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Dean JLS, Winkler VS, Boyer MA, Sibert EL, Fournier JA. Investigating Intramolecular H Atom Transfer Dynamics in β-Diketones with Ultrafast Infrared Spectroscopies and Theoretical Modeling. J Phys Chem A 2023; 127:9258-9272. [PMID: 37882618 DOI: 10.1021/acs.jpca.3c05417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
Abstract
The vibrational signatures and ultrafast dynamics of the intramolecular H-bond in a series of β-diketones are investigated with 2D IR spectroscopy and computational modeling. The chosen β-diketones exhibit a range of H atom donor-acceptor distances and asymmetry along the H atom transfer coordinate that tunes the intramolecular H-bond strength. The species with the strongest H-bonds are calculated to have very soft H atom potentials, resulting in highly red-shifted OH stretch fundamental frequencies and dislocation of the H atom upon vibrational excitation. These soft potentials lead to significant coupling to the other normal mode coordinates and give rise to the very broad vibrational signatures observed experimentally. The 2D IR spectra in both the OH and OD stretch regions of the light and deuterated isotopologues reveal broadened and long-lived ground-state bleach signatures of the vibrationally hot molecules. Polarization-sensitive transient absorption measurements in the OH and OD stretch regions reveal notable isotopic differences in orientational dynamics. Orientational relaxation was measured to occur on ∼600 fs and ∼2 ps time scales for the light and deuterated isotopologues, respectively. The orientational dynamics are interpreted in terms of activated H/D atom transfer events driven by collective intramolecular structural rearrangements.
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Affiliation(s)
- Jessika L S Dean
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Valerie S Winkler
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Mark A Boyer
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin Madison, Madison, Wisconsin 53706, United States
| | - Edwin L Sibert
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin Madison, Madison, Wisconsin 53706, United States
| | - Joseph A Fournier
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, United States
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Zhang B, Zhang J, Zhang Y, Zuo Q, Zheng H. Ce(IV)-Based Metal-Organic Gel for Ultrafast Removal of Trace Arsenate from Water. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023. [PMID: 37515556 DOI: 10.1021/acs.langmuir.3c01079] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/31/2023]
Abstract
As a potential replacement for metal-organic frameworks (MOFs), constructing metal-organic gels (MOGs) is an appealing but challenging topic since MOGs are a kind of shapeable MOF gels. Also, the rapid adsorption of trace heavy metal ions in aqueous media remains a serious challenge. Herein, a simple strategy for the synthesis of Ce(IV)-based metal-organic gel (Ce-MOG) was first developed for the rapid adsorption of trace As(V). The (NH4)2Ce(NO3)6 obtains hydroxide bridges after adding apposite NaOH, leading to [Ce6O4(OH)4]12+ clustering and inducing fast and excessive nucleation rates, which also leads to coordination disturbance of MOF nanocrystals to obtain Ce-MOG. The Ce-OH groups are the key to gel formation through hydrogen bonding and are the active site for the ultrafast adsorption of As(V). As expected, the resultant Ce-MOG has an excellent adsorption rate, making it possible to effectively decontaminate 500 ppb of As(V) to below the World Health Organization (WHO) recommended threshold for drinking water (10 ppb) within 1 min. It achieves equilibrium adsorption in 10 min, and the final arsenate-removing efficiency reaches 99.8%. For Ce-MOF, the effluent concentration of As(V) is higher than the drinking water standard, while equilibrium adsorption takes 60 min. The initial adsorption rate of Ce-MOG, h(k2qe2) is calculated and indicated to be 67.67 mg g-1 min-1, about 19.96 times that of Ce-MOF (3.39 mg g-1 min-1). As such, the excellent As(V) decontamination rate, selectivity, and reusability of Ce-MOG indicate its great potential for practical drinking water purification.
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Affiliation(s)
- Baichao Zhang
- Engineering Research Center of Ministry of Education for Geological Carbon Storage and Low Carbon Utilization of Resources, Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083, China
| | - Jiejing Zhang
- Engineering Research Center of Ministry of Education for Geological Carbon Storage and Low Carbon Utilization of Resources, Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083, China
| | - Yu Zhang
- Engineering Research Center of Ministry of Education for Geological Carbon Storage and Low Carbon Utilization of Resources, Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083, China
| | - Qi Zuo
- Engineering Research Center of Ministry of Education for Geological Carbon Storage and Low Carbon Utilization of Resources, Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083, China
| | - Hong Zheng
- Engineering Research Center of Ministry of Education for Geological Carbon Storage and Low Carbon Utilization of Resources, Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083, China
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Mang A, Rotthowe N, Beltako K, Linseis M, Pauly F, Winter RF. Single-molecule conductance studies on quasi- and metallaaromatic dibenzoylmethane coordination compounds and their aromatic analogs. NANOSCALE 2023; 15:5305-5316. [PMID: 36811332 DOI: 10.1039/d2nr05670d] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The ability to predict the conductive behaviour of molecules, connected to macroscopic electrodes, represents a crucial prerequisite for the design of nanoscale electronic devices. In this work, we investigate whether the notion of a negative relation between conductance and aromaticity (the so-called NRCA rule) also pertains to quasi-aromatic and metallaaromatic chelates derived from dibenzoylmethane (DBM) and Lewis acids (LAs) that either do or do not contribute two extra dπ electrons to the central resonance-stabilised β-ketoenolate binding pocket. We therefore synthesised a family of methylthio-functionalised DBM coordination compounds and subjected them, along with their truly aromatic terphenyl and 4,6-diphenylpyrimidine congeners, to scanning tunneling microscope break-junction (STM-BJ) experiments on gold nanoelectrodes. All molecules share the common motif of three π-conjugated, six-membered, planar rings with a meta-configuration at the central ring. According to our results, their molecular conductances fall within a factor of ca. 9 in an ordering aromatic < metallaaromatic < quasi-aromatic. The experimental trends are rationalised by quantum transport calculations based on density functional theory (DFT).
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Affiliation(s)
- André Mang
- Chemistry Department, University of Konstanz, 78457 Konstanz, Germany.
| | - Nils Rotthowe
- Chemistry Department, University of Konstanz, 78457 Konstanz, Germany.
| | - Katawoura Beltako
- Physics Department, University of Lomé, 1515 Lomé, Togo
- Institute of Physics, University of Augsburg, 86159 Augsburg, Germany.
| | - Michael Linseis
- Chemistry Department, University of Konstanz, 78457 Konstanz, Germany.
| | - Fabian Pauly
- Institute of Physics, University of Augsburg, 86159 Augsburg, Germany.
| | - Rainer F Winter
- Chemistry Department, University of Konstanz, 78457 Konstanz, Germany.
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Wagen CC, Jacobsen EN. Evidence for Oxonium Ions in Ethereal "Hydrogen Chloride". Org Lett 2022; 24:8826-8831. [PMID: 36450043 PMCID: PMC9879297 DOI: 10.1021/acs.orglett.2c03622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Although solutions of hydrogen chloride in ethereal solvents like diethyl ether or dioxane are commonly employed in the laboratory, the solution structure of these reagents has yet to be firmly established. Here, we analyze solutions of ethereal hydrogen chloride or deuterium chloride in toluene, in dichloromethane, or in the absence of a co-solvent by in situ infrared spectroscopy. The resulting spectra are inconsistent with free HCl or often-proposed 1:1 HCl-ether complexes but closely match the predicted spectra of oxonium ions generated via protonation of diethyl ether. Molecular dynamics simulation of the oxonium chloride complexes provides evidence for an outer-sphere contact ion pair. These results suggest new approaches for tuning the acidity of strong Brønsted acids in organic solvents and demonstrate the importance of conducting spectroscopic measurements under reaction-relevant conditions.
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Affiliation(s)
- Corin C. Wagen
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Eric N. Jacobsen
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
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Tanaka H, Kuwahata K, Tachikawa M, Udagawa T. Low-Barrier Hydrogen Bond in Fujikurin A-D: A Computational Study. ACS OMEGA 2022; 7:14244-14251. [PMID: 35559150 PMCID: PMC9089377 DOI: 10.1021/acsomega.2c00857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 04/05/2022] [Indexed: 06/15/2023]
Abstract
The compounds Fujikurin A, B, and D, recently isolated from Fusarium fujikuroi, possess intramolecular low-barrier hydrogen bonds (LBHBs), which are hydrogen bonds with a very low-energy barrier for proton transfer. The isolated compounds have a hydrogen-bonded proton that appears to rapidly switch between two equilibrium states via a transition state (TS). To understand the characteristics of these intramolecular LBHBs in detail, we performed path integral molecular dynamics (PIMD) simulations, which can consider nuclear quantum effects (NQEs) under a finite temperature. The PIMD simulations predicted that the NQE completely washed out the energy barrier for the proton transfer reaction. Consequently, a single-well shape emerged in the results, along with the effective free-energy potential surface for the hydrogen-bonded proton distribution. Thus, we conclude that the hydrogen-bonded proton in Fujikurin does not in fact transfer between two equilibrium structures but widely delocalizes around the global minimum structure involving the TS region.
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Affiliation(s)
- Hikaru Tanaka
- Department
of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Kazuaki Kuwahata
- Graduate
School of NanobioScience, Yokohama City
University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027, Japan
| | - Masanori Tachikawa
- Graduate
School of NanobioScience, Yokohama City
University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027, Japan
| | - Taro Udagawa
- Department
of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
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Brehm M, Thomas M, Gehrke S, Kirchner B. TRAVIS—A free analyzer for trajectories from molecular simulation. J Chem Phys 2020; 152:164105. [DOI: 10.1063/5.0005078] [Citation(s) in RCA: 164] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Affiliation(s)
- M. Brehm
- Institut für Chemie, Martin-Luther-Universität Halle–Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany
| | - M. Thomas
- Institut für Chemie, Martin-Luther-Universität Halle–Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany
| | - S. Gehrke
- Mulliken Center for Theoretical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstr. 4+6, D-53115 Bonn, Germany
| | - B. Kirchner
- Mulliken Center for Theoretical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstr. 4+6, D-53115 Bonn, Germany
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Jonely M, Noriega R. Role of Polar Protic Solvents in the Dissociation and Reactivity of Photogenerated Radical Ion Pairs. J Phys Chem B 2020; 124:3083-3089. [PMID: 32239936 DOI: 10.1021/acs.jpcb.9b11299] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The UV photolysis of bimolecular charge transfer complexes is employed to yield reactive radical ions in their solvent-equilibrated electronic ground state. In polar protic media, noncovalent complexes of 1,2,4,5-tetracyanobenzene and toluene undergo efficient, ultrafast dissociation to ion pairs and equilibrate with their solvent environment before the resulting radical ions engage in electron transfer and proton abstraction on subnanosecond time scales. Solvent molecules play a critical role in these reactive pathways and in the dissociation and relaxation processes that precede them. We report a clear separation of time scales for these relaxation and reactive processes, which implies that solvent-solute interactions can be used as a tool for tuning the reaction pathways of equilibrated radical ions in solution.
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Affiliation(s)
- McKenzie Jonely
- Department of Chemistry, University of Utah, 315 S. 1400 E, Salt Lake City, Utah 84112, United States
| | - Rodrigo Noriega
- Department of Chemistry, University of Utah, 315 S. 1400 E, Salt Lake City, Utah 84112, United States
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Milovanović B, Stanković IM, Petković M, Etinski M. Elucidating Solvent Effects on Strong Intramolecular Hydrogen Bond: DFT-MD Study of Dibenzoylmethane in Methanol Solution. Chemphyschem 2019; 20:2852-2859. [PMID: 31544323 DOI: 10.1002/cphc.201900704] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 08/31/2019] [Indexed: 11/10/2022]
Abstract
The dynamic aspect of solvation plays a crucial role in determining properties of strong intramolecular hydrogen bonds since solvent fluctuations modify instantaneous hydrogen-bonded proton transfer barriers. Previous studies pointed out that solvent-solute interactions in the first solvation shell govern the position of the proton but the ability of the electric field due to other solvent molecules to localize the proton remains an important issue. In this work, we examine the structure of the O-H⋅⋅⋅O intramolecular hydrogen bond of dibenzoylmethane in methanol solution by employing density functional theory-based molecular dynamics and quantum chemical calculations. Our computations showed that homogeneous electric fields with intensities corresponding to those found in polar solvents are able to considerably alter the proton transfer barrier height in the gas phase. In methanol solution, the proton position is correlated with the difference in electrostatic potentials on the oxygen atoms of dibenzoylmethane even when dibenzoylmethane-methanol hydrogen bonding is lacking. On a timescale of our simulation, the hydrogen bonding and solvent electrostatics tend to localize the proton on different oxygen atoms. These findings provide an insight into the importance of the solvent electric field on the structure of a strong intramolecular hydrogen bond.
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Affiliation(s)
- Branislav Milovanović
- Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11000, Belgrade, Serbia
| | | | - Milena Petković
- Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11000, Belgrade, Serbia
| | - Mihajlo Etinski
- Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11000, Belgrade, Serbia
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Kojić M, Lyskov I, Milovanović B, Marian CM, Etinski M. The UVA response of enolic dibenzoylmethane: beyond the static approach. Photochem Photobiol Sci 2019; 18:1324-1332. [DOI: 10.1039/c9pp00005d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The nπ* and ππ* states of dibenzoylmethane are vibronically coupled and their crossing occurs during the excited-state intramolecular proton transfer.
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Affiliation(s)
- Marko Kojić
- Faculty of Physical Chemistry
- University of Belgrade
- 11000 Belgrade
- Serbia
| | - Igor Lyskov
- Chemical and Quantum Physics Group
- ARC Centre of Excellence in Exciton Science
- School of Science
- RMIT University
- Melbourne
| | | | - Christel M. Marian
- Institute of Theoretical and Computational Chemistry
- Heinrich Heine University Düsseldorf
- D-40225 Düsseldorf
- Germany
| | - Mihajlo Etinski
- Faculty of Physical Chemistry
- University of Belgrade
- 11000 Belgrade
- Serbia
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