Proton Transfer Reactions in the Excited Electronic State

Томин, В. И.

doi:10.1002/9780470669143.ch22

Cited by 12 publications

(9 citation statements)

References 114 publications

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“…Proton-transfer (PT) reactions are intensively investigated since they play important roles in a wide variety of chemical and biological processes, such as acid–base reactions, biochemistry, and catalysis (see Scheme for molecules involved in PT reactions discussed here). ,− ,− Moreover, the study of these reactions has resulted in the development of many applications, such as fluorescent chemosensors, , laser dyes, − ultraviolet (UV) photostabilizers, photoswitches, − and organic optoelectronic materials. − …”

Section: Ensemble Average Time-resolved Studies Of Photoinduced Proce...mentioning

confidence: 99%

“…These reactions occur between proton (or hydrogen atom) donor (typically −OH, −NH 2 , and −SH) and acceptor (CO, −N, base and some solvents) groups. The reaction can be inter- or intramolecular and can be activated thermally or by light; the process can occur through or without a barrier. ,,,, Aromatic molecules that contain an acidic proton in their structures can undergo intermolecular PT reactions in both the ground (ground-state proton transfer, GSPT) and the electronically excited (excited-state proton transfer, ESPT) states. ,,,, Upon electronic excitation, these molecules become strong acids (photoacids) that can undergo an ESPT reaction with a neighboring base molecule, such as water, alcohols, or amines. ,,− Since Weller’s and Eigen’s works, ,− the mechanisms of PT reactions have been intensively investigated from experimental and theoretical points of view. ,,,,,− The Smoluchowski-Collins-Kimball (SCK) model has been used to describe this type of reactions. − This model shows how the diffusion of the acid and the base through the solvent plays an important role in the mechanism, as the reactants should approach each other at a specific distance for the PT reaction to occur. The surrounding environment may play a key factor in solute/solvent interactions and subsequent reorganization.…”

Section: Ensemble Average Time-resolved Studies Of Photoinduced Proce...mentioning

confidence: 99%

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Photochemistry and Photophysics in Silica-Based Materials: Ultrafast and Single Molecule Spectroscopy Observation

et al. 2017

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Silica-based materials (SBMs) are widely used in catalysis, photonics, and drug delivery. Their pores and cavities act as hosts of diverse guests ranging from classical dyes to drugs and quantum dots, allowing changes in the photochemical behavior of the confined guests. The heterogeneity of the guest populations as well as the confinement provided by these hosts affect the behavior of the formed hybrid materials. As a consequence, the observed reaction dynamics becomes significantly different and complex. Studying their photobehavior requires advanced laser-based spectroscopy and microscopy techniques as well as computational methods. Thanks to the development of ultrafast (spectroscopy and imaging) tools, we are witnessing an increasing interest of the scientific community to explore the intimate photobehavior of these composites. Here, we review the recent theoretical and ultrafast experimental studies of their photodynamics and discuss the results in comparison to those in homogeneous media. The discussion of the confined dynamics includes solvation and intra- and intermolecular proton-, electron-, and energy transfer events of the guest within the SBMs. Several examples of applications in photocatalysis, (photo)sensors, photonics, photovoltaics, and drug delivery demonstrate the vast potential of the SBMs in modern science and technology.

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Section: Ensemble Average Time-resolved Studies Of Photoinduced Proce...mentioning

confidence: 99%

Section: Ensemble Average Time-resolved Studies Of Photoinduced Proce...mentioning

confidence: 99%

Photochemistry and Photophysics in Silica-Based Materials: Ultrafast and Single Molecule Spectroscopy Observation

et al. 2017

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“…Since the seminal work of Sengupta and Kasha in 1979, the photophysical properties of 3HF have attracted the attention of several research groups. In particular, 3HF has been largely studied as a model compound in the investigation of excited-state intramolecular proton-transfer processes (ESIPT). − The intramolecular hydrogen bond between the 3-hydroxyl (3OH) group and the CO carbonyl moiety in 3HF is considered to play a key role in proton transfer occurring from the excited state of 3HF (N*), to form the excited tautomer (T*, Scheme Figure ). Whereas emission at ca.…”

Section: Introductionmentioning

confidence: 99%

Polarizable QM/Classical Approaches for the Modeling of Solvation Effects on UV–Vis and Fluorescence Spectra: An Integrated Strategy

et al. 2017

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Hybrid methods combining quantum chemistry and classical models are largely used to describe solvent effects in absorption and emission processes of solvated chromophores. Here we compare three different formulations of these hybrid approaches, using a continuum, an atomistic, or a mixed description of the solvent. In all cases mutual polarization effects between the quantum and the classical subsystems are taken into account. As a molecular probe, 3-hydroxyflavone has been selected due to its rich photophysics, which involves different tautomeric and anionic forms. We show that a clear assignment of the measured spectroscopic signals to each specific form can be achieved by combining the different solvation models into an integrated and cost-effective strategy. Previously proposed mechanisms for the excited-state proton transfer (ESIPT), specific solvent perturbation effects on ESIPT, and solvent-assisted anion formation are also validated in terms of short- and long-range solvation effects.

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“…Various experimental studies have shown that both the steady state fluorescence and the time resolved properties strongly depend on the solvent. [34][35][36][37][38] More specifically, in hydrogen-bonding solvents, the emission from both N and T forms is observed, whereas in non-hydrogen-bonding solvents, only T fluorescence is observed. Moreover, time-resolved studies have shown that the ESIPT process is characterized by two components, a fast (several tens of femtoseconds) component and a slower (around 10 ps) component.…”

Section: Introductionmentioning

confidence: 98%

An enhanced sampling QM/AMOEBA approach: The case of the excited state intramolecular proton transfer in solvated 3-hydroxyflavone

Nottoli

Bondanza

Lipparini

et al. 2021

The Journal of Chemical Physics

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We present an extension of the polarizable quantum mechanical (QM)/AMOEBA approach to enhanced sampling techniques. This is achieved by connecting the enhanced sampling PLUMED library to the machinery based on the interface of Gaussian and Tinker to perform QM/AMOEBA molecular dynamics. As an application, we study the excited state intramolecular proton transfer of 3-hydroxyflavone in two solvents: methanol and methylcyclohexane. By using a combination of molecular dynamics and umbrella sampling, we find an ultrafast component of the transfer, which is common to the two solvents, and a much slower component, which is active in the protic solvent only. The mechanisms of the two components are explained in terms of intramolecular vibrational redistribution and intermolecular hydrogenbonding, respectively. Ground and excited state free energies along an effective reaction coordinate are finally obtained allowing for a detailed analysis of the solvent mediated mechanism.

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Proton Transfer Reactions in the Excited Electronic State

Cited by 12 publications

References 114 publications

Photochemistry and Photophysics in Silica-Based Materials: Ultrafast and Single Molecule Spectroscopy Observation

Photochemistry and Photophysics in Silica-Based Materials: Ultrafast and Single Molecule Spectroscopy Observation

Polarizable QM/Classical Approaches for the Modeling of Solvation Effects on UV–Vis and Fluorescence Spectra: An Integrated Strategy

An enhanced sampling QM/AMOEBA approach: The case of the excited state intramolecular proton transfer in solvated 3-hydroxyflavone

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