Use of polarizability and chemical hardness to locate the transition state and the potential energy curve for double proton transfer reaction: A DFT based study

Beg, Hasibul; De, Sankar Prasad; Ash, Sankarlal; Misra, Ajay

doi:10.1016/j.comptc.2011.12.018

Cited by 15 publications

(8 citation statements)

References 46 publications

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“…Particularly for the N E triphenylimidazole derivative, an excellent agreement between experimental and calculated absorption data has been observed using the B3LYP functional [ 35 ]. B3LYP has been applied successfully [ 58 , 65 , 66 , 67 , 68 , 69 , 70 ] in similar systems, when compared to available experimental data, although this functional has been shown to present limitations due to its generality (see for example reference [ 71 ]). Therefore, we have evaluated the N E absorption spectrum with different functionals (B3LYP, M06, wB97X-D3, and M06-2X, Table S2 ).…”

Section: Resultsmentioning

confidence: 99%

“…The potential energy curves for the proton transfer (conversion from enolic to ketonic species, both in S 0 and in S 1 ), were constructed at B3LYP/6-31G(2d,2p) level: for the ground state a relaxed scan for the variation of the O–H bond, with a 0.06 Å step was performed and, for each step, vertical transitions were calculated with TD-DFT. This technique was used before to construct potential energy curves in the excited state and has provided good results when compared to experimental data [ 58 , 65 , 66 , 67 , 68 , 69 , 70 ]. Emission wavelength in Table 5 was calculated based on the energy difference between the minimum at the excited state of ketonic form and the same geometry at the ground state.…”

Section: Methodsmentioning

confidence: 99%

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Density Functional Theory Applied to Excited State Intramolecular Proton Transfer in Imidazole-, Oxazole-, and Thiazole-Based Systems

et al. 2018

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Excited state intramolecular proton transfer (ESIPT) is a photoinduced process strongly associated to hydrogen bonding within a molecular framework. In this manuscript, we computed potential energy data using Time Dependent Density Functional Theory (TDDFT) for triphenyl-substituted heterocycles, which evidenced an energetically favorable proton transfer on the excited state (i.e., ESIPT) but not on the ground state. Moreover, we describe how changes on heterocyclic functionalities, based on imidazole, oxazole, and thiazole systems, affect the ESIPT process that converts an enolic species to a ketonic one through photon-induced proton transfer. Structural and photophysical data were obtained theoretically by means of density functional theory (DFT) calculations and contrasted for the three heterocyclics. Different functionals were used, but B3LYP was the one that adequately predicted absorption data. It was observed that the intramolecular hydrogen bond is strengthened in the excited state, supporting the occurrence of ESIPT. Finally, it was observed that, with the formation of the excited state, there is a decrease in electronic density at the oxygen atom that acts as proton donor, while there is a substantial increase in the corresponding density at the nitrogen atom that serves as proton acceptor, thus, indicating that proton transfer is indeed favored after photon absorption.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Density Functional Theory Applied to Excited State Intramolecular Proton Transfer in Imidazole-, Oxazole-, and Thiazole-Based Systems

et al. 2018

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“…247 Thus, theoretical studies of polarizability in terms of transition state theory are currently performed. 248 Endofullerene polarizability provides a universal model for description of screening effects and the conned molecules' behavior under electric elds. This model is easily extrapolated to the more complex encapsulated objects (see, e.g., ref.…”

Section: Discussionmentioning

confidence: 99%

Polarizability as a landmark property for fullerene chemistry and materials science

Sabirov

2014

RSC Adv.

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“…Therefore, analysis of the reaction pathway allows for joint observation of the processes in two directions. The IRC studies by the DFT computational method have already been performed for the formamide dimer, its sulfur analogue and the corresponding mixed dimer. − The concerted, though not synchronous mechanism of the proton transfer has been suggested …”

Section: Introductionmentioning

confidence: 99%

Bond Softening Indices Studied by the Fragility Spectra for Proton Migration in Formamide and Related Structures

et al. 2019

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Computational scheme to obtain bond softening index λ, defined within the conceptual DFT, has been obtained with the use of the reaction fragility (RF) concept. Numerical results were obtained with the RF spectra for the proton transfer reaction in formamide molecule (H2NCHO) and the water assisted proton migration in H2NCHO·H2O complex. Double proton transfer reaction in the formamide dimer, (H2NCHO)2, and its analogues, (H2NCHS)2 and (H2NCHO)·(H2NCHS), have also been studied. The atomic and bond RF spectra clearly describe the density reorganization in the backbone of each molecule, resulting from proton displacement in the systems. The obtained softening indices have been calculated for hydrogen atoms in the reactant state (RS) and product state (PS) configuration. These indices provide fine characteristics for the local sensitivity of the reacting system to a disturbance of the position of a chosen atom.

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Use of polarizability and chemical hardness to locate the transition state and the potential energy curve for double proton transfer reaction: A DFT based study

Cited by 15 publications

References 46 publications

Density Functional Theory Applied to Excited State Intramolecular Proton Transfer in Imidazole-, Oxazole-, and Thiazole-Based Systems

Density Functional Theory Applied to Excited State Intramolecular Proton Transfer in Imidazole-, Oxazole-, and Thiazole-Based Systems

Polarizability as a landmark property for fullerene chemistry and materials science

Bond Softening Indices Studied by the Fragility Spectra for Proton Migration in Formamide and Related Structures

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