scholarly journals Excited-state intramolecular proton transfer in a bioactive flavonoid provides fluorescence observables for recognizing its engagement with target proteins

2019 ◽  
Vol 18 (9) ◽  
pp. 2270-2280 ◽  
Author(s):  
Davide Vanossi ◽  
Monica Caselli ◽  
Giorgia Pavesi ◽  
Chiara Borsari ◽  
Pasquale Linciano ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Excited State ◽  
Proton Transfer ◽  
Bond Formation ◽  
Intermolecular Hydrogen Bond ◽  
Intramolecular Proton Transfer ◽  
Hydrogen Bond Formation ◽  
Target Proteins ◽  
Emission Properties

Intra- vs. intermolecular hydrogen-bond formation and ESIPT in a bioactive flavonoid result in different emission properties and provide a clue for recognizing its binding to target proteins.

scholarly journals Theoretical Investigation of Excited-State Intramolecular Double-Proton Transfer Mechanism of Substituent Modified 1, 3-Bis (2-pyridylimino)-4,7-dihydroxyisoindole in Dichloromethane Solution

2021 ◽  
pp. 1-12
Author(s):  
Xiumin Liu ◽  
Heyao Yuan ◽  
Yuxi Wang ◽  
Yaping Tao ◽  
Yi Wang ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Excited State ◽  
Proton Transfer ◽  
Density Functional ◽  
Photophysical Properties ◽  
Substituent Effects ◽  
Intramolecular Proton Transfer ◽  
Hydrogen Bond Formation ◽  
Dichloromethane Solution ◽  
Double Proton Transfer

In this paper, density functional theory (DFT) and time-dependent DFT (TDDFT) methods were used to investigate substituent effects and excited-state intramolecular double-proton transfer (ESIDPT) in 1, 3-bis (2-pyridylimino)-4, 7-dihydroxyisoindole (BPI–OH) and its derivatives. The results of a systematic study of the substituent effects of electron-withdrawing groups (F, Cl and Br) on the adjacent sites of the benzene ring were used to regulate the photophysical properties of the molecules and the dynamics of the proton-transfer process. Geometric structure comparisons and infrared (IR) spectroscopic analysis confirmed that strengthening of the intramolecular hydrogen bond in the first excited state (S1) facilitated proton transfer. Functional analysis of the reduced density gradient confirmed these conclusions. Double-proton transfer in BPI–OH is considered to occur in two steps, i.e., BPI–OH (N) [Formula: see text] BPI–OH (T1) [Formula: see text] BPI–OH (T2), in the ground state (S0) and the S1 state. The potential-energy curves (PECs) for two-step proton transfer were scanned for both the S0 and S1 states to clarify the mechanisms and pathways of proton transfer. The stepwise path in which two protons are consecutively transferred has a low energy barrier and is more rational and favorable. This study shows that the presence or absence of coordinating groups, and the type of coordinating group, affect the hydrogen-bond strength. A coordinating group enhances hydrogen-bond formation, i.e., it promotes excited-state intramolecular proton transfer (ESIPT).

scholarly journals Theoretical Investigation of Excited-State Intramolecular Double-Proton Transfer Mechanism of Substituent Modified 1, 3-Bis (2-pyridylimino)-4,7-dihydroxyisoindole in Dichloromethane Solution

2021 ◽  
Author(s):  
Xiumin Liu ◽  
Wenzhi Li ◽  
Yuxi Wang ◽  
Yaping Tao ◽  
Yi Wang ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Excited State ◽  
Proton Transfer ◽  
Density Functional ◽  
Photophysical Properties ◽  
Substituent Effects ◽  
Intramolecular Proton Transfer ◽  
Hydrogen Bond Formation ◽  
Dichloromethane Solution ◽  
Double Proton Transfer

Abstract Density functional theory (DFT) and time-dependent DFT (TDDFT) methods were used to investigate substituent effects and excited-state intramolecular double-proton transfer in 1, 3-bis (2-pyridylimino)-4, 7-dihydroxyisoindole (BPI-OH) and its derivatives. The results of a systematic study of the substituent effects of electron-withdrawing groups (F, Cl, and Br) on the adjacent sites of the benzene ring were used to regulate the photophysical properties of the molecules and the dynamics of the proton-transfer process. Geometric structure comparisons and infrared spectroscopic analysis confirmed that strengthening of the intramolecular hydrogen bond in the first excited state (S1) facilitated proton transfer. Functional analysis of the reduction density gradient confirmed these conclusions. Double-proton transfer in BPI-OH is considered to occur in two steps, i.e., BPI-OH (N) →BPI-OH (T1) →BPI-OH (T2), in the ground state (S0) and the S1 state. The potential-energy curves for two-step proton transfer were scanned for both the S0 and S1 states to clarify the mechanisms and pathways of proton transfer. The stepwise path in which two protons are consecutively transferred has a low energy barrier and is more rational and favorable. This study shows that the presence or absence of coordinating groups, and the type of coordinating group, affect the hydrogen-bond strength. A coordinating group enhances hydrogen-bond formation, i.e., it promotes excited-state intramolecular proton transfer.

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.

Intramolecular hydrogen bonds: common motifs, probabilities of formation and implications for supramolecular organization

2000 ◽  
Vol 56 (5) ◽  
pp. 849-856 ◽  
Author(s):  
Clair Bilton ◽  
Frank H. Allen ◽  
Gregory P. Shields ◽  
Judith A. K. Howard
Keyword(s):  
Hydrogen Bond ◽  
Bond Formation ◽  
Intermolecular Hydrogen Bond ◽  
The Other ◽  
Supramolecular Organization ◽  
Intermolecular Bond ◽  
Hydrogen Bond Formation ◽  
Ability To Act ◽  
Structural Database ◽  
Intramolecular Hydrogen

A systematic survey of the Cambridge Structural Database (CSD) has identified all intramolecular hydrogen-bonded ring motifs comprising less than 20 atoms with N and O donors and acceptors. The probabilities of formation Pm of the 50 most common motifs, which chiefly comprise five- and six-membered rings, have been derived by considering the number of intramolecular motifs which could possibly form. The most probable motifs (Pm > 85%) are planar conjugated six-membered rings with a propensity for resonance-assisted hydrogen bonding and these form the shortest contacts, whilst saturated six-membered rings typically have Pm < 10%. The influence of intramolecular-motif formation on intermolecular hydrogen-bond formation has been assessed for a planar conjugated model substructure, showing that a donor-H is considerably less likely to form an intermolecular bond if it forms an intramolecular one. On the other hand, the involvement of a carbonyl acceptor in an intramolecular bond does not significantly affect its ability to act as an intermolecular acceptor and thus carbonyl acceptors display a substantially higher inclination for bifurcation if one hydrogen bond is intramolecular.

scholarly journals Proton transfer equilibria, temperature and substituent effects on hydrogen bonded complexes between chloranilic acid and anilines

2000 ◽  
Vol 14 (3) ◽  
pp. 99-107 ◽  
Author(s):  
Gamal A. Gohar ◽  
Moustafa M. Habeeb
Keyword(s):  
Hydrogen Bond ◽  
Complex Formation ◽  
Proton Transfer ◽  
Equilibrium Constants ◽  
Bond Formation ◽  
Substituent Effects ◽  
Substituted Anilines ◽  
Chloranilic Acid ◽  
Hydrogen Bond Formation ◽  
Linear Relationships

The proton transfer equilibrium constants (KPT) for 1 : 1 complex formation between Chloranilic Acid (CA) and a series ofp- andm‒substituted anilines have been measured in 1,4-dioxane spectrophotometrically. The results supported the concept of amine-solvent hydrogen bond formation (short range solvation effect). Beside, this effect, theKPTvalues were apparently affected by the electron donation power of the aniline ring substituent, which was transmitted to the interaction center via resonance and inductive effects. Linear relationships betweenKPTand σ-Hammett substituent constants, or pKvalues formandpanilines,were obtained verifying the above conclusions. The solute-solvent hydrogen bond formation might increase the reactivity of the aniline nitrogen than would the inductive effect of the alkyl group, in case of CA-N-alkyl aniline complexes. The thermodynamic parameters for the proton transfer complex formation were estimated and it was indicated that the solvent–aniline hydrogen bond formation was preferred in the case ofp-substituted aniline complexes more than in the case of the correspondingm‒isomer. It has been found that the proton transfer process was enthalpy and entropy controlled.

Equilibrium of Hydrogen-Bond Formation in the Excited State

Nature ◽  
1955 ◽  
Vol 175 (4460) ◽  
pp. 731-732 ◽  
Author(s):  
NOBORU MATAGA ◽  
YOZO KAIBE ◽  
MASAO KOIZUMI
Keyword(s):  
Hydrogen Bond ◽  
Excited State ◽  
Bond Formation ◽  
Hydrogen Bond Formation
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