1
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Gary S, Woolley J, Goia S, Bloom S. Unlocking flavin photoacid catalysis through electrophotochemistry. Chem Sci 2024; 15:11444-11454. [PMID: 39055006 PMCID: PMC11268482 DOI: 10.1039/d4sc03054k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Accepted: 06/17/2024] [Indexed: 07/27/2024] Open
Abstract
Molecular flavins are one of the most versatile photocatalysts. They can coordinate single and multiple electron transfer processes, gift hydrogen atoms, form reversible covalent linkages that support group transfer mechanisms, and impart photonic energy to ground state molecules, priming them for downstream reactions. But one mechanism that has not featured extensively is the ability of flavins to act as photoacids. Herein, we disclose our proof-of-concept studies showing that electrophotochemistry can transform fully oxidized flavin quinones to super-oxidized flavinium photoacids that successfully guide proton-transfer and deliver acid-catalyzed products. We also show that these species can adopt a second mechanism wherein they react with water to release hydroxyl radicals that facilitate hydrogen-atom abstraction and sp3C-H functionalization protocols. Together, this unprecedented bimodal reactivity enables electro-generated flavinium salts to affect synthetic chemistries previously unknown to flavins, greatly expanding their versatility as catalysts.
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Affiliation(s)
- Samuel Gary
- Department of Medicinal Chemistry, University of Kansas Lawrence 66045 USA
| | - Jack Woolley
- Department of Physics, University of Warwick Coventry CV4 7AL UK
| | - Sofia Goia
- Forensic Centre for Digital Scanning and 3D Printing, WMG, University of Warwick Coventry CV4 7AL UK
| | - Steven Bloom
- Department of Medicinal Chemistry, University of Kansas Lawrence 66045 USA
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2
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Aaboub T, Boukhriss A, Gmouh S, Werts MHV. Determination of photoluminescence quantum yields in dilute solution using non-monochromatic excitation light. Photochem Photobiol Sci 2023; 22:465-475. [PMID: 36269517 DOI: 10.1007/s43630-022-00325-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 10/13/2022] [Indexed: 11/26/2022]
Abstract
The photoluminescence (PL) quantum yields (QYs) of fluorophores in dilute solutions can be determined fluorimetrically according to the comparative method employing standards of known PLQY. This method has recently been demonstrated to become more robust when the absorption of the excitation light and the PL emission are measured simultaneously using a transmitted light detector integrated in the fluorimeter. Herein, aided by fiber-coupled spectroscopic equipment and computerized data processing, we elaborate on this method by measuring the full corrected intensity spectrum of the excitation light transmitted through the sample. This further releases constraints on the monochromatic character of the excitation light and enables the use of broad-band excitation sources such as light-emitting diodes (LEDs). Furthermore, the protocol includes measurements at increasing dye concentration, rigorously verifying the required proportionality between absorbed and emitted light intensities. The PLQYs of solutions of fluorophores determined using the new method are in close agreement with published values.
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Affiliation(s)
- Tarik Aaboub
- Ecole Normale Supérieure de Rennes, SATIE, Campus de Ker Lann, 35170, Bruz, France
- Univ Rennes, CNRS, SATIE-UMR8029, 35000, Rennes, France
- Univ Hassan II de Casablanca, LIMAT, 20000, Casablanca, Morocco
- Ecole Supérieure des Industries du Textile et de l'habillement, REMTEX, Casablanca, Morocco
| | - Aicha Boukhriss
- Ecole Supérieure des Industries du Textile et de l'habillement, REMTEX, Casablanca, Morocco
| | - Said Gmouh
- Univ Hassan II de Casablanca, LIMAT, 20000, Casablanca, Morocco
| | - Martinus H V Werts
- Ecole Normale Supérieure de Rennes, SATIE, Campus de Ker Lann, 35170, Bruz, France.
- Univ Rennes, CNRS, SATIE-UMR8029, 35000, Rennes, France.
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3
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Knorr J, Sülzner N, Geissler B, Spies C, Grandjean A, Kutta RJ, Jung G, Nuernberger P. Ultrafast transient absorption and solvation of a super-photoacid in acetoneous environments. PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES : OFFICIAL JOURNAL OF THE EUROPEAN PHOTOCHEMISTRY ASSOCIATION AND THE EUROPEAN SOCIETY FOR PHOTOBIOLOGY 2022; 21:2179-2192. [PMID: 36178669 DOI: 10.1007/s43630-022-00287-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 08/08/2022] [Indexed: 12/13/2022]
Abstract
The phenomenon of photoacidity, i.e., an increase in acidity by several orders of magnitude upon electronic excitation, is frequently encountered in aromatic alcohols capable of transferring a proton to a suitable acceptor. A promising new class of neutral super-photoacids based on pyranine derivatives has been shown to exhibit pronounced solvatochromic effects. To disclose the underlying mechanisms contributing to excited-state proton transfer (ESPT) and the temporal characteristics of solvation and ESPT, we scrutinize the associated ultrafast dynamics of the strongest photoacid of this class, namely tris(1,1,1,3,3,3-hexafluoropropan-2-yl)8-hydroxypyrene-1,3,6-trisulfonate, in acetoneous environment, thereby finding experimental evidence for ESPT even under these adverse conditions for proton transfer. Juxtaposing results from time-correlated single-photon counting and femtosecond transient absorption measurements combined with a complete decomposition of all signal components, i.e., absorption of ground and excited states as well as stimulated emission, we disclose dynamics of solvation, rotational diffusion, and radiative relaxation processes in acetone and identify the relevant steps of ESPT along with the associated time scales.
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Affiliation(s)
- Johannes Knorr
- Physikalische Chemie II, Ruhr-Universität Bochum, 44780, Bochum, Germany.,Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Paul-Gordan-Straße 6, 91052, Erlangen, Germany
| | - Niklas Sülzner
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780, Bochum, Germany.,Physikalische Chemie II, Ruhr-Universität Bochum, 44780, Bochum, Germany
| | - Bastian Geissler
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, Universitätsstraße 31, 95053, Regensburg, Germany.,Physikalische Chemie II, Ruhr-Universität Bochum, 44780, Bochum, Germany
| | - Christian Spies
- Biophysikalische Chemie, Universität des Saarlandes, 66123, Saarbrücken, Germany.,Physikalische Chemie II, Ruhr-Universität Bochum, 44780, Bochum, Germany
| | - Alexander Grandjean
- Biophysikalische Chemie, Universität des Saarlandes, 66123, Saarbrücken, Germany
| | - Roger Jan Kutta
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, Universitätsstraße 31, 95053, Regensburg, Germany
| | - Gregor Jung
- Biophysikalische Chemie, Universität des Saarlandes, 66123, Saarbrücken, Germany
| | - Patrick Nuernberger
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, Universitätsstraße 31, 95053, Regensburg, Germany. .,Physikalische Chemie II, Ruhr-Universität Bochum, 44780, Bochum, Germany.
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4
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Nandi R, Amdursky N. The Dual Use of the Pyranine (HPTS) Fluorescent Probe: A Ground-State pH Indicator and an Excited-State Proton Transfer Probe. Acc Chem Res 2022; 55:2728-2739. [PMID: 36053265 PMCID: PMC9494743 DOI: 10.1021/acs.accounts.2c00458] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Indexed: 01/19/2023]
Abstract
Molecular fluorescent probes are an essential experimental tool in many fields, ranging from biology to chemistry and materials science, to study the localization and other environmental properties surrounding the fluorescent probe. Thousands of different molecular fluorescent probes can be grouped into different families according to their photophysical properties. This Account focuses on a unique class of fluorescent probes that distinguishes itself from all other probes. This class is termed photoacids, which are molecules exhibiting a change in their acid-base transition between the ground and excited states, resulting in a large change in their pKa values between these two states, which is thermodynamically described using the Förster cycle. While there are many different photoacids, we focus only on pyranine, which is the most used photoacid, with pKa values of ∼7.4 and ∼0.4 for its ground and excited states, respectively. Such a difference between the pKa values is the basis for the dual use of the pyranine fluorescent probe. Furthermore, the protonated and deprotonated states of pyranine absorb and emit at different wavelengths, making it easy to focus on a specific state. Pyranine has been used for decades as a fluorescent pH indicator for physiological pH values, which is based on its acid-base equilibrium in the ground state. While the unique excited-state proton transfer (ESPT) properties of photoacids have been explored for more than a half-century, it is only recently that photoacids and especially pyranine have been used as fluorescent probes for the local environment of the probe, especially the hydration layer surrounding it and related proton diffusion properties. Such use of photoacids is based on their capability for ESPT from the photoacid to a nearby proton acceptor, which is usually, but not necessarily, water. In this Account, we detail the photophysical properties of pyranine, distinguishing between the processes in the ground state and the ones in the excited state. We further review the different utilization of pyranine for probing different properties of the environment. Our main perspective is on the emerging use of the ESPT process for deciphering the hydration layer around the probe and other parameters related to proton diffusion taking place while the molecule is in the excited state, focusing primarily on bio-related materials. Special attention is given to how to perform the experiments and, most importantly, how to interpret their results. We also briefly discuss the breadth of possibilities in making pyranine derivatives and the use of pyranine for controlling dynamic reactions.
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Affiliation(s)
- Ramesh Nandi
- Schulich Faculty of Chemistry, Technion − Israel Institute of Technology, Haifa 3200003, Israel
| | - Nadav Amdursky
- Schulich Faculty of Chemistry, Technion − Israel Institute of Technology, Haifa 3200003, Israel
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5
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Sülzner N, Hättig C. Theoretical Study on the Photoacidity of Hydroxypyrene Derivatives in DMSO Using ADC(2) and CC2. J Phys Chem A 2022; 126:5911-5923. [PMID: 36037028 DOI: 10.1021/acs.jpca.2c04436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This work applies the thermodynamic Förster cycle to theoretically investigate the pKa*, i.e., excited-state pKa values of pyranine-derived superphotoacids developed by Jung and co-workers. The latter photoacids are strong enough to transfer a proton to the aprotic solvent dimethyl sulfoxide (DMSO). The Förster cycle provides access to pKa* via the ground-state pKa and the electronic excitation energies. We use the conductor-like screening model for real solvents (COSMO-RS) to compute the ground-state pKa and the correlated wavefunction-based methods ADC(2) and CC2 with the continuum solvation model COSMO to calculate the pKa change upon excitation. A comparison of the calculated UV/Vis absorption and fluorescence emission energies to the experimental results leads us to infer that this approach allows for a proper description of the electronic excitations. In particular, implicit solvation by means of the COSMO model appears to be sufficient for the treatment of these photoacids in DMSO. The calculations confirm the presumption that a charge redistribution from the hydroxy group to the aromatic ring and the electron-withdrawing substituents is the origin of photoacidity for these photoacids. Moreover, the calculations with the continuum solvation model predict that the pKa jump upon excitation decreases with increasing solvent polarity, as rationalized based on the Förster cycle.
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Affiliation(s)
- Niklas Sülzner
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Christof Hättig
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
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6
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Sülzner N, Geissler B, Grandjean A, Jung G, Nuernberger P. Excited‐state Proton Transfer Dynamics of a Super‐Photoacid in Acetone‐Water Mixtures. CHEMPHOTOCHEM 2022. [DOI: 10.1002/cptc.202200041] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Niklas Sülzner
- Ruhr-Universitat Bochum Lehrstuhl für Theoretische Chemie GERMANY
| | - Bastian Geissler
- Universitat Regensburg Institut für Physikalische und Theoretische Chemie GERMANY
| | | | - Gregor Jung
- Universitat des Saarlandes Biophysikalische Chemie GERMANY
| | - Patrick Nuernberger
- Universitat Regensburg Institut für Physikalische und Theoretische Chemie Universitätsstraße 31 93053 Regensburg GERMANY
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7
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Bitsch M, Boehm AK, Grandjean A, Jung G, Gallei M. Embedding Photoacids into Polymer Opal Structures: Synergistic Effects on Optical and Stimuli-Responsive Features. Molecules 2021; 26:7350. [PMID: 34885932 PMCID: PMC8659009 DOI: 10.3390/molecules26237350] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 11/26/2021] [Accepted: 11/30/2021] [Indexed: 11/23/2022] Open
Abstract
Opal films with their vivid structural colors represent a field of tremendous interest and obtained materials offer the possibility for many applications, such as optical sensors or anti-counterfeiting materials. A convenient method for the generation of opal structures relies on the tailored design of core-interlayer-shell (CIS) particles. Within the present study, elastomeric opal films were combined with stimuli-responsive photoacids to further influence the optical properties of structurally colored materials. Starting from cross-linked polystyrene (PS) core particles featuring a hydroxy-rich and polar soft shell, opal films were prepared by application of the melt-shear organization technique. The photoacid tris(2,2,2-trifluoroethyl) 8-hydroxypyrene-1,3,6-trisulfonate (TFEHTS) could be conveniently incorporated during freeze-drying the particle dispersion and prior to the melt-shear organization. Furthermore, the polar opal matrix featuring hydroxylic moieties enabled excited-state proton transfer (ESPT), which is proved by spectroscopic evaluation. Finally, the influence of the photoacid on the optical properties of the 3-dimensional colloidal crystals were investigated within different experimental conditions. The angle dependence of the emission spectra unambiguously shows the selective suppression of the photoacid's fluorescence in its deprotonated state.
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Affiliation(s)
- Martin Bitsch
- Polymer Chemistry, Saarland University, Campus Saarbrücken C4 2, 66123 Saarbrücken, Germany; (M.B.); (A.K.B.)
| | - Anna Katharina Boehm
- Polymer Chemistry, Saarland University, Campus Saarbrücken C4 2, 66123 Saarbrücken, Germany; (M.B.); (A.K.B.)
| | - Alexander Grandjean
- Biophysical Chemistry, Saarland University, Campus B2 2, 66123 Saarbrücken, Germany;
| | - Gregor Jung
- Biophysical Chemistry, Saarland University, Campus B2 2, 66123 Saarbrücken, Germany;
| | - Markus Gallei
- Polymer Chemistry, Saarland University, Campus Saarbrücken C4 2, 66123 Saarbrücken, Germany; (M.B.); (A.K.B.)
- Saarene-Saarland Center for Energy Materials and Sustainability, Campus C4 2, 66123 Saarbrücken, Germany
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8
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Capistran BA, Yuwono SH, Moemeni M, Maity S, Vahdani A, Borhan B, Jackson JE, Piecuch P, Dantus M, Blanchard GJ. Intramolecular Relaxation Dynamics Mediated by Solvent-Solute Interactions of Substituted Fluorene Derivatives. Solute Structural Dependence. J Phys Chem B 2021; 125:12486-12499. [PMID: 34752096 DOI: 10.1021/acs.jpcb.1c06475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Several fluorene derivatives exhibit excited-state reactivity and relaxation dynamics that remain to be understood fully. We report here the spectral relaxation dynamics of two fluorene derivatives to evaluate the role of structural modification in the intramolecular relaxation dynamics and intermolecular interactions that characterize this family of chromophores. We have examined the time-resolved spectral relaxation dynamics of two compounds, NCy-FR0 and MK-FR0, in protic and aprotic solvents using steady-state and time-resolved emission spectroscopy and quantum chemical computations. Both compounds exhibit spectral relaxation characteristics similar to those seen in FR0, indicating that hydrogen bonding interactions between the chromophore and solvent protons play a significant role in determining the relaxation pathways available to three excited electronic states.
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Affiliation(s)
- Briana A Capistran
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Stephen H Yuwono
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Mehdi Moemeni
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Soham Maity
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Aria Vahdani
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Babak Borhan
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - James E Jackson
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Piotr Piecuch
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States.,Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, United States
| | - Marcos Dantus
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States.,Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, United States
| | - G J Blanchard
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
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9
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Capistran BA, Yuwono SH, Moemeni M, Maity S, Vahdani A, Borhan B, Jackson JE, Piecuch P, Dantus M, Blanchard GJ. Excited-State Dynamics of a Substituted Fluorene Derivative. The Central Role of Hydrogen Bonding Interactions with the Solvent. J Phys Chem B 2021; 125:12242-12253. [PMID: 34726920 PMCID: PMC9254887 DOI: 10.1021/acs.jpcb.1c06474] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Substituted fluorene structures have demonstrated unusual photochemical properties. Previous reports on the substituted fluorene Schiff base FR0-SB demonstrated super photobase behavior with a ΔpKb of ∼14 upon photoexcitation. In an effort to understand the basis for this unusual behavior, we have examined the electronic structure and relaxation dynamics of the structural precursor of FR0-SB, the aldehyde FR0, in protic and aprotic solvents using time-resolved fluorescence spectroscopy and quantum chemical calculations. The calculations show three excited singlet states in relatively close energetic proximity. The spectroscopic data are consistent with relaxation dynamics from these electronic states that depend on the presence and concentration of solvent hydroxyl functionality. These results underscore the central role of solvent hydrogen bonding to the FR0 aldehyde oxygen in mediating the relaxation dynamics within this molecule.
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Affiliation(s)
- Briana A Capistran
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Stephen H Yuwono
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Mehdi Moemeni
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Soham Maity
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Aria Vahdani
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Babak Borhan
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - James E Jackson
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Piotr Piecuch
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, United States
| | - Marcos Dantus
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, United States
| | - G J Blanchard
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
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10
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Burnstine‐Townley A, Mondal S, Agam Y, Nandi R, Amdursky N. Light‐Modulated Cationic and Anionic Transport across Protein Biopolymers**. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202111024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Alex Burnstine‐Townley
- Schulich Faculty of Chemistry Technion—Israel Institute of Technology Haifa 3200003 Israel
| | - Somen Mondal
- Schulich Faculty of Chemistry Technion—Israel Institute of Technology Haifa 3200003 Israel
| | - Yuval Agam
- Schulich Faculty of Chemistry Technion—Israel Institute of Technology Haifa 3200003 Israel
| | - Ramesh Nandi
- Schulich Faculty of Chemistry Technion—Israel Institute of Technology Haifa 3200003 Israel
| | - Nadav Amdursky
- Schulich Faculty of Chemistry Technion—Israel Institute of Technology Haifa 3200003 Israel
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11
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Burnstine-Townley A, Mondal S, Agam Y, Nandi R, Amdursky N. Light-Modulated Cationic and Anionic Transport across Protein Biopolymers*. Angew Chem Int Ed Engl 2021; 60:24676-24685. [PMID: 34492153 DOI: 10.1002/anie.202111024] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Indexed: 12/13/2022]
Abstract
Light is a convenient source of energy and the heart of light-harvesting natural systems and devices. Here, we show light-modulation of both the chemical nature and ionic charge carrier concentration within a protein-based biopolymer that was covalently functionalized with photoacids or photobases. We explore the capability of the biopolymer-tethered photoacids and photobases to undergo excited-state proton transfer and capture, respectively. Electrical measurements show that both the photoacid- and photobase-functionalized biopolymers exhibit an impressive light-modulated increase in ionic conductivity. Whereas cationic protons are the charge carriers for the photoacid-functionalized biopolymer, water-derived anionic hydroxides are the suggested charge carriers for the photobase-functionalized biopolymer. Our work introduces a versatile toolbox to photomodulate both protons and hydroxides as charge carriers in polymers, which can be of interest for a variety of applications.
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Affiliation(s)
- Alex Burnstine-Townley
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa, 3200003, Israel
| | - Somen Mondal
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa, 3200003, Israel
| | - Yuval Agam
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa, 3200003, Israel
| | - Ramesh Nandi
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa, 3200003, Israel
| | - Nadav Amdursky
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa, 3200003, Israel
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12
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Grandjean A, Pérez Lustres JL, Jung G. Solvent‐Controlled Intermolecular Proton‐Transfer Follows an Irreversible Eigen‐Weller Model from fs to ns. CHEMPHOTOCHEM 2021. [DOI: 10.1002/cptc.202100177] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Alexander Grandjean
- Biophysikalische Chemie Universität des Saarlandes FR Chemie, Gebäude B2 2, Postfach 151150 D-66041 Saarbrücken Germany
| | - J. Luis Pérez Lustres
- Current Address: Fachbereich Physik Freie Universität Berlin Arnimallee 14 14195 Berlin Germany
- Experimental work conducted at former affiliation Physikalisch Chemisches Institut Universität Heidelberg Im Neuenheimer Feld 229 D-69120 Heidelberg Germany
| | - Gregor Jung
- Biophysikalische Chemie Universität des Saarlandes FR Chemie, Gebäude B2 2, Postfach 151150 D-66041 Saarbrücken Germany
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13
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Klaus M, Zurek PJ, Kaminski TS, Pushpanath A, Neufeld K, Hollfelder F. Ultrahigh-Throughput Detection of Enzymatic Alcohol Dehydrogenase Activity in Microfluidic Droplets with a Direct Fluorogenic Assay. Chembiochem 2021; 22:3292-3299. [PMID: 34643305 PMCID: PMC9291573 DOI: 10.1002/cbic.202100322] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 09/13/2021] [Indexed: 12/02/2022]
Abstract
The exploration of large DNA libraries of metagenomic or synthetic origin is greatly facilitated by ultrahigh‐throughput assays that use monodisperse water‐in‐oil emulsion droplets as sequestered reaction compartments. Millions of samples can be generated and analysed in microfluidic devices at kHz speeds, requiring only micrograms of reagents. The scope of this powerful platform for the discovery of new sequence space is, however, hampered by the limited availability of assay substrates, restricting the functions and reaction types that can be investigated. Here, we broaden the scope of detectable biochemical transformations in droplet microfluidics by introducing the first fluorogenic assay for alcohol dehydrogenases (ADHs) in this format. We have synthesized substrates that release a pyranine fluorophore (8‐hydroxy‐1,3,6‐pyrenetrisulfonic acid, HPTS) when enzymatic turnover occurs. Pyranine is well retained in droplets for >6 weeks (i. e. 14‐times longer than fluorescein), avoiding product leakage and ensuring excellent assay sensitivity. Product concentrations as low as 100 nM were successfully detected, corresponding to less than one turnover per enzyme molecule on average. The potential of our substrate design was demonstrated by efficient recovery of a bona fide ADH with an >800‐fold enrichment. The repertoire of droplet screening is enlarged by this sensitive and direct fluorogenic assay to identify dehydrogenases for biocatalytic applications.
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Affiliation(s)
- Miriam Klaus
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, CB2 1GA, Cambridge, UK.,Current address: ICB Nuvisan GmbH, Müllerstraße 178, 13353, Berlin, Germany
| | - Paul Jannis Zurek
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, CB2 1GA, Cambridge, UK.,Johnson Matthey Plc, 260 Cambridge Science Park, CB4 0WE, Cambridge, UK.,Current address: BioNTech Cell & Gene Therapies GmbH, An der Goldgrube 12, 55131, Mainz, Germany
| | - Tomasz S Kaminski
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, CB2 1GA, Cambridge, UK.,Current address: Department of Environmental Microbiology and Biotechnology, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland
| | - Ahir Pushpanath
- Johnson Matthey Plc, 260 Cambridge Science Park, CB4 0WE, Cambridge, UK
| | - Katharina Neufeld
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, CB2 1GA, Cambridge, UK.,Johnson Matthey Plc, 260 Cambridge Science Park, CB4 0WE, Cambridge, UK.,Current address: Janssen Pharmaceutica, Turnhoutseweg 30, 2340, Beerse, Belgium
| | - Florian Hollfelder
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, CB2 1GA, Cambridge, UK
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14
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Abstract
Living systems use catalysis to achieve chemical transformations to comply with their needs in terms of energy and building blocks. The pH is a powerful means to regulate such processes, which also influences synthetic systems. In fact, the pH sensitivity of artificial photocatalysts, such as bismuth vanadate, bears the strong potential of flexibly influencing both the motion pattern and the speed of catalytic microswimmers, but it has rarely been investigated to date. In this work, we first present a comprehensive view of the motion behavior of differently shaped bismuth vanadate microswimmers, discuss influences, such as shape, pH, and conductivity of the solutions, and find that the motion pattern of the swimmers switches between upright and horizontal at their point of zero charge. We then apply an immobilizable hydroxypyrene derivative to our substrates to locally influence the pH of the solution by excited-state proton transfer. We find that the motion pattern of our swimmers is strongly influenced by this functionalization and a third motion mode, called tumbling, is introduced. Taking other effects, such as an increased surface roughness of the modified substrates, into account, we critically discuss possible future developments.
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15
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Grandjean A, Pérez Lustres JL, Muth S, Maus D, Jung G. Steady-State Spectroscopy to Single Out the Contact Ion Pair in Excited-State Proton Transfer. J Phys Chem Lett 2021; 12:1683-1689. [PMID: 33560847 DOI: 10.1021/acs.jpclett.0c03593] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Despite the outstanding relevance of proton transfer reactions, investigations of the solvent dependence on the elementary step are scarce. We present here a probe system of a pyrene-based photoacid and a phosphine oxide, which forms stable hydrogen-bonded complexes in aprotic solvents of a broad polarity range. By using a photoacid, an excited-state proton transfer (ESPT) along the hydrogen bond can be triggered by a photon and observed via fluorescence spectroscopy. Two emission bands could be identified and assigned to the complexed photoacid (CPX) and the hydrogen-bonded ion pair (HBIP) by a solvatochromism analysis based on the Lippert-Mataga model. The latter indicates that the difference in the change of the permanent dipole moment of the two species upon excitation is ∼3 D. This implies a displacement of the acidic hydrogen by ∼65 pm, which is in quantitative agreement with a change of the hydrogen bond configuration from O-H···O to -O···H-O+.
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Affiliation(s)
- Alexander Grandjean
- Universität des Saarlandes, Biophysikalische Chemie, Campus, Geb. B2.2, D-66123 Saarbrücken, Germany
| | - J Luis Pérez Lustres
- Universität Heidelberg, Physikalisch Chemisches Institut, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany
| | - Stephan Muth
- Universität des Saarlandes, Biophysikalische Chemie, Campus, Geb. B2.2, D-66123 Saarbrücken, Germany
| | - Daniel Maus
- Universität des Saarlandes, Biophysikalische Chemie, Campus, Geb. B2.2, D-66123 Saarbrücken, Germany
| | - Gregor Jung
- Universität des Saarlandes, Biophysikalische Chemie, Campus, Geb. B2.2, D-66123 Saarbrücken, Germany
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16
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Sittig M, Tom JC, Elter JK, Schacher FH, Dietzek B. Quinoline Photobasicity: Investigation within Water-Soluble Light-Responsive Copolymers. Chemistry 2021; 27:1072-1079. [PMID: 32986286 PMCID: PMC7839697 DOI: 10.1002/chem.202003815] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 09/14/2020] [Indexed: 01/13/2023]
Abstract
Quinoline photobases exhibit a distinctly higher pKa in their electronically excited state than in the ground state, thereby enabling light-controlled proton transfer reactions, for example, in molecular catalysis. The absorption of UV light translates to a pKa jump of approximately 10 units, as established for small-molecule photobases. This contribution presents the first synthesis of quinoline-based polymeric photobases prepared by reversible addition-fragmentation chain-transfer (RAFT) polymerization. The integration of quinolines as photobase chromophores within copolymers offers new possibilities for light-triggered proton transfer in nanostructured materials, that is, in nanoparticles, at surfaces, membranes and interfaces. To exploit the light-triggered reactivity of photobases within such materials, we first investigated how the ground- and excited-state properties of the quinoline unit changes upon polymer integration. To address this matter, we combined absorption and emission spectroscopy with time-resolved transient-absorption studies to reveal photoinduced proton-transfer dynamics in various solvents. The results yield important insights into the thermodynamic and kinetic properties of these polymeric quinoline photobases.
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Affiliation(s)
- Maria Sittig
- Department of Functional InterfacesLeibniz Institute of Photonic Technology JenaAlbert-Einstein-Strasse 907745JenaGermany
- Institute of Physical Chemistry and Abbe Center of PhotonicsFriedrich-Schiller-University JenaHelmholtzweg 407743JenaGermany
- Jena Center for Soft Matter (JCSM)Friedrich Schiller University JenaPhilosophenweg 707743JenaGermany
| | - Jessica C. Tom
- Institute of Organic Chemistry and Macromolecular Chemistry (IOMC)Friedrich Schiller University JenaHumboldtstrasse 1007743JenaGermany
- Jena Center for Soft Matter (JCSM)Friedrich Schiller University JenaPhilosophenweg 707743JenaGermany
| | - Johanna K. Elter
- Institute of Organic Chemistry and Macromolecular Chemistry (IOMC)Friedrich Schiller University JenaHumboldtstrasse 1007743JenaGermany
- Jena Center for Soft Matter (JCSM)Friedrich Schiller University JenaPhilosophenweg 707743JenaGermany
| | - Felix H. Schacher
- Institute of Organic Chemistry and Macromolecular Chemistry (IOMC)Friedrich Schiller University JenaHumboldtstrasse 1007743JenaGermany
- Jena Center for Soft Matter (JCSM)Friedrich Schiller University JenaPhilosophenweg 707743JenaGermany
| | - Benjamin Dietzek
- Department of Functional InterfacesLeibniz Institute of Photonic Technology JenaAlbert-Einstein-Strasse 907745JenaGermany
- Institute of Physical Chemistry and Abbe Center of PhotonicsFriedrich-Schiller-University JenaHelmholtzweg 407743JenaGermany
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17
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Lee C, Chung S, Song H, Rhee YM, Lee E, Joo T. Excited State Proton Transfer of Quinone Cyanine 9: Implications on the Origin of Super‐Photoacidity. CHEMPHOTOCHEM 2020. [DOI: 10.1002/cptc.202000254] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Changmin Lee
- Department of Chemistry Pohang University of Science and Technology (POSTECH) Pohang 37673 Republic of Korea
| | - Seyoung Chung
- Department of Chemistry Pohang University of Science and Technology (POSTECH) Pohang 37673 Republic of Korea
| | - Hayoung Song
- Department of Chemistry Pohang University of Science and Technology (POSTECH) Pohang 37673 Republic of Korea
| | - Young Min Rhee
- Department of Chemistry Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea
| | - Eunsung Lee
- Department of Chemistry Pohang University of Science and Technology (POSTECH) Pohang 37673 Republic of Korea
| | - Taiha Joo
- Department of Chemistry Pohang University of Science and Technology (POSTECH) Pohang 37673 Republic of Korea
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18
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Menges JA, Grandjean A, Clasen A, Jung G. Kinetics of Palladium(0)‐Allyl Interactions in the Tsuji‐Trost Reaction, derived from Single‐Molecule Fluorescence Microscopy. ChemCatChem 2020. [DOI: 10.1002/cctc.202000032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Johannes A. Menges
- Department of Biophysical Chemistry Saarland University Building B2 2 66123 Saarbrücken Germany
| | - Alexander Grandjean
- Department of Biophysical Chemistry Saarland University Building B2 2 66123 Saarbrücken Germany
| | - Anne Clasen
- Department of Biophysical Chemistry Saarland University Building B2 2 66123 Saarbrücken Germany
| | - Gregor Jung
- Department of Biophysical Chemistry Saarland University Building B2 2 66123 Saarbrücken Germany
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19
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Fang C, Tang L, Chen C. Unveiling coupled electronic and vibrational motions of chromophores in condensed phases. J Chem Phys 2019; 151:200901. [PMID: 31779327 DOI: 10.1063/1.5128388] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The quest for capturing molecular movies of functional systems has motivated scientists and engineers for decades. A fundamental understanding of electronic and nuclear motions, two principal components of the molecular Schrödinger equation, has the potential to enable the de novo rational design for targeted functionalities of molecular machines. We discuss the development and application of a relatively new structural dynamics technique, femtosecond stimulated Raman spectroscopy with broadly tunable laser pulses from the UV to near-IR region, in tracking the coupled electronic and vibrational motions of organic chromophores in solution and protein environments. Such light-sensitive moieties hold broad interest and significance in gaining fundamental knowledge about the intramolecular and intermolecular Hamiltonian and developing effective strategies to control macroscopic properties. Inspired by recent experimental and theoretical advances, we focus on the in situ characterization and spectroscopy-guided tuning of photoacidity, excited state proton transfer pathways, emission color, and internal conversion via a conical intersection.
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Affiliation(s)
- Chong Fang
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - Longteng Tang
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - Cheng Chen
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
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20
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Clasen A, Wenderoth S, Tavernaro I, Fleddermann J, Kraegeloh A, Jung G. Kinetic and spectroscopic responses of pH-sensitive nanoparticles: influence of the silica matrix. RSC Adv 2019; 9:35695-35705. [PMID: 35528098 PMCID: PMC9074731 DOI: 10.1039/c9ra06047b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Accepted: 10/04/2019] [Indexed: 11/21/2022] Open
Abstract
Intracellular pH sensing with fluorescent nanoparticles is an emerging topic as pH plays several roles in physiology and pathologic processes. Here, nanoparticle-sized pH sensors (diameter far below 50 nm) for fluorescence imaging have been described. Consequently, a fluorescent derivative of pH-sensitive hydroxypyrene with pK a = 6.1 was synthesized and subsequently embedded in core and core-shell silica nanoparticles via a modified Stöber process. The detailed fluorescence spectroscopic characterization of the produced nanoparticles was carried out for retrieving information about the environment within the nanoparticle core. Several steady-state and time-resolved fluorescence spectroscopic methods hint to the screening of the probe molecule from the solvent, but it sustained interactions with hydrogen bonds similar to that of water. The incorporation of the indicator dye in the water-rich silica matrix neither changes the acidity constant nor dramatically slows down the protonation kinetics. However, cladding by another SiO2 shell leads to the partial substitution of water and decelerating the response of the probe molecule toward pH. The sensor is capable of monitoring pH changes in a physiological range by using ratiometric fluorescence excitation with λ ex = 405 nm and λ ex = 488 nm, as confirmed by the confocal fluorescence imaging of intracellular nanoparticle uptake.
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Affiliation(s)
- Anne Clasen
- Biophysical Chemistry, Saarland University Campus B2 2 66123 Saarbrücken Germany
| | - Sarah Wenderoth
- INM - Leibniz-Institute for New Materials Campus D2 2 66123 Saarbrücken Germany
| | - Isabella Tavernaro
- INM - Leibniz-Institute for New Materials Campus D2 2 66123 Saarbrücken Germany
| | - Jana Fleddermann
- INM - Leibniz-Institute for New Materials Campus D2 2 66123 Saarbrücken Germany
| | - Annette Kraegeloh
- INM - Leibniz-Institute for New Materials Campus D2 2 66123 Saarbrücken Germany
| | - Gregor Jung
- Biophysical Chemistry, Saarland University Campus B2 2 66123 Saarbrücken Germany
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21
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Lahiri J, Moemeni M, Kline J, Borhan B, Magoulas I, Yuwono SH, Piecuch P, Jackson JE, Dantus M, Blanchard GJ. Proton Abstraction Mediates Interactions between the Super Photobase FR0-SB and Surrounding Alcohol Solvent. J Phys Chem B 2019; 123:8448-8456. [PMID: 31532676 DOI: 10.1021/acs.jpcb.9b06580] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report on the motional and proton transfer dynamics of the super photobase FR0-SB in the series of normal alcohols C1 (methanol) through C8 (n-octanol) and ethylene glycol. Steady-state and time-resolved fluorescence data reveal that the proton abstraction dynamics of excited FR0-SB depend on the identity of the solvent and that the transfer of the proton from solvent to FR0-SB*, forming FR0-HSB+*, fundamentally alters the nature of interactions between the excited molecule and its surroundings. In its unprotonated state, solvent interactions with FR0-SB* are consistent with slip limit behavior, and in its protonated form, intermolecular interactions are consistent with a much stronger interaction of FR0-HSB+* with the deprotonated solvent RO-. We understand the excited-state population dynamics in the context of a kinetic model involving a transition state wherein FR0-HSB+* is still bound to the negatively charged alkoxide, prior to solvation of the two charged species. Data acquired in ethylene glycol confirm the hypothesis that the rotational diffusion dynamics of FR0-SB* are largely mediated by solvent viscosity while proton transfer dynamics are mediated by the lifetime of the transition state. Taken collectively, our results demonstrate that FR0-SB* extracts solvent protons efficiently and in a predictable manner, consistent with a ca. 3-fold increase in dipole moment upon photoexcitation as determined by ab initio calculations based on the equation-of-motion coupled-cluster theory.
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22
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Lennox JC, Danilov EO, Dempsey JL. Delayed photoacidity produced through the triplet-triplet annihilation of a neutral pyranine derivative. Phys Chem Chem Phys 2019; 21:16353-16358. [PMID: 31309943 DOI: 10.1039/c9cp02929j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A novel pyranine derivative, EtHPTA-OH, was synthesized via the substitution of the anionic sulfonate groups with neutral diethylsulfonamide groups. The photophysical and photochemical properties of EtHPTA-OH were studied using photoluminescence quenching and transient absorption spectroscopy. The singlet state of EtHPTA-OH was found to be highly photoacidic (pKa* = 8.74 in acetonitrile). A series of aniline and pyridine bases were used to investigate excited-state proton transfer (ESPT) from singlet EtHPTA-OH, and rate constants for singlet quenching via ESPT were determined (kq = 5.18 × 109 to 1.05 × 1010 M-1 s-1). EtHPTA-OH was also found to exhibit a long-lived triplet state which reacts through a triplet-triplet annihilation (TTA) process to reform singlet EtHPTA-OH on timescales of up to 80 μs. Detection of ESPT photoproducts on timescales comparable to that of TTA singlet regeneration provides strong evidence for photoacidic behavior stemming from the regenerated singlet EtHPTA-OH.
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Affiliation(s)
- J Christian Lennox
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina, USA27599.
| | - Evgeny O Danilov
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina, USA27695
| | - Jillian L Dempsey
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina, USA27599.
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23
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Roy S, Ardo S, Furche F. 5-Methoxyquinoline Photobasicity Is Mediated by Water Oxidation. J Phys Chem A 2019; 123:6645-6651. [DOI: 10.1021/acs.jpca.9b05341] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Saswata Roy
- Department of Chemistry, University of California, Irvine, 1102 Natural Sciences II, Irvine, California 92697-2025, United States
| | - Shane Ardo
- Department of Chemistry, University of California, Irvine, 1102 Natural Sciences II, Irvine, California 92697-2025, United States
| | - Filipp Furche
- Department of Chemistry, University of California, Irvine, 1102 Natural Sciences II, Irvine, California 92697-2025, United States
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24
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Mena LD, Vera DMA, Baumgartner MT, Jimenez LB. Adiabatic deprotonation as an important competing pathway to ESIPT in photoacidic 2-phenylphenols. Phys Chem Chem Phys 2019; 21:12231-12240. [PMID: 31134981 DOI: 10.1039/c9cp02028d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
ESIPT (Excited State Intramolecular Proton Transfer) to C atom in 2-phenylphenol is known to be an intrinsically inefficient process. However, to the best of our knowledge, a structure-ESIPT efficiency relationship has not been elucidated yet. Here, we show that there exists a competitive interplay between photoacidity and ESIPT efficiency for the 2-phenylphenol system. The attachment of electron withdrawing groups to the phenol moiety promotes adiabatic deprotonation in the excited state and diminishes the charge transfer character of the excitations, and both these factors contribute in decreasing the ESIPT reaction yield. On the other hand, unfavorable conformational distribution in the ground state also appears as another important aspect responsible for the low ESIPT extent of 2-phenylphenol. A new derivative bearing electron donating, bulky substituents at ortho and para positions of the phenol ring shows an outstanding ESIPT performance, which demonstrates that the efficiency of the process can be significantly enhanced by modifying the substitution pattern. We anticipate that our results will help to guide the molecular designing of new compounds with high ESIPT efficiency.
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Affiliation(s)
- Leandro D Mena
- INFIQC, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba Ciudad Universitaria, Córdoba, Argentina.
| | - D M A Vera
- QUIAMM-INBIOTEC-Departamento de Química, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina
| | - Maria T Baumgartner
- INFIQC, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba Ciudad Universitaria, Córdoba, Argentina.
| | - Liliana B Jimenez
- INFIQC, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba Ciudad Universitaria, Córdoba, Argentina.
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25
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Interfacial and Nanoconfinement Effects Decrease the Excited-State Acidity of Polymer-Bound Photoacids. Chem 2019. [DOI: 10.1016/j.chempr.2019.04.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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26
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Chen C, Zhu L, Baranov MS, Tang L, Baleeva NS, Smirnov AY, Yampolsky IV, Solntsev KM, Fang C. Photoinduced Proton Transfer of GFP-Inspired Fluorescent Superphotoacids: Principles and Design. J Phys Chem B 2019; 123:3804-3821. [DOI: 10.1021/acs.jpcb.9b03201] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Cheng Chen
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, United States
| | - Liangdong Zhu
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, United States
| | - Mikhail S. Baranov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia
- Pirogov Russian National Research Medical University, Ostrovitianov 1, Moscow 117997, Russia
| | - Longteng Tang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, United States
| | - Nadezhda S. Baleeva
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia
| | - Alexander Yu. Smirnov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia
| | - Ilia V. Yampolsky
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia
- Pirogov Russian National Research Medical University, Ostrovitianov 1, Moscow 117997, Russia
| | - Kyril M. Solntsev
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates
| | - Chong Fang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, United States
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27
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Menges JA, Clasen A, Jourdain M, Beckmann J, Hoffmann C, König J, Jung G. Surface Preparation for Single-Molecule Chemistry. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:2506-2516. [PMID: 30664351 DOI: 10.1021/acs.langmuir.8b03603] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Immobilization procedures, intended to enable prolonged observation of single molecules by fluorescence microscopy, may generate heterogeneous microenvironments, thus inducing heterogeneity in the molecular behavior. On that account, we propose a straightforward surface preparation procedure for studying chemical reactions on the single-molecule level. Sensor fluorophores were developed, which exhibit dual-emissive characteristics in a homogeneously catalyzed showcase reaction. These molecules undergo a shift of fluorescence wavelength of about 100 nm upon Pd(0)-induced deallylation in the Tsuji-Trost reaction, allowing for separate visualization of the starting material and product. Whereas a simultaneous immobilization of dye and inert silane leads to strongly polydisperse reaction kinetics, a consecutive immobilization routine with deposition of dye molecules as the last step provides substrates underlying the kinetics of ensemble experiments. Also, the found kinetics are unaffected by the chemical variation of inert silanes, nearly uniform, and therefore well reproducible. Additional parameters like photostability, signal-to-noise ratio, dye-molecule density, and spatial distribution of dye molecules are, as well, hardly affected by surface modification in the successive immobilization scheme.
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Affiliation(s)
- Johannes A Menges
- Biophysical Chemistry , Saarland University , Building B2.2 , 66123 Saarbrücken , Germany
| | - Anne Clasen
- Biophysical Chemistry , Saarland University , Building B2.2 , 66123 Saarbrücken , Germany
| | - Matthias Jourdain
- Biophysical Chemistry , Saarland University , Building B2.2 , 66123 Saarbrücken , Germany
| | - Julian Beckmann
- Biophysical Chemistry , Saarland University , Building B2.2 , 66123 Saarbrücken , Germany
| | - Caroline Hoffmann
- Biophysical Chemistry , Saarland University , Building B2.2 , 66123 Saarbrücken , Germany
| | - Julien König
- Biophysical Chemistry , Saarland University , Building B2.2 , 66123 Saarbrücken , Germany
| | - Gregor Jung
- Biophysical Chemistry , Saarland University , Building B2.2 , 66123 Saarbrücken , Germany
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28
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Exploring fast proton transfer events associated with lateral proton diffusion on the surface of membranes. Proc Natl Acad Sci U S A 2019; 116:2443-2451. [PMID: 30679274 DOI: 10.1073/pnas.1812351116] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Proton diffusion (PD) across biological membranes is a fundamental process in many biological systems, and much experimental and theoretical effort has been employed for deciphering it. Here, we report on a spectroscopic probe, which can be tightly tethered to the membrane, for following fast (nanosecond) proton transfer events on the surface of membranes. Our probe is composed of a photoacid that serves as our light-induced proton source for the initiation of the PD process. We use our probe to follow PD, and its pH dependence, on the surface of lipid vesicles composed of a zwitterionic headgroup, a negative headgroup, a headgroup that is composed only from the negative phosphate group, or a positive headgroup without the phosphate group. We reveal that the PD kinetic parameters are highly sensitive to the nature of the lipid headgroup, ranging from a fast lateral diffusion at some membranes to the escape of protons from surface to bulk (and vice versa) at others. By referring to existing theoretical models for membrane PD, we found that while some of our results confirm the quasi-equilibrium model, other results are in line with the nonequilibrium model.
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29
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Maus D, Grandjean A, Jung G. Toward Magic Photoacids: Proton Transfer in Concentrated Sulfuric Acid. J Phys Chem A 2018; 122:9025-9030. [PMID: 30359029 DOI: 10.1021/acs.jpca.8b09974] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Photoacids are the most convenient way to deliver protons on demand. So far, their photoacidity allows for studying excited-state proton transfer (ESPT) only to protic or strongly basic solvent molecules. The strongest superphotoacids known so far exhibit excited-state lifetimes of their conjugate base on the order of 100 ps before recapturing the proton again. Here, we describe how we developed a new aminopyrene-based superphotoacid with an excited-state lifetime of its conjugate base of several nanoseconds. It will be shown by fluorescence titration and via Förster cycle that the excited-state acidity is as high as concentrated sulfuric acid and thus exceeding any previous photoacidity by several orders of magnitude. Its outstanding chemical stability and fluorescent properties make it suitable for time-resolved proton-transfer studies in concentrated mineral acids and organic solvents of low basicity.
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Affiliation(s)
- Daniel Maus
- Biophysical Chemistry , Saarland University , Campus B2 2, 66123 Saarbruecken , Germany
| | - Alexander Grandjean
- Biophysical Chemistry , Saarland University , Campus B2 2, 66123 Saarbruecken , Germany
| | - Gregor Jung
- Biophysical Chemistry , Saarland University , Campus B2 2, 66123 Saarbruecken , Germany
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30
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Alazaly AM, Amer AS, Fathi AM, Abdel-Shafi AA. Photoacids as singlet oxygen photosensitizers: Direct determination of the excited state acidity by time-resolved spectroscopy. J Photochem Photobiol A Chem 2018. [DOI: 10.1016/j.jphotochem.2018.07.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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31
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Joung JF, Kim S, Park S. Cationic Effect on the Equilibria and Kinetics of the Excited-State Proton Transfer Reaction of a Photoacid in Aqueous Solutions. J Phys Chem B 2018; 122:5087-5093. [DOI: 10.1021/acs.jpcb.8b00588] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
| | - Sangin Kim
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Sungnam Park
- Department of Chemistry, Korea University, Seoul 02841, Korea
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32
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Wang YF, Cheng YC. Molecular electrostatic potential on the proton-donating atom as a theoretical descriptor of excited state acidity. Phys Chem Chem Phys 2018; 20:4351-4359. [PMID: 29367985 DOI: 10.1039/c7cp01948c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Organic photoacids with enhanced acidities in the excited states have received much attention both experimentally and theoretically because of their applications in nanotechnology and chemistry. In this study, we investigate the excited-state acidities of 14 hydroxyl-substituted aromatic photoacids, with a focus on using theoretical molecular electrostatic potential (MEP) as an effective descriptor for photoacidity. For these model photoacids, we applied time-dependent density functional theory (TDDFT) at the ωB97X-D/6-31G(d) level to calculate the molecular electrostatic potentials of S1 excited states and show that the molecular electrostatic potential on the proton-donating atom exhibits a linear relationship with the observed excited-state logarithmic acid dissociation constant (pKa*). As a result, the molecular electrostatic potential on the proton-donating atom can be used to estimate the pKa* values based on simple TDDFT calculations for a broad range of hydroxyl-substituted aromatic compounds. Furthermore, we explore the molecular electrostatic potential as a quantum descriptor for the photoacidities of cationic photoacids, and show a universal behavior of the pKa*-MEP dependence. We also investigate the solvent effects on the photoacidity using TDDFT calculations with implicit solvent models. Finally, we discuss the physical insights implicated by the molecular electrostatic potential as a successful measure for photoacidity on the mechanism of proton transfer in the molecular excited states. This pKa* descriptor provides an effective means to quantify the tendency of excited-state proton transfer with a relatively small computational cost, which is expected to be useful in the design of functional photoacids.
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Affiliation(s)
- Yu-Fu Wang
- Department of Chemistry, National Taiwan University, Taipei City 106, Taiwan.
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Kumpulainen T, Lang B, Rosspeintner A, Vauthey E. Ultrafast Elementary Photochemical Processes of Organic Molecules in Liquid Solution. Chem Rev 2016; 117:10826-10939. [DOI: 10.1021/acs.chemrev.6b00491] [Citation(s) in RCA: 249] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Tatu Kumpulainen
- Department of Physical Chemistry,
Sciences II, University of Geneva, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - Bernhard Lang
- Department of Physical Chemistry,
Sciences II, University of Geneva, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - Arnulf Rosspeintner
- Department of Physical Chemistry,
Sciences II, University of Geneva, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - Eric Vauthey
- Department of Physical Chemistry,
Sciences II, University of Geneva, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
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Schäfer K, Ihmels H, Bohne C, Valente KP, Granzhan A. Hydroxybenzo[b]quinolizinium Ions: Water-Soluble and Solvatochromic Photoacids. J Org Chem 2016; 81:10942-10954. [PMID: 27755869 DOI: 10.1021/acs.joc.6b01991] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
It is shown by photometric and fluorimetric analysis, along with supporting theoretical calculations, that hydroxy-substituted benzo[b]quinolizinium derivatives display the characteristic features of organic photoacids. Specifically, the experimental and theoretical results confirm the strong acidity of these compounds in the excited state (pKa* < 0). The combination of the prototropic properties of 8- and 9-hydroxybenzo[b]quinolizinium with the particular solvent-solute interactions of the excited acid and its conjugate base leads to a pronounced fluorosolvatochromism, hence the emission maxima shift from 468 nm (8-hydroxybenzo[b]quinolizinium) or 460 nm (9-hydroxybenzo[b]quinolizinium) in CH3CN to 507 and 553 nm in DMF, respectively. This novel type of photoacid represents several features that may be used for applications as water-soluble fluorescent probes or as a source for the photoinduced supply of acidity.
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Affiliation(s)
- Katy Schäfer
- Department of Chemistry - Biology and Center of Micro and Nanochemistry and Engineering, University of Siegen , Adolf-Reichwein-Strasse 2, D-57068 Siegen, Germany
| | - Heiko Ihmels
- Department of Chemistry - Biology and Center of Micro and Nanochemistry and Engineering, University of Siegen , Adolf-Reichwein-Strasse 2, D-57068 Siegen, Germany
| | - Cornelia Bohne
- Department of Chemistry, University of Victoria , PO Box 1700 STN CSC, Victoria, BC Canada V8W 2Y2
| | - Karolina Papera Valente
- Department of Chemistry, University of Victoria , PO Box 1700 STN CSC, Victoria, BC Canada V8W 2Y2
| | - Anton Granzhan
- Institut Curie, PSL Research University and Université Paris Sud, Université Paris-Saclay, CNRS UMR9187, INSERM U1196 , F-91405 Orsay, France
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Vester M, Grueter A, Finkler B, Becker R, Jung G. Biexponential photon antibunching: recombination kinetics within the Förster-cycle in DMSO. Phys Chem Chem Phys 2016; 18:10281-8. [PMID: 27020473 DOI: 10.1039/c6cp00718j] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Time-resolved experiments with pulsed-laser excitation are the standard approach to map the dynamic evolution of excited states, but ground-state kinetics remain hidden or require pump-dump-probe schemes. Here, we exploit the so-called photon antibunching, a purely quantum-optical effect related to single molecule detection to assess the rate constants for a chemical reaction in the electronic ground state. The measurement of the second-order correlation function g((2)), i.e. the evaluation of inter-photon arrival times, is applied to the reprotonation in a Förster-cycle. We find that the antibunching of three different photoacids in the aprotic solvent DMSO significantly differs from the behavior in water. The longer decay constant of the biexponential antibunching tl is linked to the bimolecular reprotonation kinetics of the fully separated ion-pair, independent of the acidic additives. The value of the corresponding bimolecular rate constant, kp = 4 × 10(9) M(-1) s(-1), indicates diffusion-controlled reprotonation. The analysis of tl also allows for the extraction of the separation yield of proton and the conjugated base after excitation and amounts to approximately 15%. The shorter time component ts is connected to the decay of the solvent-separated ion pair. The associated time constant for geminate reprotonation is approximately 3 ± 1 ns in agreement with independent tcspc experiments. These experiments verify that the transfer of quantum-optical experiments to problems in chemistry enables mechanistic conclusions which are hardly accessible by other methods.
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Affiliation(s)
- Michael Vester
- Biophysical Chemistry, Saarland University, 66123 Saarbrücken, Germany.
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Finkler B, Riemann I, Vester M, Grüter A, Stracke F, Jung G. Monomolecular pyrenol-derivatives as multi-emissive probes for orthogonal reactivities. Photochem Photobiol Sci 2016; 15:1544-1557. [DOI: 10.1039/c6pp00290k] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Chameleons in a test tube: up to four easily distinguishable emission colors result from conversion by two hydrolytic enzymes at opposite reaction sites.
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Affiliation(s)
- Björn Finkler
- Biophysical Chemistry
- Saarland University
- 66123 Saarbrücken
- Germany
| | | | - Michael Vester
- Biophysical Chemistry
- Saarland University
- 66123 Saarbrücken
- Germany
| | - Andreas Grüter
- Biophysical Chemistry
- Saarland University
- 66123 Saarbrücken
- Germany
| | | | - Gregor Jung
- Biophysical Chemistry
- Saarland University
- 66123 Saarbrücken
- Germany
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Huynh AM, Menges J, Vester M, Dier T, Huch V, Volmer DA, Jung G. Monofluorination and Trifluoromethylation of BODIPY Dyes for Prolonged Single-Molecule Detection. Chemphyschem 2015; 17:433-42. [DOI: 10.1002/cphc.201500869] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Revised: 11/25/2015] [Indexed: 12/27/2022]
Affiliation(s)
- Anh Minh Huynh
- Biophysical Chemistry; Saarland University, Campus Building B22; 66123 Saarbrücken Germany
| | - Johannes Menges
- Biophysical Chemistry; Saarland University, Campus Building B22; 66123 Saarbrücken Germany
| | - Michael Vester
- Biophysical Chemistry; Saarland University, Campus Building B22; 66123 Saarbrücken Germany
| | - Tobias Dier
- Institute of Bioanalytical Chemistry; Saarland University; 66123 Saarbrücken Germany
| | - Volker Huch
- Inorganic and General Chemistry; Saarland University; 66123 Saarbrücken Germany
| | - Dietrich A. Volmer
- Institute of Bioanalytical Chemistry; Saarland University; 66123 Saarbrücken Germany
| | - Gregor Jung
- Biophysical Chemistry; Saarland University, Campus Building B22; 66123 Saarbrücken Germany
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Kumpulainen T, Bakker BH, Brouwer AM. Complexes of a naphthalimide photoacid with organic bases, and their excited-state dynamics in polar aprotic organic solvents. Phys Chem Chem Phys 2015. [PMID: 26204802 DOI: 10.1039/c5cp02556g] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Complex formation and intermolecular excited-state proton transfer (ESPT) between a dihydroxy-1,8-naphthalimide photoacid and organic bases are investigated in polar aprotic solvents. First, quantum chemical calculations are used to explore the acid-base and spectroscopic properties and to identify energetically favorable complexes. The two hydroxyl groups of the photoacid enable stepwise formation of 1 : 1 and 1 : 2 complexes. Weak bases exhibit only hydrogen-bonding interactions whereas strong bases are able to deprotonate one of the hydroxyl groups resulting in strong negative cooperativity (K1≫ 4K2) in the formation of the 1 : 2 complex. Time-resolved fluorescence studies of the complexes provide strong indications of a three-step dissociation process. The species involved in the model are: a hydrogen-bonded complex, a hydrogen-bonded ion pair, a solvent separated ion pair, and a free ion pair.
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Affiliation(s)
- Tatu Kumpulainen
- Van't Hoff Institute for Molecular Sciences, Faculty of Science, University of Amsterdam, P. O. Box 94157, 1090 GD Amsterdam, The Netherlands.
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Spies C, Shomer S, Finkler B, Pines D, Pines E, Jung G, Huppert D. Solvent dependence of excited-state proton transfer from pyranine-derived photoacids. Phys Chem Chem Phys 2015; 16:9104-14. [PMID: 24700348 DOI: 10.1039/c3cp55292f] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Steady-state and time-resolved techniques were employed to study the excited-state proton-transfer (ESPT) rate of two newly synthesized 8-hydroxy-1,3,6-pyrenetrisulfonate (pyranine, HPTS) derived photoacids in three protic solvents, water, methanol and ethanol. The ESPT rate constant k(PT) of tris(1,1,1,3,3,3-hexafluoropropan-2-yl)-8-hydroxypyrene-1,3,6-trisulfonate, 1a, whose pK(a)* ~ -4, in water, methanol and ethanol is 3 × 10(11) s(-1), 8 × 10(9) s(-1) and 5 × 10(9) s(-1) respectively. (8-Hydroxy-N1,N3,N6-tris(2-hydroxyethyl)-N1,N3,N6-trimethylpyrene-1,3,6 trisulfonamide, 1b) is a weaker acid than 1a but still a strong photoacid with pK(a)* ~ -1 and the ESPT rate in water, methanol and ethanol is 7 × 10(10) s(-1), 4 × 10(8) s(-1) and 2 × 10(8) s(-1). We qualitatively explain our kinetic results by a Marcus-like free-energy correlation which was found to have a general form suitable for describing proton transfer reactions in both the proton-adiabatic and the proton-non-adiabatic limits.
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Affiliation(s)
- Christian Spies
- Biophysical Chemistry, Saarland University, Campus, Building B2 2, D-66123 Saarbrücken, Germany.
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Abstract
The direct observation of chemical reactions on the single-molecule level is an ultimate goal in single-molecule chemistry, which also includes kinetic analyses. To analyze the lifetime of reaction intermediates, very sophisticated excitation schemes are often required. Here we focus on the kinetic analysis of the ground-state proton transfer within the photocycle of a photoacid. In detail, we demonstrate the determination of the bimolecular rate constant of this process with nanosecond resolution. The procedure relies on the exploration of a purely quantum-optical effect, namely, photon antibunching, and thus on evaluating interphoton arrival times to extract the reaction rate constant.
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Affiliation(s)
- Michael Vester
- †Biophysikalische Chemie, Universität des Saarlandes, Campus B2.2, 66123 Saarbrücken, Germany
| | - Tobias Staut
- †Biophysikalische Chemie, Universität des Saarlandes, Campus B2.2, 66123 Saarbrücken, Germany
| | - Jörg Enderlein
- ‡III. Physikalisches Institut für Biophysik und Komplexe Systeme, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Gregor Jung
- †Biophysikalische Chemie, Universität des Saarlandes, Campus B2.2, 66123 Saarbrücken, Germany
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Simkovitch R, Shomer S, Gepshtein R, Huppert D. How Fast Can a Proton-Transfer Reaction Be beyond the Solvent-Control Limit? J Phys Chem B 2014; 119:2253-62. [DOI: 10.1021/jp506011e] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Ron Simkovitch
- Raymond
and Beverly Sackler
Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Shay Shomer
- Raymond
and Beverly Sackler
Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Rinat Gepshtein
- Raymond
and Beverly Sackler
Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Dan Huppert
- Raymond
and Beverly Sackler
Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
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