3′,4′-methylenedioxy-3-hydroxyflavone: switchover from reversible to irreversible ESIPT along the n-alcohol series

Ghosh, Deborin; Ahamed, Giasuddin; Batuta, Shaikh; Begum, Naznin Ara; Mandal, Debabrata

doi:10.1016/j.jphotochem.2016.05.008

Cited by 11 publications

(8 citation statements)

References 30 publications

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“…The 13 C NMR spectrum proved to be more complicated to assign for the free ligands. 13 C attached proton test (APT) experiments were carried out to unambiguously give the different chemical shifts of the carbon atoms (Figures S19−S21 for probe 3 and Figure S28 for probe 7).…”

Section: Resultsmentioning

confidence: 99%

“…NMR Studies. Both the coordination compounds [Zn(X) 2 ], where X = 3 and 7, and the corresponding free enamine ligands (compounds 3 and 7) were extensively studied using one-dimensional (1D) 1 H and 13 C NMR and two-dimensional (2D) NMR (HSQC and HMBC). The numbering scheme of the ligands 3 and 7 and their respective coordination complexes are shown in Figures S16, S25, S31, and S40, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…Interestingly, compound 3 did not show appreciable hydrolysis, presumably because of the lack of nitrogen atoms in the ring system. 50 The 1 H and 13 C NMR assignments of the [Zn(3) 2 ] and [Zn (7) the free compound 3 and the coordination complex. The most significant change in the 1 H NMR spectrum is the loss of the NH signal.…”

Section: Resultsmentioning

confidence: 99%

“…The most significant change in the 1 H NMR spectrum is the loss of the NH signal. However, the chemical environment of the carbon atoms that make up the chelating motif of ligand 3 showed significant changes in the 13 C NMR spectrum upon zinc(II) coordination and, in particular, in the 13 C APT experiment, in which the sp 2 -hybridized C(9)H showed a positive signal seen at 153.6 ppm in the ligand, whereas this carbon signal shifted downfield to 165.7 ppm in the zinc(II) complex (Δδ 12.1 ppm). Carbon 10, seen as a negative signal at 138.7 ppm in the 13 C ATP experiment for the free ligand, shifted to 148.9 (Δδ 10.2 ppm) in the zinc(II) complex.…”

Section: Resultsmentioning

confidence: 99%

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Structural Features of a Family of Coumarin–Enamine Fluorescent Chemodosimeters for Ion Pairs

et al. 2021

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A family of coumarin–enamine chemodosimeters is evaluated for their potential use as fluorescent molecular probes for multiple analytes [cadmium(II), cobalt(II), copper(II), iron(II), nickel(II), lead(II), and zinc(II)], as their chloride and acetate salts. These fluorophores displayed excellent optical spectroscopic modulation when exposed to ion pairs with different Lewis acidic and basic properties in dimethyl sulfoxide (DMSO). The chemodosimeters were designed to undergo excited-state intramolecular proton transfer (ESIPT), which leads to significant Stokes shifts (ca. 225 nm) and lower-energy fluorescence emission (ca. 575 nm). A more basic anion, e.g., acetate, inhibited the ESIPT mechanism by deprotonation of the enol, producing a binding pocket (N^O– chelate) that can coordinate to an appropriate metal ion. Coordination of the metal ions enhances the fluorescent intensity via the chelation-enhanced fluorescence emission mechanism. Subjecting the spectroscopic data to linear discriminant analysis provided insights into the source of these systems’ markedly different behavior toward ion pairs, despite the subtle structural differences in the organic framework. These compounds are examples of versatile, low-molecular-weight, dual-channel fluorescent sensors for ion-pair recognition. This study paves the way for using these probes as practical components of a sensing array for different metal ions and their respective anions.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Structural Features of a Family of Coumarin–Enamine Fluorescent Chemodosimeters for Ion Pairs

et al. 2021

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“…3-Hydroxyflavone (3HFFigure ), a specific flavonoid representative, is commonly used as a fluorescent chemosensor because of its strong fluorescence emission. Moreover, it is largely studied and well-known for its proton-transfer reactionsespecially excited state intramolecular proton transfer (ESIPT)which can be monitored by the variation of the fluorescence intensities. − 3HF is also a very good chelating agent via its hydroxy-keto group, and metal-ion complexation by 3HF has been the subject of numerous studies. The study of the complexation of several different ions such as Al III , − Zn II , ,, Cd II , Pb II , ,, and V IV O has been processed.…”

Section: Introductionmentioning

confidence: 99%

Electronic Spectroscopies Combined with Quantum Chemistry Calculations: Study of the Interactions of 3-Hydroxyflavone with Copper Ions

2018

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The current study aims at obtaining a better understanding of the mechanisms involved in the complexation of copper ions by 3-hydroxyflavone (3HF), which is one of the most studied compounds of the flavonoid family. To achieve this goal, quantum chemistry calculations combined with electronic spectroscopies, including absorption, fluorescence emission, and excitation, have been used. The formation of successive complexes of stoichiometry (metal/ligand) 1:2, 1:1, and 3:2 has been highlighted. Even under acidic conditions (pH = 4.0), the α-hydroxy-keto function of the molecule presents a high complexing power with regard to copper ions, insofar as a stable complex of 1:2 stoichiometry is obtained with a large conditional stability constant (log β = 8.7). The formation of this predominant species induces a quenching of the dual fluorescence of 3HF, whereas the second complex of stoichiometry 1:1 presents a fluorescence emission.

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A theoretical study of solvent effect on the excited state intramolecular proton transfer of 3‐hydroxyflavone

2022

J of Physical Organic Chem

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In order to study the effect of solvents polarity on the excited state intramolecular proton transfer (ESIPT) processes of 3‐hydroxyflavone (3HF) in detail, the ESIPT processes of 3HF in toluene, dichloromethane (DCM), and acetonitrile (ACN) were investigated using theoretical methods. The stable configurations of 3HF in ground (S0) and excited (S1) states were optimized. The critical configuration parameters, infrared (IR) vibrational spectra, absorption and fluorescence spectra, frontier molecular orbitals (MOs), charge distribution, and potential energy curves were calculated. The intramolecular hydrogen bonds are obviously enhanced and the electronic density redistributes when excited to S1 state. The strengthening of intramolecular hydrogen bonds and the redistribution of electronic density are beneficial to the ESIPT processes. The analysis of potential energy curves show that the proton transfer processes are feasible in thermodynamics in S1 state, but not in S0 state. In addition, the intramolecular hydrogen bonds gradually weaken when the solvents polarity increases from toluene, DCM to ACN. As the solvents polarity increases, the ESIPT processes are more and more difficult to occur. It can be concluded that the strength of intramolecular hydrogen bonds will be affected by the solvents polarity, and the strength of intramolecular hydrogen bonds are directly related to the difficulty of the ESIPT processes.

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3′,4′-methylenedioxy-3-hydroxyflavone: switchover from reversible to irreversible ESIPT along the n-alcohol series

Cited by 11 publications

References 30 publications

Structural Features of a Family of Coumarin–Enamine Fluorescent Chemodosimeters for Ion Pairs

Structural Features of a Family of Coumarin–Enamine Fluorescent Chemodosimeters for Ion Pairs

Electronic Spectroscopies Combined with Quantum Chemistry Calculations: Study of the Interactions of 3-Hydroxyflavone with Copper Ions

A theoretical study of solvent effect on the excited state intramolecular proton transfer of 3‐hydroxyflavone

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