Understanding the aggregation induced emission enhancement for a compound with excited state intramolecular proton transfer character

2011 ◽  
Vol 13 (6) ◽  
pp. 2044-2051 ◽  
Author(s):  
Rui Hu ◽  
Shayu Li ◽  
Yi Zeng ◽  
Jinping Chen ◽  
Shuangqing Wang ◽  
...  
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Intramolecular Proton Transfer ◽  
Aggregation Induced Emission ◽  
Emission Enhancement

scholarly journals Nitrile-Substituted 2-(Oxazolinyl)-Phenols: Minimalistic Excited-State Intramolecular Proton Transfer (ESIPT)-Based Fluorophores

2020 ◽  
Author(s):  
Dominik Göbel ◽  
Daniel Duvinage ◽  
Tim Stauch ◽  
Boris Nachtsheim
Keyword(s):  
Excited State ◽  
Solid State ◽  
Proton Transfer ◽  
Density Functional ◽  
Intramolecular Proton Transfer ◽  
Crystal Structure Analysis ◽  
Quantum Yields ◽  
Functional Theory ◽  
Emission Properties ◽  
Emission Enhancement

Herein, we present minimalistic single-benzene, excited-state intramolecular proton transfer (ESIPT) based fluorophores as powerful solid state emitters. The very simple synthesis gave access to all four regioisomers of nitrile-substituted 2(oxazolinyl)phenols (MW = 216.1). In respect of their emission properties they can be divided into aggregation-induced emission enhancement (AIEE) luminophores (1-CN and 2-CN), dual state emission (DSE) emitters (3-CN) and aggregation-caused quenching (ACQ) fluorophores (4‐CN). Remarkably, with compound 1-CN we discovered a minimalistic ESIPT based fluorophore with extremely high quantum yield in the solid state ΦF = 87.3% at λem = 491 nm. Furthermore, quantum yields in solution were determined up to ΦF = 63.0%, combined with Stokes shifts up till 11.300 cm–1. Temperature dependent emission mapping, crystal structure analysis and time-dependent density functional theory (TDDFT) calculations gave deep insight into the origin of the emission properties.<br>

Fluorescence turn-on detection of cysteine over homocysteine and glutathione based on “ESIPT” and “AIE”

2015 ◽  
Vol 7 (12) ◽  
pp. 5028-5033 ◽  
Author(s):  
Hualong Liu ◽  
Xiaoyan Wang ◽  
Yu Xiang ◽  
Aijun Tong
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Intramolecular Proton Transfer ◽  
Aggregation Induced Emission ◽  
Emission Properties ◽  
Turn On ◽  
Fluorescence Turn On

A turn-on detection of cysteine (Cys) based on excited-state intramolecular proton transfer and aggregation-induced emission properties of a salicylaldehyde azine derivative has been established.

Aggregation induced enhanced and exclusively highly Stokes shifted emission from an excited state intramolecular proton transfer exhibiting molecule

2017 ◽  
Vol 196 ◽  
pp. 71-90 ◽  
Author(s):  
Santosh Kumar Behera ◽  
Anwesha Murkherjee ◽  
G. Sadhuragiri ◽  
Palani Elumalai ◽  
M. Sathiyendiran ◽  
...  
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Cell Imaging ◽  
Inner Filter Effect ◽  
Intramolecular Proton Transfer ◽  
Additional Advantage ◽  
Filter Effect ◽  
Emission Enhancement ◽  
Butyl Phenol ◽  
Tetrahydrofuran Solution

The inner filter effect due to self-quenching dominates the normal emission of dyes at higher concentrations, which would limit their applications. Since normal emission was also observed with aggregation induced emission enhancement (AIEE) active excited state intramolecular proton transfer (ESIPT) exhibiting molecules, two new molecules are synthesized and studied to obtain normal emission free AIEE. The molecules are 4-(3-(benzo[d]thiazol-2-yl)-5-tert-butyl-4-hydroxybenzyl)-2-(benzo[d]thiazol-2-yl)-6-tert-butyl phenol (bis-HPBT) and its oxazole analogue (bis-HPBO). Of these molecules, bis-HPBT, which is weakly fluorescent in tetrahydrofuran solution, shows a sudden high enhancement in fluorescence upon addition of 70% water due to the formation of aggregates. Though the normal emission is also observed in tetrahydrofuran, it is completely eliminated in the aggregates, and the aggregates display exclusive tautomer emission. However, bis-HPBO does not emit such an exclusive tautomer emission in the water/tetrahydrofuran mixture. The enhancement in the fluorescence quantum yield of bis-HPBT in 70% water is ∼300 times higher than that in tetrahydrofuran. The modulated molecular structure of bis-HPBT is the cause of this outstanding AIEE. The observation of almost exclusive tautomer emission is a new additional advantage of AIEE from bis-HPBT over other ESIPT molecules. Since the tautomer emission is highly Stokes shifted, no overlap with the absorption spectrum occurs and therefore, the inner filter effect is averted. The aggregated structure acts as a good fluorescence chemosensor for metal ions as well as anions. The aggregated structure is cell permeable and can be used for cell imaging.

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