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 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).

Competitive excited-state single or double proton transfer mechanisms for bis-2,5-(2-benzoxazolyl)-hydroquinone and its derivatives

2015 ◽  
Vol 17 (18) ◽  
pp. 11990-11999 ◽  
Author(s):  
Jinfeng Zhao ◽  
Junsheng Chen ◽  
Jianyong Liu ◽  
Mark R. Hoffmann
Keyword(s):  
Density Functional Theory ◽  
Excited State ◽  
Proton Transfer ◽  
Density Functional ◽  
Intramolecular Proton Transfer ◽  
Time Dependent ◽  
Functional Theory ◽  
Double Proton Transfer ◽  
Transfer Mechanisms ◽  
Dependent Density

The excited state intramolecular proton transfer (ESIPT) mechanism of HBO, BBHQ and DHBO have been investigated using time-dependent density functional theory (TDDFT).

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.

Elaborating a new excited state intramolecular proton transfer (ESPT) mechanism for a new π-conjugated dye 2, 2′-((5-(2-(4-methoxyphenyl)ethenyl)-benzene-1,1-diyl)-bis-(nitrilomethylylidene)-diphenol)

2018 ◽  
Vol 96 (3) ◽  
pp. 351-357 ◽  
Author(s):  
Dapeng Yang ◽  
Min Jia ◽  
Xiaoyan Song ◽  
Qiaoli Zhang
Keyword(s):  
Hydrogen Bond ◽  
Excited State ◽  
Charge Transfer ◽  
Hydrogen Bonds ◽  
Proton Transfer ◽  
Density Functional ◽  
Dynamical Behavior ◽  
Intramolecular Proton Transfer ◽  
Intramolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen

In this work, the excited state dynamical behavior of a novel π-conjugated dye 2,2′-((5-(2-(4-methoxyphenyl)ethenyl)-benzene-1,1-diyl)-bis-(nitrilomethylylidene)-diphenol) (C1) has been investigated. Two intramolecular hydrogen bonds of C1 are tested to pre-existing in the ground state via AIM and reduced density gradient. Using a time-dependent density functional theory (TDDFT) method, it has been substantiated that the intramolecular hydrogen bonds of C1 should be strengthened in the S1 state via analyzing fundamental bond length, bond angles, and corresponding infrared vibrational modes. The most obvious variation of these two hydrogen bonds is the O4–H5···N6 bond, which might play important roles in excited state behavior for the C1 system. Furthermore, based on electronic excitation, charge transfer could occur. Just due to this kind of charge re-distribution, two hydrogen bonds should be tighter in the first excited state, which is consistent with the variation of hydrogen bond lengths. Thus, the phenomenon of charge transfer is reasonable evidence for confirming the occurrence of the excited state proton transfer (ESPT) process in the S1 state. Our theoretically constructed potential energy surfaces of C1 show that excited state single proton transfer should occur along with the O4–H5···N6 hydrogen bond rather than the O1–H2···N3 bond. We not only clarify the ESIPT mechanism for C1 but put forward new affiliation and explain a previous experiment successfully.

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>

Effect of number and different types of proton donors on excited-state intramolecular single and double proton transfer in bipyridine derivatives: theoretical insights

2020 ◽  
Vol 44 (19) ◽  
pp. 8018-8031
Author(s):  
Komsun Chaihan ◽  
Nawee Kungwan
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Vibrational Mode ◽  
Photophysical Properties ◽  
Reaction Energy ◽  
Topology Analysis ◽  
Double Proton Transfer ◽  
And Topology ◽  
Proton Donors ◽  
Different Types

Intra-HBs are strengthened upon photoexcitation, confirmed by red-shift in vibrational mode and topology analysis. Number and type of donors result in difference in photophysical properties. Occurrence of ESIPT depends on barrier and reaction energy.

Effects of π-expansion, an additional hydroxyl group, and substitution on the excited state single and double proton transfer of 2-hydroxybenzaldehyde and its relative compounds: TD-DFT static and dynamic study

2019 ◽  
Vol 43 (48) ◽  
pp. 19107-19119 ◽  
Author(s):  
Chanatkran Prommin ◽  
Khanittha Kerdpol ◽  
Tinnakorn Saelee ◽  
Nawee Kungwan
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Photophysical Properties ◽  
Dynamic Study ◽  
Hydroxyl Group ◽  
Single Proton ◽  
Double Proton Transfer ◽  
Td Dft ◽  
The Double Proton Transfer

The effects of π-expansion, an extra hydroxyl group, and substituents on the photophysical properties, the excited state single proton transfer and the double proton transfer of 2-hydroxybenzaldehyde and its relatives have been theoretically investigated using TD-DFT.

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