1
|
Mandal I, Karimova NV, Zakai I, Gerber RB. Formation of Chlorine in the Atmosphere by Reaction of Hypochlorous Acid with Seawater. J Phys Chem Lett 2024; 15:432-438. [PMID: 38189241 DOI: 10.1021/acs.jpclett.3c03035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
The highly reactive dihalogens play a significant role in the oxidative chemistry of the troposphere. One of the main reservoirs of these halogens is hypohalous acids, HOX, which produce dihalogens in the presence of halides (Y-), where X, Y = Cl, Br, I. These reactions occur in and on aerosol particles and seawater surfaces and have been studied experimentally and by field observations. However, the mechanisms of these atmospheric reactions are still unknown. Here, we establish the atomistic mechanism of HOCl + Cl- → Cl2 + OH- at the surface of the water slab by performing ab initio molecular dynamics (AIMD) simulations. Main findings are (1) This reaction proceeds by halogen-bonded complexes of (HOCl)···(Cl-)aq surrounded with the neighboring water molecules. (2) The halogen bonded (HOCl)···(Cl-)aq complexes undergo charge transfer from Cl- to OH- to form transient Cl2 at neutral pH. (3) The addition of a proton to one proximal water greatly facilitates the Cl2 formation, which explains the enhanced rate at low pH.
Collapse
Affiliation(s)
- Imon Mandal
- The Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Natalia V Karimova
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Itai Zakai
- The Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - R Benny Gerber
- The Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- Department of Chemistry, University of California, Irvine, California 92697, United States
| |
Collapse
|
2
|
Daub CD, Zakai I, Valiev R, Salo VT, Gerber RB, Kurtén T. Energy transfer, pre-reactive complex formation and recombination reactions during the collision of peroxy radicals. Phys Chem Chem Phys 2022; 24:10033-10043. [PMID: 35415732 DOI: 10.1039/d1cp04720e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In this paper we study collisions between polyatomic radicals - an important process in fields ranging from biology to combustion. Energy transfer, formation of intermediate complexes and recombination reactions are treated, with applications to peroxy radicals in atmospheric chemistry. Multi-reference perturbation theory, supplemented by coupled-cluster calculations, describes the potential energy surfaces with high accuracy, including the interaction of singlet and triplet spin states during radical recombination. Our multi-reference molecular dynamics (MD) trajectories on methyl peroxy radicals confirm the reaction mechanism postulated in earlier studies. Specifically, they show that if suitable pre-reactive complexes are formed, they will rapidly lead to the formation and subsequent decomposition of tetroxide intermediates. However, generating multi-reference MD trajectories is exceedingly computationally demanding, and we cannot adequately sample the whole conformational space. To answer this challenge, we promote the use of a novel simplified semi-empirical MD methodology. It assumes the collision is governed by two states, a singlet (S0) and a triplet (T1) state. The method predicts differences between collisions on S0 and T1 surfaces, and qualitatively includes not only pre-reactive complex formation, but also recombination processes such as tetroxide formation. Finally, classical MD simulations using force-fields for non-reactive collisions are employed to generate thousands of collision trajectories, to verify that the semi-empirical method is sampling collisions adequately, and to carry out preliminary investigations of larger systems. For systems with low activation energies, the experimental rate coefficient is surprisingly well reproduced by simply multiplying the gas-kinetic collision rate by the simulated probability for long-lived complex formation.
Collapse
Affiliation(s)
| | - Itai Zakai
- Department of Chemistry, Hebrew University of Jerusalem, Jerusalem, Israel.
| | - Rashid Valiev
- Department of Chemistry, University of Helsinki, P.O. Box 55, Helsinki 00014, Finland.
| | - Vili-Taneli Salo
- Department of Chemistry, University of Helsinki, P.O. Box 55, Helsinki 00014, Finland.
| | - R Benny Gerber
- Department of Chemistry, Hebrew University of Jerusalem, Jerusalem, Israel. .,Department of Chemistry, University of California Irvine, Irvine, CA 92697, USA
| | - Theo Kurtén
- Department of Chemistry, University of Helsinki, P.O. Box 55, Helsinki 00014, Finland.
| |
Collapse
|
3
|
Stropoli SJ, Khuu T, Messinger JP, Karimova NV, Boyer MA, Zakai I, Mitra S, Lachowicz AL, Yang N, Edington SC, Gerber RB, McCoy AB, Johnson MA. Preparation and Characterization of the Halogen-Bonding Motif in the Isolated Cl -·IOH Complex with Cryogenic Ion Vibrational Spectroscopy. J Phys Chem Lett 2022; 13:2750-2756. [PMID: 35315676 DOI: 10.1021/acs.jpclett.2c00218] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In the presence of a halide ion, hypohalous acids can adopt two binding motifs upon formation of the ion-molecule complexes [XHOY]- (X, Y = Cl, Br, I): a hydrogen (HB) bond to the acid OH group and a halogen (XB) bond between the anion and the acid halogen. Here we isolate the X-bonded Cl-·IOH ion-molecule complex by collisions of I-·(H2O)n clusters with HOCl vapor and measure its vibrational spectrum by IR photodissociation of the H2-tagged complex. Anharmonic analysis of its vibrational band pattern reveals that formation of the XB complex results in dramatic lowering of the HOI bending fundamental frequency and elongation of the O-I bond (by 168 cm-1 and 0.13 Å, respectively, relative to isolated HOI). The frequency of the O-I stretch (estimated 436 cm-1) is also encoded in the spectrum by the weak v = 0 → 2 overtone transition at 872 cm-1.
Collapse
Affiliation(s)
- Santino J Stropoli
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Thien Khuu
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Joseph P Messinger
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Natalia V Karimova
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States
| | - Mark A Boyer
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Itai Zakai
- Institute of Chemistry and the Fritz-Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem 91905, Israel
| | - Sayoni Mitra
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Anton L Lachowicz
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Nan Yang
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Sean C Edington
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - R Benny Gerber
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States
- Institute of Chemistry and the Fritz-Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem 91905, Israel
| | - Anne B McCoy
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Mark A Johnson
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| |
Collapse
|
4
|
Zakai I, Grinstein D, Welner S, Gerber RB. Structures, Stability, and Decomposition Dynamics of the Polynitrogen Molecule N5+B(N3)4– and Its Dimer [N5+]2[B(N3)4–]2. J Phys Chem A 2019; 123:7384-7393. [DOI: 10.1021/acs.jpca.9b03704] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Itai Zakai
- Institute of Chemistry and The Fritz Haber Research Center, The Hebrew University, Jerusalem 9190401, Israel
| | - Dan Grinstein
- Institute of Chemistry and The Fritz Haber Research Center, The Hebrew University, Jerusalem 9190401, Israel
| | - Shmuel Welner
- Institute of Chemistry and The Fritz Haber Research Center, The Hebrew University, Jerusalem 9190401, Israel
| | - R. Benny Gerber
- Institute of Chemistry and The Fritz Haber Research Center, The Hebrew University, Jerusalem 9190401, Israel
- Department of Chemistry, University of California, Irvine, California 92697, United States
| |
Collapse
|
5
|
Zakai I, Varner ME, Gerber RB. Concerted transfer of multiple protons in acid-water clusters: [(HCl)(H 2O)] 2 and [(HF)(H 2O)] 4. Phys Chem Chem Phys 2017; 19:20641-20646. [PMID: 28737803 DOI: 10.1039/c7cp04006g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Molecular dynamics simulations using directly ab initio potentials are carried out for the ionically bonded clusters [(Cl-)(H3O+)]2 and [(F-)(H3O+)]4 to explore their transitions to the hydrogen-bonded [(HCl)(H2O)]2 and [(HF)(H2O)]4 structures during the first picosecond of simulation. Both the ionic and the H-bonded structures that are formed are highly symmetric. It is found that proton transfers are concerted in all trajectories for [(Cl-)(H3O+)]2. For [(F-)(H3O+)]4, the fully concerted mechanism is dominant but partially concerted transfers of two or three protons at the same time also occur. The concerted mechanism also holds for the reverse process of ionization of neutral acid molecules. It is suggested that the high symmetry of the ionic and the H-bonded structures plays a role in the preference for concerted transfers. Possible implications of the results for proton transfers in other systems are discussed.
Collapse
Affiliation(s)
- I Zakai
- Institute of Chemistry and The Fritz Haber Research Center, The Hebrew University, Jerusalem 91904, Israel
| | | | | |
Collapse
|