Chemistry › Physical and Theoretical Chemistry

Photochemistry and Electron Transfer Studies

Works Count: 76552

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This cluster of papers focuses on the mechanisms, dynamics, and applications of excited-state proton transfer, intramolecular charge transfer, solvation dynamics, and hydrogen bonding. It also explores the use of these phenomena in luminescent solar concentrators and organic optoelectronic materials.

Keywords

Excited-State Proton Transfer; Intramolecular Charge Transfer; Solvation Dynamics; Luminescent Solar Concentrators; Hydrogen Bonding; Fluorescence Quantum Yields; Organic Optoelectronic Materials; Electron Transfer; Photoinduced Proton Transfer; Solvatochromism

Handbook of Fluorescence Spectra of Aromatic Molecules

1971-01-01

Isadore B. Berlman

Photophysics of aromatic molecules

1970-01-01

J. B. Birks

Intramolecular Long-Distance Electron Transfer in Organic Molecules

1988-04-22

G. L. Closs , John R. Miller

Intramolecular long-distance electron transfer (EI) has been actively studied in recent years in order to test existing theories in a quantitative way and to provide the necessary constants for predicting … Intramolecular long-distance electron transfer (EI) has been actively studied in recent years in order to test existing theories in a quantitative way and to provide the necessary constants for predicting ET rates from simple structural parameters. Theoretical predictions of an "inverted region," where increasing the driving force of the reaction will decrease its rate, have begun to be experimentally confirmed. A predicted nonlinear dependence of ET rates on the polarity of the solvent has also been confirmed. This work has implications for the design of efficient photochemical charge-separation devices. Other studies have been directed toward determining the distance dependence of ET reactions. Model studies on different series of compounds give similar distance dependences. When different stereochemical structures are compared, it becomes apparent that geometrical factors must be taken into account. Finally, the mechanism of coupling between donor and acceptor in weakly interacting systems has become of major importance. The theoretical and experimental evidence favors a model in which coupling is provided by the interaction with the orbitals of the intervening molecular fragments, although more experimental evidence is needed.

Ru(II) polypyridine complexes: photophysics, photochemistry, eletrochemistry, and chemiluminescence

1988-03-01

Alberto Juris , Vincenzo Balzani , F. Barigelletti +3 more

Time-dependent density functional theory within the Tamm–Dancoff approximation

1999-12-01

So Hirata , Martin Head‐Gordon

Design and construction of molecular assemblies with large second-order optical nonlinearities. Quantum chemical aspects

1994-01-01

David R. Kanis , Mark A. Ratner , Tobin J. Marks

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDesign and construction of molecular assemblies with large second-order optical nonlinearities. Quantum chemical aspectsDavid R. Kanis, Mark A. Ratner, and Tobin J. MarksCite this: Chem. Rev. 1994, … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDesign and construction of molecular assemblies with large second-order optical nonlinearities. Quantum chemical aspectsDavid R. Kanis, Mark A. Ratner, and Tobin J. MarksCite this: Chem. Rev. 1994, 94, 1, 195–242Publication Date (Print):January 1, 1994Publication History Published online1 May 2002Published inissue 1 January 1994https://pubs.acs.org/doi/10.1021/cr00025a007https://doi.org/10.1021/cr00025a007research-articleACS PublicationsRequest reuse permissionsArticle Views4725Altmetric-Citations2057LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Approximate Self-Consistent Molecular-Orbital Theory. V. Intermediate Neglect of Differential Overlap

1967-09-15

John A. Pople , D. L. Beveridge , Paul A. Dobosh

A new approximate self-consistent-field method for the determination of molecular orbitals for all valence electrons of a molecule is proposed. This method features neglect of differential overlap in all electron-interaction … A new approximate self-consistent-field method for the determination of molecular orbitals for all valence electrons of a molecule is proposed. This method features neglect of differential overlap in all electron-interaction integrals except those involving one center only. The parameters involved in the calculation are generally obtained semi-empirically. The new method is known as the Intermediate Neglect of Differential Overlap (INDO) method, and may be regarded as an improvement over the CNDO method proposed in Part I, in that atomic term-level splittings and unpaired spin distributions are better accommodated. Calculations on geometries of AB2 and AB3 molecules are reported to substantiate the proposed method, and calculated unpaired spin distributions for methyl and ethyl radicals are discussed.

Solvent Effects upon Fluorescence Spectra and the Dipolemoments of Excited Molecules

1956-04-01

Noboru Mataga , Y. Kaifu , Masao Koizumi

Abstract A general formula for the difference of solvent shifts of fluorescence and absorption spectra in the approximation of long range dipolar interaction was derived using Ooshika’s theory of light … Abstract A general formula for the difference of solvent shifts of fluorescence and absorption spectra in the approximation of long range dipolar interaction was derived using Ooshika’s theory of light absorption in solution. Measurements of fluorescence and absorption spectra of some naphthalene derivatives in various organic solvents were undertaken, and the data were analysed by the theoretical formula. The formula reproduces the experimental data satisfactorily, and from this fact it was concluded that the most predominant factor which determines the difference of solvent shifts of fluorescence and absorption spectra of these molecules is the interaction energy between solute and solvent molecules due to orientation polarization. The incremental values of dipolemoments in the excited state were estimated, and those for α-, β-naphthols and β-naphthyl methyl ether were interpreted as due to the increase of electron migration from the substituent in the excited state.

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Relationship between Absorption Intensity and Fluorescence Lifetime of Molecules

1962-08-15

S. J. Strickler , Robert A. Berg

The equations usually given relating fluorescence lifetime to absorption intensity are strictly applicable only to atomic systems, whose transitions are sharp lines. This paper gives the derivation of a modified … The equations usually given relating fluorescence lifetime to absorption intensity are strictly applicable only to atomic systems, whose transitions are sharp lines. This paper gives the derivation of a modified formula 1/τ0=2.880×10−9n2〈ν̃f−3〉Av−1(gl/gu) ∫ εdlnν̃,which should be valid for broad molecular bands when the transition is strongly allowed. Lifetimes calculated by this formula have been compared with measured lifetimes for a number of organic molecules in solution. In most cases the values agree within experimental error, indicating that the formula is valid for such systems. The limitations of the formula and the results expected for weak or forbidden transitions are also discussed.

Environmental effects on vibronic band intensities in pyrene monomer fluorescence and their application in studies of micellar systems

1977-03-01

K. Kalyanasundaram , J. K. Thomas

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEnvironmental effects on vibronic band intensities in pyrene monomer fluorescence and their application in studies of micellar systemsK. Kalyanasundaram and J. K. ThomasCite this: J. Am. Chem. … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEnvironmental effects on vibronic band intensities in pyrene monomer fluorescence and their application in studies of micellar systemsK. Kalyanasundaram and J. K. ThomasCite this: J. Am. Chem. Soc. 1977, 99, 7, 2039–2044Publication Date (Print):March 1, 1977Publication History Published online1 May 2002Published inissue 1 March 1977https://pubs.acs.org/doi/10.1021/ja00449a004https://doi.org/10.1021/ja00449a004research-articleACS PublicationsRequest reuse permissionsArticle Views12766Altmetric-Citations3159LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Photophysics of preassociated pyrenes in aqueous polymer solutions and in other organized media

1993-03-01

Françoise M. Winnik

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotophysics of preassociated pyrenes in aqueous polymer solutions and in other organized mediaFrancoise M. WinnikCite this: Chem. Rev. 1993, 93, 2, 587–614Publication Date (Print):March 1, 1993Publication History … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotophysics of preassociated pyrenes in aqueous polymer solutions and in other organized mediaFrancoise M. WinnikCite this: Chem. Rev. 1993, 93, 2, 587–614Publication Date (Print):March 1, 1993Publication History Published online1 May 2002Published inissue 1 March 1993https://pubs.acs.org/doi/10.1021/cr00018a001https://doi.org/10.1021/cr00018a001research-articleACS PublicationsRequest reuse permissionsArticle Views7416Altmetric-Citations1619LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Toward a systematic molecular orbital theory for excited states

1992-01-01

James B. Foresman , Martin Head‐Gordon , John A. Pople +1 more

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTToward a systematic molecular orbital theory for excited statesJames B. Foresman, Martin Head-Gordon, John A. Pople, and Michael J. FrischCite this: J. Phys. Chem. 1992, 96, 1, … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTToward a systematic molecular orbital theory for excited statesJames B. Foresman, Martin Head-Gordon, John A. Pople, and Michael J. FrischCite this: J. Phys. Chem. 1992, 96, 1, 135–149Publication Date (Print):January 1, 1992Publication History Published online1 May 2002Published inissue 1 January 1992https://pubs.acs.org/doi/10.1021/j100180a030https://doi.org/10.1021/j100180a030research-articleACS PublicationsRequest reuse permissionsArticle Views5891Altmetric-Citations2188LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access options Get e-Alerts

On the Theory of Electron-Transfer Reactions. VI. Unified Treatment for Homogeneous and Electrode Reactions

1965-07-15

R. A. Marcus

A unified theory of homogeneous and electrochemical electron-transfer rates is developed using statistical mechanics. The treatment is a generalization of earlier papers of this series and is concerned with seeking … A unified theory of homogeneous and electrochemical electron-transfer rates is developed using statistical mechanics. The treatment is a generalization of earlier papers of this series and is concerned with seeking a fairly broad basis for the quantitative correlations among chemical and electrochemical rate constants predicted in these earlier papers. The atomic motions inside the inner coordination shell of each reactant are treated as vibrations. The motions outside are treated by the ``particle description,'' which emphasizes the functional dependence of potential energy and free energy on molecular properties and which avoids, thereby, some unnecessary assumptions about the molecular interactions.

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A Semi-Empirical Theory of the Electronic Spectra and Electronic Structure of Complex Unsaturated Molecules. II

1953-05-01

Rudolph Pariser , Robert G. Parr

The theory of electronic spectra and electronic structure, the elucidation of which was begun in the first paper of this series, is further developed and applied to ethylene, butadiene, benzene, … The theory of electronic spectra and electronic structure, the elucidation of which was begun in the first paper of this series, is further developed and applied to ethylene, butadiene, benzene, pyridine, pyrimidine, pyrazine, and s-triazine. A realistic and consistent LCAO-MO π-electron theory should allow the σ-electrons to adjust themselves to the instantaneous positions of the mobile π-electrons. This is accomplished in the theory by assignment of empirical values to the Coulomb electronic repulsion integrals and Coulomb penetration integrals which enter the formulas, these values being obtained in a prescribed way from valence state ionization potentials and electron affinities of atoms. Use of the empirical values in the molecular orbital theory reduces the magnitude of computed singlet-triplet splittings and the effects of configuration interaction without complicating the mathematics. From the valence-bond point of view, ionic structures may be said to be enhanced. The applications to hydrocarbons and heteromolecules which are considered show that the theory can correlate known π-electron spectral wavelengths and intensities very successfully, which, together with the simple structure of the theory, signals that manifold applications of the theory are in order elsewhere.

Contemporary Issues in Electron Transfer Research

1996-01-01

Paul F. Barbara , Thomas J. Meyer , Mark A. Ratner

This is an overview of some of the important, challenging, and problematic issues in contemporary electron transfer research. After a qualitative discussion of electron transfer, its time and distance scales, … This is an overview of some of the important, challenging, and problematic issues in contemporary electron transfer research. After a qualitative discussion of electron transfer, its time and distance scales, energy curves, and basic parabolic energy models are introduced to define the electron transfer process. Application of transition state theory leads to the standard Marcus formulation of electron transfer rate constants. Electron transfer in solution is coupled to solvent polarization effects, and relaxation processes can contribute to and even control electron transfer. The inverted region, in which electron transfer rate constants decrease with increasing exoergicity, is one of the most striking phenomena in electron transfer chemistry. It is predicted by both semiclassical and quantum mechanical models, with the latter appropriate if there are coupled high- or medium-frequency vibrations. The intramolecular reorganizational energy has different contributions from different vibrational modes, which, in favorable cases, can be measured on a mode-by-mode basis by resonance Raman spectroscopy. Alternatively, mode-averaging procedures are available for including multimode contributions based on absorption or emission spectra. Rate constants for intramolecular electron transfer depend on electronic coupling and orbital overlap and, therefore, on distance. Mixed-valence systems have provided an important experimental platform for investigating solvent and structural effects and the transition between localized and delocalized behavior. One of the important developments in electron transfer is the use of absorption and emission measurements to calculate electron transfer rate constants. Ultrafast electron transfer measurements have been used to uncover nonequilibrium relaxation effects, an area that presents special challenges to the understanding of the dynamics and relaxation of the coupled processes. Electron transfer in the gas phase offers substantial insights into the nature of the electron transfer process. Similarly, electron transport in conductive polymers and synthetic metals depends on the basic principles of electron transfer, with some special nuances of their own.

The IEF version of the PCM solvation method: an overview of a new method addressed to study molecular solutes at the QM ab initio level

1999-05-01

J. Tomasi , Benedetta Mennucci , Éric Cancès

Use of the CNDO Method in Spectroscopy. I. Benzene, Pyridine, and the Diazines

1968-02-15

Janet E. Del Bene , H. H. Jaffé

The CNDO method has been modified by substitution of semiempirical Coulomb integrals similar to those used in the Pariser-Parr-Pople method, and by the introduction of a new empirical parameter κ … The CNDO method has been modified by substitution of semiempirical Coulomb integrals similar to those used in the Pariser-Parr-Pople method, and by the introduction of a new empirical parameter κ to differentiate resonance integrals between σ orbitals from those between π orbitals. The CNDO method with this change in parameterization is extended to the calculation of electronic spectra and applied to the isoelectronic compounds benzene, pyridine, pyridazine, pyrimidine, and pyrazine. The results obtained were refined by a limited CI calculation and compared with the best available experimental data. It was found that the agreement was quite satisfactory for both n→π* and π→π* singlet-singlet transitions. The relative energies of the pi and lone-pair orbitals in pyridine and the diazines are compared and an explanation proposed for the observed orders. Also, the nature of the “lone pairs” in these compounds is discussed.

Electron transfers in chemistry and biology

1985-08-01

R. A. Marcus , Norman Sutin

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Photosensitization by reversible electron transfer: theories, experimental evidence, and examples

1986-04-01

George J. Kavarnos , Nicholas J. Turro

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotosensitization by reversible electron transfer: theories, experimental evidence, and examplesGeorge J. Kavarnos and Nicholas J. TurroCite this: Chem. Rev. 1986, 86, 2, 401–449Publication Date (Print):April 1, 1986Publication … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotosensitization by reversible electron transfer: theories, experimental evidence, and examplesGeorge J. Kavarnos and Nicholas J. TurroCite this: Chem. Rev. 1986, 86, 2, 401–449Publication Date (Print):April 1, 1986Publication History Published online1 May 2002Published inissue 1 April 1986https://pubs.acs.org/doi/10.1021/cr00072a005https://doi.org/10.1021/cr00072a005research-articleACS PublicationsRequest reuse permissionsArticle Views6016Altmetric-Citations1314LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Influence of Energy Transfer by the Exchange Mechanism on Donor Luminescence

1965-09-15

Mitio Inokuti , Fumio Hirayama

The decay of donor luminescence in a rigid solution when modified by electronic energy transfer by the exchange mechanism is treated theoretically. The rate constant for the elementary process of … The decay of donor luminescence in a rigid solution when modified by electronic energy transfer by the exchange mechanism is treated theoretically. The rate constant for the elementary process of energy transfer is taken to be of the Dexter form, const exp(−2R/L), where R is the donor—acceptor distance and L is a positive constant. Calculations are made of the yield and decay time of the donor luminescence as functions of the acceptor concentration. The resulting relationship among the above quantities enables one to analyze experimental data in a quantitative manner, and thereby to obtain information about an intermolecular exchange interaction. As an example of such an analysis, Ermolaev's data on triplet—triplet transfer between some aromatic molecules are compared with our results, and very good agreement is found with a choice of the single parameter L.

The exciton model in molecular spectroscopy

1965-01-01

Michael Kasha , H. Ralph Rawls , M. Ashraf El‐Bayoumi

The molecular exciton model has received its most extensive development and application in the field of molecular crystals1'2. More recently, numerous applications to non-crystalline molecular composite systems have been made, … The molecular exciton model has received its most extensive development and application in the field of molecular crystals1'2. More recently, numerous applications to non-crystalline molecular composite systems have been made, including van der Waals and hydrogen-bonded dimers, trimers, and higher order aggregates. Another type of composite system has also been investigated, namely the composite molecule consisting of covalently bonded molecular units, with intrinsic individual unsaturated electronic systems so isolated by single bonds that but little or insignificant electronic overlap between units may occur. It is now well established that in molecular aggregates and in composite molecules, exciton effects may be observed if sufficiently strong electronic transitions exist in the component sub-units. The result of exciton splitting of excited states in the composite molecule may be the appearance of strong spectral shifts or splittings (which may be of the order of 2000 cm—1) of the absorption bands for the component molecules. At the same time, as a consequence of the exciton splitting of the excited state manifold, an enhancement of triplet state excitation may result. The purpose of this paper is to present a summary of the various type cases for molecular dimers, trimers and double and triple molecules in the description of the molecular exciton strong-coupling model. Then it will be shown by new experimental examples that, even in those cases where no significant exciton effect is observable in the singlet—singlet absorption spectrum for the composite molecule (intermediate and weak coupling cases), the enhancement of lowest triplet state excitation may still be conspicuous and significant. The ideas which are summarized in this paper have a curious history. Long ago, Kautsky and Merkel3 demonstrated experimentally that aggregation of dyes facilitated their action as photophysical sensitizers in photochemical reactions, at the same time diminishing their fluorescence efficiency. Kautsky attributed these easily demonstrated effects to enhancement of metastable state excitation in the aggregate dye. There is no doubt today that the metastable state he described is the lowest triplet state of the molecules studied. However, he did not distinguish between intrinsic and enhanced metastable (triplet) state excitation, so his interpretations were largely overlooked. Forster in l946 used the quasi-classical vector model to

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How Easily Oxidizable Is DNA? One-Electron Reduction Potentials of Adenosine and Guanosine Radicals in Aqueous Solution

1997-01-01

Steen Steenken , Slobodan V. Jovanović

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTHow Easily Oxidizable Is DNA? One-Electron Reduction Potentials of Adenosine and Guanosine Radicals in Aqueous SolutionSteen Steenken and Slobodan V. JovanovicView Author Information Max-Planck-Institut für Strahlenchemie D-45413 … ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTHow Easily Oxidizable Is DNA? One-Electron Reduction Potentials of Adenosine and Guanosine Radicals in Aqueous SolutionSteen Steenken and Slobodan V. JovanovicView Author Information Max-Planck-Institut für Strahlenchemie D-45413 Mülheim, Germany Department of Chemistry, University of Ottawa 10 Marie Curie, Ottawa, Canada K1N 6N5Cite this: J. Am. Chem. Soc. 1997, 119, 3, 617–618Publication Date (Web):January 22, 1997Publication History Received3 July 1996Published online22 January 1997Published inissue 1 January 1997https://pubs.acs.org/doi/10.1021/ja962255bhttps://doi.org/10.1021/ja962255brapid-communicationACS PublicationsCopyright © 1997 American Chemical SocietyRequest reuse permissionsArticle Views6116Altmetric-Citations1242LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Absorption,Equilibrium,Genetics,Nucleic acids,Redox reactions Get e-Alerts

Subpicosecond Measurements of Polar Solvation Dynamics: Coumarin 153 Revisited

1995-11-01

Miin Liang Horng , Joseph A. Gardecki , Arno Papazyan +1 more

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSubpicosecond Measurements of Polar Solvation Dynamics: Coumarin 153 RevisitedM. L. Horng, J. A. Gardecki, A. Papazyan, and M. MaroncelliCite this: J. Phys. Chem. 1995, 99, 48, 17311–17337Publication … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSubpicosecond Measurements of Polar Solvation Dynamics: Coumarin 153 RevisitedM. L. Horng, J. A. Gardecki, A. Papazyan, and M. MaroncelliCite this: J. Phys. Chem. 1995, 99, 48, 17311–17337Publication Date (Print):November 1, 1995Publication History Published online1 May 2002Published inissue 1 November 1995https://pubs.acs.org/doi/10.1021/j100048a004https://doi.org/10.1021/j100048a004research-articleACS PublicationsRequest reuse permissionsArticle Views6745Altmetric-Citations1904LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsSupporting Info (3)»Supporting Information Supporting Information Get e-Alerts

Geometries and properties of excited states in the gas phase and in solution: Theory and application of a time-dependent density functional theory polarizable continuum model

2006-02-28

Giovanni Scalmani , Michael J. Frisch , Benedetta Mennucci +3 more

In this paper we present the theory and implementation of analytic derivatives of time-dependent density functional theory (TDDFT) excited states energies, both in vacuo and including solvent effects by means … In this paper we present the theory and implementation of analytic derivatives of time-dependent density functional theory (TDDFT) excited states energies, both in vacuo and including solvent effects by means of the polarizable continuum model. The method is applied to two case studies: p-nitroaniline and 4-(dimethyl)aminobenzonitrile. For both molecules PCM-TDDFT is shown to be successful in supporting the analysis of experimental data with useful insights for a better understanding of photophysical and photochemical pathways in solution.

The calculations of excited-state properties with Time-Dependent Density Functional Theory

2012-11-02

Carlo Adamo , Denis Jacquemin

In this tutorial review, we show how Time-Dependent Density Functional Theory (TD-DFT) has become a popular tool for computing the signatures of electronically excited states, and more specifically, the properties … In this tutorial review, we show how Time-Dependent Density Functional Theory (TD-DFT) has become a popular tool for computing the signatures of electronically excited states, and more specifically, the properties directly related to the optical (absorption and emission) spectra of molecules. We discuss the properties that can be obtained with widely available programs as well as how to account for the environmental effects (solvent and surfaces) and present recent applications in these fields. We next expose the transformation of the TD-DFT results into chemically intuitive parameters (colours as well as charge-transfer distances). Eventually, the non-specialised reader will find a series of advices and warnings necessary to perform her/his first TD-DFT calculations.

Spectral Absorption and Fluorescence of Dyes in the Molecular State

1936-12-01

Edwin E. Jelley

Quantum chemical probes of electron-transfer kinetics: the nature of donor-acceptor interactions

1991-07-01

Marshall D. Newton

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTQuantum chemical probes of electron-transfer kinetics: the nature of donor-acceptor interactionsMarshall D. NewtonCite this: Chem. Rev. 1991, 91, 5, 767–792Publication Date (Print):July 1, 1991Publication History Published online1 … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTQuantum chemical probes of electron-transfer kinetics: the nature of donor-acceptor interactionsMarshall D. NewtonCite this: Chem. Rev. 1991, 91, 5, 767–792Publication Date (Print):July 1, 1991Publication History Published online1 May 2002Published inissue 1 July 1991https://pubs.acs.org/doi/10.1021/cr00005a007https://doi.org/10.1021/cr00005a007research-articleACS PublicationsRequest reuse permissionsArticle Views6163Altmetric-Citations1307LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Mechanisms of Tryptophan Fluorescence Shifts in Proteins

2001-05-01

James T. Vivian , Patrik R. Callis

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An intermediate neglect of differential overlap technique for spectroscopy: Pyrrole and the azines

1973-01-01

Joan E. Ridley , Michael C. Zerner

Electron transfer in a new highly conducting donor-acceptor complex

1973-02-01

John P. Ferraris , D. O. Cowan , Vernon Walatka +1 more

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectron transfer in a new highly conducting donor-acceptor complexJohn. Ferraris, D. O. Cowan, V. Walatka, and J. H. PerlsteinCite this: J. Am. Chem. Soc. 1973, 95, 3, … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectron transfer in a new highly conducting donor-acceptor complexJohn. Ferraris, D. O. Cowan, V. Walatka, and J. H. PerlsteinCite this: J. Am. Chem. Soc. 1973, 95, 3, 948–949Publication Date (Print):February 1, 1973Publication History Published online1 May 2002Published inissue 1 February 1973https://pubs.acs.org/doi/10.1021/ja00784a066https://doi.org/10.1021/ja00784a066research-articleACS PublicationsRequest reuse permissionsArticle Views8614Altmetric-Citations1623LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Zwischenmolekulare Energiewanderung und Fluoreszenz

1948-01-01

Th. Förster

Abstract In Weiterentwicklung früherer Theorien von J. und F. Perrin und klassischphysikalischer Überlegungen des Verfassers wird eine quantenmechanische Behandlung des Übergangs von Elektronenanregungsenergie zwischen gleichartigen Molekülen in Lösung gegeben. Der … Abstract In Weiterentwicklung früherer Theorien von J. und F. Perrin und klassischphysikalischer Überlegungen des Verfassers wird eine quantenmechanische Behandlung des Übergangs von Elektronenanregungsenergie zwischen gleichartigen Molekülen in Lösung gegeben. Der kritische Molekülabstand, unterhalb dessen der übergang während der Anregungsdauer stattfindet, läßt sich aus den Absorptions‐ und Fluoreszenzspektren und der Anregungsdauer der Moleküle berechnen. Für Fluorescein und Chlorophyll a ergeben sich Werte von 50 bzw. 80 ÅE, entsprechend den mittleren Molekülabständen in Lösungen von 3,2 · 10 −3 bzw. 7,7 · 10 −4 Molen/Liter. Für die Bereiche oberhalb und unterhalb der kritischen Konzentration werden Formeln zur Berechnung der Energieabwanderung vom Primärmolekül angegeben, die mit den vorliegenden Messungen der Konzentrationsdepolarisation der Fluoreszenz gut übereinstimmen. Die Anwendung auf analoge Energiewanderungsprobleme in Molekülkristallen und im Assimilationsapparat der Pflanze wird diskutiert.

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Charge Separation in Excited States of Decoupled Systems—TICT Compounds and Implications Regarding the Development of New Laser Dyes and the Primary Process of Vision and Photosynthesis

1986-11-01

Wolfgang Rettig

Abstract The understanding of the dual fluorescence of certain aromatic systems has greatly advanced in recent years. The accompanying large charge separation has been shown to be linked to a … Abstract The understanding of the dual fluorescence of certain aromatic systems has greatly advanced in recent years. The accompanying large charge separation has been shown to be linked to a twisted (or small overlap) arrangement of the chromophores. Recent theoretical models are able to describe the excited‐state twisting of both single bonds (TICT compounds) and double bonds (olefins) in a unified picture. These models can help to elucidate the photophysical behavior of many organic, inorganic, and biologically relevant compounds, and their application to laser dyes and fluorescent probes provides a route to new “tailor‐made” fluorescent materials. Applied to the primary processes of vision and photosynthesis, these models can lead to a deeper understanding of basic photobiological processes.

Spin—Orbit Coupling and the Radiationless Processes in Nitrogen Heterocyclics

1963-06-15

Mostafa A. El‐Sayed

The matrix elements of the spin—orbit operator between the zero-order (spin-free) (n, π*) states of nitrogen heterocyclics are examined. It is found that generally, to the first order, there is … The matrix elements of the spin—orbit operator between the zero-order (spin-free) (n, π*) states of nitrogen heterocyclics are examined. It is found that generally, to the first order, there is no spin—orbit coupling between singlet and triplet states of the same configuration. The coupling between states of different configurations due to differences in the occupancy of the π* orbitals, but having the same nonbonding orbital, is found to have matrix elements similar to those resulting from the coupling between (π, π*) states, which McClure has shown to be unimportant. For the diazines (or polyazines), the coupling between different configurations due to a different occupancy of the nonbonding orbitals is found to have matrix elements which cancel one another. The general conclusion is thus reached that spin—orbit (s.o.) coupling between singlet and triplet (n, π*) states is unimportant to the first order. Using the observed polarization and lifetime data, it is estimated that the ratio |〈S(n,π*)|Hs.o.|T(n,π*)〉〈S(π,π*)|Hs.o.|T(n,π*)〉|2has an upper value of 10—3. These results as well as vibrational overlap considerations suggest that the enhancement of the efficiency of the intersystem crossing in nitrogen heterocyclics with the lowest singlet state of the (n, π*) type might be due to an S(n, π*)→T(π, π*) rather than an S(n, π*)→T(n, π*) radiationless process. An alternative explanation to the one previously given for the observation of fluorescence of 9, 10-diazaphenanthrene and s-tetrazine is thus suggested. In these molecules, the strong interaction between the (n, π*) singlet levels might cause the lowest S(n, π*) excited level to have a lower energy value than the (π, π*) triplet level. This would therefore lead to a retardation of the intersystem crossing process and allow the fluorescence to be observed. The characteristics of the observed weak phosphorescence of 9,10-diazaphenanthrene give spectroscopic support for this proposal. For nitrogen heterocyclic molecules with the lowest singlet and lowest triplet states of the (π, π*) types, an examination of the quinoline total emission in comparison with that of the parent hydrocarbon, nath-thalene, suggests an increase in the efficiency of the intersystem crossing process in quinoline. This is suggested to be due to the efficient S1(π, π*)→T2(n, π*)→T1(π, π*) radiationless process. A probable enhancement of the internal conversion processes in these molecules is suggested to be due to an increase in the density of states and the efficiency of the S(π, π*)↔S(n, π*) radiationless process due to a large vibrational overlap integral.

The properties of organic liquids that are relevant to their use as solvating solvents

1993-01-01

Yizhak Marcus

The first page of this article is displayed as the abstract. The first page of this article is displayed as the abstract.

Proton Transfer, Acid‐Base Catalysis, and Enzymatic Hydrolysis. Part I: ELEMENTARY PROCESSES

1964-01-01

Manfred Eigen

The proton occupies a special position as a promoter and mediator in chemical reactions occurring in solution. Many reactions in organic chemistry are catalysed by acids or bases; likewise, most … The proton occupies a special position as a promoter and mediator in chemical reactions occurring in solution. Many reactions in organic chemistry are catalysed by acids or bases; likewise, most enzymes contain active groups which promote acid-base catalysis. To understand the reaction mechanisms involved, it is necessary to identify the elementary steps as well as their course in time. Systematic investigation of these elementary steps as well as their course in time. Systematic investigation of these elementary steps has become possible only with the development of new methods for studying very fast reactions. The present paper reviews the information obtained in this type of investigation. The result is a relatively complete picture of the elementary proton transfer mechanisms and a comprehensive description of the modes and laws of acid-base and enzymatic catalysis.

Electron Transfer Reactions in Chemistry: Theory and Experiment (Nobel Lecture)

1993-08-01

R. A. Marcus

Abstract Since the late 1940s, the field of electron transfer processes has grown enormously, both in chemistry and biology. The development of the field, experimentally and theoretically, as well as … Abstract Since the late 1940s, the field of electron transfer processes has grown enormously, both in chemistry and biology. The development of the field, experimentally and theoretically, as well as its relation to the study of other kinds of chemical reactions, presents to us an intriguing history, one in which many threads have been brought together. In this lecture, some history, recent trends, and my own involvement in this research are described.

Standards for photoluminescence quantum yield measurements in solution (IUPAC Technical Report)

2011-08-31

Albert M. Brouwer

The use of standards for the measurement of photoluminescence quantum yields (QYs) in dilute solutions is reviewed. Only three standards can be considered well established. Another group of six standards … The use of standards for the measurement of photoluminescence quantum yields (QYs) in dilute solutions is reviewed. Only three standards can be considered well established. Another group of six standards has been investigated by several independent researchers. A large group of standards is frequently used in recent literature, but the validity of these is less certain. The needs for future development comprise: (i) confirmation of the validity of the QY values of many commonly used standard materials, preferably in the form of SI traceable standards; (ii) extension of the set of standard materials to the UV and near-IR spectral ranges; and (iii) good standards or robust protocols for the measurements of low QYs.

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Kinetics of Fluorescence Quenching by Electron and H‐Atom Transfer

1970-01-01

Dieter Rehm , Albert Weller

Abstract Fluorescence quenching rate constants, k q , ranging from 10 6 to 2 × 10 10 M −1 sec −1 , of more than 60 typical electron donor‐acceptor systems … Abstract Fluorescence quenching rate constants, k q , ranging from 10 6 to 2 × 10 10 M −1 sec −1 , of more than 60 typical electron donor‐acceptor systems have been measured in de‐oxygenated acetonitrile and are shown to be correlated with the free enthalpy change, Δ G 23 , involved in the actual electron transfer process magnified image in the encounter complex and varying between + 5 and −60 kcal/mole. The correlation which is based on the mechanism of adiabatic outer‐sphere electron transfer requires Δ G ≠ 23 , the activation free enthalpy of this process to be a monotonous function of Δ G 23 and allows the calculation of rate constants of electron transfer quenching from spectroscopic and electrochemical data. A detailed study of some systems where the calculated quenching constants differ from the experimental ones by several orders of magnitude revealed that the quenching mechanism operative in these cases was hydrogen‐atom rather than electron transfer. The conditions under which these different mechanisms apply and their consequences are discussed.

Scales of solute hydrogen-bonding: their construction and application to physicochemical and biochemical processes

1993-01-01

Michael H. Abraham

The first page of this article is displayed as the abstract. The first page of this article is displayed as the abstract.

Structural Changes Accompanying Intramolecular Electron Transfer: Focus on Twisted Intramolecular Charge-Transfer States and Structures

2003-09-17

Zbigniew R. Grabowski , Krystyna Rotkiewicz , Wolfgang Rettig

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructural Changes Accompanying Intramolecular Electron Transfer: Focus on Twisted Intramolecular Charge-Transfer States and StructuresZbigniew R. Grabowski, Krystyna Rotkiewicz, and Wolfgang RettigView Author Information Institute of Physical Chemistry, … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructural Changes Accompanying Intramolecular Electron Transfer: Focus on Twisted Intramolecular Charge-Transfer States and StructuresZbigniew R. Grabowski, Krystyna Rotkiewicz, and Wolfgang RettigView Author Information Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland, and Institute of Chemistry, Akademia Świȩtokrzyska, Chȩcińska 5, 25-020 Kielce, Poland Institute of Chemistry, Humboldt University, Brook-Taylor-Strasse 2, D-12489 Berlin, Germany Cite this: Chem. Rev. 2003, 103, 10, 3899–4032Publication Date (Web):September 17, 2003Publication History Received20 June 2001Published online17 September 2003Published inissue 1 October 2003https://pubs.acs.org/doi/10.1021/cr940745lhttps://doi.org/10.1021/cr940745lresearch-articleACS PublicationsCopyright © 2003 American Chemical SocietyRequest reuse permissionsArticle Views35683Altmetric-Citations3094LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Fluorescence,Molecules,Polarity,Reaction products,Solvents Get e-Alerts

Hydrogen Bonding in the Electronic Excited State

2011-11-09

G. Zhao , Keli Han

Because of its fundamental importance in many branches of science, hydrogen bonding is a subject of intense contemporary research interest. The physical and chemical properties of hydrogen bonds in the … Because of its fundamental importance in many branches of science, hydrogen bonding is a subject of intense contemporary research interest. The physical and chemical properties of hydrogen bonds in the ground state have been widely studied both experimentally and theoretically by chemists, physicists, and biologists. However, hydrogen bonding in the electronic excited state, which plays an important role in many photophysical processes and photochemical reactions, has scarcely been investigated. Upon electronic excitation of hydrogen-bonded systems by light, the hydrogen donor and acceptor molecules must reorganize in the electronic excited state because of the significant charge distribution difference between the different electronic states. The electronic excited-state hydrogen-bonding dynamics, which are predominantly determined by the vibrational motions of the hydrogen donor and acceptor groups, generally occur on ultrafast time scales of hundreds of femtoseconds. As a result, state-of-the-art femtosecond time-resolved vibrational spectroscopy is used to directly monitor the ultrafast dynamical behavior of hydrogen bonds in the electronic excited state. It is important to note that the excited-state hydrogen-bonding dynamics are coupled to the electronic excitation. Fortunately, the combination of femtosecond time-resolved spectroscopy and accurate quantum chemistry calculations of excited states resolves this issue in laser experiments. Through a comparison of the hydrogen-bonded complex to the separated hydrogen donor or acceptor in ground and electronic excited states, the excited-state hydrogen-bonding structure and dynamics have been obtained. Moreover, we have also demonstrated the importance of hydrogen bonding in many photophysical processes and photochemical reactions. In this Account, we review our recent advances in electronic excited-state hydrogen-bonding dynamics and the significant role of electronic excited-state hydrogen bonding on internal conversion (IC), electronic spectral shifts (ESS), photoinduced electron transfer (PET), fluorescence quenching (FQ), intramolecular charge transfer (ICT), and metal-to-ligand charge transfer (MLCT). The combination of various spectroscopic experiments with theoretical calculations has led to tremendous progress in excited-state hydrogen-bonding research. We first demonstrated that the intermolecular hydrogen bond in the electronic excited state is greatly strengthened for coumarin chromophores and weakened for thiocarbonyl chromophores. We have also clarified that the intermolecular hydrogen-bond strengthening and weakening correspond to red-shifts and blue-shifts, respectively, in the electronic spectra. Moreover, radiationless deactivations (via IC, PET, ICT, MLCT, and so on) can be dramatically influenced through the regulation of electronic states by hydrogen-bonding interactions. Consequently, the fluorescence of chromophores in hydrogen-bonded surroundings is quenched or enhanced by hydrogen bonds. Our research expands our understanding of the nature of hydrogen bonding by delineating the interaction between hydrogen bonds and photons, thereby providing a basis for excited-state hydrogen bonding studies in photophysics, photochemistry, and photobiology.

Photophysics of aromatic molecules

1971-07-01

Marl Sharnoff

Electronic Structure and Spectra of Nitrogen Heterocycles

1957-11-01

Time-Dependent Density Functional Response Theory for Molecules

1995-11-01

Mark E. Casida

Excited-state intramolecular proton-transfer (ESIPT) based fluorescence sensors and imaging agents

2018-01-01

Adam C. Sedgwick , Luling Wu , Hai‐Hao Han +7 more

We review recent advances in the design and application of excited-state intramolecular proton-transfer (ESIPT) based fluorescent probes. These sensors and imaging agents (probes) are important in biology, physiology, pharmacology, and … We review recent advances in the design and application of excited-state intramolecular proton-transfer (ESIPT) based fluorescent probes. These sensors and imaging agents (probes) are important in biology, physiology, pharmacology, and environmental science.

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Photoisomerization dynamics of stilbenes

1991-05-01

David H. Waldeck

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotoisomerization dynamics of stilbenesDavid H. WaldeckCite this: Chem. Rev. 1991, 91, 3, 415–436Publication Date (Print):May 1, 1991Publication History Published online1 May 2002Published inissue 1 May 1991https://pubs.acs.org/doi/10.1021/cr00003a007https://doi.org/10.1021/cr00003a007research-articleACS PublicationsRequest … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotoisomerization dynamics of stilbenesDavid H. WaldeckCite this: Chem. Rev. 1991, 91, 3, 415–436Publication Date (Print):May 1, 1991Publication History Published online1 May 2002Published inissue 1 May 1991https://pubs.acs.org/doi/10.1021/cr00003a007https://doi.org/10.1021/cr00003a007research-articleACS PublicationsRequest reuse permissionsArticle Views8073Altmetric-Citations1186LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Electron transfer reactions in chemistry. Theory and experiment

1993-07-01

R. A. Marcus

Since the late 1940s, the field of electron transfer pro- cesses has grown enormously, both in chemistry and biol- ogy.The development of the field, experimentally and theoretically, as well as … Since the late 1940s, the field of electron transfer pro- cesses has grown enormously, both in chemistry and biol- ogy.The development of the field, experimentally and theoretically, as well as its relation to the study of other kinds of chemical reactions, represents to us an intrigu- ing history, one in which many threads have been brought together.In this lecture, some history, recent trends, and my own involvement in this research are de- scribed.The early experiments in the electron transfer field were on "isotopic exchange reactions" (self-exchange reactions) and, later, "cross reactions." These experiments rejected two principal inAuences.One of these was the availability after the Second World War of many radioac- tive isotopes, which permitted the study of a large num- ber of isotopic exchange electron transfer reactions, such as Fe +Fe' ~Fe ++Pe* + Ce ++Ce*"+-+Ce ++Ce* +(2) available information.

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Higher Excited States of Polyatomic Molecules

1975-01-01

Melvin B. Robin

Activated electron transfer at zero reorganization energy induced by a fluctuating donor–acceptor coupling

2025-06-25

Stephanie Valianti , Spiros S. Skourtis | The Journal of Chemical Physics

We study analytically and numerically a rate model for donor-to-acceptor charge transfer in the case of a fluctuating donor–acceptor coupling and of zero reorganization energy. The model applies to situations … We study analytically and numerically a rate model for donor-to-acceptor charge transfer in the case of a fluctuating donor–acceptor coupling and of zero reorganization energy. The model applies to situations where the donor and acceptor reorganization energies are very low such that there is no polaron formation and the donor-to-acceptor transition arises purely from dynamic disorder in the coupling. We consider both quantum and classical limits for the reaction coordinate that modulates the coupling and describe the adiabaticity parameter for charge-transfer induced by coupling fluctuations, analogous to the Landau–Zener parameter used in the case of transfer induced by energy-level fluctuations. Our purpose is to explore the magnitudes of the charge-transfer rate for realistic parameter values, the transition from non-adiabatic to adiabatic transfer, and the behavior of the rate as a function of the donor–acceptor energy gap and temperature. We find that the coupling-fluctuation mechanism can lead to fast rates. Furthermore, the energy-gap and temperature dependencies can differ from Marcus theory describing polaron transfer. Therefore, these dependencies may be used to identify experimentally whether charge transfer is induced by coupling fluctuations.

Counterintuitive Photochemistry of an Isolated Acridinyl Radical: ConPET via Preassembly, Solvated Electrons, or a Long‐Lived Excited State?

2025-06-24

Samuel J. Horsewill , Katherine M. M. Sharrock , Péter Pál Fehér +3 more | Angewandte Chemie

Photoredox chemistry has seen a dramatic rise in popularity in recent years, but mechanistic understanding has persistently lagged behind reaction development itself. This is particularly true for the emerging area … Photoredox chemistry has seen a dramatic rise in popularity in recent years, but mechanistic understanding has persistently lagged behind reaction development itself. This is particularly true for the emerging area of consecutive photoinduced electron transfer (conPET), which has attracted both great interest due to its ability to activate inert substrates selectively and under mild conditions, and continuing controversy over its mechanistic feasibility. We describe herein the isolation of the key radical intermediate state of an acridinium‐based conPET catalyst and detailed investigations of its photochemistry by a suite of (photo)reactivity, photoluminescence, and transient absorption techniques, supported by computational studies. We observe strong wavelength and solvent dependencies in the reactivity profile, which correlate well with observations of a long‐lived, fluorescent excited state that would be compatible with diffusion‐limited reactivity. However, photoluminescence and transient absorption spectroscopies suggest that, counter‐intuitively, this state does not actually participate in reactivity. Instead, changes occur far faster than the diffusion limit, which provides strong, direct evidence for preassembly of the photocatalyst and substrate prior to photoexcitation. Further inspection also indicates parallel formation of solvated electrons, likely providing the major pathway under previously reported synthetic conditions, suggesting that otherwise competing rationales for conPET can in fact operate simultaneously.

Counterintuitive Photochemistry of an Isolated Acridinyl Radical: ConPET via Preassembly, Solvated Electrons, or a Long‐Lived Excited State?

2025-06-24

Samuel J. Horsewill , Katherine M. M. Sharrock , Péter Pál Fehér +3 more | Angewandte Chemie International Edition

Photoredox chemistry has seen a dramatic rise in popularity in recent years, but mechanistic understanding has persistently lagged behind reaction development itself. This is particularly true for the emerging area … Photoredox chemistry has seen a dramatic rise in popularity in recent years, but mechanistic understanding has persistently lagged behind reaction development itself. This is particularly true for the emerging area of consecutive photoinduced electron transfer (conPET), which has attracted both great interest due to its ability to activate inert substrates selectively and under mild conditions, and continuing controversy over its mechanistic feasibility. We describe herein the isolation of the key radical intermediate state of an acridinium-based conPET catalyst and detailed investigations of its photochemistry by a suite of (photo)reactivity, photoluminescence, and transient absorption techniques, supported by computational studies. We observe strong wavelength and solvent dependencies in the reactivity profile, which correlate well with observations of a long-lived, fluorescent excited state that would be compatible with diffusion-limited reactivity. However, photoluminescence and transient absorption spectroscopies suggest that, counter-intuitively, this state does not actually participate in reactivity. Instead, changes occur far faster than the diffusion limit, which provides strong, direct evidence for preassembly of the photocatalyst and substrate prior to photoexcitation. Further inspection also indicates parallel formation of solvated electrons, likely providing the major pathway under previously reported synthetic conditions, suggesting that otherwise competing rationales for conPET can in fact operate simultaneously.

Vibrational Spectroscopic and Quantum-Chemical Study of Indole–Ketone Hydrogen-Bonded Complexes

2025-06-21

Branislav Jović , Nataša Negru , Dušan Dimić +1 more | Molecules

This study investigates the structural and energetic properties of hydrogen-bonded complexes between indole and a range of aliphatic, cyclic, and aromatic ketones using a combined vibrational spectroscopic and quantum-chemical approach. … This study investigates the structural and energetic properties of hydrogen-bonded complexes between indole and a range of aliphatic, cyclic, and aromatic ketones using a combined vibrational spectroscopic and quantum-chemical approach. FTIR measurements in CCl4 revealed redshifts in the N-H stretching vibration of indole upon complexation, with formation constants (Ka) ranging from 0.3 to 6.6 M−1. Cyclohexanone displayed the strongest binding, while benzophenone exhibited the weakest interaction. Quantum-chemical calculations, employing CREST and MMFF94 conformational sampling, along with M06-2X/6-311++G(d,p) optimizations, confirmed the formation of hydrogen bonds and additional weak interactions that govern the stability of the complex. QTAIM analysis revealed moderate closed-shell hydrogen bonds with electron densities at the bond critical points (ρ) ranging from 0.010 to 0.019 a.u. and potential energy densities (V) from −18.4 to −36.4 kJ mol−1. Multivariate regression analysis established strong correlations (R2 = 0.928 and 0.957) between experimental binding constants and theoretical descriptors, including binding energy, NBO charge on oxygen atom, ionization potential, and electrophilicity index, highlighting the interplay between geometric, electronic, and global reactivity factors. This comprehensive study underlines the predictive power of spectroscopic and quantum descriptors for assessing hydrogen bonding in biologically relevant systems.

Photoluminescence Dependance of 2-Bromo-3-aminobenzo[de]anthracene-7-one on Solvent Polarity for Potential Applications in Color-Tunable Optoelectronics

2025-06-20

Emmanuel Karungani , Elena Kirilova , Lı̅ga Avotiņa +5 more | Molecules

The novel benzanthrone derivative, 2-bromo-3-aminobenzo[de]anthracene-7-one (2-Br-3-NH2BA), was synthesized and extensively characterized to investigate its photophysical behavior in various solvents. It was prepared through selective bromination of 3-aminobenzanthrone using N-bromosuccinimide in … The novel benzanthrone derivative, 2-bromo-3-aminobenzo[de]anthracene-7-one (2-Br-3-NH2BA), was synthesized and extensively characterized to investigate its photophysical behavior in various solvents. It was prepared through selective bromination of 3-aminobenzanthrone using N-bromosuccinimide in dimethylformamide at −20 °C. Featuring a donor–π–acceptor (D–π–A) structure, 2-Br-3-NH2BA exhibits pronounced solvatochromism due to the intramolecular charge transfer (ICT) between the amino donor and the carbonyl acceptor groups. Optical measurements conducted in eight solvents of varying polarity revealed a significant bathochromic shift in both absorption and fluorescence emission, with emission maxima red-shifting by over 110 nm from non-polar to polar environments. Corresponding reductions in the optical band gap energies, as calculated from Tauc plots, further support solvent-induced electronic state modulation. Additionally, quantum yield analysis showed higher fluorescence efficiency in non-polar solvents, while polar solvents induced twisted intramolecular charge transfer (TICT), leading to emission quenching. These findings demonstrate the sensitivity of 2-Br-3-NH2BA to environmental polarity, making it a promising candidate for color-tunable luminescent applications in optoelectronics and sensing. However, further studies in the solid state are required to validate its applicability in device architectures such as OLEDs.

Simulation of Pump–Push Molecular Dynamics in the Heptazine–H2O Complex

2025-06-20

Sebastian V. Pios , Maxim F. Gelin , Wolfgang Domcke +1 more | The Journal of Physical Chemistry Letters

Pump-push-probe spectroscopy was employed for the exploration of charge-separation processes in organic photovoltaic blends as well as for proton-coupled electron-transfer (PCET) reactions in hydrogen-bonded complexes of trianisole-heptazine with substituted phenols … Pump-push-probe spectroscopy was employed for the exploration of charge-separation processes in organic photovoltaic blends as well as for proton-coupled electron-transfer (PCET) reactions in hydrogen-bonded complexes of trianisole-heptazine with substituted phenols in organic solvents. In the present work, the electron and proton transfer dynamics driven by a femtosecond pump pulse and a time-delayed femtosecond push pulse has been studied with ab initio on-the-fly non-adiabatic trajectory calculations for the hydrogen-bonded heptazine-H2O complex. While the dynamics following the pump pulse is dominated by ultrafast radiationless energy relaxation to the long-lived lowest singlet excited state (S1) of the heptazine chromophore with only minor PCET reactivity, the re-excitation of the transient S1 population by the push pulse results in a much higher PCET reaction probability. These results illustrate that pump-push excitation has the potential to unravel the individual electron and proton transfer processes of PCET reactions on femtosecond time scales.

CIDNP study of photoinduced electron transfer in His-Glu-Tyr-Gly peptide and its conjugate His-Gln(BP)-Tyr-Gly

2025-06-20

Natalya N. Fishman , Kevin Herr , Olga B. Morozova +6 more | Scientific Reports

Abstract Photoinduced intramolecular electron transfer (ET) is essential for understanding charge transport in biological and synthetic systems. This study examines ET in peptide His-Glu-Tyr-Gly (1) and the conjugate His-Gln(BP)-Tyr-Gly (2) … Abstract Photoinduced intramolecular electron transfer (ET) is essential for understanding charge transport in biological and synthetic systems. This study examines ET in peptide His-Glu-Tyr-Gly (1) and the conjugate His-Gln(BP)-Tyr-Gly (2) with benzophenone (BP) as a photoactive electron acceptor and His or Tyr as donors. Time-resolved and field-dependent chemically induced dynamic nuclear polarization (CIDNP) techniques were employed to investigate ET mechanisms and kinetics. Peptide 1 with 3,3’,4,4’-tetracarboxy benzophenone as a photosensitizer initially forms two types of radical with radical center at either His or Tyr residue, the consequent intra- and intermolecular ET electron transfer from Tyr residue to the His radical takes place with rate constants k e(intra) =(1.5±0.5)×10 5 s − 1 and k e(inter) =(1.3±0.4)×10 7 M − 1 s − 1 at pH 8.8. Conjugate 2 forms two types of biradicals under irradiation: with radical centers at Tyr and BP across the entire pH range, and with radical centers at His and BP at slightly basic pH. Field-dependent CIDNP revealed nonzero electronic exchange interaction (2J ex = − 8.78 mT) at acidic pH, indicating proximity between BP and Tyr radicals. Low-field CIDNP spectra showed strong emissive polarization patterns, with pH-dependent exchange interaction and biradical geometry. Notably, no electron transfer from tyrosine to histidine radicals was observed in the conjugate 2, distinguishing its behavior from peptide 1.

Regulating ESIPT Behavior and Fluorescent Properties by Introducing -CN Group at Different Positions of BACN: A TD-DFT Study

2025-06-20

Jing Zhang , Hua Fang | Journal of Fluorescence

Tracking Photoinduced Charge Redistribution in a Cu(I) Diimine Donor–Bridge–Acceptor System with Time-Resolved Infrared Spectroscopy

2025-06-19

Sean A. Roget , Wade C. Henke , Maxwell Taub +5 more | Photochem

Understanding electron density migration along excited-state pathways in photochemical systems is critical for optimizing solar energy conversion processes. In this study, we investigate photoinduced electron transfer (PET) in a covalently … Understanding electron density migration along excited-state pathways in photochemical systems is critical for optimizing solar energy conversion processes. In this study, we investigate photoinduced electron transfer (PET) in a covalently linked donor–bridge–acceptor (D-B-A) system, where [Cu(I)-bis(1,10-phenanthroline)]+ acts as an electron donor, and anthraquinone, tethered to one of the phenanthroline ligands via a vibrationally active ethyne bridge, behaves as an electron acceptor. Visible transient absorption spectroscopy revealed the dynamic processes occurring in the excited state, including PET to the acceptor species. This was indicated by the spectral features of the anthraquinone radical anion that appeared on a timescale of 30 ps in polar solvents. Time-resolved infrared (TRIR) spectroscopy of the alkyne vibration (CC stretch) of the ethyne bridge provided insight into electronic structural changes in the metal-to-ligand charge transfer (MLCT) state and along the PET reaction coordinate. The observed spectral shift and enhanced transition dipole moment of the CC stretch demonstrated that there was already partial delocalization to the anthraquinone acceptor following MLCT excitation, verified by DFT calculations. An additional excited-state TRIR signal unrelated to the vibrational mode highlighted delocalization between the phenanthroline ligands in the MLCT state. This signal decayed and the CC stretch narrowed and shifted towards the ground-state frequency following PET, indicating a degree of localization onto the acceptor species. This study experimentally elucidates charge redistribution during PET in a Cu(I) diimine D-B-A system, yielding important information on the ligand design for optimizing PET reactions.

Impact of Aryl Extension on the Proton-Triggered Transition Switch in Azaheterocycle-Functionalized ESIPT Fluorophores

2025-06-18

Timothée Stoerkler , Théo Andris , Gilles Ulrich +3 more | Dyes and Pigments

Quantum Mechanical Approach to Kinetic Modeling of Singlet Oxygen Generation: A Case Study of Heavy-Atom-Free Photosensitizers

2025-06-18

Nisha Job , Kalishankar Bhattacharyya | The Journal of Physical Chemistry A

Singlet oxygen (1O2) generation involves an intermolecular energy transfer (EnT) process between a photosensitizer and molecular oxygen. In particular, evaluating the kinetics that govern singlet oxygen production remains a significant … Singlet oxygen (1O2) generation involves an intermolecular energy transfer (EnT) process between a photosensitizer and molecular oxygen. In particular, evaluating the kinetics that govern singlet oxygen production remains a significant challenge. In this work, we employ a simple computational protocol for kinetic calculations to estimate the EnT process. Here, we adapt the classical Marcus theory to determine the free energy barrier of the process and provide a qualitative performance analysis of the model in comparison to the experimental data for a series of organic chromophores. We also perform excited state analyses to understand the higher excited states and their relationship. This work offers a simple computational framework for straightforward calculations of the kinetics of singlet oxygen generation in molecular photosensitization.

Modulating Excited State Lifetimes in Cu(I) Complexes: The Role of Surface Binding Motifs

2025-06-18

Henry C. London , Jiaqi Chen , Emmanuel Adu Fosu +5 more | ACS Applied Energy Materials

Solvatochromic effects on anionic and protonated forms of methyl orange dye: An experimental and theoretical study

2025-06-16

R.T. Alves , Pâmela Santos Terceiro , Cid B. de Araújo +5 more | Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy

Vertical Excitation Energies of Organic Molecules Calculated by the MC23 Hybrid Meta On-Top Functional as Compared to Other Multireference Methods

2025-06-16

Aiswarya M. Parameswaran , Dayou Zhang , Donald G. Truhlar | The Journal of Physical Chemistry A

The success of multiconfiguration pair-density functional theory depends on the quality of the on-top functional. We have tested the recently published MC23 hybrid meta on-top pair-density functionals, three other on-top … The success of multiconfiguration pair-density functional theory depends on the quality of the on-top functional. We have tested the recently published MC23 hybrid meta on-top pair-density functionals, three other on-top functionals, CASPT2, and XMS-CASPT2 against the benchmark results of Loos et al. [J. Chem. Theory Comput. 2020, 16, 1711-1741] for 102 singlet-singlet and 65 singlet-triplet transition excitation energies of organic molecules with 4-6 nonhydrogenic atoms. We find that the tPBE, tPBE0, and MC23 on-top functionals all yield more accurate results on average than CASPT2 by factors of 1.3-1.7. The excitation energies are more accurate for singlet-triplet transitions than for singlet-singlet transitions, and they are more accurate with manually determined active spaces than with automatically generated ones.

Experimental and theoretical study of luminescent solar concentrators based on vertically stacked arrays of optical fibers

2025-06-12

José Maria Soares Barata , Jon Grandes , J. Arrué +5 more | Solar Energy Materials and Solar Cells

p-Cresol quantum-classical photodynamics, photostatic UV, IR and Raman spectra

2025-06-01

Vladimir A. Pomogaev , E. N. Bocharnikova , Павел В. Аврамов +1 more | Journal of Molecular Structure

Unveiling the Effect of Amino Substitution on Intramolecular Electron/Energy Transfer and Intersystem Crossing in the Naphthalimide-Pyrene Donor-Acceptor Dyads

2025-06-01

Muhammad Imran , Junpeng Deng , Zhaogang Nie +4 more | Dyes and Pigments

Solvent‐Dependent Excited‐State Dynamics of 1‐Aminoanthraquinone Revealed by Transient Absorption Spectroscopy

2025-06-01

Shuyun Qiao , Xiaosong Liu , Weilong Liu +1 more | ChemistrySelect

Abstract This study investigates hydrogen bonding and intramolecular charge transfer (ICT) dynamics in 1‐aminoanthraquinone (1‐NH₂‐AQ) using transient absorption spectroscopy and quantum chemical calculations. In acetone, excitation at 440 nm (absorption … Abstract This study investigates hydrogen bonding and intramolecular charge transfer (ICT) dynamics in 1‐aminoanthraquinone (1‐NH₂‐AQ) using transient absorption spectroscopy and quantum chemical calculations. In acetone, excitation at 440 nm (absorption peak: 503 nm) revealed a 23 nm red‐shift attributed to π→π* transitions, with excess energy of 2846 cm⁻¹ above the S ₀→ S ₁ transition. Analysis of N─H vibrational modes (3211/3312 cm⁻¹) and fluorescence‐absorption energy gaps (2550 cm⁻¹) demonstrated insufficient energy for intramolecular N─H⋯O═C hydrogen bond formation. Solute‐solvent hydrogen bonding was also precluded due to incompatible donor‐acceptor pairing between 1‐NH₂‐AQ and acetone. Quantum calculations showed highest occupied molecular orbital (HOMO) electron density localized on the amino group, while lowest unoccupied molecular orbital (LUMO) density was depleted there, confirming charge transfer character. In n ‐hexane, hydrogen bonding was prohibited by the solvent's nonpolar nature. Notably, a 90° amino group torsion in the S ₁ state facilitated ICT from the amino donor to anthraquinone acceptor, with acetone solutions showing a 454 ps fluorescence lifetime. In contrast, n ‐hexane induced complete fluorescence quenching due to ICT state destabilization. The torsional barrier extended ICT lifetimes beyond typical femtosecond timescales, highlighting the interplay between molecular conformation and charge transfer dynamics.

Elucidating the role of water-mediated hydrogen bonds in the ESIPT process of a reversible fluorescent probe: A TD-DFT investigation

2025-06-01

Yifu Zhang , Yihan Gao , Xiaonan Wang +3 more | Computational and Theoretical Chemistry

Scalable Perovskite Quantum Dot Glass Nanocomposites for High‐Efficiency Luminescent Solar Concentrators

2025-06-01

Emre İlter , Utku Ekim , Elshan Asadi +4 more | Advanced Functional Materials

Abstract Achieving 2050 climate targets requires scalable and efficient renewable energy solutions. Luminescent solar concentrators (LSCs) offer a promising approach for building‐integrated photovoltaics (BIPVs) by harvesting and guiding sunlight to … Abstract Achieving 2050 climate targets requires scalable and efficient renewable energy solutions. Luminescent solar concentrators (LSCs) offer a promising approach for building‐integrated photovoltaics (BIPVs) by harvesting and guiding sunlight to photovoltaic cells. While perovskite quantum dots (PQDs) are highly efficient luminophores for LSCs, their instability in polymeric and liquid matrices hinders real‐world deployment. Glass nanocomposites (GNCs) provide a durable alternative, yet scalability and efficiency trade‐offs remain underexplored. This study investigates CsPbBr 3 PQD GNC LSCs across various sizes, addressing this gap. Standardized 2.5 mm‐thick samples with surface areas from 1 × 1 to 5 × 5 cm 2 are fabricated and Monte Carlo simulations extend predictions up to 1 m 2 . A record‐high photoluminescence quantum yield (PLQY) of 97% is achieved for a reference sample, highlighting exceptional emission efficiency. The highest power conversion efficiency (PCE) of 3.17% is recorded for small‐scale devices, declining to 0.38% at 5 × 5 cm 2 . Simulations predict retention of 0.30% for 1 m 2 LSCs, demonstrating scalability. Efficiency losses plateau beyond a critical size, enabling upscaling without major performance degradation. These findings establish PQD GNC LSCs as durable, scalable, and high‐performance materials for next‐generation BIPVs, supporting net‐zero energy goals.

Investigations on the Multiple Excited State Intramolecular Proton Transfer Processes and Twisted Intramolecular Charge Transfer/Twisted Intramolecular Charge Shuttle States of a Fluorescence Sensor Based on Schiff Base

2025-05-30

Bingqing Sun , Haoyang Song , Yi Nan +2 more | The Journal of Physical Chemistry A

Excited state intramolecular proton transfer (ESIPT), twisted intramolecular charge transfer (TICT), and twisted intramolecular charge shuttle (TICS) play fundamental roles in the photophysical process of dyes and sensors. In this … Excited state intramolecular proton transfer (ESIPT), twisted intramolecular charge transfer (TICT), and twisted intramolecular charge shuttle (TICS) play fundamental roles in the photophysical process of dyes and sensors. In this paper, four ESIPT processes, two TICT states, and two TICS states are observed on the excited state potential energy surface of a turn-on sensor based on Schiff base with the aid of DFT and TDDFT. All these TICT/TICS states are dark states and responsible for the weak fluorescence of the sensor. Interestingly, these TICT and TICS states are generated under intrinsically different mechanisms. The isomerization of the C═N bond of the Schiff base leads to two TICS states, while the isomerization of the adjacent C-C bond leads to two TICT states. Transition states, energy barriers, and rate constants for all of these dynamic processes are obtained to clarify their relationship and evaluate their chances of happening. It is demonstrated that among the four dark states, the TICT-1 state is the global minimum with the lowest energy barrier and highest reaction rate. This state is the major factor that induces fluorescence quenching of the sensor. Besides, the Zn2+ sensing mechanism is clarified after getting a clear picture of the photophysical process.

Photophysical Properties of Coumarin-annulated Thiazole Derivatives: A Combined Experimental and Computational Study

2025-05-29

Sintu Ganai , Deblina Mallick , Hamid Shaikh +3 more | Journal of Molecular Structure

Comment on “Influence of Solvents and Halogenation on ESIPT of Benzimidazole Derivatives for Designing Turn-on Fluorescence Probes”

2025-05-28

Daniela Antonová , Liudmil Antonov | ACS Omega

In the paper, listed in the title, unproper conformation analysis of a series of potentially tautomeric benzimidazole derivatives has been performed by Rivelino, Canuto, and coauthors (ACS Omega2024, 9 (20), … In the paper, listed in the title, unproper conformation analysis of a series of potentially tautomeric benzimidazole derivatives has been performed by Rivelino, Canuto, and coauthors (ACS Omega2024, 9 (20), 22102). They described existence of only 3 conformers of the enol tautomer and one for the keto form for each of the studied compounds. Actually, we found more than 50 additional conformers for the tautomers of the unsubstituted compound (H). When one bears in mind the structural similarity with the rest of the compounds, the situation with them should be the same. More importantly, Rivelino, Canuto, and coauthors discuss in detail the properties of the conformers that are not the most stable ones, which strongly limits the practical value of the published massive data output. Due to the improperly done theoretical work along with the lack of understanding of the existing experimental data and principles of excited state intramolecular proton transfer (ESIPT), the suggested photocycle in the Br substituted compound (Br) is doubtful.

Theoretical Unveiling Photoinduced Excited State Behaviors for BP(OH)2DCEt2 Fluorophore: Effects of Solvent Polarity

2025-05-28

Zhi‐Xun Shen , Chang Liu , Jinfeng Zhao +1 more | The Journal of Physical Chemistry A

In this work, the influence of solvent polarities on the excited-state intramolecular proton transfer (ESIPT) process of BP(OH)2DCEt2 fluorophore has been systematically investigated in three solvents with distinct polarities (acetonitrile, … In this work, the influence of solvent polarities on the excited-state intramolecular proton transfer (ESIPT) process of BP(OH)2DCEt2 fluorophore has been systematically investigated in three solvents with distinct polarities (acetonitrile, chloroform, and cyclohexane) through DFT and TDDFT methodologies. We mainly focus on elucidating the related excited-state double proton transfer (ESDPT) mechanism in BP(OH)2DCEt2. We analyze geometric configurations, infrared (IR) vibrational spectra, and core-valence bifurcation (CVB) indexes to verify the enhancement of the dual hydrogen bonds in the excited state. Meanwhile, we detected the HOMO and LUMO orbitals to investigate the effects of charge redistribution on the ESIPT/ESDPT process. The reactional potential energy surfaces (PESs) are scanned and transition state (TS) forms are searched to testify the stepwise ESDPT mechanism for BP(OH)2DCEt2 systems in three solvents. We also propose that the increase of solvent polarity can promote the occurrence of the step-by-step ESDPT reaction processes for the BP(OH)2DCEt2 system based on the calculated S1-state potential energy barriers in the surrounding environment.

Reply to the Comment on “Influence of Solvents and Halogenation on ESIPT of Benzimidazole Derivatives for Designing Turn-on Fluorescence Probes”

2025-05-27

Murillo H. Queiroz , Joel Leitão Nascimento , Tiago Vinicius Alves +2 more

Quantitative comparison of time-dependent-density-functional-theory–calculated high-harmonic yields in ring-shaped organic molecules

2025-05-27

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