Synthesis and Fluorescence Mechanism of the Aminoimidazolone Analogues of the Green Fluorescent Protein: Towards Advanced Dyes with Enhanced Stokes Shift, Quantum Yield and Two‐Photon Absorption

Kovács, E.; Cseri, Levente; Jancsó, Attila; Terényi, Ferenc; Fulop, Anna; Rózsa, Balázs; Galbács, Gábor; Mucsi, Zoltán

doi:10.1002/ejoc.202101173

Cited by 11 publications

(13 citation statements)

References 69 publications

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“…Despite the increasing number of reported luminescent compounds, their “a priori” rational design searching for tunable properties is not a trivial task due to the high number of variables involved: charge separation, conformational restrictions, planarity, electronic delocalization, presence (or not) of metals, among others . Due to these facts, it is still not possible to make accurate predictions about luminescence and, in general, modular approaches are used . Therefore, gathering additional information for the building of new luminescent systems is highly desirable.…”

Section: Introductionmentioning

confidence: 99%

Fluorescence Amplification of Unsaturated Oxazolones Using Palladium: Photophysical and Computational Studies

et al. 2023

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Weakly fluorescent (Z)-4-arylidene-5-(4H)-oxazolones (1), ΦPL < 0.1%, containing a variety of conjugated aromatic fragments and/or charged arylidene moieties, have been orthopalladated by reaction with Pd(OAc)2. The resulting dinuclear complexes (2) have the oxazolone ligands bonded as a C^N-chelate, restricting intramolecular motions involving the oxazolone. From 2, a variety of mononuclear derivatives, such as [Pd(C^N-oxazolone)(O2CCF3)(py)] (3), [Pd(C^N-oxazolone)(py)2](ClO4) (4), [Pd(C^N-oxazolone)(Cl)(py)] (5), and [Pd(C^N-oxazolone)(X)(NHC)] (6, 7), have been prepared and fully characterized. Most of complexes 3–6 are strongly fluorescent in solution in the range of wavelengths from green to yellow, with values of ΦPL up to 28% (4h), which are among the highest values of quantum yield ever reported for organometallic Pd complexes with bidentate ligands. This means that the introduction of the Pd in the oxazolone scaffold produces in some cases an amplification of the fluorescence of several orders of magnitude from the free ligand 1 to complexes 3–6. Systematic variations of the substituents of the oxazolones and the ancillary ligands show that the wavelength of emission is tuned by the nature of the oxazolone, while the quantum yield is deeply influenced by the change of ligands. TD-DFT studies of complexes 3–6 show a direct correlation between the participation of the Pd orbitals in the HOMO and the loss of emission through non-radiative pathways. This model allows the understanding of the amplification of the fluorescence and the future rational design of new organopalladium systems with improved properties.

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Section: Introductionmentioning

confidence: 99%

Fluorescence Amplification of Unsaturated Oxazolones Using Palladium: Photophysical and Computational Studies

et al. 2023

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“…The addition of a dialkylamino substituent on the benzylidene ring led to a two orders of magnitude enhancement in the quantum yields. Furthermore, an enhanced two-photon cross-section was observed for compounds 23f-k, which is relevant for certain neurobiological applications [38].…”

Section: Intramolecular Hydrogen Bondmentioning

confidence: 92%

“…Figure23. GFPc analogues with a benzimidazole ring substituted with nitrogen, and intramolecular hydrogen bond[38,39].…”

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confidence: 99%

Locking the GFP Fluorophore to Enhance Its Emission Intensity

et al. 2022

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The Green Fluorescent Protein (GFP) and its analogues have been widely used as fluorescent biomarkers in cell biology. Yet, the chromophore responsible for the fluorescence of the GFP is not emissive when isolated in solution, outside the protein environment. The most accepted explanation is that the quenching of the fluorescence results from the rotation of the aryl–alkene bond and from the Z/E isomerization. Over the years, many efforts have been performed to block these torsional rotations, mimicking the environment inside the protein β-barrel, to restore the emission intensity. Molecule rigidification through chemical modifications or complexation, or through crystallization, is one of the strategies used. This review presents an overview of the strategies developed to achieve highly emissive GFP chromophore by hindering the torsional rotations.

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“…To obtain an explanation for the spectral changes which take into account the electronic structure of the species, a previously tested calculation protocol was adopted [41][42][43]. The geometry optimization of solvated molecules (DAA-DIA) was carried out by using M06 [44] density functional combined with triple-ζ Karlsruhe basis set (TZVP) [45].…”

Section: Density Functional Theory (Dft) Calculationsmentioning

confidence: 99%

Optical Study of Solvatochromic Isocyanoaminoanthracene Dyes and 1,5-Diaminoanthracene

Nagy

Fiser

Szőri

et al. 2022

IJMS

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Isocyanoaminoarenes (ICAAr-s) are a novel and versatile group of solvatochromic fluorophores. Despite their versatile applicability, such as antifungals, cancer drugs and analytical probes, they still represent a mostly unchartered territory among intramolecular charge-transfer (ICT) dyes. The current paper describes the preparation and detailed optical study of novel 1-isocyano-5-aminoanthrace (ICAA) and its N-methylated derivatives along with the starting 1,5-diaminoanthracene. The conversion of one of the amino groups of the diamine into an isocyano group significantly increased the polar character of the dyes, which resulted in a significant 50–70 nm (2077–2609 cm−1) redshift of the emission maximum and a broadened solvatochromic range. The fluorescence quantum yield of ICAAs is strongly influenced by the polarity of the solvent. The starting anthracene-diamine is highly fluorescent in every solvent (√f = 12–53%), while the isocyano derivatives are practically nonfluorescent in solvents more polar than dioxane. This phenomenon implies the potential application of ICAAs to probe the polarity of the medium and is favorable in practical applications, such as cell-staining, resulting in a reduced background fluorescence. The ICT character of the emission states of ICAAs are in good agreement with the computational findings presented in TD-DFT calculations and molecular electrostatic potential (MESP) isosurfaces.

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Synthesis and Fluorescence Mechanism of the Aminoimidazolone Analogues of the Green Fluorescent Protein: Towards Advanced Dyes with Enhanced Stokes Shift, Quantum Yield and Two‐Photon Absorption

Cited by 11 publications

References 69 publications

Fluorescence Amplification of Unsaturated Oxazolones Using Palladium: Photophysical and Computational Studies

Fluorescence Amplification of Unsaturated Oxazolones Using Palladium: Photophysical and Computational Studies

Locking the GFP Fluorophore to Enhance Its Emission Intensity

Optical Study of Solvatochromic Isocyanoaminoanthracene Dyes and 1,5-Diaminoanthracene

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