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Open accessJournal ArticleDOI: 10.1021/ACSOMEGA.0C06252

Progress in Tuning Emission of the Excited-State Intramolecular Proton Transfer (ESIPT)-Based Fluorescent Probes

04 Mar 2021-Vol. 6, Iss: 10, pp 6547-6553
Abstract: In this review, we will summarize our recent progress in the design and application of novel organic sensors with emission in the near-infrared region (600-900 nm). By coupling different functional groups with excited-state intramolecular proton transfer (ESIPT) segments, new probes are developed to achieve a large Stokes shift, high sensitivity, and selectivity and to tune the emission toward the near-infrared region. The developed probes exhibit attractive optical properties for bioimaging and environmental science applications. In addition, we further discuss the photophysical properties of ESIPT dyes and how their fluorescence could be affected by structural/environmental factors, which should be considered during the development of robust ESIPT-based fluorescence probes. Their potential applications as imaging reagents are illustrated for intracellular membranes, mitochondria, lysosomes, and some biomolecules.

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10 results found


Journal ArticleDOI: 10.1039/D1CE00317H
01 Jun 2021-CrystEngComm
Abstract: Stimuli-responsive organic solid state fluorescent materials are considered as potential candidates for optoelectronic application as well as in the biomedical field. Molecular design and supramolecular interaction controlled organization in the solid state played an important role in producing switchable and tunable fluorescent materials. Excited state intramolecular proton transfer (ESIPT) mechanism-based solid state fluorescent materials showed unique photophysical properties such as a large Stokes shift and local environment (pH, polarity, ions and viscosity) responsive fluorescence modulation. The unique photophysical properties of ESIPT molecules made them interesting for various fields including laser dyes, molecular probes, optoelectronics, white emissive materials and optical information storage materials. Systematic fluorophore structural engineering has been performed over the years to gain insight on the ESIPT mechanism in order to improve the quantum efficiency and introduce desirable material attributes for functional applications. The substitutional unit, molecular conformation and supramolecular interactions played a significant role in transforming planar ESIPT fluorophores to stimuli-induced fluorescence switching materials either between two states or off–on states. In this review article, we have presented the recent developments in ESIPT-based solid state fluorescent materials and external stimuli-induced fluorescence switching.

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Topics: Fluorophore (52%)

6 Citations


Open accessJournal ArticleDOI: 10.3390/MOLECULES26175140
25 Aug 2021-Molecules
Abstract: The excited-state intramolecular proton transfer (ESIPT) phenomenon is nowadays widely acknowledged to play a crucial role in many photobiological and photochemical processes. It is an extremely fast transformation, often taking place at sub-100 fs timescales. While its experimental characterization can be highly challenging, a rich manifold of theoretical approaches at different levels is nowadays available to support and guide experimental investigations. In this perspective, we summarize the state-of-the-art quantum-chemical methods, as well as molecular- and quantum-dynamics tools successfully applied in ESIPT process studies, focusing on a critical comparison of their specific properties.

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3 Citations


Journal ArticleDOI: 10.1002/CHEM.202101650
Kosuke Nakashima1, Anton Petek2, Yutaro Hori1, Anton Georgiev3  +5 moreInstitutions (3)
Abstract: The reimagined concept of long-range tautomeric proton transfer using crane subunits is shown by designing and synthesising two new acylhydrazones containing a 7-hydroxyquinoline (7-OHQ) platform. The acylhydrazone subunits attached to the 7-OHQ at the 8th position act as crane arms for delivering proton cargo to the quinoline nitrogen. Light-induced tautomerization to their keto forms leads to Z/E isomerization of the C=C axle bond, followed by proton delivery to the quinoline nitrogen by the formation of covalent or hydrogen bonds. The axle's being either an imine or ketimine bond is the structural difference between the studied compounds. The -CH3 group in the latter provides steric strain, resulting in different proton transport pathways. Both compounds show long thermal stability in the switched state, which creates a tuneable action of bidirectional proton cargo transport by using different wavelengths of irradiation. Upon the addition of acid, the quinoline nitrogen is protonated; this results in E/Z configuration switching of the acylhydrazone subunits. This was proven by single-crystal X-ray structure analysis and NMR spectroscopy.

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Topics: Proton transport (63%), Tautomer (53%), Quinoline (52%) ... show more

1 Citations


Journal ArticleDOI: 10.1039/D1NJ01277K
Narissa Kanlayakan1, Nawee Kungwan1Institutions (1)
Abstract: A molecular screening has been carried out for fluorescent probes harnessing excited-stated intramolecular proton transfer (ESIPT) of NH-type molecules having aminophenyl or tosylaminophenyl as a proton donor and benzimidazole, benzoxazole, benzothiazole, or imidazo[1,2-a]pyridine as a proton acceptor with different substituents using time-dependent density functional theory. Among the designed ESIPT molecules, 2-(2′-tosylaminophenyl)benzimidazole, 2-(2′-tosylaminophenyl)benzothiazole, and 2-(2′-tosylaminophenyl)imidazo[1,2-a]pyridine with dimethylamino in the tosylaminophenyl and/or cyano in the benzimidazole, benzothiazole, and imidazo[1,2-a]pyridine, respectively, were revealed to be the best five candidates because they passed the screening requirements, including photophysical, kinetics, and thermodynamic parameters. Here, these five candidates required less photo-absorption around 380 nm and emitted the tautomer peaks in the near infrared (NIR) region, leading to large Stokes shifts (∼200 nm) with no self-reabsorption, which are important characteristics for fluorescent probes. The NIR emission is caused by the intramolecular charge-transfer character of the strong electron-donating dimethylamino in the tosylaminophenyl moiety and heteroatoms in the benzimidazole/benzothiazole/imidazo[1,2-a]pyridine moiety as evidenced by the electron-density differences and frontier molecular orbitals. In addition, they exhibit high photo-acidity and photo-basicity (low PT barrier with highly exothermic) to warrantee the ESIPT. Therefore, the obtained screening information in this work could be beneficial for designing new ESIPT fluorescent-based probes.

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Topics: Benzothiazole (57%), Benzoxazole (52%), Intramolecular force (51%) ... show more

Journal ArticleDOI: 10.1016/J.MOLLIQ.2021.117753
Lihong Wang1, Zheng Haixia1, Kaibo Zheng1, Jiaying Yan1  +2 moreInstitutions (1)
Abstract: In this paper, we have designed and synthesized HBT-fused aryl-imidazole derivatives HBTA, HBTB, HBTC and HBTD through π-expanded system, which have large absorption extinction coefficients, relatively high quantum yields, large Stokes shifts. The dyes HBTB, HBTC and HBTD still retained excited state intramolecular proton-transfer property (E* and K* emission). They also exhibited good ESIPT properties in serum. The experimental results and theoretical calculations verified that the nonplanar and nitrogen heterocyclic structure of π-expanded rings was beneficial for the k* emission under the same conditions. Moreover, The HBTA, HBTB, HBTC and HBTD were successfully applied for the imaging in living cells and zebrafish.

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Topics: Excited state (52%), Benzothiazole (51%), Intramolecular force (50%)

References
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24 results found


Journal ArticleDOI: 10.1016/J.CBPA.2003.08.007
John V. Frangioni1Institutions (1)
Abstract: Photon penetration into living tissue is highly dependent on the absorption and scattering properties of tissue components. The near-infrared region of the spectrum offers certain advantages for photon penetration, and both organic and inorganic fluorescence contrast agents are now available for chemical conjugation to targeting molecules. This review focuses on those parameters that affect image signal and background during in vivo imaging with near-infrared light and exogenous contrast agents. Recent examples of in vivo near-infrared fluorescence imaging of animals and humans are presented, including imaging of normal and diseased vasculature, tissue perfusion, protease activity, hydroxyapatite and cancer.

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2,277 Citations



Open accessJournal ArticleDOI: 10.1039/C8CS00185E
Adam C. Sedgwick1, Luling Wu1, Hai Hao Han2, Steven D. Bull1  +7 moreInstitutions (5)
Abstract: In this review we will explore recent advances in the design and application of excited-state intramolecular proton-transfer (ESIPT) based fluorescent probes. Fluorescence based sensors and imaging agents (probes) are important in biology, physiology, pharmacology, and environmental science for the selective detection of biologically and/or environmentally important species. The development of ESIPT-based fluorescence probes is particularly attractive due to their unique properties, which include a large Stokes shift, environmental sensitivity and potential for ratiometric sensing.

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473 Citations


Open accessJournal ArticleDOI: 10.1021/CB500078U
Luke D. Lavis1, Ronald T. Raines2Institutions (2)
Abstract: Small-molecule fluorophores manifest the ability of chemistry to solve problems in biology. As we noted in a previous review (Lavis, L. D.; Raines, R. T. ACS Chem. Biol. 2008, 3, 142–155), the extant collection of fluorescent probes is built on a modest set of “core” scaffolds that evolved during a century of academic and industrial research. Here, we survey traditional and modern synthetic routes to small-molecule fluorophores and highlight recent biological insights attained with customized fluorescent probes. Our intent is to inspire the design and creation of new high-precision tools that empower chemical biologists.

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311 Citations


Open accessJournal ArticleDOI: 10.1042/0264-6021:3630417
Abstract: The endolysosomal system comprises a unique environment for proteolysis, which is regulated in a manner that apparently does not involve protease inhibitors. The system comprises a series of membrane-bound intracellular compartments, within which endocytosed material and redundant cellular components are hydrolysed. Endocytosed material tends to flow vectorially through the system, proceeding through the early endosome, the endosome carrier vesicle, the late endosome and the lysosome. Phagocytosis and autophagy provide alternative entry points into the system. Late endosomes, lysosome/late endosome hybrid organelles, phagosomes and autophagosomes are the principal sites for proteolysis. In each case, hydrolytic competence is due to components of the endolysosomal system, i.e. proteases, lysosome-associated membrane proteins, H(+)-ATPases and possibly cysteine transporters. The view is emerging that lysosomes are organelles for the storage of hydrolases, perhaps in an inactivated form. Once a substrate has entered a proteolytically competent environment, the rate-limiting proteolytic steps are probably effected by cysteine endoproteinases. As these are affected by pH and possibly redox potential, they may be regulated by the organelle luminal environment. Regulation is probably also affected, among other factors, by organelle fusion reactions, whereby the meeting of enzyme and substrate may be controlled. Such systems would permit simultaneous regulation of a number of unrelated hydrolases.

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Topics: Late endosome (65%), Organelle fusion (58%), Endosome (58%) ... show more

279 Citations