (DFT) and time-dependent DFT study of TOP, and several related fluorophores, to elucidate the novel photophysical origin for the "giga" Stokes shift of TOP. The resulting computational models revealed that photoexcitation of TOP yields a zwitterionic excited state that undergoes significant structural relaxation prior to emission. Most notably, TOP has two orthogonal moieties in the ground state that adopt a coplanar geometry in the excited state. According to Huckel's rule, both the heterocycle and phenyl moieties of TOP should be aromatic in an orthogonal ground state. However, according to Baird's rule, these individual moieties should be anti-aromatic in the excited state. By relaxing to a coplanar conformation in the excited state, TOP likely forms a single aromatic system consisting of both the heterocycle and phenyl moieties.

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“…All geometrical structures of PAOA and PAIOA derivatives in the S 0 and S 1 states were optimized using DFT and TD-DFT methods using B3LYP functional and 6-311 + G** as basis set. Based on the optimizations of S 0 and S 1 states geometrical structures; the frequency calculations were carried out to con rm the local minima of the structures using B3LYP/6-311 + G** level of theory [31][32][33][34]. The S 0 and S 1 states of the solvated substrates were optimized using the conductor polarizable model (CPCM) [35][36][37].…”

Section: Computational Detailsmentioning

confidence: 99%

Substituent and Solvent Effects on Excited-State Intramolecular Proton Transfer Reactions of Orotic and Isoorotic Azo Dyes

Elroby

Aloufi

Aziz

et al. 2022

Preprint

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This study provides a complete analysis of the electronic and photophysical properties of orotic (OA) and isoorotic (IOA) azo dyes. The ability of the dye to work as an excited state intramolecular proton transfer (ESIPT) was investigated by using Density Functional Theory (DFT) and Time Dependent Density Functional Theory (TD-DFT) methods. The effect of electron-donating substituents (CH3 and NMe2) and an electron-withdrawing one (NO2) was examined. In addition, the effect of the solvent polarity on the ESIPT process is studied. All the geometrical structures in the singlet ground (S0) and excited (S1) states, were optimized using B3LYP/6-311+G** level of theory. The intramolecular hydrogen bond parameters (IHBs), and the Infra-Red vibrational analysis of the O-H bond show that the IHBs are enhanced in the S1 state. Furthermore, the absorption spectra were simulated and the values of stokes shifts were observed. The PAIOA derivative with an electron withdrawing group shows large stokes shift compared with those having electron-donating ones. Therefore, we can safely conclude that the substitutents groups and the different solvents are extremely impactful on the ESIPT process.

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The effect of ring aromaticity on ESIPT behavior and photophysical properties of 2-(2′-hydroxyphenyl)- 4-chloromethylthiazole derivatives: A TD-DFT study

Cited by 22 publications

References 63 publications

Theoretical Investigation on the ESIPT Process and Detection Mechanism for Dual-Proton Type Fluorescent Probe

Theoretical Investigation on the ESIPT Process and Detection Mechanism for Dual-Proton Type Fluorescent Probe

Beyond “Mega”: Origin of the “Giga” Stokes Shift for Triazolopyridiniums

Substituent and Solvent Effects on Excited-State Intramolecular Proton Transfer Reactions of Orotic and Isoorotic Azo Dyes

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