1
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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.
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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
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2
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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.
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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
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3
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Antalicz B, Versluis J, Bakker HJ. Observing Aqueous Proton-Uptake Reactions Triggered by Light. J Am Chem Soc 2023; 145:6682-6690. [PMID: 36940392 PMCID: PMC10064335 DOI: 10.1021/jacs.2c11441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2023]
Abstract
Proton-transfer reactions in water are essential to chemistry and biology. Earlier studies reported on aqueous proton-transfer mechanisms by observing light-triggered reactions of strong (photo)acids and weak bases. Similar studies on strong (photo)base-weak acid reactions would also be of interest because earlier theoretical works found evidence for mechanistic differences between aqueous H+ and OH- transfer. In this work, we study the reaction of actinoquinol, a water-soluble strong photobase, with the water solvent and the weak acid succinimide. We find that in aqueous solutions containing succinimide, the proton-transfer reaction proceeds via two parallel and competing reaction channels. In the first channel, actinoquinol extracts a proton from water, after which the newly generated hydroxide ion is scavenged by succinimide. In the second channel, succinimide forms a hydrogen-bonded complex with actinoquinol and the proton is transferred directly. Interestingly, we do not observe proton conduction in water-separated actinoquinol-succinimide complexes, which makes the newly studied strong base-weak acid reaction essentially different from previously studied strong acid-weak base reactions.
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Affiliation(s)
- Balázs Antalicz
- AMOLF, Ultrafast Spectroscopy, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Jan Versluis
- AMOLF, Ultrafast Spectroscopy, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Huib J Bakker
- AMOLF, Ultrafast Spectroscopy, Science Park 104, 1098 XG Amsterdam, The Netherlands
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4
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Maiti S, Mitra S, Johnson CA, Gronborg KC, Garrett-Roe S, Donaldson PM. pH Jumps in a Protic Ionic Liquid Proceed by Vehicular Proton Transport. J Phys Chem Lett 2022; 13:8104-8110. [PMID: 35997534 PMCID: PMC9442784 DOI: 10.1021/acs.jpclett.2c01457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 08/15/2022] [Indexed: 06/15/2023]
Abstract
The dynamics of excess protons in the protic ionic liquid (PIL) ethylammonium formate (EAF) have been investigated from femtoseconds to microseconds using visible pump mid-infrared probe spectroscopy. The pH jump following the visible photoexcitation of a photoacid (8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt, HPTS) results in proton transfer to the formate of the EAF. The proton transfer predominantly (∼70%) occurs over picoseconds through a preformed hydrogen-bonded tight complex between HPTS and EAF. We investigate the longer-range and longer-time-scale proton-transport processes in the PIL by obtaining the ground-state conjugate base (RO-) dynamics from the congested transient-infrared spectra. The spectral kinetics indicate that the protons diffuse only a few solvent shells from the parent photoacid before recombining with RO-. A kinetic isotope effect of nearly unity (kH/kD ≈ 1) suggests vehicular transfer and the transport of excess protons in this PIL. Our findings provide comprehensive insight into the complete photoprotolytic cycle of excess protons in a PIL.
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Affiliation(s)
- Sourav Maiti
- Central
Laser Facility, RCaH, STFC-Rutherford Appleton
Laboratory, Harwell Science
and Innovation Campus, Didcot OX11 0QX, United Kingdom
| | - Sunayana Mitra
- Department
of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Clinton A. Johnson
- Department
of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Kai C. Gronborg
- Department
of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Sean Garrett-Roe
- Department
of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Paul M. Donaldson
- Central
Laser Facility, RCaH, STFC-Rutherford Appleton
Laboratory, Harwell Science
and Innovation Campus, Didcot OX11 0QX, United Kingdom
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5
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Yang Q, Peng Y, Liu Y. The invalidity of intermolecular proton transfer triggered twisted intramolecular charge transfer in excited state for 2‐(4′‐diethylamino‐2′‐hydroxyphenyl)‐1
H
‐imidazo‐[4,5‐b]pyridine. J CHIN CHEM SOC-TAIP 2022. [DOI: 10.1002/jccs.202200293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Qian Yang
- Department of Physics, College of Physical Science and Technology Bohai University Jinzhou China
| | - Ya‐Jing Peng
- Department of Physics, College of Physical Science and Technology Bohai University Jinzhou China
| | - Yu‐Hui Liu
- Department of Physics, College of Physical Science and Technology Bohai University Jinzhou China
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian China
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6
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Bhide R, Feltenberger CN, Phun GS, Barton G, Fishman D, Ardo S. Quantification of Excited-State Brønsted-Lowry Acidity of Weak Photoacids Using Steady-State Photoluminescence Spectroscopy and a Driving-Force-Dependent Kinetic Theory. J Am Chem Soc 2022; 144:14477-14488. [PMID: 35917469 DOI: 10.1021/jacs.2c00554] [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
Photoacids and photobases constitute a class of molecules that upon absorption of light undergoes a reversible change in acidity, i.e. pKa. Knowledge of the excited-state pKa value, pKa*, is critical for predicting excited-state proton-transfer behavior. A reasonable approximation of pKa* is possible using the Förster cycle analysis, but only when the ground-state pKa is known. This poses a challenge for the study of weak photoacids (photobases) with less acidic (basic) excited states (pKa* (pKb*) > 7), because ground-state pKa (pKb) values are >14, making it difficult to quantify them accurately in water. Another method to determine pKa* relies on acid-base titrations with photoluminescence detection and Henderson-Hasselbalch analysis. This method requires that the acid dissociation reaction involving the thermally equilibrated electronic excited state reaches chemical quasi-equilibrium, which does not occur for weak photoacids (photobases) due to slow rates of excited-state proton transfer. Herein, we report a method to overcome these limitations. We demonstrate that liquid water and aqueous hydroxide are unique proton-accepting quenchers of excited-state photoacids. We determine that Stern-Volmer quenching analysis is appropriate to extract rate constants for excited-state proton transfer in aqueous solutions from a weak photoacid, 5-aminonaphthalene-1-sulfonate, to a series of proton-accepting quenchers. Analysis of these data by Marcus-Cohen bond-energy-bond-order theory yields an accurate value for pKa* of 5-aminonaphthalene-1-sulfonate. Our method is broadly accessible because it only requires readily available steady-state photoluminescence spectroscopy. Moreover, our results for weak photoacids are consistent with those from previous studies of strong photoacids, each showing the applicability of kinetic theories to interpret driving-force-dependent rate constants for proton-transfer reactions.
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Affiliation(s)
- Rohit Bhide
- Department of Chemistry, University of California─Irvine, Irvine, California 92697, United States
| | - Cassidy N Feltenberger
- 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
| | - Grant Barton
- Department of Chemistry, University of California─Irvine, Irvine, California 92697, United States
| | - Dmitry Fishman
- Department of Chemistry, University of California─Irvine, Irvine, California 92697, United States.,Laser Spectroscopy Laboratories, 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
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7
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Photoacid-induced aqueous acid-base reactions probed by femtosecond infrared spectroscopy. Photochem Photobiol Sci 2022; 21:1419-1431. [PMID: 35526216 DOI: 10.1007/s43630-022-00232-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 04/13/2022] [Indexed: 10/18/2022]
Abstract
Acid-base reactions involving an excited photoacid have typically been investigated at high base concentrations, but the mechanisms at low base concentrations require clarification. Herein, the dynamics of acid-base reactions induced by an excited photoacid, pyranine (DA), were investigated in the presence of azide ion (N3-) in D2O solution using femtosecond infrared spectroscopy. Specifically, the spectral characteristics of four species (DA, electronically excited DA (DA*), the conjugate base of DA* (A*-), and the conjugate base of DA (A-)) were probed in the spectral region of 1400-1670 cm-1 in the time range of 1 ps-1 μs. This broad timescale encompassed all the acid-base reactions initiated by photoexcitation at 400 nm; thus, reactions related to both DA* and A- could be probed. Furthermore, changes in the populations of N3- and DN3 were monitored using the absorption bands at 2042 and 2133 cm-1, respectively. Following excitation, approximately half of DA* relaxed to DA with a time constant of 0.44 ± 0.04 ns. The remainder underwent an acid-base reaction to produce A*-, which relaxed to A- with a time constant of 3.9 ± 0.3 ns. The acid-base reaction proceeded via two paths, namely, proton exchange with the added base or simple deuteron release to D2O (protolysis). Notably, all the acid-base reactions were well described by the rate constant at the steady-state limit. Thus, although the acid-base reactions at low base concentrations (< 0.1 M) were diffusion controlled, they could be described using a simple rate equation.
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8
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Kaiser C, Halbritter T, Heckel A, Wachtveitl J. Proton-Transfer Dynamics of Photoacidic Merocyanines in Aqueous Solution. Chemistry 2021; 27:9160-9173. [PMID: 33929051 PMCID: PMC8361770 DOI: 10.1002/chem.202100168] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Indexed: 01/22/2023]
Abstract
Photoacids attract increasing scientific attention, as they are valuable tools to spatiotemporally control proton‐release reactions and pH values of solutions. We present the first time‐resolved spectroscopic study of the excited state and proton‐release dynamics of prominent merocyanine representatives. Femtosecond transient absorption measurements of a pyridine merocyanine with two distinct protonation sites revealed dissimilar proton‐release mechanisms: one site acts as a photoacid generator as its pKa value is modulated in the ground state after photoisomerization, while the other functions as an excited state photoacid which releases its proton within 1.1 ps. With a pKa drop of 8.7 units to −5.5 upon excitation, the latter phenolic site is regarded a super‐photoacid. The 6‐nitro derivative exhibits only a phenolic site with similar, yet slightly less photoacidic characteristics and both compounds transfer their proton to methanol and ethanol. In contrast, for the related 6,8‐dinitro compound an intramolecular proton transfer to the ortho‐nitro group is suggested that is involved in a rapid relaxation into the ground state.
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Affiliation(s)
- Christoph Kaiser
- Institute for Physical and Theoretical Chemistry, Goethe University Frankfurt/Main, Max-von-Laue-Str. 7, 60438, Frankfurt/Main, Germany
| | - Thomas Halbritter
- Current address: Department of Chemistry, Science Institute, University of Iceland, Dunhaga 3, Reykjavik, postcode is missing, Iceland.,Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt/Main, Max-von-Laue-Str. 7, 60438, Frankfurt/Main, Germany
| | - Alexander Heckel
- Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt/Main, Max-von-Laue-Str. 7, 60438, Frankfurt/Main, Germany
| | - Josef Wachtveitl
- Institute for Physical and Theoretical Chemistry, Goethe University Frankfurt/Main, Max-von-Laue-Str. 7, 60438, Frankfurt/Main, Germany
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9
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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.
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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
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10
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Lee C, Chung S, Song H, Rhee YM, Lee E, Joo T. Excited State Proton Transfer of Quinone Cyanine 9: Implications on the Origin of Super‐Photoacidity. CHEMPHOTOCHEM 2020. [DOI: 10.1002/cptc.202000254] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Changmin Lee
- Department of Chemistry Pohang University of Science and Technology (POSTECH) Pohang 37673 Republic of Korea
| | - Seyoung Chung
- Department of Chemistry Pohang University of Science and Technology (POSTECH) Pohang 37673 Republic of Korea
| | - Hayoung Song
- Department of Chemistry Pohang University of Science and Technology (POSTECH) Pohang 37673 Republic of Korea
| | - Young Min Rhee
- Department of Chemistry Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea
| | - Eunsung Lee
- Department of Chemistry Pohang University of Science and Technology (POSTECH) Pohang 37673 Republic of Korea
| | - Taiha Joo
- Department of Chemistry Pohang University of Science and Technology (POSTECH) Pohang 37673 Republic of Korea
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11
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Aminov D, Pines D, Kiefer PM, Daschakraborty S, Hynes JT, Pines E. Intact carbonic acid is a viable protonating agent for biological bases. Proc Natl Acad Sci U S A 2019; 116:20837-20843. [PMID: 31570591 PMCID: PMC6800339 DOI: 10.1073/pnas.1909498116] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Carbonic acid H2CO3 (CA) is a key constituent of the universal CA/bicarbonate/CO2 buffer maintaining the pH of both blood and the oceans. Here we demonstrate the ability of intact CA to quantitatively protonate bases with biologically-relevant pKas and argue that CA has a previously unappreciated function as a major source of protons in blood plasma. We determine with high precision the temperature dependence of pKa(CA), pKa(T) = -373.604 + 16,500/T + 56.478 ln T. At physiological-like conditions pKa(CA) = 3.45 (I = 0.15 M, 37 °C), making CA stronger than lactic acid. We further demonstrate experimentally that CA decomposition to H2O and CO2 does not impair its ability to act as an ordinary carboxylic acid and to efficiently protonate physiological-like bases. The consequences of this conclusion are far reaching for human physiology and marine biology. While CA is somewhat less reactive than (H+)aq, it is more than 1 order of magnitude more abundant than (H+)aq in the blood plasma and in the oceans. In particular, CA is about 70× more abundant than (H+)aq in the blood plasma, where we argue that its overall protonation efficiency is 10 to 20× greater than that of (H+)aq, often considered to be the major protonating agent there. CA should thus function as a major source for fast in vivo acid-base reactivity in the blood plasma, possibly penetrating intact into membranes and significantly helping to compensate for (H+)aq's kinetic deficiency in sustaining the large proton fluxes that are vital for metabolic processes and rapid enzymatic reactions.
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Affiliation(s)
- Daniel Aminov
- Department of Chemistry, Ben-Gurion University of the Negev, 84105 Beer-Sheva, Israel
| | - Dina Pines
- Department of Chemistry, Ben-Gurion University of the Negev, 84105 Beer-Sheva, Israel
| | - Philip M Kiefer
- Department of Chemistry, University of Colorado Boulder, Boulder, CO 80309-0215
| | | | - James T Hynes
- Department of Chemistry, University of Colorado Boulder, Boulder, CO 80309-0215;
- PASTEUR, Départmente de Chimie, Ecole Normale Supérieure, PSL Research University, Sorbonne Université, UPMC Université Paris 06, CNRS, 75005 Paris, France
| | - Ehud Pines
- Department of Chemistry, Ben-Gurion University of the Negev, 84105 Beer-Sheva, Israel;
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12
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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.
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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
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13
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Amoruso G, Taylor VCA, Duchi M, Goodband E, Oliver TAA. Following Bimolecular Excited-State Proton Transfer between Hydroxycoumarin and Imidazole Derivatives. J Phys Chem B 2019; 123:4745-4756. [DOI: 10.1021/acs.jpcb.9b01475] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Giordano Amoruso
- School of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Victoria C. A. Taylor
- School of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
- Bristol Centre for Functional Nanomaterials, School of Physics, University of Bristol, Bristol BS8 1TH, United Kingdom
| | - Marta Duchi
- School of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Emma Goodband
- School of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Thomas A. A. Oliver
- School of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
- Bristol Centre for Functional Nanomaterials, School of Physics, University of Bristol, Bristol BS8 1TH, United Kingdom
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14
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Joung JF, Kim S, Park S. Cationic Effect on the Equilibria and Kinetics of the Excited-State Proton Transfer Reaction of a Photoacid in Aqueous Solutions. J Phys Chem B 2018; 122:5087-5093. [DOI: 10.1021/acs.jpcb.8b00588] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
| | - Sangin Kim
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Sungnam Park
- Department of Chemistry, Korea University, Seoul 02841, Korea
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15
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Van Hoozen BL, Petersen PB. Vibrational tug-of-war: The pKAdependence of the broad vibrational features of strongly hydrogen-bonded carboxylic acids. J Chem Phys 2018; 148:134309. [PMID: 29626887 DOI: 10.1063/1.5026675] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Brian L. Van Hoozen
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA
| | - Poul B. Petersen
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA
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16
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Koeppe B, Pylaeva SA, Allolio C, Sebastiani D, Nibbering ETJ, Denisov GS, Limbach HH, Tolstoy PM. Polar solvent fluctuations drive proton transfer in hydrogen bonded complexes of carboxylic acid with pyridines: NMR, IR and ab initio MD study. Phys Chem Chem Phys 2018; 19:1010-1028. [PMID: 27942642 DOI: 10.1039/c6cp06677a] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
We study a series of intermolecular hydrogen-bonded 1 : 1 complexes formed by chloroacetic acid with 19 substituted pyridines and one aliphatic amine dissolved in CD2Cl2 at low temperature by 1H and 13C NMR and FTIR spectroscopy. The hydrogen bond geometries in these complexes vary from molecular (O-HN) to zwitterionic (O-H-N+) ones, while NMR spectra show the formation of short strong hydrogen bonds in intermediate cases. Analysis of C[double bond, length as m-dash]O stretching and asymmetric CO2- stretching bands in FTIR spectra reveal the presence of proton tautomerism. On the basis of these data, we construct the overall proton transfer pathway. In addition to that, we also study by use of ab initio molecular dynamics the complex formed by chloroacetic acid with 2-methylpyridine, surrounded by 71 CD2Cl2 molecules, revealing a dual-maximum distribution of hydrogen bond geometries in solution. The analysis of the calculated trajectory shows that the proton jumps between molecular and zwitterionic forms are indeed driven by dipole-dipole solvent-solute interactions, but the primary cause of the jumps is the formation/breaking of weak CHO bonds from solvent molecules to oxygen atoms of the carboxylate group.
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Affiliation(s)
- B Koeppe
- Department of Chemistry, Humboldt-Universität zu Berlin, Germany
| | - S A Pylaeva
- Institute of Chemistry, Martin-Luther Universität Halle-Wittenberg, Germany.
| | - C Allolio
- Institute of Chemistry, Martin-Luther Universität Halle-Wittenberg, Germany.
| | - D Sebastiani
- Institute of Chemistry, Martin-Luther Universität Halle-Wittenberg, Germany.
| | - E T J Nibbering
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Berlin, Germany.
| | - G S Denisov
- Department of Physics, St.Petersburg State University, Russia
| | - H-H Limbach
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Germany
| | - P M Tolstoy
- Center for Magnetic Resonance, St. Petersburg State University, Russia.
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17
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Weinstock IA, Schreiber RE, Neumann R. Dioxygen in Polyoxometalate Mediated Reactions. Chem Rev 2017; 118:2680-2717. [DOI: 10.1021/acs.chemrev.7b00444] [Citation(s) in RCA: 196] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ira A. Weinstock
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Roy E. Schreiber
- Department of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ronny Neumann
- Department of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
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18
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Mouhat F, Sorella S, Vuilleumier R, Saitta AM, Casula M. Fully Quantum Description of the Zundel Ion: Combining Variational Quantum Monte Carlo with Path Integral Langevin Dynamics. J Chem Theory Comput 2017; 13:2400-2417. [DOI: 10.1021/acs.jctc.7b00017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Félix Mouhat
- IMPMC, Sorbonne Universités, Université Pierre et Marie Curie Paris 06, CNRS UMR 7590, IRD UMR 206, MNHN, 4 place Jussieu, 75252 Paris, France
| | - Sandro Sorella
- International
School for Advanced Studies (SISSA), Via Bonomea 26, 34136 Trieste, Italy
- INFM Democritos
National Simulation Center, 34151 Trieste, Italy
| | - Rodolphe Vuilleumier
- PASTEUR,
Département de chimie, École normale supérieure,
UPMC Univ Paris 06, CNRS, PSL Research University, 75005 Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, École normale supérieure, CNRS, Processus d’activation
sélective par transfert d’énergie uni-électronique
ou radiatif (PASTEUR), 75005 Paris, France
| | - Antonino Marco Saitta
- IMPMC, Sorbonne Universités, Université Pierre et Marie Curie Paris 06, CNRS UMR 7590, IRD UMR 206, MNHN, 4 place Jussieu, 75252 Paris, France
| | - Michele Casula
- IMPMC, Sorbonne Universités, Université Pierre et Marie Curie Paris 06, CNRS UMR 7590, IRD UMR 206, MNHN, 4 place Jussieu, 75252 Paris, France
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19
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Liu YH, Wang SM, Zhu C, Lin SH. A TDDFT study on the excited-state double proton transfer reaction of 8-hydroxyquinoline along a hydrogen-bonded bridge. NEW J CHEM 2017. [DOI: 10.1039/c7nj01325f] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The mechanism of excited-state multiple proton transfer reaction is demonstrated to be controlled by a hydrogen-bonded bridge.
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Affiliation(s)
- Yu-Hui Liu
- Department of Physics
- College of Mathematics and Physics
- Bohai University
- Jinzhou 121013
- China
| | - Shi-Ming Wang
- Department of Physics
- College of Mathematics and Physics
- Bohai University
- Jinzhou 121013
- China
| | - Chaoyuan Zhu
- Department of Applied Chemistry
- Institute of Molecular Science and Center for Interdisciplinary Molecular Science
- National Chiao-Tung University
- Hsinchu 30010
- Taiwan
| | - Sheng Hsien Lin
- Department of Applied Chemistry
- Institute of Molecular Science and Center for Interdisciplinary Molecular Science
- National Chiao-Tung University
- Hsinchu 30010
- Taiwan
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20
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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.
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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
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21
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Kumpulainen T, Lang B, Rosspeintner A, Vauthey E. Ultrafast Elementary Photochemical Processes of Organic Molecules in Liquid Solution. Chem Rev 2016; 117:10826-10939. [DOI: 10.1021/acs.chemrev.6b00491] [Citation(s) in RCA: 249] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Tatu Kumpulainen
- Department of Physical Chemistry,
Sciences II, University of Geneva, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - Bernhard Lang
- Department of Physical Chemistry,
Sciences II, University of Geneva, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - Arnulf Rosspeintner
- Department of Physical Chemistry,
Sciences II, University of Geneva, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - Eric Vauthey
- Department of Physical Chemistry,
Sciences II, University of Geneva, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
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22
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Hoffmann F, Ekimova M, Bekçioğlu-Neff G, Nibbering ETJ, Sebastiani D. Combined Experimental and Theoretical Study of the Transient IR Spectroscopy of 7-Hydroxyquinoline in the First Electronically Excited Singlet State. J Phys Chem A 2016; 120:9378-9389. [DOI: 10.1021/acs.jpca.6b07843] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Felix Hoffmann
- Institut
für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz
4, 06120 Halle (Saale), Germany
| | - Maria Ekimova
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, 12489 Berlin, Germany
| | - Gül Bekçioğlu-Neff
- Institut
für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz
4, 06120 Halle (Saale), Germany
- Physics
Department, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Erik T. J. Nibbering
- 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
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23
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Eisenhart TT, Howland WC, Dempsey JL. Proton-Coupled Electron Transfer Reactions with Photometric Bases Reveal Free Energy Relationships for Proton Transfer. J Phys Chem B 2016; 120:7896-905. [DOI: 10.1021/acs.jpcb.6b04011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Thomas T. Eisenhart
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| | - William C. Howland
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| | - Jillian L. Dempsey
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
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24
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Alarcos N, Cohen B, Douhal A. A slowing down of proton motion from HPTS to water adsorbed on the MCM-41 surface. Phys Chem Chem Phys 2016; 18:2658-71. [PMID: 26705542 DOI: 10.1039/c5cp04548g] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
We report on the steady-state and femtosecond-nanosecond (fs-ns) behaviour of 8-hydroxypyrene-1,3,6-trisulfonate (pyranine, HPTS) and its interaction with mesoporous silica based materials (MCM-41) in both solid-state and dichloromethane (DCM) suspensions in the absence and presence of water. In the absence of water, HPTS forms aggregates which are characterized by a broad emission spectrum and multiexponential behavior (τsolid-state/DCM = 120 ps, 600 ps, 2.2 ns). Upon interaction with MCM41, the aggregate population is found to be lower, leading to the formation of adsorbed monomers. In the presence of water (1%), HPTS with and without MCM41 materials in DCM suspensions undergoes an excited-state intermolecular proton-transfer (ESPT) reaction in the protonated form (ROH*) producing a deprotonated species (RO(-)*). The long-time emission decays of the ROH* in different systems in the presence of water are multiexponential, and are analysed using the diffusion-assisted geminate recombination model. The obtained proton-transfer and recombination rate constants for HPTS and HPTS/MCM41 complexes in DCM suspensions in the presence of water are kPT = 13 ns(-1), krec = 7.5 Å ns(-1), and kPT = 5.4 ns(-1), krec = 2.2 Å ns(-1), respectively, The slowing down of both processes in the latter case is explained in terms of specific interactions of the dye and of the water molecules with the silica surface. The ultrafast dynamics (fs-regime) of the HPTS/MCM41 complexes in DCM suspensions, without and with water, shows two components which are assigned to intramolecular vibrational-energy relaxation (IVR) (∼120 fs vs. ∼0.8 ps), and vibrational relaxation/cooling (VC), and charge transfer (CT) processes (∼2 ps without water and ∼5 ps with water) of the adsorbed ROH*. Our results provide new knowledge on the interactions and the proton-transfer reaction dynamics of HPTS adsorbed on mesoporous materials.
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Affiliation(s)
- Noemí Alarcos
- Departamento de Química Física, Facultad de Ciencias Ambientales y Bioquímica, and INAMOL, Universidad de Castilla-La Mancha, Avenida Carlos III, S.N., 45071 Toledo, Spain.
| | - Boiko Cohen
- Departamento de Química Física, Facultad de Ciencias Ambientales y Bioquímica, and INAMOL, Universidad de Castilla-La Mancha, Avenida Carlos III, S.N., 45071 Toledo, Spain.
| | - Abderrazzak Douhal
- Departamento de Química Física, Facultad de Ciencias Ambientales y Bioquímica, and INAMOL, Universidad de Castilla-La Mancha, Avenida Carlos III, S.N., 45071 Toledo, Spain.
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25
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Lee MJ, Kang JS, Kang YS, Chung DY, Shin H, Ahn CY, Park S, Kim MJ, Kim S, Lee KS, Sung YE. Understanding the Bifunctional Effect for Removal of CO Poisoning: Blend of a Platinum Nanocatalyst and Hydrous Ruthenium Oxide as a Model System. ACS Catal 2016. [DOI: 10.1021/acscatal.5b02580] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Myeong Jae Lee
- Center
for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, Republic of Korea
- School
of Chemical and Biological Engineering, College of Engineering, Seoul National University, Seoul 151-742, Republic of Korea
| | - Jin Soo Kang
- Center
for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, Republic of Korea
- School
of Chemical and Biological Engineering, College of Engineering, Seoul National University, Seoul 151-742, Republic of Korea
| | - Yun Sik Kang
- Center
for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, Republic of Korea
- School
of Chemical and Biological Engineering, College of Engineering, Seoul National University, Seoul 151-742, Republic of Korea
| | - Dong Young Chung
- Center
for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, Republic of Korea
- School
of Chemical and Biological Engineering, College of Engineering, Seoul National University, Seoul 151-742, Republic of Korea
| | - Heejong Shin
- Center
for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, Republic of Korea
- School
of Chemical and Biological Engineering, College of Engineering, Seoul National University, Seoul 151-742, Republic of Korea
| | - Chi-Yeong Ahn
- Center
for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, Republic of Korea
- School
of Chemical and Biological Engineering, College of Engineering, Seoul National University, Seoul 151-742, Republic of Korea
| | - Subin Park
- Center
for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, Republic of Korea
- School
of Chemical and Biological Engineering, College of Engineering, Seoul National University, Seoul 151-742, Republic of Korea
| | - Mi-Ju Kim
- Center
for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, Republic of Korea
- School
of Chemical and Biological Engineering, College of Engineering, Seoul National University, Seoul 151-742, Republic of Korea
| | - Sungjun Kim
- Center
for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, Republic of Korea
- School
of Chemical and Biological Engineering, College of Engineering, Seoul National University, Seoul 151-742, Republic of Korea
| | - Kug-Seung Lee
- Beamline
Research Division, Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Yung-Eun Sung
- Center
for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, Republic of Korea
- School
of Chemical and Biological Engineering, College of Engineering, Seoul National University, Seoul 151-742, Republic of Korea
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26
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Pines D, Ditkovich J, Mukra T, Miller Y, Kiefer PM, Daschakraborty S, Hynes JT, Pines E. How Acidic Is Carbonic Acid? J Phys Chem B 2016; 120:2440-51. [PMID: 26862781 DOI: 10.1021/acs.jpcb.5b12428] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Carbonic, lactic, and pyruvic acids have been generated in aqueous solution by the transient protonation of their corresponding conjugate bases by a tailor-made photoacid, the 6-hydroxy-1-sulfonate pyrene sodium salt molecule. A particular goal is to establish the pK(a) of carbonic acid H2CO3. The on-contact proton transfer (PT) reaction rate from the optically excited photoacid to the carboxylic bases was derived, with unprecedented precision, from time-correlated single-photon-counting measurements of the fluorescence lifetime of the photoacid in the presence of the proton acceptors. The time-dependent diffusion-assisted PT rate was analyzed using the Szabo-Collins-Kimball equation with a radiation boundary condition. The on-contact PT rates were found to follow the acidity order of the carboxylic acids: the stronger was the acid, the slower was the PT reaction to its conjugate base. The pK(a) of carbonic acid was found to be 3.49 ± 0.05 using both the Marcus and Kiefer-Hynes free energy correlations. This establishes H2CO3 as being 0.37 pK(a) units stronger and about 1 pK(a) unit weaker, respectively, than the physiologically important lactic and pyruvic acids. The considerable acid strength of intact carbonic acid indicates that it is an important protonation agent under physiological conditions.
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Affiliation(s)
- Dina Pines
- Department of Chemistry, Ben-Gurion University of the Negev , P. O. Box 653, Beer-Sheva 84105, Israel
| | - Julia Ditkovich
- Department of Chemistry, Ben-Gurion University of the Negev , P. O. Box 653, Beer-Sheva 84105, Israel
| | - Tzach Mukra
- Department of Chemistry, Ben-Gurion University of the Negev , P. O. Box 653, Beer-Sheva 84105, Israel
| | - Yifat Miller
- Department of Chemistry, Ben-Gurion University of the Negev , P. O. Box 653, Beer-Sheva 84105, Israel
| | - Philip M Kiefer
- Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309-0215, United States
| | - Snehasis Daschakraborty
- Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309-0215, United States
| | - James T Hynes
- Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309-0215, United States.,Ecole Normale Supérieure-PSL Research University, Chemistry Department, Sorbonne Universités-UPMC University Paris 06, CNRS UMR 8640 Pasteur, 24 rue Lhomond, 75005 Paris, France
| | - Ehud Pines
- Department of Chemistry, Ben-Gurion University of the Negev , P. O. Box 653, Beer-Sheva 84105, Israel
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27
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Ditkovich J, Pines D, Pines E. Controlling reactivity by remote protonation of a basic side group in a bifunctional photoacid. Phys Chem Chem Phys 2016; 18:16106-15. [DOI: 10.1039/c5cp07672b] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ultrafast reactivity-switch is achieved by remote-protonation caused by protons diffusing from acidic to basic side-groups of bifunctional photoacids.
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Affiliation(s)
- Julia Ditkovich
- Department of Chemistry
- Ben-Gurion University of the Negev
- Beer-Sheva 84105
- Israel
| | - Dina Pines
- Department of Chemistry
- Ben-Gurion University of the Negev
- Beer-Sheva 84105
- Israel
| | - Ehud Pines
- Department of Chemistry
- Ben-Gurion University of the Negev
- Beer-Sheva 84105
- Israel
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28
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Pines D, Nibbering ETJ, Pines E. Monitoring the Microscopic Molecular Mechanisms of Proton Transfer in Acid-base Reactions in Aqueous Solutions. Isr J Chem 2015. [DOI: 10.1002/ijch.201500057] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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29
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Spies C, Shomer S, Finkler B, Pines D, Pines E, Jung G, Huppert D. Solvent dependence of excited-state proton transfer from pyranine-derived photoacids. Phys Chem Chem Phys 2015; 16:9104-14. [PMID: 24700348 DOI: 10.1039/c3cp55292f] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Steady-state and time-resolved techniques were employed to study the excited-state proton-transfer (ESPT) rate of two newly synthesized 8-hydroxy-1,3,6-pyrenetrisulfonate (pyranine, HPTS) derived photoacids in three protic solvents, water, methanol and ethanol. The ESPT rate constant k(PT) of tris(1,1,1,3,3,3-hexafluoropropan-2-yl)-8-hydroxypyrene-1,3,6-trisulfonate, 1a, whose pK(a)* ~ -4, in water, methanol and ethanol is 3 × 10(11) s(-1), 8 × 10(9) s(-1) and 5 × 10(9) s(-1) respectively. (8-Hydroxy-N1,N3,N6-tris(2-hydroxyethyl)-N1,N3,N6-trimethylpyrene-1,3,6 trisulfonamide, 1b) is a weaker acid than 1a but still a strong photoacid with pK(a)* ~ -1 and the ESPT rate in water, methanol and ethanol is 7 × 10(10) s(-1), 4 × 10(8) s(-1) and 2 × 10(8) s(-1). We qualitatively explain our kinetic results by a Marcus-like free-energy correlation which was found to have a general form suitable for describing proton transfer reactions in both the proton-adiabatic and the proton-non-adiabatic limits.
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Affiliation(s)
- Christian Spies
- Biophysical Chemistry, Saarland University, Campus, Building B2 2, D-66123 Saarbrücken, Germany.
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30
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Snodin D, Teasdale A. Mutagenic Alkyl-Sulfonate Impurities in Sulfonic Acid Salts: Reviewing the Evidence and Challenging Regulatory Perceptions. Org Process Res Dev 2015. [DOI: 10.1021/op500397h] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- David Snodin
- Xiphora Biopharma Consulting, Bristol, BS6 7BG, U.K
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31
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Cuny J, Hassanali AA. Ab Initio Molecular Dynamics Study of the Mechanism of Proton Recombination with a Weak Base. J Phys Chem B 2014; 118:13903-12. [DOI: 10.1021/jp507246e] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Jérôme Cuny
- Laboratoire
de Chimie et Physique Quantiques (LCPQ), Université de Toulouse III [UPS] and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
- Department
of Chemistry and Applied Biosciences, Eidgenössische Technische Hochschule Zürich and Università della Svizzera Italiana, CH-6900 Lugano, Switzerland
| | - Ali A. Hassanali
- Condensed
Matter Physics Section, The Abdus Salaam International Center for Theoretical Physics, Strada Costiera 11, Trieste I-34151, Italy
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32
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Ditkovich J, Mukra T, Pines D, Huppert D, Pines E. Bifunctional Photoacids: Remote Protonation Affecting Chemical Reactivity. J Phys Chem B 2014; 119:2690-701. [DOI: 10.1021/jp509104x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Julia Ditkovich
- Department
of Chemistry, Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva 84105, Israel
| | - Tzach Mukra
- Department
of Chemistry, Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva 84105, Israel
| | - Dina Pines
- Department
of Chemistry, Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva 84105, Israel
| | - Dan Huppert
- Raymond
and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ehud Pines
- Department
of Chemistry, Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva 84105, Israel
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33
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Rivard U, Thomas V, Bruhacs A, Siwick B, Iftimie R. Donor-Bridge-Acceptor Proton Transfer in Aqueous Solution. J Phys Chem Lett 2014; 5:3200-3205. [PMID: 26276332 DOI: 10.1021/jz501378d] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We use ab initio molecular dynamics to study proton transfer in a donor-bridge-acceptor system in which the bridge is a single water molecule and the entire system is embedded in aqueous solution. The results, based on a large number of proton transfer trajectories, demonstrate that the dominant charge-transfer pathway is a subpicosecond "through bridge" event in which the bridge adopts an Eigen-like (hydronium) structure. We also identify another state in which the bridge forms a Zundel-like configuration with the acceptor that appears to be a dead end for the charge transfer. The reaction coordinate is inherently multidimensional and, as we demonstrate, cannot be given in terms of either local structural parameters of the donor-bridge-acceptor system or local solvent coordination numbers.
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Affiliation(s)
- Ugo Rivard
- †Département de Chimie, Université de Montréal, CP 6128, succursale Centre-Ville, Montréal H3C3J7, Canada
| | - Vibin Thomas
- †Département de Chimie, Université de Montréal, CP 6128, succursale Centre-Ville, Montréal H3C3J7, Canada
| | - Andrew Bruhacs
- ‡Departments of Chemistry and Physics, Center for the Physics of Materials, McGill University, 801 Sherbrooke Street West, Montréal H3A2K6, Canada
| | - Bradley Siwick
- ‡Departments of Chemistry and Physics, Center for the Physics of Materials, McGill University, 801 Sherbrooke Street West, Montréal H3A2K6, Canada
| | - Radu Iftimie
- †Département de Chimie, Université de Montréal, CP 6128, succursale Centre-Ville, Montréal H3C3J7, Canada
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34
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Keinan S, Pines D, Kiefer PM, Hynes JT, Pines E. Solvent-Induced O–H Vibration Red-Shifts of Oxygen-Acids in Hydrogen-Bonded O–H···Base Complexes. J Phys Chem B 2014; 119:679-92. [DOI: 10.1021/jp502553r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sharon Keinan
- 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
| | - Philip M. Kiefer
- Department
of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
| | - James T. Hynes
- Department
of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
- Chemistry
Department, École Normale Supérieure, UMR ENS-CNRS-UPMC 8640, 24 rue Lhomond, 75005 Paris, France
| | - Ehud Pines
- Department
of Chemistry, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva, 84105, Israel
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35
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Dagrada M, Casula M, Saitta AM, Sorella S, Mauri F. Quantum Monte Carlo Study of the Protonated Water Dimer. J Chem Theory Comput 2014; 10:1980-93. [DOI: 10.1021/ct401077x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mario Dagrada
- Institut
de Minéralogie, de Physique des Matériaux, et de Cosmochimie
(IMPMC), Sorbonne Universités - UPMC Paris 06, UMR CNRS 7590, Muséum
National d’Histoire Naturelle, IRD UMR 206, 4 Place Jussieu, 75005 Paris, France
| | - Michele Casula
- Institut
de Minéralogie, de Physique des Matériaux, et de Cosmochimie
(IMPMC), Sorbonne Universités - UPMC Paris 06, UMR CNRS 7590, Muséum
National d’Histoire Naturelle, IRD UMR 206, 4 Place Jussieu, 75005 Paris, France
| | - Antonino M. Saitta
- Institut
de Minéralogie, de Physique des Matériaux, et de Cosmochimie
(IMPMC), Sorbonne Universités - UPMC Paris 06, UMR CNRS 7590, Muséum
National d’Histoire Naturelle, IRD UMR 206, 4 Place Jussieu, 75005 Paris, France
| | - Sandro Sorella
- International School for Advanced Studies (SISSA) Via Beirut 2,4 34014 Trieste, Italy and INFM Democritos National Simulation Center, Trieste, Italy
| | - Francesco Mauri
- Institut
de Minéralogie, de Physique des Matériaux, et de Cosmochimie
(IMPMC), Sorbonne Universités - UPMC Paris 06, UMR CNRS 7590, Muséum
National d’Histoire Naturelle, IRD UMR 206, 4 Place Jussieu, 75005 Paris, France
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36
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Bekçioğlu G, Allolio C, Ekimova M, Nibbering ETJ, Sebastiani D. Competition between excited state proton and OH− transport via a short water wire: solvent effects open the gate. Phys Chem Chem Phys 2014; 16:13047-51. [DOI: 10.1039/c4cp00970c] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We investigate the acid–base proton exchange reaction in a microsolvated bifunctional chromophore by means of quantum chemical calculations.
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Affiliation(s)
- Gül Bekçioğlu
- Physics Department
- Freie Universität Berlin
- 14195 Berlin, Germany
- Institut für Chemie
- Martin-Luther-Universität Halle-Wittenberg
| | - Christoph Allolio
- Institut für Chemie
- Martin-Luther-Universität Halle-Wittenberg
- 06120 Halle (Saale), Germany
| | - Maria Ekimova
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie
- D-12489 Berlin, Germany
| | - Erik T. J. Nibbering
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie
- D-12489 Berlin, Germany
| | - Daniel Sebastiani
- Institut für Chemie
- Martin-Luther-Universität Halle-Wittenberg
- 06120 Halle (Saale), Germany
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37
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Sen Mojumdar S, Chowdhury R, Mandal AK, Bhattacharyya K. In what time scale proton transfer takes place in a live CHO cell? J Chem Phys 2013; 138:215102. [PMID: 23758398 DOI: 10.1063/1.4807862] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Supratik Sen Mojumdar
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
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38
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Sigalov MV, Kalish N, Carmeli B, Pines D, Pines E. Probing Small Protonated Water Clusters in Acetonitrile Solutions by 1H NMR. ACTA ACUST UNITED AC 2013. [DOI: 10.1524/zpch.2013.0399] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Abstract
In a previous publication by Kalish et al. (J. Phys. Chem. A 115 (2011) 4063) the existence of well defined small protonated water clusters in acetonitrile has been established by IR spectroscopy. Here we report on a 1H NMR study of triflic acid, CF3SO3H, in acetonitrile-water solutions. Using NMR we are able to corroborate the general solvation scheme we have proposed for the hydrated proton in acetonitrile as a function of the molar ratio between the strong mineral acid and water, n = [H2O]/[acid]. According to this scheme, backed now by both IR absorption spectroscopy and NMR measurements, the very strong triflic acid completely dissociates in acetonitrile/water solutions to yield the aqueous proton and the triflate anion when n > 1. Furthermore, increasing n results in the proton solvated in increasingly larger water clusters formed within the acetonitrile solution.
Clearly distinguishable by NMR are the smallest protonated water clusters, the protonated water monomer, H3
+O, and the protonated water dimer, H5
+O2, which dominate the solution for n = 1,2,3. For larger n the NMR study indicates the gradual increase of the average protonated water cluster size as a function of n while the proton inner solvation core more closely retaining the characteristics of a deformed protonated water dimer, (H2O-H+⋯OH2)
s
than that of the protonated water monomer (H3
+O)
s
.
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Affiliation(s)
- Mark V. Sigalov
- Ben-Gurion University of the Negev, Department of Chemistry, Beer-Sheva 84125, Israel
| | - Noah Kalish
- Ben-Gurion University of the Negev, Department of Chemistry, Beer-Sheva 84125, Israel
| | - Benny Carmeli
- Ben-Gurion University of the Negev, Department of Chemistry, Beer-Sheva 84125, Israel
| | - Dina Pines
- Ben-Gurion University of the Negev, Department of Chemistry, Beer-Sheva 84125, Israel
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39
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Prémont-Schwarz M, Barak T, Pines D, Nibbering ETJ, Pines E. Ultrafast Excited-State Proton-Transfer Reaction of 1-Naphthol-3,6-Disulfonate and Several 5-Substituted 1-Naphthol Derivatives. J Phys Chem B 2013; 117:4594-603. [DOI: 10.1021/jp308746x] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mirabelle Prémont-Schwarz
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Str. 2 A, D-12489 Berlin, Germany
| | - Tamar Barak
- Department of Chemistry, Ben-Gurion University of the Negev,
P.O.B. 653, Beer-Sheva 84105, Israel
| | - Dina Pines
- Department of Chemistry, Ben-Gurion University of the Negev,
P.O.B. 653, Beer-Sheva 84105, Israel
| | - Erik T. J. Nibbering
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Str. 2 A, D-12489 Berlin, Germany
| | - Ehud Pines
- Department of Chemistry, Ben-Gurion University of the Negev,
P.O.B. 653, Beer-Sheva 84105, Israel
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40
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Thomas V, Rivard U, Maurer P, Bruhács A, Siwick BJ, Iftimie R. Concerted and Sequential Proton Transfer Mechanisms in Water-Separated Acid-Base Encounter Pairs. J Phys Chem Lett 2012; 3:2633-2637. [PMID: 26295883 DOI: 10.1021/jz3012639] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The proton transfer mechanisms involved inside aqueous, solvent-separated encounter complexes between phenol and carboxyl moieties are studied using ab initio molecular dynamics and computational time-resolved vibrational spectroscopy. This model framework can be viewed as a ground-state analog of the excited-state proton transfer reactions that have been actively investigated using ultrafast spectroscopy. Three qualitatively distinct proton transfer pathways are observed in the simulations. These can be described as direct concerted, direct sequential, and through bulk transfers. The primary difference between the sequential and concerted mechanism is the involvement of a reaction intermediate in which the proton fluctuates for several picoseconds through the hydrogen bonds connecting donor and acceptor but resides primarily on an intervening water molecule in the encounter complex. These results contribute to our molecular level understanding of the diverse processes involved in proton transfer within water-separated encounter complexes.
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Affiliation(s)
- Vibin Thomas
- †Département de Chimie, Université de Montréal,CP 6128, succursale Centre-Ville, Montréal H3C3J7, Canada
| | - Ugo Rivard
- †Département de Chimie, Université de Montréal,CP 6128, succursale Centre-Ville, Montréal H3C3J7, Canada
| | - Patrick Maurer
- †Département de Chimie, Université de Montréal,CP 6128, succursale Centre-Ville, Montréal H3C3J7, Canada
| | - Andrew Bruhács
- ‡Departments of Chemistry and Physics, Center for the Physics of Materials, McGill University, 801 Sherbrooke Street West, Montréal, Canada
| | - Bradley J Siwick
- ‡Departments of Chemistry and Physics, Center for the Physics of Materials, McGill University, 801 Sherbrooke Street West, Montréal, Canada
| | - Radu Iftimie
- †Département de Chimie, Université de Montréal,CP 6128, succursale Centre-Ville, Montréal H3C3J7, Canada
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41
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Verdel N, Jerman I, Krasovec R, Bukovec P, Zupancic M. Possible time-dependent effect of ions and hydrophilic surfaces on the electrical conductivity of aqueous solutions. Int J Mol Sci 2012; 13:4048-4068. [PMID: 22605965 PMCID: PMC3344201 DOI: 10.3390/ijms13044048] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Revised: 02/28/2012] [Accepted: 03/13/2012] [Indexed: 11/17/2022] Open
Abstract
The purpose of this work was to determine the influence of mechanical and electrical treatment on the electrical conductivity of aqueous solutions. Solutions were treated mechanically by iteration of two steps: 1:100 dilution and vigorous shaking. These two processes were repeated until extremely dilute solutions were obtained. For electrical treatment the solutions were exposed to strong electrical impulses. Effects of mechanical (as well as electrical) treatment could not be demonstrated using electrical conductivity measurements. However, significantly higher conductivity than those of the freshly prepared chemically analogous solutions was found in all aged solutions except for those samples stored frozen. The results surprisingly resemble a previously observed weak gel-like behavior in water stored in closed flasks. We suggest that ions and contact with hydrophilic glass surfaces could be the determinative conditions for the occurrence of this phenomenon.
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Affiliation(s)
- Nada Verdel
- Institute Bion d. o. o., Stegne 21, 1000 Ljubljana, Slovenia; E-Mails: (I.J.); (R.K.)
| | - Igor Jerman
- Institute Bion d. o. o., Stegne 21, 1000 Ljubljana, Slovenia; E-Mails: (I.J.); (R.K.)
| | - Rok Krasovec
- Institute Bion d. o. o., Stegne 21, 1000 Ljubljana, Slovenia; E-Mails: (I.J.); (R.K.)
| | - Peter Bukovec
- Department of Chemistry, University of Ljubljana, Aškerčeva 5, 1000 Ljubljana, Slovenia; E-Mails: (P.B.); (M.Z.)
| | - Marija Zupancic
- Department of Chemistry, University of Ljubljana, Aškerčeva 5, 1000 Ljubljana, Slovenia; E-Mails: (P.B.); (M.Z.)
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42
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Klíčová Ĺ, Šebej P, Šolomek T, Hellrung B, Slavíček P, Klán P, Heger D, Wirz J. Adiabatic Triplet State Tautomerization of p-Hydroxyacetophenone in Aqueous Solution. J Phys Chem A 2012; 116:2935-44. [DOI: 10.1021/jp3011469] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ĺubica Klíčová
- Department
of Chemistry, Faculty
of Science, Masaryk University, Kamenice
5/A8, 625 00 Brno, Czech Republic
| | - Peter Šebej
- Department
of Chemistry, Faculty
of Science, Masaryk University, Kamenice
5/A8, 625 00 Brno, Czech Republic
- Research Centre for Toxic Compounds
in the Environment, Faculty of Science, Masaryk University, Kamenice 3, 625 00 Brno, Czech Republic
| | - Tomáš Šolomek
- Department
of Chemistry, Faculty
of Science, Masaryk University, Kamenice
5/A8, 625 00 Brno, Czech Republic
- Research Centre for Toxic Compounds
in the Environment, Faculty of Science, Masaryk University, Kamenice 3, 625 00 Brno, Czech Republic
- Institute of Chemical Technology, Technická 5, 166 28 Prague, Czech Republic
| | - Bruno Hellrung
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056
Basel, Switzerland
| | - Petr Slavíček
- Institute of Chemical Technology, Technická 5, 166 28 Prague, Czech Republic
| | - Petr Klán
- Department
of Chemistry, Faculty
of Science, Masaryk University, Kamenice
5/A8, 625 00 Brno, Czech Republic
- Research Centre for Toxic Compounds
in the Environment, Faculty of Science, Masaryk University, Kamenice 3, 625 00 Brno, Czech Republic
| | - Dominik Heger
- Department
of Chemistry, Faculty
of Science, Masaryk University, Kamenice
5/A8, 625 00 Brno, Czech Republic
- Research Centre for Toxic Compounds
in the Environment, Faculty of Science, Masaryk University, Kamenice 3, 625 00 Brno, Czech Republic
| | - Jakob Wirz
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056
Basel, Switzerland
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43
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Verdel N, Jerman I, Bukovec P. The "autothixotropic" phenomenon of water and its role in proton transfer. Int J Mol Sci 2011; 12:7481-94. [PMID: 22174612 PMCID: PMC3233418 DOI: 10.3390/ijms12117481] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 10/16/2011] [Accepted: 10/20/2011] [Indexed: 01/25/2023] Open
Abstract
In an experimental study, significantly higher conductivity values than those of freshly prepared chemically analogous solutions were found in aged (~one year old) aqueous solutions, except for those stored frozen. The results surprisingly resemble a previously noticed phenomenon in liquid water, which develops when water is stored in closed vessels. This was observed as a disturbing phenomenon in gravimetric measurements and in luminescence spectroscopy measurements. The phenomenon was termed “autothixotropy of water” due to the weak gel-like behavior which develops spontaneously over time, in which ions seem to play an important role. Here, according to experimental results we propose that contact with hydrophilic surfaces also plays an important role. The role of the “autothixotropy of water” in proton transfer is also discussed.
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Affiliation(s)
- Nada Verdel
- Institute Bion, Stegne 21, 1000 Ljubljana, Slovenia; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +386-41-959-546; Fax: +386-1-513-1147
| | - Igor Jerman
- Institute Bion, Stegne 21, 1000 Ljubljana, Slovenia; E-Mail:
| | - Peter Bukovec
- Department of Inorganic Chemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, 1000 Ljubljana, Slovenia; E-Mail:
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44
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Cohen B, Martin Álvarez C, Alarcos Carmona N, Organero JA, Douhal A. Proton-Transfer Reaction Dynamics within the Human Serum Albumin Protein. J Phys Chem B 2011; 115:7637-47. [DOI: 10.1021/jp200294q] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Boiko Cohen
- Departamento de Química Física, Facultad de Ciencias Ambientales y Bioquímica, and INAMOL, Universidad de Castilla-La Mancha, Avenida Carlos III, S/N, 45071 Toledo, Spain
| | - Cristina Martin Álvarez
- Departamento de Química Física, Facultad de Ciencias Ambientales y Bioquímica, and INAMOL, Universidad de Castilla-La Mancha, Avenida Carlos III, S/N, 45071 Toledo, Spain
| | - Noemí Alarcos Carmona
- Departamento de Química Física, Facultad de Ciencias Ambientales y Bioquímica, and INAMOL, Universidad de Castilla-La Mancha, Avenida Carlos III, S/N, 45071 Toledo, Spain
| | - Juan Angel Organero
- Departamento de Química Física, Facultad de Ciencias Ambientales y Bioquímica, and INAMOL, Universidad de Castilla-La Mancha, Avenida Carlos III, S/N, 45071 Toledo, Spain
| | - Abderrazzak Douhal
- Departamento de Química Física, Facultad de Ciencias Ambientales y Bioquímica, and INAMOL, Universidad de Castilla-La Mancha, Avenida Carlos III, S/N, 45071 Toledo, Spain
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45
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Kalish NBM, Shandalov E, Kharlanov V, Pines D, Pines E. Apparent stoichiometry of water in proton hydration and proton dehydration reactions in CH3CN/H2O solutions. J Phys Chem A 2011; 115:4063-75. [PMID: 21417385 DOI: 10.1021/jp110873t] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Gradual solvation of protons by water is observed in liquids by mixing strong mineral acids with various amounts of water in acetonitrile solutions, a process which promotes rapid dissociation of the acids in these solutions. The stoichiometry of the reaction XH(+) + n(H(2)O) = X + (H(2)O)(n)H(+) was studied for strong mineral acids (negatively charged X, X = ClO(4)¯, Cl¯, Br¯, I¯, CF(3)SO(3)¯) and for strong cationic acids (uncharged X, X = R*NH(2), H(2)O). We have found by direct quantitative analysis preference of n = 2 over n = 1 for both groups of proton transfer reactions at relatively low water concentrations in acetonitrile. At high water concentrations, we have found that larger water solvates must also be involved in the solvation of the proton while the spectral features already observed for n = 2, H(+)(H(2)O)(2), remain almost unchanged at large n values up to at least 10 M of water.
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46
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47
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Maurer P, Thomas V, Iftimie R. A computational study of ultrafast acid dissociation and acid–base neutralization reactions. II. The relationship between the coordination state of solvent molecules and concerted versus sequential acid dissociation. J Chem Phys 2011; 134:094505. [DOI: 10.1063/1.3554654] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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48
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49
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Maurer P, Thomas V, Rivard U, Iftimie R. A computational study of ultrafast acid dissociation and acid-base neutralization reactions. I. The model. J Chem Phys 2010; 133:044108. [PMID: 20687634 DOI: 10.1063/1.3461162] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Ultrafast, time-resolved investigations of acid-base neutralization reactions have recently been performed using systems containing the photoacid 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS) and various Bronsted bases. Two conflicting neutralization mechanisms have been formulated by Mohammed et al. [Science 310, 83 (2005)] and Siwick et al. [J. Am. Chem. Soc. 129, 13412 (2007)] for the same acid-base system. Herein an ab initio molecular dynamics based computational model is formulated, which is able to investigate the validity of the proposed mechanisms in the general context of ground-state acid-base neutralization reactions. Our approach consists of using 2,4,6-tricyanophenol (exp. pKa congruent with 1) as a model for excited-state HPTS( *) (pKa congruent with 1.4) and carboxylate ions for the accepting base. We employ our recently proposed dipole-field/quantum mechanics (QM) treatment [P. Maurer and R. Iftimie, J. Chem. Phys. 132, 074112 (2010)] of the proton donor and acceptor molecules. This approach allows one to tune the free energy of neutralization to any desired value as well as model initial nonequilibrium hydration effects caused by a sudden increase in acidity, making it possible to achieve a more realistic comparison with experimental data than could be obtained via a full-QM treatment of the entire system. It is demonstrated that the dipole-field/QM model reproduces correctly key properties of the 2,4,6-tricyanophenol acid molecule including gas-phase proton dissociation energies and dipole moments, and condensed-phase hydration structure and pKa values.
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Affiliation(s)
- Patrick Maurer
- Département de Chimie, Université de Montréal, CP 6128, succursale Centre-Ville, Canada
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50
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Erez Y, Huppert D. Excited-state intermolecular proton transfer of the firefly's chromophore D-luciferin. J Phys Chem A 2010; 114:8075-82. [PMID: 20684579 DOI: 10.1021/jp103264y] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Steady-state absorption and emission as well as time-resolved emission spectroscopies were employed to study the photophysics and photochemistry of D-luciferin, the firefly active bioluminescent compound. In aqueous solution the electronically excited-state protonated D-luciferin compound undergoes an efficient process of proton transfer to the solvent, with a rate constant k(PT) = 3.0 x 10(10) s(-1). We found a kinetic isotope effect of about 2.5 for this process. The deprotonated form of D-luciferin in the excited state recombines irreversibly with the geminate proton. Hence, the fluorescence decay of the deprotonated form is nonexponential, and the fluorescence quantum yield is low.
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Affiliation(s)
- Yuval Erez
- Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
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