Intramolecular, Exciplex-Mediated, Proton-Coupled, Charge-Transfer Processes in <i>N,N</i>-Dimethyl-3-(1-pyrenyl)propan-1-ammonium Cations: Influence of Anion, Solvent Polarity, and Temperature

Safko, Trevor M.; Faleiros, Marcelo Meira; Atvars, Teresa Dib Zambon; Weiss, Richard G.

doi:10.1021/acs.jpca.6b01519

Cited by 5 publications

(2 citation statements)

References 30 publications

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“…15 They are sometimes part of more complex photophysical processes. 16,17 * Corresponding author: sorana@gw-chimie.math.unibuc.ro…”

Section: Introduction *mentioning

confidence: 99%

Exciplex formation in the phenoxathiin-thioxanthone system

Tablet¹,

Ionescu²

2021

Rev.Roum.Chim.

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Amines and other nitrogen-containing compounds, due to their electron donor character, can form excited state emissive complexes in systems that comprise an electron acceptor. Sulphur-containing heteroaromatic compounds such as phenoxathiin are also well-known for their electron donor character. Starting from these two considerations, we aimed at finding exciplexes in which the electron donor contains sulphur. We studied several D-A pairs in solvents of different polarity and found out that the system phenoxathiin-thioxanthone presents a new emission band at longer wavelength than the D and A bands in non-polar solvents, which is quenched in polar ones. In order to explain the exciplex formation, which is determined by an electron transfer process, the standard free enthalpy for the latter was calculated according to the Rehm-Weller equation. The equilibrium constants and the activation barrier for the exciplex formation were determined as well from steady-state emission data at different donor concentrations and at different temperatures, respectively.

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“…15 They are sometimes part of more complex photophysical processes. 16,17 * Corresponding author: sorana@gw-chimie.math.unibuc.ro…”

Section: Introduction *mentioning

confidence: 99%

Exciplex formation in the phenoxathiin-thioxanthone system

Tablet¹,

Ionescu²

2021

Rev.Roum.Chim.

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“…The importance of proton-coupled electron transfer (PCET) is substantially realized in many biophysical and catalytic processes. − Concerted electron and proton transfer is essential to avoid high energy intermediates. − However, the signatures of the PCET process are not too different from the conventional charge transfer (CT) or electron transfer (ET) . The similarity of features between PCET and ET often creates confusion to track down the actual nature of the process.…”

Section: Introductionmentioning

confidence: 99%

Photo-induced Electron Transfer or Proton-Coupled Electron Transfer in Methylbipyridine/Phenol Complexes: A Time-Dependent Density Functional Theory Investigation

Hossen

Sahu

2019

J. Phys. Chem. A

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It is often difficult to assign the nature of an excited-state process unambiguously based on a limited number of experimental evidence. The methylbipyridine/phenol complex is a classic example, where experimental observations support a proton-coupled electron transfer (PCET) or a photo-induced electron transfer (PET) process. Here, we implemented time-dependent density functional theory calculation to elucidate the nature of the process. We found that PCET is possible only when mediated by a H-bond between methylbipyridine and phenol. However, a conventional PET can occur through π–π stacking interaction between the donor and the acceptor. Thus, the photophysical process in the complex is indeed governed by competition of H-bonding versus π–π interaction. Our calculations including the solvent model based on density (SMD) suggest that π–π stacking is more favorable than H-bonding, and hence, conventional PET is a more favorable excited-state process for the methylbipyridine/methoxyphenol complex than PCET.

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Proton-coupled charge-transfer reactions and photoacidity of N, N -dimethyl-3-arylpropan-1-ammonium chloride salts

Safko

Jiang

Zhang

et al. 2017

Photochem Photobiol Sci

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Photoinduced intermolecular proton-transfer processes from N,N-dimethyl-3-arylpropan-1-ammonium chloride salts (ArCl, with aryl as 1-pyrenyl, 9-anthryl, and 2-naphtyl) to a solvent molecule have been investigated by steady-state and dynamic spectroscopic methods. The intermolecular proton-transfers are coupled either to the formation of an exciplex or to a solvent-separated ion pair in what we have termed a 'proton-coupled charge-transfer reaction'. A range of solvents has been observed to mediate both the ground-state conformations of the ArCl and the extent of electron transfer. Unlike typical photoacids, in which through-bond interactions control photoacidity, through-space charge-transfer interactions are responsible in the excited singlet states of the ArCl. Transient absorption experiments reveal a range of electronic comportments in the excited-states of the ArCl. Excited-state pK values of -3.4, 1.3, and -3.3 in THF were calculated using a Förster-like approach for the 1-pyrenyl, 9-anthryl, and 2-naphthyl salts, respectively. The observed rate of proton-transfer was found to be independent of the thermodynamic driving force and the short-term reversibility of these reactions has been approximated. The data suggest how other systems may be designed to facilitate this novel process.

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Intramolecular, Exciplex-Mediated, Proton-Coupled, Charge-Transfer Processes in N,N-Dimethyl-3-(1-pyrenyl)propan-1-ammonium Cations: Influence of Anion, Solvent Polarity, and Temperature

Cited by 5 publications

References 30 publications

Exciplex formation in the phenoxathiin-thioxanthone system

Exciplex formation in the phenoxathiin-thioxanthone system

Photo-induced Electron Transfer or Proton-Coupled Electron Transfer in Methylbipyridine/Phenol Complexes: A Time-Dependent Density Functional Theory Investigation

Proton-coupled charge-transfer reactions and photoacidity of N, N -dimethyl-3-arylpropan-1-ammonium chloride salts

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