Unraveling the Mechanisms of the Excited‐State Intermolecular Proton Transfer (ESPT) for a D‐π‐A Molecular Architecture

Hong, Dan‐Li; Luo, Yang‐Hui; He, Xiaotong; Zheng, Zi-Yue; Su, Shan; Wang, Jiaying; Chen, Chen; Sun, Bai‐Wang

doi:10.1002/chem.201900856

Cited by 10 publications

(1 citation statement)

References 43 publications

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“…[17,36] We suppose that the main fluorescence mechanism for amine 6 in isopropanol changes from ICT to excited state intermolecular proton transfer (ESPT) (Scheme 2). Thus, ESPT with the formation of quinoid-type emissive excited states was studied for different heterocyclic systems [37][38][39][40] and a competition between ICT and ESPT for heterocyclic D-π-A molecular architecture has been reported recently [41].…”

Section: Photophysical Properties Of Cinnoline-based Azide-amine Pairmentioning

confidence: 99%

4-Azidocinnoline—Cinnoline-4-amine Pair as a New Fluorogenic and Fluorochromic Environment-Sensitive Probe

et al. 2021

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A new type of fluorogenic and fluorochromic probe based on the reduction of weakly fluorescent 4-azido-6-(4-cyanophenyl)cinnoline to the corresponding fluorescent cinnoline-4-amine was developed. We found that the fluorescence of 6-(4-cyanophenyl)cinnoline-4-amine is strongly affected by the nature of the solvent. The fluorogenic effect for the amine was detected in polar solvents with the strongest fluorescence increase in water. The environment-sensitive fluorogenic properties of cinnoline-4-amine in water were explained as a combination of two types of fluorescence mechanisms: aggregation-induced emission (AIE) and excited state intermolecular proton transfer (ESPT). The suitability of an azide–amine pair as a fluorogenic probe was tested using a HepG2 hepatic cancer cell line with detection by fluorescent microscopy, flow cytometry, and HPLC analysis of cells lysates. The results obtained confirm the possibility of the transformation of the azide to amine in cells and the potential applicability of the discovered fluorogenic and fluorochromic probe for different analytical and biological applications in aqueous medium.

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Section: Photophysical Properties Of Cinnoline-based Azide-amine Pairmentioning

confidence: 99%

4-Azidocinnoline—Cinnoline-4-amine Pair as a New Fluorogenic and Fluorochromic Environment-Sensitive Probe

et al. 2021

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ESIPT‐Active Pyrene‐imidazole Fluorophores: GSIPT, Dual Solid‐ and Solution‐State Emission plus Counter‐Intuitive Crystal Packing**

Venkatareddy,

Kumar,

Singh

et al. 2023

ChemPhotoChem

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We report a new excited‐state intramolecular proton transfer (ESIPT)‐inspired hydroxyl (OH)‐substituted pyrene‐imidazole that promote unprecedented intramolecular proton transfer in the ground state (GSIPT). The enol and keto isomers are in equilibrium, with a high keto‐isomer component in the solid state. In conjunction with DFT calculations, the photophysical studies and crystal structure analysis shred substantial evidence for the ground state transformation. The ESIPT‐active compounds also show the rare feature of high dual solution (φf=70 %) and solid state (φf=41 %) emission characteristics and counter‐intuitive stronger intermolecular interactions in the solid state versus the ESIPT‐inactive counterparts.

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Easily Accessible Schiff Base ESIPT Molecules with Tunable Solid State Fluorescence: Mechanofluorochromism and Highly Selective Co²⁺ Fluorescence Sensing

et al. 2020

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Schiff base molecules of 1–4 ((E)‐N′‐benzylidene‐2‐hydroxybenzohydrazide derivatives) showed structure controlled solid state fluorescence tuning, reversible stimuli induced fluorescence switching and highly selective Co2+ sensing. The strong intramolecular H‐bonding between imine and amine facilitates excited state intramolecular proton transfer (ESIPT) and large red shifted solid state fluorescence. Positional isomers and substitutional change tuned the solid state fluorescence (460 to 605 nm). The substituents and positions control stimuli‐induced fluorescence switching. ESIPT fluorophores showed strong fluorescence in DMF (Φf=0.057 to 0.35 compared to quinine sulphate). ESIPT fluorophores (2–4) exhibited highly selective fluorescence sensing of Co2+ ions without significant interference from other metal ions. Concentration dependent studies of fluorophores show the detection limit (LOD) of 54 nM that is much lower than the Environmental Protection Agency (EPA) guideline value (1.7 μM) in drinking water. Solid state fluorescence of ESIPT fluorophores have been made use to fabricate solid fluorescence assay (PVA polymer composite thin films) and demonstrated highly selective fluorescence sensing of Co2+ upon dipping into aqueous metal ions solution. Thus, the present studies demonstrate the versatility of Schiff base molecules for developing ESIPT fluorophores for stimuli responsive materials and highly selective fluorescence sensing both in solution and solid state.

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Unraveling the Mechanisms of the Excited‐State Intermolecular Proton Transfer (ESPT) for a D‐π‐A Molecular Architecture

Cited by 10 publications

References 43 publications

4-Azidocinnoline—Cinnoline-4-amine Pair as a New Fluorogenic and Fluorochromic Environment-Sensitive Probe

4-Azidocinnoline—Cinnoline-4-amine Pair as a New Fluorogenic and Fluorochromic Environment-Sensitive Probe

ESIPT‐Active Pyrene‐imidazole Fluorophores: GSIPT, Dual Solid‐ and Solution‐State Emission plus Counter‐Intuitive Crystal Packing**

Easily Accessible Schiff Base ESIPT Molecules with Tunable Solid State Fluorescence: Mechanofluorochromism and Highly Selective Co²⁺ Fluorescence Sensing

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Unraveling the Mechanisms of the Excited‐State Intermolecular Proton Transfer (ESPT) for a D‐π‐A Molecular Architecture

Cited by 10 publications

References 43 publications

4-Azidocinnoline—Cinnoline-4-amine Pair as a New Fluorogenic and Fluorochromic Environment-Sensitive Probe

4-Azidocinnoline—Cinnoline-4-amine Pair as a New Fluorogenic and Fluorochromic Environment-Sensitive Probe

ESIPT‐Active Pyrene‐imidazole Fluorophores: GSIPT, Dual Solid‐ and Solution‐State Emission plus Counter‐Intuitive Crystal Packing**

Easily Accessible Schiff Base ESIPT Molecules with Tunable Solid State Fluorescence: Mechanofluorochromism and Highly Selective Co2+ Fluorescence Sensing

Contact Info

Product

Resources

About

Easily Accessible Schiff Base ESIPT Molecules with Tunable Solid State Fluorescence: Mechanofluorochromism and Highly Selective Co²⁺ Fluorescence Sensing