1
|
Bhide R, Phun GS, Ardo S. Elementary Reaction Steps That Precede or Follow a Unimolecular Reaction Step Can Obfuscate Interpretation of the Driving-Force Dependence to Its Rate Constant. J Phys Chem A 2024; 128:4177-4188. [PMID: 38752741 DOI: 10.1021/acs.jpca.3c08228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
Assessing the validity of a driving-force-dependent kinetic theory for a unimolecular elementary reaction step is difficult when the observed reaction rate is strongly influenced by properties of the preceding or following elementary reaction step. A well-known example occurs for bimolecular reactions with weak orbital overlap, such as outer-sphere electron transfer, where bimolecular collisional encounters that precede a fast unimolecular electron-transfer step can limit the observed rate. A lesser-appreciated example occurs for bimolecular reactions with stronger orbital overlap, including many proton-transfer reactions, where equilibration of an endergonic unimolecular proton-transfer step results in a relatively small concentration of reaction products, thus slowing the rate of the following step such that it becomes rate limiting. Incomplete consideration of these points has led to discrepancies in interpretation of data from the literature. Our reanalysis of these data suggests that proton-transfer elementary reaction steps have a nonzero intrinsic free energy barrier, implying, in the parlance of Marcus theory, that there is non-negligible nuclear reorganization. Outcomes from our analyses are generalizable to inner-sphere electron-transfer reactions such as those involved in (photo)electrochemical fuel-forming reactions.
Collapse
Affiliation(s)
- Rohit Bhide
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
| | - Gabriel S Phun
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
| | - Shane Ardo
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
- Department of Chemical & Biomolecular Engineering, University of California Irvine, Irvine, California 92697, United States
- Department of Materials Science & Engineering, University of California Irvine, Irvine, California 92697, United States
| |
Collapse
|
2
|
Jang T, Lee S, Pang Y. Anomalous proton transfer of a photoacid HPTS in nonaqueous reverse micelles. Phys Chem Chem Phys 2024; 26:11283-11294. [PMID: 38456549 DOI: 10.1039/d3cp05710k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
The proton transfer reaction is one of the fundamental chemical reactions where the reaction dynamics strongly depend on solvent properties such as acidity or basicity. A photoacid 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS) shows a sharp decrease of pKa (7.7 → 0.5) upon photoexcitation, and the excited-state proton transfer (ESPT) occurs with ultrafast time constants of 2.5 and 89 ps in bulk aqueous solution. However, the two-step proton transfers via the contact ion pair formation and the proton diffusion are strongly limited inside the nanopools of reverse micelles (RMs). The confinement in small RMs strongly impeded the proton transfer reactions. In this work, we report the ESPT of HPTS confined in methanol-in-oil RMs by steady-state and time-resolved electronic spectroscopy. Interestingly, HPTS shows substantial deprotonation in the excited state only in small RMs, while the ESPT of HPTS does not occur in bulk methanol solution due to the low basicity of aliphatic alcohols. The kinetic analysis of time-resolved fluorescence and transient absorption measurements will compare the proton transfer dynamics of HPTS in the water-in-oil and methanol-in-oil RMs. The ESPT of photoacids, especially in the nonaqueous RMs, can be crucial in understanding many important chemical reactions involving proton transfer in the confined environments of cells and membranes.
Collapse
Affiliation(s)
- Taehyung Jang
- Department of Chemistry, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, Republic of Korea.
| | - Sebok Lee
- Department of Chemistry, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, Republic of Korea.
| | - Yoonsoo Pang
- Department of Chemistry, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, Republic of Korea.
| |
Collapse
|
3
|
Xie J, Nealon RE, Egan ZT, Takematsu K. Effect of cyano-addition on the photoacidity switch in 5-cyano-8-amino-2-naphthol. Phys Chem Chem Phys 2023. [PMID: 38050989 DOI: 10.1039/d3cp04845d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Cyano- or CN-additions are often utilized in the design of photoacids to enhance and/or enable excited state proton transfer (ESPT) from the protic site to aqueous and nonaqueous solvents. In diprotic photoacid 8-amino-2-naphthol (8N2OH), the protonation state of the amino group (NH3+/NH2) acts as an on-off switch for ESPT at the OH site in water. This study investigated whether the addition of CN in 5-cyano-8-amino-2-naphthol (5CN8) could override this switch and promote new ESPT pathways. Analysis of the steady-state and time-resolved emission data showed that in the presence of protonated NH3+, CN enhances OH photoacidity (vs. in 8N2OH) and activates the ESPT pathway at NH3+. Both protic sites, OH and NH3+, can also donate a proton to methanol upon excitation. In contrast, in the presence of deprotonated NH2, despite the addition of CN, ESPT is still not observed at the OH site for 5CN8. Thus, the addition of CN cannot override or negate the inhibiting effect of NH2 on OH photoacidity. Potential causes for this inhibition are discussed, including electronic and antiaromaticity effects of CN and NH2 substitution.
Collapse
Affiliation(s)
- Jialin Xie
- Department of Chemistry, Bowdoin College, Brunswick, ME 04011, USA.
| | - Rachel E Nealon
- Department of Chemistry, Bowdoin College, Brunswick, ME 04011, USA.
| | - Zelia T Egan
- Department of Chemistry, Bowdoin College, Brunswick, ME 04011, USA.
| | - Kana Takematsu
- Department of Chemistry, Bowdoin College, Brunswick, ME 04011, USA.
| |
Collapse
|
4
|
Han GR, Lim E, Kang J, Hwang D, Heo J, Kim SK, Lee JW. Alcoholic Solvent-Mediated Excited-State Proton Transfer Dynamics of a Novel Dihydroxynaphthalene Dye. J Phys Chem A 2023; 127:7884-7891. [PMID: 37723599 DOI: 10.1021/acs.jpca.3c03170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/20/2023]
Abstract
The excited-state proton transfer (ESPT) reaction is an important primary photochemical process because it is closely related to photophysical properties. Although ESPT research in aqueous solutions is predominant, alcoholic solvent-mediated ESPT studies are also significant in terms of photoacid-based reactions. Especially, the research for dihydroxynaphthalenes (DHNs) has been largely neglected due to the challenging data interpretation of two hydroxyl groups. A novel fluorescent dye, resveratrone, synthesized by light irradiation of resveratrol, which is famous for its antioxidant properties, can be regarded as a type of DHN, and it has distinctive optical properties, including high quantum yield, a large two-photon absorption coefficient, a large Stokes shift, and very high biocompatibility. In this study, we investigate the overall kinetics of the optical properties of resveratrone and find evidence for alcoholic solvent-mediated ESPT involvement in the radiative properties of resveratrone with a large Stokes shift. Our investigation provides an opportunity to revisit the overlooked photophysical properties of intriguing photoacid behavior and the large Stokes shift of the dihydroxynaphthalene dye.
Collapse
Affiliation(s)
- Gi Rim Han
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Eunhak Lim
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Jooyeon Kang
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Doyk Hwang
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Jiyoung Heo
- Department of Green Chemical Engineering, Sangmyung University, Chungnam 31066, Republic of Korea
| | - Seong Keun Kim
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Jong Woo Lee
- Department of Applied Chemistry, University of Seoul, 163 Seoulsiripdae-ro, Dongdaemun-gu, Seoul 02504, Republic of Korea
| |
Collapse
|
5
|
Codescu MA, Kunze T, Weiß M, Brehm M, Kornilov O, Sebastiani D, Nibbering ETJ. Ultrafast Proton Transfer Pathways Mediated by Amphoteric Imidazole. J Phys Chem Lett 2023; 14:4775-4785. [PMID: 37186569 DOI: 10.1021/acs.jpclett.3c00595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Imidazole, being an amphoteric molecule, can act both as an acid and as a base. This property enables imidazole, as an essential building block, to effectively facilitate proton transport in high-temperature proton exchange membrane fuel cells and in proton channel transmembrane proteins, enabling those systems to exhibit high energy conversion yields and optimal biological function. We explore the amphoteric properties of imidazole by following the proton transfer exchange reaction dynamics with the bifunctional photoacid 7-hydroxyquinoline (7HQ). We show with ultrafast ultraviolet-mid-infrared pump-probe spectroscopy how for imidazole, in contrast to expectations based on textbook knowledge of acid-base reactivity, the preferential reaction pathway is that of an initial proton transfer from 7HQ to imidazole, and only at a later stage a transfer from imidazole to 7HQ, completing the 7HQ tautomerization reaction. An assessment of the molecular distribution functions and first-principles calculations of proton transfer reaction barriers reveal the underlying reasons for our observations.
Collapse
Affiliation(s)
- Marius-Andrei Codescu
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, 12489 Berlin, Germany
| | - Thomas Kunze
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Moritz Weiß
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Martin Brehm
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Oleg Kornilov
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, 12489 Berlin, Germany
| | - Daniel Sebastiani
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Erik T J Nibbering
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, 12489 Berlin, Germany
| |
Collapse
|
6
|
Nachliel E, Gutman M. Reaction within the coulomb-cage; science in retrospect. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184071. [PMID: 36244436 DOI: 10.1016/j.bbamem.2022.184071] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 08/01/2022] [Accepted: 09/30/2022] [Indexed: 11/06/2022]
Abstract
The Coulomb-cage is defined as the space where the electrostatic interaction between two bodies is more intensive than the thermal energy (kBT). For small molecule, the Coulomb-cage is a small sphere, extending only few water molecules towards the bulk and its radius is sensitive to the ionic strength of the solution. For charged proteins or membranal structures, the Coulomb-cage can engulf large fraction of the surface and provides a preferred pathway for ion propagation along the surface. Similarly, electrostatic potential at the inner space of a channel can form preferential trajectories passage for ions. The dynamics of ions inside the Coulomb-cage of ions was formulated by the studies of proton-anion recombination of excited photoacids. In the present article, we recount the study of intra- Coulomb-cage reaction taking place on the surface of macro-molecular bodies like micelles, membranes, proteins and intra-protein cavities. The study progressed stepwise, tracing the dynamics of a proton ejected from a photo-acid molecule located at defined sites (on membrane, inter-membrane space, active site of enzyme, inside Large Pore Channels etc.). Accumulation of experimental observations encouraged us to study of the reaction mechanism by molecular dynamics simulations of ions within the Coulomb-cage of proteins surface or inside large pores. The intra-Coulomb-cage proton transfer events follows closely the fine structure of the electrostatic field inside the cage and reflects the shape of nearby dielectric boundaries, the temporal ordering of the solvent molecules and the structural fluctuations of the charged side chains. The article sums some 40 years of research, which in retrospect clarifies the intra-Coulomb-cage reaction mechanism.
Collapse
Affiliation(s)
- E Nachliel
- Laser Laboratory for Fast Reactions, Dep. Of Biochemistry and Molecular Biology, Life Sciences, Tel Aviv University, Israel
| | - M Gutman
- Laser Laboratory for Fast Reactions, Dep. Of Biochemistry and Molecular Biology, Life Sciences, Tel Aviv University, Israel.
| |
Collapse
|
7
|
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.
Collapse
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.
| |
Collapse
|
8
|
Joung JF, Jeong M, Park S. Reliable experimental method for determination of photoacidity revealed by quantum chemical calculations. Phys Chem Chem Phys 2022; 24:21714-21721. [PMID: 36074805 DOI: 10.1039/d2cp03308a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photoacids are aromatic acids that exhibit significantly different acidities when they are electronically excited. Three experimental methods have been extensively used to determine the photoacidity, : fluorescence titration, the Förster cycle, and time-resolved experiments. However, the photoacidities determined by these experimental methods are not consistent. In this work, we used a theoretical method to evaluate the reliability of experimentally determined values. In particular, density functional theory (DFT) and time-dependent DFT calculations were used to obtain the changes in Gibbs free energy for acid dissociation reactions which are directly related to values. The Förster cycle, which is frequently used to experimentally determine the photoacidity due to its simplicity, yielded inconsistent results depending on how the transition energy was defined. We evaluated six empirical parameters extracted from the absorption and emission spectra of acidic and basic species of photoacids to adequately define the transition energy in the Förster cycle. And we found that the values obtained using the optical bandgap as the transition energy in the Förster cycle were in the best agreement with the results of quantum chemical calculations.
Collapse
Affiliation(s)
- Joonyoung F Joung
- Department of Chemistry and Research Institute for Natural Science, Korea University, Seoul, 02841, Korea.
| | - Minseok Jeong
- Department of Chemistry and Research Institute for Natural Science, Korea University, Seoul, 02841, Korea.
| | - Sungnam Park
- Department of Chemistry and Research Institute for Natural Science, Korea University, Seoul, 02841, Korea.
| |
Collapse
|
9
|
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.
Collapse
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
| |
Collapse
|
10
|
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.
Collapse
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
| |
Collapse
|
11
|
Pan X, Han T, Long J, Xie B, Du Y, Zhao Y, Zheng X, Xue J. Excited state proton transfer of triplet state p-nitrophenylphenol to amine and alcohol: a spectroscopic and kinetic study. Phys Chem Chem Phys 2022; 24:18427-18434. [PMID: 35881619 DOI: 10.1039/d2cp02503e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Hydroxyaromatic compounds (ArOHs) have a wide range of applications in catalytic synthesis and biological processes due to their increased acidity upon photo-excitation. The proton transfer of ArOHs via the excited singlet state has been extensively studied. However, there has still been a debate on the unique type of ArOH that can undergo an ultrafast intersystem crossing. The nitro group in p-nitrophenylphenol (NO2-Bp-OH) enhances the spin-orbit coupling between excited singlet states and the triplet manifold, enabling ultrafast intersystem crossing and the formation of the long-lived lowest excited triplet state (T1) with a high yield. In this work, we used time-resolved transient absorption to investigate the excited state proton transfer of NO2-Bp-OH in its T1 state to t-butylamine, methanol, and ethanol. The T1 state of the deprotonated form NO2-Bp-O- was first observed and identified in the case of t-butylamine. Kinetic analysis demonstrates that the formation of the hydrogen-bonded complex with methanol and ethanol as proton acceptors involves their trimers. The alcohol oligomer size required in the excited state proton transfer process is dependent on the excited acidity of photoacid.
Collapse
Affiliation(s)
- Xinghang Pan
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou, 310018, China.
| | - Ting Han
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou, 310018, China.
| | - Jing Long
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou, 310018, China.
| | - Binbin Xie
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, Hangzhou, 310018, China
| | - Yong Du
- Centre for THz Research, China Jiliang University, Hangzhou, 310018, China
| | - Yanying Zhao
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou, 310018, China. .,Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou, 310018, China
| | - Xuming Zheng
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou, 310018, China.
| | - Jiadan Xue
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou, 310018, China. .,Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou, 310018, China
| |
Collapse
|
12
|
Eckert S, Winghart MO, Kleine C, Banerjee A, Ekimova M, Ludwig J, Harich J, Fondell M, Mitzner R, Pines E, Huse N, Wernet P, Odelius M, Nibbering ETJ. Electronic Structure Changes of an Aromatic Amine Photoacid along the Förster Cycle. Angew Chem Int Ed Engl 2022; 61:e202200709. [PMID: 35325500 PMCID: PMC9322478 DOI: 10.1002/anie.202200709] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Indexed: 11/15/2022]
Abstract
Photoacids show a strong increase in acidity in the first electronic excited state, enabling real‐time studies of proton transfer in acid‐base reactions, proton transport in energy storage devices and biomolecular sensor protein systems. Several explanations have been proposed for what determines photoacidity, ranging from variations in solvation free energy to changes in electronic structure occurring along the four stages of the Förster cycle. Here we use picosecond nitrogen K‐edge spectroscopy to monitor the electronic structure changes of the proton donating group in a protonated aromatic amine photoacid in solution upon photoexcitation and subsequent proton transfer dynamics. Probing core‐to‐valence transitions locally at the amine functional group and with orbital specificity, we clearly reveal pronounced electronic structure, dipole moment and energetic changes on the conjugate photobase side. This result paves the way for a detailed electronic structural characterization of the photoacidity phenomenon.
Collapse
Affiliation(s)
- Sebastian Eckert
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, 12489, Berlin, Germany
| | - Marc-Oliver Winghart
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, 12489, Berlin, Germany
| | - Carlo Kleine
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, 12489, Berlin, Germany
| | - Ambar Banerjee
- Department of Physics, Stockholm University, AlbaNova University Center, 106 91, Stockholm, Sweden
| | - Maria Ekimova
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, 12489, Berlin, Germany
| | - Jan Ludwig
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, 12489, Berlin, Germany
| | - Jessica Harich
- Institute for Nanostructure and Solid State Physics, Center for Free-Electron Laser Science, Luruper Chaussee 149, 22761, Hamburg, Germany
| | - Mattis Fondell
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489, Berlin, Germany
| | - Rolf Mitzner
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489, Berlin, Germany
| | - Ehud Pines
- Department of Chemistry, Ben Gurion University of the Negev, P.O.B. 653, Beersheva, 84105, Israel
| | - Nils Huse
- Institute for Nanostructure and Solid State Physics, Center for Free-Electron Laser Science, Luruper Chaussee 149, 22761, Hamburg, Germany
| | - Philippe Wernet
- Department of Physics and Astronomy, Uppsala University, Box 516 Lägerhyddsvägen 1, 751 20, Uppsala, Sweden
| | - Michael Odelius
- Department of Physics, Stockholm University, AlbaNova University Center, 106 91, Stockholm, Sweden
| | - Erik T J Nibbering
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, 12489, Berlin, Germany
| |
Collapse
|
13
|
Excited-State Dynamics of Imiquimod in Aqueous Solutions. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2022.113998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
14
|
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
| |
Collapse
|
15
|
Eckert S, Winghart MO, Kleine C, Banerjee A, Ekimova M, Ludwig J, Harich J, Fondell M, Mitzner R, Pines E, Huse N, Wernet P, Odelius M, Nibbering ET. Electronic Structure Changes of an Aromatic Amine Photoacid along the Förster Cycle. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202200709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Sebastian Eckert
- Max Born Institute for Non-Linear Optics and Short Pulse Spectroscopy: Max-Born-Institut fur Nichtlineare Optik und Kurzzeitspektroskopie C1 GERMANY
| | - Marc-Oliver Winghart
- Max Born Institute for Non-Linear Optics and Short Pulse Spectroscopy: Max-Born-Institut fur Nichtlineare Optik und Kurzzeitspektroskopie C1 GERMANY
| | - Carlo Kleine
- Max Born Institute for Non-Linear Optics and Short Pulse Spectroscopy: Max-Born-Institut fur Nichtlineare Optik und Kurzzeitspektroskopie C1 GERMANY
| | - Ambar Banerjee
- Stockholm University: Stockholms Universitet Chemistry SWEDEN
| | - Maria Ekimova
- Max Born Institute for Non-Linear Optics and Short Pulse Spectroscopy: Max-Born-Institut fur Nichtlineare Optik und Kurzzeitspektroskopie C1 GERMANY
| | - Jan Ludwig
- Max Born Institute for Non-Linear Optics and Short Pulse Spectroscopy: Max-Born-Institut fur Nichtlineare Optik und Kurzzeitspektroskopie C1 GERMANY
| | - Jessica Harich
- Center for Free Electron Laser Science Institute for Nanostructure and Solid State Physics GERMANY
| | - Mattis Fondell
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH: Helmholtz-Zentrum Berlin fur Materialien und Energie GmbH Institute for Methods and Instrumentation for Synchrotron Radiation Research GERMANY
| | - Rolf Mitzner
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH: Helmholtz-Zentrum Berlin fur Materialien und Energie GmbH Institute for Methods and Instrumentation for Synchrotron Radiation Research GERMANY
| | - Ehud Pines
- Ben-Gurion University of the Negev Chemistry ISRAEL
| | - Nils Huse
- Center for Free Electron Laser Science Institute for Nanostructure and Solid State Physics GERMANY
| | | | - Michael Odelius
- Stockholm University: Stockholms Universitet Chemistry SWEDEN
| | - Erik T.J. Nibbering
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie C1 Max Born Strasse 2A D-12489 Berlin GERMANY
| |
Collapse
|
16
|
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: 0] [Impact Index Per Article: 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.
Collapse
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
| |
Collapse
|
17
|
Kataoka S, Harada M, Okada T. Microscale pH inhomogeneity in frozen NaCl solutions. Phys Chem Chem Phys 2021; 23:18595-18601. [PMID: 34612396 DOI: 10.1039/d1cp01655e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
When an aqueous solution freezes at temperatures above the eutectic point, a freeze concentrated solution (FCS) is separated from the ice phase. Reactions of environmental importance often occur in the FCS and, in some cases, are accelerated compared to those in solution conditions. The pH of the FCS is an essential factor governing the thermodynamics and kinetics of the reactions occurring therein. It is known that freezing of aqueous NaCl causes an increase in the FCS pH, which arises from the difference in the partition to the ice phase between Na+ and Cl-. It has also been shown that H+ and other ions show surface-specific behaviors on ice. Although the details are not known, the ice/FCS interface can also affect the behaviors of ions. In this study, the pH distribution in the FCS is evaluated using ratiometric fluorescence microscopy, and the pH inhomogeneity is confirmed for frozen aqueous NaCl. However, interestingly, buffered solutions and frozen aqueous glycerol result in a uniform pH value. The pH in frozen NaCl is always higher near the ice/FCS interface than in the middle of the FCS vein.
Collapse
Affiliation(s)
- Shun Kataoka
- Department of Chemistry, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551, Japan.
| | | | | |
Collapse
|
18
|
Codescu MA, Weiß M, Brehm M, Kornilov O, Sebastiani D, Nibbering ETJ. Switching between Proton Vacancy and Excess Proton Transfer Pathways in the Reaction between 7-Hydroxyquinoline and Formate. J Phys Chem A 2021; 125:1845-1859. [PMID: 33651619 PMCID: PMC7957860 DOI: 10.1021/acs.jpca.0c10191] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Bifunctional or amphoteric
photoacids simultaneously present donor
(acidic) and acceptor (basic) properties making them useful tools
to analyze proton transfer reactions. In protic solvents, the proton
exchange between the acid and the base is controlled by the acidity
or basicity strength and typically occurs on two different pathways
known as protolysis and hydrolysis. We report here how the addition
of a formate base will alter the relative importance of the possible
reaction pathways of the bifunctional photoacid 7-hydroxyquinoline
(7HQ), which has been recently understood to predominantly involve
a hydroxide/methoxide transport mechanism between the basic proton-accepting
quinoline nitrogen site toward the proton-donating OH group with a
time constant of 360 ps in deuterated methanol (CD3OD).
We follow the reaction dynamics by probing the IR-active marker modes
of the different charged forms of photoexcited 7HQ, and of formic
acid (HCOOD) in CD3OD solution. A comparison of the transient
IR spectra as a function of formate concentration, and classical molecular
dynamics simulations enables us to identify distinct contributions
of “tight” (meaning “contact”) and “loose”
(i.e., “solvent-separated”) 7HQ–formate reaction
pairs in our data. Our results suggest that depending on the orientation
of the OH group with respect to the quinoline aromatic ring system,
the presence of the formate molecule in a proton relay pathway facilitates
a net proton transfer from the proton-donating OH group of 7HQ-N*
via the methanol/formate bridge toward the quinoline N site.
Collapse
Affiliation(s)
- Marius-Andrei Codescu
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, 12489 Berlin, Germany
| | - Moritz Weiß
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle Saale, Germany
| | - Martin Brehm
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle Saale, Germany
| | - Oleg Kornilov
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, 12489 Berlin, Germany
| | - Daniel Sebastiani
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle Saale, Germany
| | - Erik T J Nibbering
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, 12489 Berlin, Germany
| |
Collapse
|
19
|
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+.
Collapse
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
| |
Collapse
|
20
|
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
| |
Collapse
|
21
|
Dey N. Naked-eye sensing of phytic acid at sub-nanomolar levels in 100% water medium by a charge transfer complex derived from off-the-shelf ingredients. Analyst 2020; 145:4937-4941. [PMID: 32496500 DOI: 10.1039/d0an00671h] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Naked-eye sensing of phytic acid, one of the most abundant antinutrients, was achieved in 100% water medium using a charge transfer complex, composed of pyranine and methyl viologen. Since both the ingredients are commercially available, the design of such sensory systems needs zero synthetic effort, which essentially makes it economically viable. Only the physical mixture of both of these compounds showed a color-changing response from brown to yellow in the presence of phytic acid with a turn-on fluorescence response (LOD: 0.56 nM). The electrostatic interaction leads to charge pairing between phytic acid and methyl viologen, which releases free pyranine in solution. Considering its high sensitivity, low-cost test strips were developed for the on-site detection of phytic acid, even in remote locations. Additionally, estimation of phytic acid was achieved in grain samples with a sufficiently high accuracy, as evident from a sufficiently low relative standard deviation (<5%).
Collapse
Affiliation(s)
- Nilanjan Dey
- Department of Undergraduate Studies, Indian Institute of Science, Bangalore-560012, Karnataka, India.
| |
Collapse
|
22
|
Pines E, Pines D, Gajst O, Huppert D. Reversible intermolecular-coupled-intramolecular (RICI) proton transfer occurring on the reaction-radius a of 2-naphthol-6,8-disulfonate photoacid. J Chem Phys 2020; 152:074205. [PMID: 32087655 DOI: 10.1063/1.5134760] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Steady-state and time-resolved fluorescence techniques were employed to study the excited-state proton transfer (ESPT) from a reversibly dissociating photoacid, 2-naphthol-6,8-disulfonate (2N68DS). The reaction was carried out in water and in acetonitrile-water solutions. We find by carefully analyzing the geminate recombination dynamics of the photobase-proton pair that follows the ESPT reaction that there are two targets for the proton back-recombination reaction: the original O- dissociation site and the SO3 - side group at the 8 position which is closest to the proton OH dissociation site. This observation is corroborated in acetonitrile-water mixtures of χwater < 0.14, where a slow intramolecular ESPT occurs on a time scale of about 1 ns between the OH group and the SO3 - group via H-bonding water. The proton-transferred R*O- fluorescence band in mixtures of χwater < 0.14 where only intramolecular ESPT occurs is red shifted by about 2000 cm-1 from the free R*O- band in neat water. As the water content in the mixture increases above χwater = 0.14, the R*O- fluorescence band shifts noticeably to the blue region. For χwater > 0.23 the band resembles the free anion band observed in pure water. Concomitantly, the ESPT rate increases when χwater increases because the intermolecular ESPT to the solvent (bulk water) gradually prevails over the much slower intramolecular via the water-bridges ESPT process.
Collapse
Affiliation(s)
- Ehud Pines
- Department of Chemistry, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105, Israel
| | - Dina Pines
- Department of Chemistry, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105, Israel
| | - Oren Gajst
- 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
| |
Collapse
|
23
|
Nandi R, Yucknovsky A, Mazo MM, Amdursky N. Exploring the inner environment of protein hydrogels with fluorescence spectroscopy towards understanding their drug delivery capabilities. J Mater Chem B 2020; 8:6964-6974. [DOI: 10.1039/d0tb00818d] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Time-resolved fluorescence have used to explore the inner surface and solvation dynamics within protein hydrogels assisting in rationalizing their drug binding and release capabilities.
Collapse
Affiliation(s)
- Ramesh Nandi
- Schulich Faculty of Chemistry
- Technion Israel Institute of Technology
- Haifa-3200003
- Israel
| | - Anna Yucknovsky
- Schulich Faculty of Chemistry
- Technion Israel Institute of Technology
- Haifa-3200003
- Israel
| | - Manuel M. Mazo
- Cell Therapy Area
- Clinica Universidad de Navarra, and Regenerative Medicine Program
- Cima Universidad de Navarra
- Pamplona
- Spain
| | - Nadav Amdursky
- Schulich Faculty of Chemistry
- Technion Israel Institute of Technology
- Haifa-3200003
- Israel
| |
Collapse
|
24
|
Hossen T, Sahu K. Effect of Photoacid Strength on Fluorescence Modulation of 2-Naphthol Derivatives inside β-Cyclodextrin Cavity: Insights from Fluorescence, Isothermal Calorimetry, and Molecular Dynamics Simulations. J Phys Chem B 2019; 123:9291-9301. [PMID: 31596595 DOI: 10.1021/acs.jpcb.9b05457] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fluorescence response of a photoacid inside a confined environment often differs markedly from the bulk response. Is there any correlation between the extent of fluorescence modulation and the strength of the photoacid? Here, we used three photoacids: 2-naphthol (2OH, pKa* = 3.3), 6-sulfonate-2-naphthol (6SO3-2OH, pKa* = 3.06), and 6-cyano-2-naphthol (6CN-2OH, pKa* = 0.6) with remarkably different excited-state acidities to investigate fluorescence modulation inside the nanocavity of β-cyclodextrin (β-CD). Interestingly, we found strong fluorescence modulation for 2OH and 6SO3-2OH but almost none for 6CN-2OH. Isothermal calorimetry measurements showed that all three fluorophores form 1:1 inclusion complex with comparable binding constants (285, 420, and 580 M-1 for 2OH, 6SO3-2OH, and 6CN-2OH, respectively). Molecular dynamics simulation further revealed that binding modes are quite similar, and the distribution of water molecules around the proton-donating hydroxyl group of the photoacids are also comparable. Consequently, the difference in the fluorescence response should be accounted solely to the difference in the photoacidity strengths.
Collapse
Affiliation(s)
- Tousif Hossen
- Department of Chemistry , Indian Institute of Technology Guwahati , Guwahati 781039 , Assam , India
| | - Kalyanasis Sahu
- Department of Chemistry , Indian Institute of Technology Guwahati , Guwahati 781039 , Assam , India
| |
Collapse
|
25
|
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] [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.
Collapse
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
| |
Collapse
|
26
|
Ulrich S, Osypova A, Panzarasa G, Rossi RM, Bruns N, Boesel LF. Pyranine-Modified Amphiphilic Polymer Conetworks as Fluorescent Ratiometric pH Sensors. Macromol Rapid Commun 2019; 40:e1900360. [PMID: 31523877 DOI: 10.1002/marc.201900360] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 08/21/2019] [Indexed: 01/04/2023]
Abstract
The fluorescent dye 8-hydroxypyrene-1,3,6-trisulfonate (pyranine) combines high photostability with ratiometric pH detection in the physiological range, making it a prime candidate for optical sensors in biomedical applications, such as pH-based chronic wound monitoring. However, pyranine's high water solubility and the difficulty of covalent attachment pose severe limitations in terms of leaching from sensor matrices. Herein, pyranine-modified nanophase-separated amphiphilic polymer conetworks (APCNs) are reported as fluorescent ratiometric pH sensors. The thin, freestanding APCN membranes composed of one hydrophilic and one hydrophobic polymer provide an optically transparent, flexible, and stable ideal matrix that enables contact between dye and aqueous environment. An active ester-based conjugation approach results in a highly homogeneous and stable pyranine modification of the APCN's hydrophilic phase. This concept effectively solves the leaching challenge for pyranine without compromising its functionality, which is demonstrated by ratiometric pH detection in the range of pH 5-9.
Collapse
Affiliation(s)
- Sebastian Ulrich
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Biomimetic Membranes and Textiles, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland.,Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700, Fribourg, Switzerland
| | - Alina Osypova
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Biomimetic Membranes and Textiles, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland
| | - Guido Panzarasa
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Biomimetic Membranes and Textiles, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland
| | - René M Rossi
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Biomimetic Membranes and Textiles, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland
| | - Nico Bruns
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700, Fribourg, Switzerland.,Department of Pure and Applied Chemistry, University of Strathclyde, Thomas Graham Building, 295 Cathedral Street, Glasgow, G1 1XL, UK
| | - Luciano F Boesel
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Biomimetic Membranes and Textiles, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland
| |
Collapse
|
27
|
Ekimova M, Hoffmann F, Bekçioğlu-Neff G, Rafferty A, Kornilov O, Nibbering ETJ, Sebastiani D. Ultrafast Proton Transport between a Hydroxy Acid and a Nitrogen Base along Solvent Bridges Governed by the Hydroxide/Methoxide Transfer Mechanism. J Am Chem Soc 2019; 141:14581-14592. [PMID: 31446754 PMCID: PMC8168916 DOI: 10.1021/jacs.9b03471] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Aqueous
proton transport plays a key role in acid–base neutralization
and energy transport through biological membranes and hydrogen fuel
cells. Extensive experimental and theoretical studies have resulted
in a highly detailed elucidation of one of the underlying microscopic
mechanisms for aqueous excess proton transport, known as the von Grotthuss
mechanism, involving different hydrated proton configurations with
associated high fluxional structural dynamics. Hydroxide transport,
with approximately 2-fold-lower bulk diffusion rates compared to those
of excess protons, has received much less attention. We present femtosecond
UV/IR pump–probe experiments and ab initio molecular dynamics
simulations of different proton transport pathways of bifunctional
photoacid 7-hydroxyquinoline (7HQ) in water/methanol mixtures. For
7HQ solvent-dependent photoacidity, free-energy–reactivity
correlation behavior and quantum mechanics/molecular mechanics (QM/MM)
trajectories point to a dominant OH–/CH3O– transport pathway for all water/methanol mixing
ratios investigated. Our joint ultrafast infrared spectroscopic and
ab initio molecular dynamics study provides conclusive evidence for
the hydrolysis/methanolysis acid–base neutralization pathway,
as formulated by Manfred Eigen half a century ago. Our findings on
the distinctly different acid–base reactivities for aromatic
hydroxyl and aromatic nitrogen functionalities suggest the usefulness
of further exploration of these free-energy–reactivity correlations
as a function of solvent polarity. Ultimately the determination of
solvent-dependent acidities will contribute to a better understanding
of proton-transport mechanisms at weakly polar surfaces and near polar
or ionic regions in transmembrane proton pump proteins or hydrogen
fuel cell materials.
Collapse
Affiliation(s)
- Maria Ekimova
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie , Max Born Str. 2A , 12489 Berlin , Germany
| | - Felix Hoffmann
- Institut für Chemie , Martin-Luther-Universität Halle-Wittenberg , Von-Danckelmann-Platz 4 , 06120 Halle , Saale , Germany
| | - Gül Bekçioğlu-Neff
- Institut für Chemie , Martin-Luther-Universität Halle-Wittenberg , Von-Danckelmann-Platz 4 , 06120 Halle , Saale , Germany
| | - Aidan Rafferty
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie , Max Born Str. 2A , 12489 Berlin , Germany
| | - Oleg Kornilov
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie , Max Born Str. 2A , 12489 Berlin , Germany
| | - Erik T J Nibbering
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie , Max Born Str. 2A , 12489 Berlin , Germany
| | - Daniel Sebastiani
- Institut für Chemie , Martin-Luther-Universität Halle-Wittenberg , Von-Danckelmann-Platz 4 , 06120 Halle , Saale , Germany
| |
Collapse
|
28
|
Norell J, Ljungdahl A, Odelius M. Interdependent Electronic Structure, Protonation, and Solvatization of Aqueous 2-Thiopyridone. J Phys Chem B 2019; 123:5555-5567. [PMID: 31244103 DOI: 10.1021/acs.jpcb.9b03084] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
2-Thiopyridone (2-TP), a common model system for excited-state proton transfer, has been simulated in aqueous solution with ab initio molecular dynamics. The interplay of electronic structure, protonation, and solvatization is investigated by comparison of three differently protonated molecular forms and between the lowest singlet and triplet electronic states. An interdependence clearly manifests in the mixed-character T1 state for the 2-TP form, systematic structural distortions of the 2-mercaptopyridine (2-MP) form, and photobase protolysis of the 2-TP- form, in the aqueous phase. In comparison, simplified continuum models for the solvatization are found to be significantly inaccurate for several of the species. To facilitate future computational studies, we therefore present a minimal representative solvatization complex for each stable form and electronic state. Our findings demonstrate the importance of explicit solvatization of the compound and sets the stage for including it also in future studies.
Collapse
Affiliation(s)
- Jesper Norell
- Department of Physics, AlbaNova University Center , Stockholm University , SE-106 91 Stockholm , Sweden
| | - Anton Ljungdahl
- Department of Physics, AlbaNova University Center , Stockholm University , SE-106 91 Stockholm , Sweden
| | - Michael Odelius
- Department of Physics, AlbaNova University Center , Stockholm University , SE-106 91 Stockholm , Sweden
| |
Collapse
|
29
|
Aqdas A, Siddique F, Nieman R, Quina FH, Aquino AJA. Photoacidity of the 7-Hydroxyflavylium Cation. Photochem Photobiol 2019; 95:1339-1344. [PMID: 31237349 DOI: 10.1111/php.13139] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 06/14/2019] [Indexed: 11/26/2022]
Abstract
Theoretical descriptions of excited state proton transfer (ESPT) have had various degrees of success. This work presents a theoretical description of the photodissociation of the 7-hydroxyflavylium cation (7-HF), the fundamental chromophoric moiety of anthocyanin natural plant pigments. ESPT of 7-HF is promoted by a significant shift of charge away from the OH group in the first singlet excited state, leading smoothly to the excited conjugate base and a protonated water cluster. Several factors contribute to the consistency of the results of the present study: (1) the theoretical approach (TD-DFT with the B3-LYP functional and def2-TZVP basis set utilizing Grimme's D3 dispersion correction); (2) the modeling of the solvent effect combining hydrogen bonding of the photoacid to a cluster of discrete water molecules in a water-like continuum solvent (COSMO); (3) the large S1 -S2 energy gap of flavylium cations; and (4) the electrostatics of the ESPT in which a proton is transferred from a cationic photoacid to water without Coulombic interaction between the proton and the conjugate base.
Collapse
Affiliation(s)
- Amna Aqdas
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - Farhan Siddique
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - Reed Nieman
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX
| | - Frank H Quina
- Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Adelia J A Aquino
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China.,Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX
| |
Collapse
|
30
|
Fan H, Jiang H, Zhu X, Guo Z, Zhang L, Liu M. Switchable circularly polarized luminescence from a photoacid co-assembled organic nanotube. NANOSCALE 2019; 11:10504-10510. [PMID: 31115419 DOI: 10.1039/c9nr01959f] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Materials with circularly polarized luminescence (CPL) are currently attracting great interest in view of their potential applications. Here, we reported self-assembled organic nanotubes with switchable CPL performance. A photoacid, 8-hydroxy-1,3,6-pyrenetrisulfonate (HPTS), was co-assembled with an amino-terminated dialkyl glutamide (LG or DG) in mixed solvents of DMF and water. The complex of LG (DG)/HPTS self-assembled into nanotube structures in the tested range of mixed solvents and showed CPL emission. Different mixing ratios of DMF to water in the solvent triggered CPL switching between different wavelengths. It was revealed that the switching of CPL resulted from the different emissions of the protonated (ROH) and deprotonated (RO-) forms of HPTS, which could be regulated by the solvent polarity. Interestingly, the addition of an acid or base could also switch the fluorescence of LG (DG)/HPTS co-assemblies and the corresponding CPL, leading to an acidity-regulated CPL switch. Thus, through a simple co-assembly strategy, switchable CPL was realized in the self-assembled organic nanotubes via both solvent polarity and acidity.
Collapse
Affiliation(s)
- Huahua Fan
- Beijing National Laboratory for Molecular Science, CAS Key Laboratory of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun North First Street 2, Beijing 100190, China.
| | | | | | | | | | | |
Collapse
|
31
|
Cotter LF, Brown PJ, Nelson RC, Takematsu K. Divergent Hammett Plots of the Ground- and Excited-State Proton Transfer Reactions of 7-Substituted-2-Naphthol Compounds. J Phys Chem B 2019; 123:4301-4310. [PMID: 31021637 DOI: 10.1021/acs.jpcb.9b01295] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The rational design of photoacids requires accessible predictive models of the electronic effect of functional groups on chemical templates of interest. Here, the effect of substituents on the photoacidity and excited-state proton transfer (PT) pathways of prototype 2-naphthol (2OH) at the symmetric C7 position was investigated through photochemical and computational studies of 7-amino-2-naphthol (7N2OH) and 7-methoxy-2-naphthol (7OMe2OH). Time-resolved emission experiments of 7N2OH revealed that the presence of an electron-withdrawing versus electron-donating group (EWG vs EDG, NH3+ vs NH2) led to a drastic decline in photoacidity: p Ka* = 1.1 ± 0.2 vs 9.6 ± 0.2. Time-dependent density functional theory calculations with explicit water molecules confirmed that the excited neutral state (x = NH2) is greatly stabilized by water, with equation-of-motion coupled cluster singles and doubles calculations supporting potential mixing between the La and Lb states. Similar suppression of photoacidity, however, was not observed for 7OMe2OH with EDG OCH3, p Ka* = 2.7 ± 0.1. Hammett plots of the ground- and excited-state PT reactions of substituted 7-x-2OH compounds (x = CN, NH3+, H, CH3, OCH3, OH, and NH2) vs Hammett parameters σp showed breaks in the linearity between the EDG and EWG regions: ρ ∼ 0 vs 1.14 and ρ* ∼ 0 vs 3.86. The divergent acidic behavior most likely arises from different mixing mechanisms of the lowest Lb state with the La and possible Bb states upon substitution of naphthalene in water.
Collapse
Affiliation(s)
- Laura F Cotter
- Department of Chemistry , Bowdoin College , Brunswick , Maine 04011 , United States
| | - Paige J Brown
- Department of Chemistry , Bowdoin College , Brunswick , Maine 04011 , United States
| | - Ryan C Nelson
- Department of Chemistry , Bowdoin College , Brunswick , Maine 04011 , United States
| | - Kana Takematsu
- Department of Chemistry , Bowdoin College , Brunswick , Maine 04011 , United States
| |
Collapse
|
32
|
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
| |
Collapse
|
33
|
Dey N, Biswakarma D, Bajpai A, Moorthy JN, Bhattacharya S. Modulation of Excited-State Proton-Transfer Dynamics inside the Nanocavity of Microheterogeneous Systems: Microenvironment-Sensitive Förster Energy Transfer to Riboflavin. Chemphyschem 2019; 20:881-889. [PMID: 30548519 DOI: 10.1002/cphc.201801085] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 08/15/2018] [Indexed: 12/11/2022]
Abstract
The excited-state proton-transfer efficiency of a tetraarylpyrene derivative, 1,3,6,8-tetrakis(4-hydroxy-2,6-dimethylphenyl)pyrene (TDMPP), was investigated thoroughly in the presence of various surfactant assemblies, such as micelles and vesicles. The confined microheterogeneous environments can significantly retard the extent of the excited-state proton-transfer process, resulting in a distinguishable optical signal compared to that in the bulk medium. Physical characteristics of the surfactant assemblies, such as order, interfacial hydration, and surface charge, influence the proton transfer process and allow multiparametric sensing. A higher degree of interfacial hydration facilitates the proton-transfer process, while the positively charged head groups of the surfactants specifically stabilize the anionic form of the probe (TDMPP-O*). Furthermore, Forster energy transfer from the probe to riboflavin was studied in a phospholipid membrane, wherein the relative ratio of the neutral versus anionic forms (TDMPP-OH/TDMPP-O*) was found to influence the extent of energy transfer. Overall, we demonstrate how an ultrafast photophysical process, that is, the excited-state proton transfer, can be influenced by the microenvironment.
Collapse
Affiliation(s)
- Nilanjan Dey
- Department of Organic Chemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Dipen Biswakarma
- Department of Organic Chemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Alankriti Bajpai
- Department of Chemistry, Indian Institute of Technology Kalyanpur, Kanpur, Uttar Pradesh, 208016
| | - Jarugu Narasimha Moorthy
- Department of Chemistry, Indian Institute of Technology Kalyanpur, Kanpur, Uttar Pradesh, 208016
| | - Santanu Bhattacharya
- Department of Organic Chemistry, Indian Institute of Science, Bangalore, 560012, India.,Current Address: Director's Research Unit, Indian Association for Cultivation of Science, Kolkata, 700032, India
| |
Collapse
|
34
|
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.
Collapse
|
35
|
Demianets I, Hunt JR, Dawlaty JM, Williams TJ. Optical pKa Control in a Bifunctional Iridium Complex. Organometallics 2019. [DOI: 10.1021/acs.organomet.8b00778] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ivan Demianets
- Donald P. and Katherine B. Loker Hydrocarbon Institute and Department of Chemistry, University of Southern California, Los Angeles, California 90089-1661, United States
| | - Jonathan R. Hunt
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Jahan M. Dawlaty
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Travis J. Williams
- Donald P. and Katherine B. Loker Hydrocarbon Institute and Department of Chemistry, University of Southern California, Los Angeles, California 90089-1661, United States
| |
Collapse
|
36
|
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.
Collapse
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
| |
Collapse
|
37
|
Liu X, Wei X, Zhou H, Meng S, Zhao Y, Xue J, Zheng X. UV and Resonance Raman Spectroscopic and Theoretical Studies on the Solvent-Dependent Ground and Excited-State Thione → Thiol Tautomerization of 4,6-Dimethyl-2-mercaptopyrimidine (DMMP). J Phys Chem A 2018; 122:5710-5720. [PMID: 29889517 DOI: 10.1021/acs.jpca.8b04525] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The vibrational spectra of 4,6-dimethyl-2-mercaptopyrimidine (DMMP) in acetonitrile, methanol, and water were assigned by resonance Raman spectroscopy through a combination of Fourier-transform infrared spectroscopy (FT-IR), FT-Raman UV-vis spectroscopy, and density functional theoretical (DFT) calculations. The FT-Raman spectra show that the neat solid DMMP is formed as a dimer due to intermolecular hydrogen bonding. In methanol and water, however, the majority of the Raman spectra were assigned to the vibrational modes of DMMP(solvent) n ( n = 1-4) clusters containing NH···O hydrogen bonds. The intermolecular NH···O hydrogen bond interactions, which are key constituents of the stable DMMP thione structure, revealed significant structural differences in acetonitrile, methanol, and water. In addition, UV-induced hydrogen transfer isomeric reactions between the thione and thiol forms of DMMP were detected in water and acetonitrile. DFT calculations indicate that the observed thione → thiol tautomerization should occur easily in lower excited states in acetonitrile and water.
Collapse
|
38
|
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
| |
Collapse
|
39
|
Chen YH, Sung R, Sung K. Synthesis and Properties of the p-Sulfonamide Analogue of the Green Fluorescent Protein (GFP) Chromophore: The Mimic of GFP Chromophore with Very Strong N-H Photoacid Strength. Org Lett 2018. [PMID: 29527893 DOI: 10.1021/acs.orglett.8b00257] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The para-sulfonamide analogue ( p-TsABDI) of a green fluorescent protein (GFP) chromophore was synthesized to mimic the GFP chromophore. Its S1 excited-state p Ka* value in dimethylsulfoxide (DMSO) is -1.5, which is strong enough to partially protonate dipolar aprotic solvents and causes excited-state proton transfer (ESPT), so it can partially mimic the GFP chromophore to further study the ESPT-related photophysics and the blinking phenomenon of GFP. In comparison with 8-hydroxypyrene-1,3,6-trisulfonate (HPTS) (p Ka = 7.4, p Ka* = 1.3 in water), p-TsABDI (p Ka = 6.7, p Ka* = -1.5 in DMSO) is a better photoacid for pH-jump studies.
Collapse
Affiliation(s)
- Yi-Hui Chen
- Department of Chemistry , National Cheng Kung University , Tainan , Taiwan
| | - Robert Sung
- Department of Chemistry , National Cheng Kung University , Tainan , Taiwan
| | - Kuangsen Sung
- Department of Chemistry , National Cheng Kung University , Tainan , Taiwan
| |
Collapse
|
40
|
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.
Collapse
Affiliation(s)
- Yu-Fu Wang
- Department of Chemistry, National Taiwan University, Taipei City 106, Taiwan.
| | | |
Collapse
|
41
|
Hong YH, Cheong BS, Cho HG. Excited-State Proton Transfer Reaction of Pyranine in Aqueous Sugar and Alcohol Solutions Investigated by Fluorescence Spectroscopy. B KOREAN CHEM SOC 2017. [DOI: 10.1002/bkcs.11293] [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)
- Young-Ho Hong
- Department of Chemistry; Incheon National University; Incheon 22012 South Korea
| | - Byeong-Seo Cheong
- Department of Chemistry; Incheon National University; Incheon 22012 South Korea
| | - Han-Gook Cho
- Department of Chemistry; Incheon National University; Incheon 22012 South Korea
| |
Collapse
|
42
|
Awasthi AA, Singh PK. Excited-State Proton Transfer on the Surface of a Therapeutic Protein, Protamine. J Phys Chem B 2017; 121:10306-10317. [PMID: 29032681 DOI: 10.1021/acs.jpcb.7b07151] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Proton transfer reactions on biosurfaces play an important role in a myriad of biological processes. Herein, the excited-state proton transfer reaction of 8-hydroxypyrene-1,3,6-trisulfonate (HPTS) has been investigated in the presence of an important therapeutic protein, Protamine (PrS), using ground-state absorption, steady-state, and detailed time-resolved emission measurements. HPTS forms a 1:1 complex with Protamine with a high association constant of 2.6 × 104 M-1. The binding of HPTS with Protamine leads to a significant modulation in the ground-state prototropic equilibrium causing a downward shift of 1.1 unit in the acidity constant (pKa). In contrast to a large number of reports of slow proton transfer of HPTS on biosurfaces, interestingly, HPTS registers a faster proton transfer event in the presence of Protamine as compared to that of even the bulk aqueous buffer medium. Furthermore, the dimensionality of the proton diffusion process is also significantly reduced on the surface of Protamine that is in contrast to the behavior of HPTS in the bulk aqueous buffer medium, where the proton diffusion process is three-dimensional. The effect of ionic strength on the binding of HPTS toward PrS suggests a predominant role of electrostatic interaction between anionic HPTS and cationic Protamine, which is further supported by molecular docking simulations which predict that the most preferable binding site for HPTS on the surface of Protamine is surrounded by multiple cationic arginine residues.
Collapse
Affiliation(s)
| | - Prabhat K Singh
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre , Mumbai 400085, India.,Homi Bhabha National Institute , Training School Complex, Anushaktinagar, Mumbai 400094, India
| |
Collapse
|
43
|
Amdursky N, Rashid MH, Stevens MM, Yarovsky I. Exploring the binding sites and proton diffusion on insulin amyloid fibril surfaces by naphthol-based photoacid fluorescence and molecular simulations. Sci Rep 2017; 7:6245. [PMID: 28740173 PMCID: PMC5524688 DOI: 10.1038/s41598-017-06030-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 06/09/2017] [Indexed: 11/18/2022] Open
Abstract
The diffusion of protons along biological surfaces and the interaction of biological structures with water are fundamental areas of interest in biology and chemistry. Here, we examine the surface of insulin amyloid fibrils and follow the binding of small molecules (photoacids) that differ according to the number and location of their sulfonic groups. We use transient fluorescence combined with a spherically-symmetric diffusion theory to show that the binding mode of different photoacids determines the efficiency of proton dissociation from the photoacid and the dimensionality of the proton’s diffusion. We use molecular dynamics simulations to examine the binding mode and mechanism of the photoacids and its influence on the unique kinetic rates and diffusion properties of the photoacid’s dissociated proton, where we also suggest a proton transfer process between one of the photoacids to proximal histidine residues. We show that the photoacids can be used as fluorescent markers for following the progression of amyloidogenic processes. The detailed characterisation of different binding modes to the surface of amyloid fibrils paves the way for better understanding of the binding mechanism of small molecules to amyloid fibrils.
Collapse
Affiliation(s)
- Nadav Amdursky
- Department of Materials, Department of Bioengineering and Institute of Biomedical Engineering, Imperial College London, London, SW7 2AZ, United Kingdom. .,Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, 3200003, Israel.
| | - M Harunur Rashid
- School of Engineering, RMIT University, Melbourne, Victoria, 3001, Australia
| | - Molly M Stevens
- Department of Materials, Department of Bioengineering and Institute of Biomedical Engineering, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Irene Yarovsky
- School of Engineering, RMIT University, Melbourne, Victoria, 3001, Australia.
| |
Collapse
|
44
|
Xiao H, Ma L, Fang W, Chen X. A pOH Jump Driven by N═N Out-of-Plane Motion in the Photoisomerization of Water-Solvated Triazabutadiene. J Phys Chem A 2017; 121:4939-4947. [DOI: 10.1021/acs.jpca.7b04817] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hongmei Xiao
- Key Laboratory of Theoretical
and Computational Photochemistry of Ministry of Education, Department
of Chemistry, Beijing Normal University, Xin-wai-da-jie No. 19, Beijing, 100875, Peoplés Republic of China
| | - Lishuang Ma
- Key Laboratory of Theoretical
and Computational Photochemistry of Ministry of Education, Department
of Chemistry, Beijing Normal University, Xin-wai-da-jie No. 19, Beijing, 100875, Peoplés Republic of China
| | - Weihai Fang
- Key Laboratory of Theoretical
and Computational Photochemistry of Ministry of Education, Department
of Chemistry, Beijing Normal University, Xin-wai-da-jie No. 19, Beijing, 100875, Peoplés Republic of China
| | - Xuebo Chen
- Key Laboratory of Theoretical
and Computational Photochemistry of Ministry of Education, Department
of Chemistry, Beijing Normal University, Xin-wai-da-jie No. 19, Beijing, 100875, Peoplés Republic of China
| |
Collapse
|
45
|
Simkovitch R, Gajst O, Zelinger E, Yarden O, Huppert D. Irradiation by blue light in the presence of a photoacid confers changes to colony morphology of the plant pathogen Colletotrichum gloeosporioides. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2017; 174:1-9. [PMID: 28738309 DOI: 10.1016/j.jphotobiol.2017.06.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 06/26/2017] [Accepted: 06/27/2017] [Indexed: 11/26/2022]
Abstract
We used the photoacid 8-hydroxy-1,3,6-pyrenetrisulfonate (HPTS) that converts blue photons to acidic protons in water, with an efficiency of close to 100%, and determined that this treatment conferred changes to colony morphology of the plant pathogen Colletotrichum gloeosporioides. The time elapsed until hyphal collapse is noticed depends on both the laser intensity in mW/cm2, and the concentration of HPTS in the Agar hydrogel. The time elapsed until hyphal collapse is noticed varies by only ±8% at HPTS concentrations of 500μM and at lower concentrations of HPTS the variance increases as the inverse of the concentration. We found that the effect on C. gloeosporioides was photoacid concentration and irradiation dose dependent. In the presence of 500μM of HPTS within the agar hydrogel-based medium, hyphae collapsed after 37±3.5min of irradiation at 405nm at an intensity of 25mW/cm2. We propose two mechanisms for such photo-alteration of C. gloeosporioides. One is based on the pH drop in the extracellular environment by the photo-protolytic process that the photoacid molecule undergoes. The second mechanism is based on an intracellular mechanism in which there is an uptake of HPTS into the interior of the fungus. We suggest that both mechanisms for photo-alteration which we found in this study may occur in plants during fungal infection.
Collapse
Affiliation(s)
- Ron Simkovitch
- Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Oren Gajst
- Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Einat Zelinger
- The Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Oded Yarden
- The Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Dan Huppert
- Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel.
| |
Collapse
|
46
|
Abstract
Steady-state and time-resolved UV-vis spectroscopies were used to study the photoprotolytic properties of lumazine, which belongs to a class of biologically important compounds-the petridines. We found that in water an excited-state proton transfer occurs with a time constant of ∼70 ps and competes with a nonradiative rate of about the same value. The nonradiative rate of the protonated form of lumazine in polar and nonpolar solvents is large knr ≥ 1.5 × 1010s-1. The fluorescence properties indicate that in water, the ground-state neutral form of lumazine is already stable in two tautomeric forms. The fluorescence of the deprotonated form is quenched by protons in acidic solutions with a diffusion-controlled reaction rate. We conclude that the neutral form of lumazine is an irreversible mild photoacid.
Collapse
Affiliation(s)
- Ron Simkovitch
- 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
| |
Collapse
|
47
|
Safko TM, Jiang S, Zhang L, Zhang Q, Weiss RG. Proton-coupled charge-transfer reactions and photoacidity of N,N-dimethyl-3-arylpropan-1-ammonium chloride salts. Photochem Photobiol Sci 2017; 16:972-984. [DOI: 10.1039/c7pp00044h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Excited-state, intermolecular proton-transfers of aromatics tethered to ammonium groups are solvent mediated and coupled to either the formation of an exciplex or a solvent-separated ion pair.
Collapse
Affiliation(s)
| | - Shenlong Jiang
- Hefei National Laboratory for Physical Sciences at the Microscale
- Department of Chemical Physics
- Synergetic Innovation Center of Quantum Information and Quantum Physics
- University of Science and Technology of China
- Hefei
| | - Lei Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale
- Department of Chemical Physics
- Synergetic Innovation Center of Quantum Information and Quantum Physics
- University of Science and Technology of China
- Hefei
| | - Qun Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale
- Department of Chemical Physics
- Synergetic Innovation Center of Quantum Information and Quantum Physics
- University of Science and Technology of China
- Hefei
| | - Richard G. Weiss
- Department of Chemistry
- Georgetown University
- Washington
- USA
- Institute for Soft Matter Synthesis and Metrology
| |
Collapse
|
48
|
Jankowska J, Barbatti M, Sadlej J, Sobolewski AL. Tailoring the Schiff base photoswitching – a non-adiabatic molecular dynamics study of substituent effect on excited state proton transfer. Phys Chem Chem Phys 2017; 19:5318-5325. [DOI: 10.1039/c6cp08545h] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Dynamics reveals how to design chemical substitutions to control excited-state proton transfer efficiency.
Collapse
Affiliation(s)
- Joanna Jankowska
- Institute of Physics
- Polish Academy of Sciences
- 02-668 Warsaw
- Poland
- Faculty of Chemistry
| | | | - Joanna Sadlej
- Faculty of Chemistry
- University of Warsaw
- 02-093 Warsaw
- Poland
| | | |
Collapse
|
49
|
Joung JF, Kim S, Park S. Ionic effects on the proton transfer mechanism in aqueous solutions. Phys Chem Chem Phys 2017; 19:25509-25517. [DOI: 10.1039/c7cp04392a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Proton dissociation (PD) reactions of weak acids and proton transfer (PT) processes in aqueous solutions are strongly influenced by ions.
Collapse
Affiliation(s)
| | - Sangin Kim
- Department of Chemistry
- Korea University
- Seoul
- Korea
| | - Sungnam Park
- Department of Chemistry
- Korea University
- Seoul
- Korea
| |
Collapse
|
50
|
Heo W, Uddin N, Park JW, Rhee YM, Choi CH, Joo T. Coherent intermolecular proton transfer in the acid–base reaction of excited state pyranine. Phys Chem Chem Phys 2017; 19:18243-18251. [DOI: 10.1039/c7cp01944k] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The acidic proton in pyranine is transferred coherently to acetate through the stretching motion of the whole molecule.
Collapse
Affiliation(s)
- Wooseok Heo
- Department of Chemistry
- Pohang University of Science and Technology (POSTECH)
- Pohang 37673
- South Korea
| | - Nizam Uddin
- Department of Chemistry
- Kyunpook National University
- Daegu 41566
- South Korea
| | - Jae Woo Park
- Department of Chemistry
- Pohang University of Science and Technology (POSTECH)
- Pohang 37673
- South Korea
| | - Young Min Rhee
- Department of Chemistry
- Pohang University of Science and Technology (POSTECH)
- Pohang 37673
- South Korea
| | - Cheol Ho Choi
- Department of Chemistry
- Kyunpook National University
- Daegu 41566
- South Korea
| | - Taiha Joo
- Department of Chemistry
- Pohang University of Science and Technology (POSTECH)
- Pohang 37673
- South Korea
| |
Collapse
|