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Heitland J, Lee JC, Ban L, Abma GL, Fortune WG, Fielding HH, Yoder BL, Signorell R. Valence Electronic Structure of Interfacial Phenol in Water Droplets. J Phys Chem A 2024; 128:7396-7406. [PMID: 39182189 DOI: 10.1021/acs.jpca.4c04269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/27/2024]
Abstract
Biochemistry and a large part of atmospheric chemistry occur in aqueous environments or at aqueous interfaces, where (photo)chemical reaction rates can be increased by up to several orders of magnitude. The key to understanding the chemistry and photoresponse of molecules in and "on" water lies in their valence electronic structure, with a sensitive probe being photoelectron spectroscopy. This work reports velocity-map photoelectron imaging of submicrometer-sized aqueous phenol droplets in the valence region after nonresonant (288 nm) and resonance-enhanced (274 nm) two-photon ionization with femtosecond ultraviolet light, complementing previous liquid microjet studies. For nonresonant photoionization, our concentration-dependent study reveals a systematic decrease in the vertical binding energy (VBE) of aqueous phenol from 8.0 ± 0.1 eV at low concentration (0.01 M) to 7.6 ± 0.1 eV at high concentration (0.8 M). We attribute this shift to a systematic lowering of the energy of the lowest cationic state with increasing concentration caused by the phenol dimer and aggregate formation at the droplet surface. Contrary to nonresonant photoionization, no significant concentration dependence of the VBE was observed for resonance-enhanced photoionization. We explain the concentration-independent VBE of ∼8.1 eV observed upon resonant ionization by ultrafast intermediate state relaxation and changes in the accessible Franck-Condon region as a consequence of the lowering of the intermediate state potential energy due to the formation of phenol excimers and excited phenol aggregates. Correcting for the influence of electron transport scattering in the droplets reduced the measured VBEs by 0.1-0.2 eV.
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Affiliation(s)
- Jonas Heitland
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
| | - Jong Chan Lee
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
| | - Loren Ban
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
| | - Grite L Abma
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
| | - William G Fortune
- Department of Chemistry, University College London, WC1H 0AJ London, U.K
| | - Helen H Fielding
- Department of Chemistry, University College London, WC1H 0AJ London, U.K
| | - Bruce L Yoder
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
| | - Ruth Signorell
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
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2
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Richter C, Dupuy R, Trinter F, Buttersack T, Cablitz L, Gholami S, Stemer D, Nicolas C, Seidel R, Winter B, Bluhm H. Surface accumulation and acid-base equilibrium of phenol at the liquid-vapor interface. Phys Chem Chem Phys 2024. [PMID: 39189878 PMCID: PMC11348876 DOI: 10.1039/d4cp02212b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Accepted: 08/21/2024] [Indexed: 08/28/2024]
Abstract
We have investigated the surfactant properties of phenol in aqueous solution as a function of pH and bulk concentration using liquid-jet photoelectron spectroscopy (LJ-PES) and surface tension measurements. The emphasis of this work is on the determination of the Gibbs free energy of adsorption and surface excess of phenol and its conjugate base phenolate at the bulk pKa (9.99), which can be determined for each species using photoelectron spectroscopy. These values are compared to those obtained in measurements well below and well above the pKa, where pure phenol or phenolate, respectively, are the dominant species, and where the Gibbs free energy of adsorption determined from surface tension and LJ-PES data are in excellent agreement. At the bulk pKa the surface-sensitive LJ-PES measurements show a deviation of the expected phenol/phenolate ratio in favor of phenol, i.e., an apparent upward shift of the at the surface. In addition, the Gibbs free energies of adsorption determined by LJ-PES at the bulk pKa for phenol and phenolate deviate from those observed for the pure solutions. We discuss these observations in view of the different surface propensity of phenol and phenolate as well as potential cooperative interactions between them in the near-surface region.
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Affiliation(s)
- Clemens Richter
- Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany.
| | - Rémi Dupuy
- CNRS, Laboratoire de Chimie Physique - Matière et Rayonnement, Sorbonne Université, F-75005 Paris Cedex 05, France
| | - Florian Trinter
- Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany.
| | - Tillmann Buttersack
- Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany.
| | - Louisa Cablitz
- Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany.
| | - Shirin Gholami
- Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany.
| | - Dominik Stemer
- Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany.
| | - Christophe Nicolas
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin - BP 48 91192, Gif-sur-Yvette Cedex, France
| | - Robert Seidel
- Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Bernd Winter
- Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany.
| | - Hendrik Bluhm
- Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany.
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3
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Tian YM, Silva W, Gschwind RM, König B. Accelerated photochemical reactions at oil-water interface exploiting melting point depression. Science 2024; 383:750-756. [PMID: 38359135 DOI: 10.1126/science.adl3092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 01/11/2024] [Indexed: 02/17/2024]
Abstract
Water can accelerate a variety of organic reactions far beyond the rates observed in classical organic solvents. However, using pure water as a solvent introduces solubility constraints that have limited the applicability of efficient photochemistry in particular. We report here the formation of aggregates between pairs of arenes, heteroarenes, enamines, or esters with different electron affinities in an aqueous medium, leading to an oil-water phase boundary through substrate melting point depression. The active hydrogen atoms in the reactants engage in hydrogen bonds with water, thereby accelerating photochemical reactions. This methodology realizes appealingly simple conditions for aqueous coupling reactions of complex solid molecules, including complex drug molecules that are poorly soluble in water.
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Affiliation(s)
- Ya-Ming Tian
- Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, 93040 Regensburg, Germany
| | - Wagner Silva
- Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, 93040 Regensburg, Germany
| | - Ruth M Gschwind
- Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, 93040 Regensburg, Germany
| | - Burkhard König
- Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, 93040 Regensburg, Germany
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4
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Sam S, Sung S, Kim D. Sensitive Detection of Biomolecular Adsorption by a Low-Density Surfactant Layer Using Sum-Frequency Vibrational Spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:17412-17419. [PMID: 38050679 DOI: 10.1021/acs.langmuir.3c02546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2023]
Abstract
Small molecules or proteins interact with a biomembrane in various ways for molecular recognition, structure stabilization, and transmembrane signaling. In this study, 1,2-dipalmitoyl-3-trimethylammonium-propane (DPTAP), having a choline group, was used to investigate this interaction by using sum-frequency vibrational spectroscopy. The sum-frequency spectrum characteristic of a neat monolayer changed to that of a bare air/water interface at a larger molecular area of the DPTAP molecules due to local laser heating. Upon introduction of the aromatic molecules in the subphase at around 120 Å2 per molecule, the sum-frequency signal suddenly reappeared due to molecular adhesion, and this was utilized to probe the adsorption of the aromatic ring molecules in the water subphase to the choline headgroup of the DPTAP by cation-π interaction. The onset concentrations of this sum-frequency signal change allowed a comparison of the relative interaction strengths between different aromatic molecules. A zwitterionic surfactant molecule (DPPC) was found to interact weakly compared to the cationic DPTAP molecule.
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Affiliation(s)
- Sokhuoy Sam
- Department of Physics, Sogang University, 35, Baekbeom-ro, Mapo-gu, Seoul, 04107, Korea
| | - Siheon Sung
- Department of Physics, Sogang University, 35, Baekbeom-ro, Mapo-gu, Seoul, 04107, Korea
| | - Doseok Kim
- Department of Physics, Sogang University, 35, Baekbeom-ro, Mapo-gu, Seoul, 04107, Korea
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5
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Shultz MJ, Bisson P, Wang J, Marmolejos J, Davies RG, Gubbins E, Xiong Z. High phase resolution: Probing interactions in complex interfaces with sum frequency generation. Biointerphases 2023; 18:058502. [PMID: 37902617 DOI: 10.1116/6.0002963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 09/20/2023] [Indexed: 10/31/2023] Open
Abstract
An often-quoted statement attributed to Wolfgang Pauli is that God made the bulk, but the surface was invented by the devil. Although humorous, the statement really reflects frustration in developing a detailed picture of a surface. In the last several decades, that frustration has begun to abate with numerous techniques providing clues to interactions and reactions at surfaces. Often these techniques require considerable prior knowledge. Complex mixtures on irregular or soft surfaces-complex interfaces-thus represent the last frontier. Two optical techniques: sum frequency generation (SFG) and second harmonic generation (SHG) are beginning to lift the veil on complex interfaces. Of these techniques, SFG with one excitation in the infrared has the potential to provide exquisite molecular- and moiety-specific vibrational data. This Perspective is intended both to aid newcomers in gaining traction in this field and to demonstrate the impact of high-phase resolution. It starts with a basic description of light-induced surface polarization that is at the heart of SFG. The sum frequency is generated when the input fields are sufficiently intense that the interaction is nonlinear. This nonlinearity represents a challenge for disentangling data to reveal the molecular-level picture. Three, high-phase-resolution methods that reveal interactions at the surface are described.
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Affiliation(s)
- Mary Jane Shultz
- Laboratory for Water and Surface Studies, Tufts University, Pearson Laboratory, 62 Talbot Ave., Medford, Massachusetts 02155
| | - Patrick Bisson
- Cambridge Polymer Group, Inc., 100 Trade Center Drive, Suite 200, Woburn, Massachusetts 01801
| | - Jing Wang
- Laboratory for Water and Surface Studies, Tufts University, Pearson Laboratory, 62 Talbot Ave., Medford, Massachusetts 02155
| | - Joam Marmolejos
- Laboratory for Water and Surface Studies, Tufts University, Pearson Laboratory, 62 Talbot Ave., Medford, Massachusetts 02155
| | - Rebecca G Davies
- Laboratory for Water and Surface Studies, Tufts University, Pearson Laboratory, 62 Talbot Ave., Medford, Massachusetts 02155
| | - Emma Gubbins
- Laboratory for Water and Surface Studies, Tufts University, Pearson Laboratory, 62 Talbot Ave., Medford, Massachusetts 02155
| | - Ziqing Xiong
- Laboratory for Water and Surface Studies, Tufts University, Pearson Laboratory, 62 Talbot Ave., Medford, Massachusetts 02155
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6
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Yang H, Gladich I, Boucly A, Artiglia L, Ammann M. Orcinol and resorcinol induce local ordering of water molecules near the liquid-vapor interface. ENVIRONMENTAL SCIENCE: ATMOSPHERES 2022; 2:1277-1291. [PMID: 36561553 PMCID: PMC9648629 DOI: 10.1039/d2ea00015f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 08/17/2022] [Indexed: 12/25/2022]
Abstract
Resorcinol and orcinol are simple members of the family of phenolic compounds present in particulate matter in the atmosphere; they are amphiphilic in nature and thus surface active in aqueous solution. Here, we used X-ray photoelectron spectroscopy to probe the concentration of resorcinol (benzene-1,3-diol) and orcinol (5-methylbenzene-1,3-diol) at the liquid-vapor interface of aqueous solutions. Qualitatively consistent surface propensity and preferential orientation was obtained by molecular dynamics simulations. Auger electron yield near-edge X-ray absorption fine structure (NEXAFS) spectroscopy was used to probe the hydrogen bonding (HB) structure, indicating that the local structure of water molecules near the surface of the resorcinol and orcinol solutions tends towards a larger fraction of tetrahedrally coordinated molecules than observed at the liquid-vapor interface of pure water. The order parameter obtained from the molecular dynamics simulations confirm these observations. This effect is being discussed in terms of the formation of an ordered structure of these molecules at the surface leading to patterns of hydrated OH groups with distances among them that are relatively close to those in ice. These results suggest that the self-assembly of phenolic species at the aqueous solution-air interface could induce freezing similar to the case of fatty alcohol monolayers and, thus, be of relevance for ice nucleation in the atmosphere. We also attempted at looking at the changes of the O 1b1, 3a2 and 1b2 molecular orbitals of liquid water, which are known to be sensitive to the HB structure as well, in response to the presence of resorcinol and orcinol. However, these changes remained negligible within uncertainty for both experimentally obtained valence spectra and theoretically calculated density of states.
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Affiliation(s)
- Huanyu Yang
- Laboratory of Environmental Chemistry, Paul Scherrer Institut5232 VilligenSwitzerland,Institute of Atmospheric and Climate Science, ETH Zürich8092 ZürichSwitzerland
| | - Ivan Gladich
- Qatar Environment & Energy Research Institute, Hamad Bin Khalifa UniversityP.O. Box 34110DohaQatar
| | - Anthony Boucly
- Laboratory of Environmental Chemistry, Paul Scherrer Institut5232 VilligenSwitzerland,Electrochemistry Laboratory, Paul Scherrer Institut5232 VilligenSwitzerland
| | - Luca Artiglia
- Laboratory of Environmental Chemistry, Paul Scherrer Institut5232 VilligenSwitzerland,Laboratory for Catalysis and Sustainable Chemistry, Paul Scherrer Institut5232 VilligenSwitzerland
| | - Markus Ammann
- Laboratory of Environmental Chemistry, Paul Scherrer Institut5232 VilligenSwitzerland
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7
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Salehi SM, Käser S, Töpfer K, Diamantis P, Pfister R, Hamm P, Rothlisberger U, Meuwly M. Hydration dynamics and IR spectroscopy of 4-fluorophenol. Phys Chem Chem Phys 2022; 24:26046-26060. [PMID: 36268728 PMCID: PMC9627945 DOI: 10.1039/d2cp02857c] [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: 06/23/2022] [Accepted: 10/05/2022] [Indexed: 11/06/2022]
Abstract
Halogenated groups are relevant in pharmaceutical applications and potentially useful spectroscopic probes for infrared spectroscopy. In this work, the structural dynamics and infrared spectroscopy of para-fluorophenol (F-PhOH) and phenol (PhOH) is investigated in the gas phase and in water using a combination of experiment and molecular dynamics (MD) simulations. The gas phase and solvent dynamics around F-PhOH and PhOH is characterized from atomistic simulations using empirical energy functions with point charges or multipoles for the electrostatics, Machine Learning (ML) based parametrizations and with full ab initio (QM) and mixed Quantum Mechanical/Molecular Mechanics (QM/MM) simulations with a particular focus on the CF- and OH-stretch region. The CF-stretch band is heavily mixed with other modes whereas the OH-stretch in solution displays a characteristic high-frequency peak around 3600 cm-1 most likely associated with the -OH group of PhOH and F-PhOH together with a characteristic progression below 3000 cm-1 due to coupling with water modes which is also reproduced by several of the simulations. Solvent and radial distribution functions indicate that the CF-site is largely hydrophobic except for simulations using point charges which renders them unsuited for correctly describing hydration and dynamics around fluorinated sites. The hydrophobic character of the CF-group is particularly relevant for applications in pharmaceutical chemistry with a focus on local hydration and interaction with the surrounding protein.
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Affiliation(s)
- Seyedeh Maryam Salehi
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland.
| | - Silvan Käser
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland.
| | - Kai Töpfer
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland.
| | - Polydefkis Diamantis
- Laboratory of Computational Chemistry and Biochemistry, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Rolf Pfister
- Department of Chemistry, University of Zurich, Switzerland
| | - Peter Hamm
- Department of Chemistry, University of Zurich, Switzerland
| | - Ursula Rothlisberger
- Laboratory of Computational Chemistry and Biochemistry, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Markus Meuwly
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland.
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8
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Sam S, Sung S, Krem S, Park S, Hwang DS, Kim D. Sum-Frequency Vibrational Spectroscopic Study of the Cation-π Interaction: Amine and Guanidine. J Phys Chem B 2022; 126:7621-7626. [PMID: 36166344 DOI: 10.1021/acs.jpcb.2c05709] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The cation-π interaction is an interaction between a positively charged cation and π electrons in an aromatic group of a molecule. It is considered to play key roles in signal transduction, stabilization of the protein structure, enzyme catalysis in biology, and wet adhesion and biomolecular condensation. In this study, octadecylguanidine hydrochloride (ODG) and octadecylamine (ODA) having guanidine and amine headgroups, respectively, are found to interact with π molecules (phenol or indole) as investigated by sum-frequency vibrational spectroscopy. ODG is unstable and does not form a neat monolayer on the water surface. However, after adding π molecules into subphase water, it becomes more stable against dissolution as evidenced by the appearance of its CHx peaks and a CH peak of the aromatic ring in the sum-frequency spectrum. Unlike ODG, ODA forms a stable monolayer on the water surface at a neutral pH. After adding π molecules into the solution, the amine-π interaction promotes the protonation of the amine headgroup and the penetration of the π molecules makes the ODA monolayer more disordered. Indole is found to be more effective in binding with the ODG as compared to phenol.
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Affiliation(s)
- Sokhuoy Sam
- Department of Physics, Sogang University, 35, Baekbeom-ro, Mapo-gu, Seoul 04107, Korea
| | - Siheon Sung
- Department of Physics, Sogang University, 35, Baekbeom-ro, Mapo-gu, Seoul 04107, Korea
| | - Sona Krem
- Department of Physics, Sogang University, 35, Baekbeom-ro, Mapo-gu, Seoul 04107, Korea
| | - Sohee Park
- Division of Environmental Science and Engineering (DESE), Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Namgu, Pohang 37673, Korea
| | - Dong Soo Hwang
- Division of Environmental Science and Engineering (DESE), Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Namgu, Pohang 37673, Korea
| | - Doseok Kim
- Department of Physics, Sogang University, 35, Baekbeom-ro, Mapo-gu, Seoul 04107, Korea
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9
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Wagner J, Wu Z, Wang H, Xiong W. Imaging Orientation of a Single Molecular Hierarchical Self-Assembled Sheet: The Combined Power of a Vibrational Sum Frequency Generation Microscopy and Neural Network. J Phys Chem B 2022; 126:7192-7201. [PMID: 36098975 PMCID: PMC9511492 DOI: 10.1021/acs.jpcb.2c05876] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 08/30/2022] [Indexed: 11/28/2022]
Abstract
In this work, we determined the tilt angles of molecular units in hierarchical self-assembled materials on a single-sheet level, which were not available previously. This was achieved by developing a fast line-scanning vibrational sum frequency generation (VSFG) hyperspectral imaging technique in combination with neural network analysis. Rapid VSFG imaging enabled polarization resolved images on a single sheet level to be measured quickly, circumventing technical challenges due to long-term optical instability. The polarization resolved hyperspectral images were then used to extract the supramolecular tilt angle of a self-assembly through a set of spectra-tilt angle relationships which were solved through neural network analysis. This unique combination of both novel techniques offers a new pathway to resolve molecular level structural information on self-assembled materials. Understanding these properties can further drive self-assembly design from a bottom-up approach for applications in biomimetic and drug delivery research.
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Affiliation(s)
- Jackson
C. Wagner
- Department
of Chemistry and Biochemistry, University
of California San Diego, La Jolla, California 92093, United States
| | - Zishan Wu
- Department
of Chemistry and Biochemistry, University
of California San Diego, La Jolla, California 92093, United States
| | - Haoyuan Wang
- Department
of Chemistry and Biochemistry, University
of California San Diego, La Jolla, California 92093, United States
| | - Wei Xiong
- Department
of Chemistry and Biochemistry, University
of California San Diego, La Jolla, California 92093, United States
- Materials
Science and Engineering Program, University
of California San Diego, La Jolla, California 92093, United States
- Department
of Electrical and Computer Engineering, University of California San Diego, La Jolla, California 92093, United States
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10
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Ishiyama T, Tahara T, Morita A. Why the Photochemical Reaction of Phenol Becomes Ultrafast at the Air-Water Interface: The Effect of Surface Hydration. J Am Chem Soc 2022; 144:6321-6325. [PMID: 35377635 PMCID: PMC9012180 DOI: 10.1021/jacs.1c13336] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Photochemical reactions at the air-water interface can show remarkably different rates from those in bulk water. The present study elucidates the reaction mechanism of phenol characteristic at the air-water interface by the combination of molecular dynamics simulation and quantum chemical calculations of the excited states. We found that incomplete hydrogen bonding to phenol at the air-water interface affects excited states associated with the conical intersection and significantly reduces the reaction barrier, resulting in the distinctively facilitated rate in comparison with the bulk phase. The present study indicates that the reaction dynamics can be substantially different at the interfaces in general, reflecting the difference in the stabilization energy of the electronic states in markedly different solvation at the interface.
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Affiliation(s)
- Tatsuya Ishiyama
- Department of Applied Chemistry, Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan
| | - Tahei Tahara
- Molecular Spectroscopy Laboratory, RIKEN, Wako 351-0198, Saitama, Japan.,Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics (RAP), Wako 351-0198, Saitama, Japan
| | - Akihiro Morita
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan.,Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, Kyoto 615-8520, Japan
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11
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Biswas B, Singh PC. Protonation State of Dopamine Neurotransmitter at the Aqueous Interface: Vibrational Sum Frequency Generation Spectroscopy Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:1380-1385. [PMID: 35030008 DOI: 10.1021/acs.langmuir.1c02505] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Dopamine is an important amine-based chemical neurotransmitter whose protonated state plays a crucial role in the recognition process. Understanding the structure and protonated state of dopamine at the aqueous interface is desired as the diffusion as well as binding of dopamine with the receptors take place frequently in the aqueous interface region. Vibrational sum frequency generation (VSFG) study of the OH stretch of water at the air/water interface in the presence of dopamine is performed and compared with its analog, phenylethylamine, and catechol. The VSFG data suggest that, unlike the bulk case, the population of the deprotonated amine group of dopamine is higher at the aqueous interface. This study suggests that the structure of dopamine at the aqueous interface is different from the bulk which may be useful in understanding the recognition process of dopamine in the interfacial region.
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Affiliation(s)
- Biswajit Biswas
- School of Chemical Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata India, 700032
| | - Prashant Chandra Singh
- School of Chemical Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata India, 700032
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12
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Biswas B, Singh PC. The enhanced dissociation and associated surface structure of the anesthetic propofol at the water interface: vibrational sum frequency generation study. Phys Chem Chem Phys 2021; 23:24646-24651. [PMID: 34704569 DOI: 10.1039/d1cp02838c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Propofol, the most administered drug for general anesthesia, affects the acid-base equilibrium at the interfacial region of arterial blood. Hence, the structure of propofol at the water interface under different pH conditions has been measured using the surface-selective vibrational sum frequency generation (VSFG) technique to understand the hydration as well as the dissociation of propofol at the water interface. Propofol remains in its neutral form at pH ≤ 5.8 in which the OH group of propofol forms a hydrogen bond with interfacial water molecules, where a few interfacial water molecules also interact with the π electron density of propofol. By contrast, propofol prefers to be in the deprotonated state at pH ≥ 7, due to which the surface of water becomes negatively charged and hence the interfacial water becomes oriented and the intensity of the OH stretch of water is enhanced. The pKa of propofol at the water interface is ∼three units lower than in the bulk medium indicating that the dissociation of propofol is notably enhanced at the water interface. These VSFG studies suggest that, unlike the bulk, propofol prefers to be in the charged state at the water interface under physiological conditions, which may be important in understanding its diffusion and acid-base equilibrium in the interfacial arterial blood region.
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Affiliation(s)
- Biswajit Biswas
- School of Chemical Sciences, Indian Association for the Cultivation of Sciences, Kolkata, West Bengal, 700032, India.
| | - Prashant Chandra Singh
- School of Chemical Sciences, Indian Association for the Cultivation of Sciences, Kolkata, West Bengal, 700032, India.
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13
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Xu S, Lukes P. Gas-liquid interface influencing electronic structure of phenol based on molecular dynamics simulations and theoretical X-ray absorption spectroscopy. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.117378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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14
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Jordan CJC, Verlet JRR. Time-resolved electronic sum-frequency generation spectroscopy with fluorescence suppression using optical Kerr gating. J Chem Phys 2021; 155:164202. [PMID: 34717361 DOI: 10.1063/5.0065460] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Excited state dynamics of molecules at interfaces can be studied using second-order non-linear spectroscopic methods such as time-resolved electronic sum-frequency generation (SFG). However, as such measurements inherently generate very small signals, they are often overwhelmed by signals originating from fluorescence. Here, this limitation is overcome by optical Kerr gating of the SFG signal to discriminate against fluorescence. The new approach is demonstrated on the excited state dynamics of malachite green at the water/air interface, in the presence of a highly fluorescent coumarin dye, and on the photo-oxidation of the phenolate anion at the water/air interface. The generality of the use of optical Kerr gating to SFG measurements is discussed.
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Affiliation(s)
- Caleb J C Jordan
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | - Jan R R Verlet
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
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15
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The photochemical reaction of phenol becomes ultrafast at the air–water interface. Nat Chem 2021; 13:306-311. [DOI: 10.1038/s41557-020-00619-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 12/04/2020] [Indexed: 11/08/2022]
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16
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A Unified Mathematical Formalism for First to Third Order Dielectric Response of Matter: Application to Surface-Specific Two-Colour Vibrational Optical Spectroscopy. Symmetry (Basel) 2021. [DOI: 10.3390/sym13010153] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
To take advantage of the singular properties of matter, as well as to characterize it, we need to interact with it. The role of optical spectroscopies is to enable us to demonstrate the existence of physical objects by observing their response to light excitation. The ability of spectroscopy to reveal the structure and properties of matter then relies on mathematical functions called optical (or dielectric) response functions. Technically, these are tensor Green’s functions, and not scalar functions. The complexity of this tensor formalism sometimes leads to confusion within some articles and books. Here, we do clarify this formalism by introducing the physical foundations of linear and non-linear spectroscopies as simple and rigorous as possible. We dwell on both the mathematical and experimental aspects, examining extinction, infrared, Raman and sum-frequency generation spectroscopies. In this review, we thus give a personal presentation with the aim of offering the reader a coherent vision of linear and non-linear optics, and to remove the ambiguities that we have encountered in reference books and articles.
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17
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Saha S, Roy S, Mathi P, Mondal JA. Adsorption of Iodine Species (I 3-, I -, and IO 3-) at the Nuclear Paint Monolayer-Water Interface and Its Relevance to a Nuclear Accident Scenario. J Phys Chem A 2020; 124:6726-6734. [PMID: 32786661 DOI: 10.1021/acs.jpca.0c04893] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Following a nuclear accident, radioactive iodine causes great concern to public health and safety. Organic iodide, because of its ability to escape reactor containment building and high environmental mobility, constitutes a predominant fraction of airborne radioiodine at places far away from the accident site. As the iodine released from a reactor core is inorganic iodine, it is vital to understand the mechanism of organic iodide formation inside reactor containment. In this context, we investigated the surface prevalence and adsorption of various inorganic iodines, I-, I3-, and IO3-, at a nuclear paint (used in nuclear installations) monolayer-water interface, mimicking the painted inner walls of an accident-affected containment building that are exposed to the iodine-containing condensed water layer. Vibrational sum frequency generation (VSFG) measurements in the OH and CH stretch regions reveal that the paint-water interface changes its charge characteristics with the pH of the water that affects the degree of interaction with the iodine species. At the acidic condition (bulk pH < 7), the paint becomes positively charged and strongly adsorbs the negatively charged iodine species dissolved in the aqueous phase, whereas at the alkaline condition (bulk pH > 9.5), the paint becomes net neutral and weakly interacts with the iodine species. These interactions change the conformation of the paint such that its hydrophobic alkyl groups orient increasingly away from the aqueous phase. The order of adsorption increases as IO3- < I- < I3- for the different iodine species studied.
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Affiliation(s)
- Subhamoy Saha
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Homi Bhabha National Institute, Trombay, Mumbai 400085, India
| | - Subhadip Roy
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Homi Bhabha National Institute, Trombay, Mumbai 400085, India
| | - P Mathi
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Homi Bhabha National Institute, Trombay, Mumbai 400085, India
| | - Jahur A Mondal
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Homi Bhabha National Institute, Trombay, Mumbai 400085, India
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18
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Ahmed M, Inoue K, Nihonyanagi S, Tahara T. Hidden Isolated OH at the Charged Hydrophobic Interface Revealed by Two‐Dimensional Heterodyne‐Detected VSFG Spectroscopy. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202002368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Mohammed Ahmed
- Molecular Spectroscopy LaboratoryRIKEN 2-1 Hirosawa Wako Saitama 351-0198 Japan
- Ultrafast Spectroscopy Research TeamRIKEN Center for Advanced Photonics (RAP), RIKEN 2-1 Hirosawa Wako Saitama 351-0198 Japan
| | - Ken‐ichi Inoue
- Molecular Spectroscopy LaboratoryRIKEN 2-1 Hirosawa Wako Saitama 351-0198 Japan
- Present address: Department of ChemistryGraduate School of ScienceTohoku University Sendai 980-8578 Japan
| | - Satoshi Nihonyanagi
- Molecular Spectroscopy LaboratoryRIKEN 2-1 Hirosawa Wako Saitama 351-0198 Japan
- Ultrafast Spectroscopy Research TeamRIKEN Center for Advanced Photonics (RAP), RIKEN 2-1 Hirosawa Wako Saitama 351-0198 Japan
| | - Tahei Tahara
- Molecular Spectroscopy LaboratoryRIKEN 2-1 Hirosawa Wako Saitama 351-0198 Japan
- Ultrafast Spectroscopy Research TeamRIKEN Center for Advanced Photonics (RAP), RIKEN 2-1 Hirosawa Wako Saitama 351-0198 Japan
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19
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Ahmed M, Inoue KI, Nihonyanagi S, Tahara T. Hidden Isolated OH at the Charged Hydrophobic Interface Revealed by Two-Dimensional Heterodyne-Detected VSFG Spectroscopy. Angew Chem Int Ed Engl 2020; 59:9498-9505. [PMID: 32189396 DOI: 10.1002/anie.202002368] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Indexed: 02/04/2023]
Abstract
Water around hydrophobic groups mediates hydrophobic interactions that play key roles in many chemical and biological processes. Thus, the molecular-level elucidation of the properties of water in the vicinity of hydrophobic groups is important. We report on the structure and dynamics of water at two oppositely charged hydrophobic ion/water interfaces, that is, the tetraphenylborate-ion (TPB- )/water and tetraphenylarsonium-ion (TPA+ )/water interfaces, which are clarified by two-dimensional heterodyne-detected vibrational sum-frequency generation (2D HD-VSFG) spectroscopy. The obtained 2D HD-VSFG spectra of the anionic TPB- interface reveal the existence of distinct π-hydrogen bonded OH groups in addition to the usual hydrogen-bonded OH groups, which are hidden in the steady-state spectrum. In contrast, 2D HD-VSFG spectra of the cationic TPA+ interface only show the presence of usual hydrogen-bonded OH groups. The present study demonstrates that the sign of the interfacial charge governs the structure and dynamics of water molecules that face the hydrophobic region.
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Affiliation(s)
- Mohammed Ahmed
- Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.,Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics (RAP), RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Ken-Ichi Inoue
- Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.,Present address: Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan
| | - Satoshi Nihonyanagi
- Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.,Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics (RAP), RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Tahei Tahara
- Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.,Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics (RAP), RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
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20
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Dondapati JS, Chen A. Quantitative structure-property relationship of the photoelectrochemical oxidation of phenolic pollutants at modified nanoporous titanium oxide using supervised machine learning. Phys Chem Chem Phys 2020; 22:8878-8888. [PMID: 32286586 DOI: 10.1039/d0cp01518k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Here we report on an advanced photoelectrochemical (PEC) oxidation of 22 phenolic pollutants based on modified nanoporous TiO2, which was directly grown on a titanium substrate electrochemically. Their degradation rate constants were experimentally determined and their physicochemical properties were computaionally calculated. The quantitative structure-property relationship (QSPR) was elucidated by employing multiple linear regression (MLR) method. A supervised machine learning approach was employed to build QSPR models. The high predictive abilities of the QSPR model were validated via leave-one-out (LOO) method and a strict regimen of statistical validation tests. The significant descriptors identified in the QSPR Model for the phenolic compounds were also assessed using a typical dye pollutant Rhodamine B, further confirming the high effectiveness and predictability of the optimized model. Our study has shown that the integrated effect of the structural, hydrophobic and topological properties along with electronic property should be considered in order to design an efficient PEC catalytic approach for environmental applications.
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Affiliation(s)
- Jesse S Dondapati
- Electrochemical Technology Center, Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
| | - Aicheng Chen
- Electrochemical Technology Center, Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
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21
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West CW, Nishitani J, Higashimura C, Suzuki T. Extreme ultraviolet time-resolved photoelectron spectroscopy of aqueous aniline solution: enhanced surface concentration and pump-induced space charge effect. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1748240] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Christopher W. West
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Junichi Nishitani
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Chika Higashimura
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Toshinori Suzuki
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, Japan
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22
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Yoshida N, Yamaguchi T. Development of a solvent-polarizable three-dimensional reference interaction-site model theory. J Chem Phys 2020; 152:114108. [DOI: 10.1063/5.0004173] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Norio Yoshida
- Department of Chemistry, Graduate School of Science, Kyushu University, 744 Motooka, Nishiku, Fukuoka 819-0395, Japan
| | - Tsuyoshi Yamaguchi
- Graduate School of Engineering, Nagoya University, Chikusa, Nagoya 464–8603, Japan
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23
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Yamada A. Multiscale coupled Maxwell's equations and polarizable molecular dynamics simulation based on charge response kernel model. J Chem Phys 2020; 152:094110. [PMID: 33480736 DOI: 10.1063/1.5143742] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
A computational scheme of coupled Maxwell's equations and polarizable molecular dynamics simulation has been developed based on a multi-scale model to describe the coupled dynamics of light electromagnetic waves and molecules in crystalline solids, where the charge response kernel model is employed to incorporate electronic polarization of the molecules. The method is applicable to electronically non-resonant light-matter interaction systems that involve atomic motions in spectroscopy and photonics. Since the scheme simultaneously traces the light propagation in a medium on a macroscopic scale and the microscopic molecular motion under the light electric field, this enables us to treat the experimental setup and mimic its measurement process. As the first applications, we demonstrate three numerical examples of basic spectroscopies of an ice crystalline solid: simulations of reflection and transmission of visible light, infrared absorption measurement, and stimulated Raman scattering measurement. These examples show the detailed behaviors of the interacting light fields and molecules in the spectroscopic processes.
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Affiliation(s)
- Atsushi Yamada
- Center for Computational Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
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24
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Sayama A, Nihonyanagi S, Ohshima Y, Tahara T. In situ observation of the potential-dependent structure of an electrolyte/electrode interface by heterodyne-detected vibrational sum frequency generation. Phys Chem Chem Phys 2020; 22:2580-2589. [DOI: 10.1039/c9cp06253j] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
HD-VSFG spectroscopy reveals the potential-dependent interfacial structure of an electrochemical interface at the molecular level.
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Affiliation(s)
- Atsushi Sayama
- Molecular Spectroscopy Laboratory
- RIKEN
- Wako
- Saitama 351-0198
- Japan
| | | | - Yasuhiro Ohshima
- Department of Chemistry
- Tokyo Institute of Technology
- Meguro
- Tokyo 152-8551
- Japan
| | - Tahei Tahara
- Molecular Spectroscopy Laboratory
- RIKEN
- Wako
- Saitama 351-0198
- Japan
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25
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Cota R, Tiwari A, Ensing B, Bakker HJ, Woutersen S. Hydration interactions beyond the first solvation shell in aqueous phenolate solution. Phys Chem Chem Phys 2020; 22:19940-19947. [DOI: 10.1039/d0cp01209b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We investigate the orientational dynamics of water molecules solvating phenolate ions using ultrafast vibrational spectroscopy and density functional theory-based molecular dynamics simulations.
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Affiliation(s)
- Roberto Cota
- Van 't Hoff Institute for Molecular Sciences
- University of Amsterdam
- 1098 XH Amsterdam
- The Netherlands
- AMOLF
| | - Ambuj Tiwari
- Van 't Hoff Institute for Molecular Sciences
- University of Amsterdam
- 1098 XH Amsterdam
- The Netherlands
| | - Bernd Ensing
- Van 't Hoff Institute for Molecular Sciences
- University of Amsterdam
- 1098 XH Amsterdam
- The Netherlands
| | | | - Sander Woutersen
- Van 't Hoff Institute for Molecular Sciences
- University of Amsterdam
- 1098 XH Amsterdam
- The Netherlands
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26
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Moberg DR, Li Q, Reddy SK, Paesani F. Water structure at the interface of alcohol monolayers as determined by molecular dynamics simulations and computational vibrational sum-frequency generation spectroscopy. J Chem Phys 2019; 150:034701. [PMID: 30660151 DOI: 10.1063/1.5072754] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Daniel R. Moberg
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, USA
| | - Qin Li
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, USA
| | - Sandeep K. Reddy
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, USA
| | - Francesco Paesani
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, USA
- Materials Science and Engineering, University of California San Diego, La Jolla, California 92093, USA
- San Diego Supercomputer Center, University of California San Diego, La Jolla, California 92093, USA
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27
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Urashima SH, Myalitsin A, Nihonyanagi S, Tahara T. The Topmost Water Structure at a Charged Silica/Aqueous Interface Revealed by Heterodyne-Detected Vibrational Sum Frequency Generation Spectroscopy. J Phys Chem Lett 2018; 9:4109-4114. [PMID: 29975846 DOI: 10.1021/acs.jpclett.8b01650] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Despite recent significant advances in interface-selective nonlinear spectroscopy, the topmost water structure at a charged silica surface is still not clearly understood. This is because, for charged interfaces, not only interfacial molecules at the topmost layer but also a large number of molecules in the electric double layer are probed even with second-order nonlinear spectroscopy. In the present study, we studied water structure at the negatively charged silica/aqueous interface at pH 12 using heterodyne-detected vibrational sum frequency generation spectroscopy, and demonstrated that the spectral component of the topmost water can be extracted by examining the ionic strength dependence of the Imχ(2) spectrum. The obtained Imχ(2) spectrum indicates that the dominant water species in the topmost layer is hydrogen-bonded to the negatively charged silanolate at the silica surface with one OH group. There also exists minor water species that weakly interacts with the oxygen atom of a siloxane bridge or the remaining silanol at the silica surface, using one OH group. The ionic strength dependence of the Imχ(2) spectrum indicates that this water structure of the topmost layer is unchanged in a wide ionic strength range from 0.01 to 2 M.
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Affiliation(s)
- Shu-Hei Urashima
- Molecular Spectroscopy Laboratory , RIKEN , 2-1 Hirosawa , Wako , Saitama 351-0198 , Japan
| | - Anton Myalitsin
- Molecular Spectroscopy Laboratory , RIKEN , 2-1 Hirosawa , Wako , Saitama 351-0198 , Japan
| | - Satoshi Nihonyanagi
- Molecular Spectroscopy Laboratory , RIKEN , 2-1 Hirosawa , Wako , Saitama 351-0198 , Japan
- Ultrafast Spectroscopy Research Team , RIKEN Center for Advanced Photonics (RAP) , 2-1 Hirosawa , Wako , Saitama 351-0198 , Japan
| | - Tahei Tahara
- Molecular Spectroscopy Laboratory , RIKEN , 2-1 Hirosawa , Wako , Saitama 351-0198 , Japan
- Ultrafast Spectroscopy Research Team , RIKEN Center for Advanced Photonics (RAP) , 2-1 Hirosawa , Wako , Saitama 351-0198 , Japan
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28
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Sanders SE, Vanselous H, Petersen PB. Water at surfaces with tunable surface chemistries. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:113001. [PMID: 29393860 DOI: 10.1088/1361-648x/aaacb5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Aqueous interfaces are ubiquitous in natural environments, spanning atmospheric, geological, oceanographic, and biological systems, as well as in technical applications, such as fuel cells and membrane filtration. Where liquid water terminates at a surface, an interfacial region is formed, which exhibits distinct properties from the bulk aqueous phase. The unique properties of water are governed by the hydrogen-bonded network. The chemical and physical properties of the surface dictate the boundary conditions of the bulk hydrogen-bonded network and thus the interfacial properties of the water and any molecules in that region. Understanding the properties of interfacial water requires systematically characterizing the structure and dynamics of interfacial water as a function of the surface chemistry. In this review, we focus on the use of experimental surface-specific spectroscopic methods to understand the properties of interfacial water as a function of surface chemistry. Investigations of the air-water interface, as well as efforts in tuning the properties of the air-water interface by adding solutes or surfactants, are briefly discussed. Buried aqueous interfaces can be accessed with careful selection of spectroscopic technique and sample configuration, further expanding the range of chemical environments that can be probed, including solid inorganic materials, polymers, and water immiscible liquids. Solid substrates can be finely tuned by functionalization with self-assembled monolayers, polymers, or biomolecules. These variables provide a platform for systematically tuning the chemical nature of the interface and examining the resulting water structure. Finally, time-resolved methods to probe the dynamics of interfacial water are briefly summarized before discussing the current status and future directions in studying the structure and dynamics of interfacial water.
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Affiliation(s)
- Stephanie E Sanders
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, United States of America
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