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Chakraborty J, Mahali K, Henaish AMA, Ahmed J, Alshehri SM, Hossain A, Roy S. Exploring the solubility and intermolecular interactions of biologically significant amino acids l-serine and L-cysteine in binary mixtures of H 2O + DMF, H 2O + DMSO and H 2O + ACN in temperature range from T = 288.15 K to 308.15 K. Biophys Chem 2024; 311:107272. [PMID: 38824845 DOI: 10.1016/j.bpc.2024.107272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 05/14/2024] [Accepted: 05/26/2024] [Indexed: 06/04/2024]
Abstract
In the presented work, a study on the solubility and intermolecular interactions of l-serine and L-cysteine was carried out in binary mixtures of H2O + dimethylformamide (DMF), H2O + dimethylsulfoxide (DMSO), and H2O + acetonitrile (ACN) in the temperature range of T = 288.15 K to 308.15 K. l-serine exhibited the highest solubility in water, while L-cysteine was more soluble in water-DMF. The solvation process was assessed through standard Gibbs energy calculations, indicating the solvation stability order: water-ACN > water-DMSO > water-DMF for l-serine, and water-DMF > water-DMSO > water-ACN for L-cysteine. This study also explored the influence of these amino acids on solvent-solvent interactions, revealing changes in chemical entropies and self-association patterns within the binary solvent mixtures.
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Affiliation(s)
- Jit Chakraborty
- Department of Chemistry, University of Kalyani, Kalyani 741235, Nadia, India; Department of Chemistry, JIS College of Engineering, Kalyani 741235, Nadia, India
| | - Kalachand Mahali
- Department of Chemistry, University of Kalyani, Kalyani 741235, Nadia, India.
| | - A M A Henaish
- Physics Department, Faculty of Science, Tanta University, Tanta 31527, Egypt; NANOTECH Center, Ural Federal University, Ekaterinburg 620002, Russia
| | - Jahangeer Ahmed
- Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Saad M Alshehri
- Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Aslam Hossain
- Smart Materials Research Institute, Southern Federal University, Sladkova 178/24, 344090 Rostov-on-Don, Russian Federation
| | - Sanjay Roy
- Department of Chemistry, School of Sciences, Netaji Subhas Open University, Kolkata, West Bengal, India.
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Chakraborty J, Mahali K, Henaish AMA, Ahmed J, Alshehri SM, Roy S. Probing pharmaceutically important amino acids L-isoleucine and L-tyrosine Solubilities: Unraveling the solvation thermodynamics in diverse mixed solvent systems. Biophys Chem 2024; 309:107229. [PMID: 38555653 DOI: 10.1016/j.bpc.2024.107229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/15/2024] [Accepted: 03/24/2024] [Indexed: 04/02/2024]
Abstract
The study specifically investigates the solubilities of L-isoleucine and L-tyrosine in water-mixed solvent systems (DMF, DMSO, and ACN), exploring the behaviour of amino acids in complex environments. The experimental methods prioritize meticulous solvent purification to ensure reliable results. The work explores solubility data, uncovering temperature-dependent trends and intricate interactions influencing solubility in the chosen mixed solvent systems. The study emphasizes the impact of thermodynamic properties, solvent-solvent interactions, and amino acid structure on solubility patterns. The broader implications highlight the relevance of understanding amino acid behaviour in diverse solvent environments, offering potential applications in cosmetics and pharmaceutical industries. The distinct solubility patterns contribute valuable insights, enhancing on the understanding of the solution stability and interactions of L-isoleucine and L-tyrosine in different solvent systems. In conclusion, work suggests the enhanced utilization of L-isoleucine and L-tyrosine in various industries, driven by a profound understanding of their solubility in mixed solvent systems. The research expands our knowledge of amino acid behaviour, paving the way for advancements in industries relying on protein-based products and technologies.
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Affiliation(s)
- Jit Chakraborty
- Department of Chemistry, University of Kalyani, Kalyani 741235, Nadia, India; Department of Chemistry, JIS College of Engineering, Kalyani 741235, Nadia, India
| | - Kalachand Mahali
- Department of Chemistry, University of Kalyani, Kalyani 741235, Nadia, India.
| | - A M A Henaish
- Physics Department, Faculty of Science, Tanta University, Tanta 31527, Egypt; NANOTECH Center, Ural Federal University, Ekaterinburg 620002, Russia
| | - Jahangeer Ahmed
- Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Saad M Alshehri
- Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Sanjay Roy
- Department of Chemistry, School of Sciences, Netaji Subhas Open University, Kolkata, West Bengal, India.
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Sensing Magnetic Field and Intermolecular Interactions in Diamagnetic Solution Using Residual Dipolar Couplings of Zephycandidine. Int J Mol Sci 2022; 23:ijms232315118. [PMID: 36499439 PMCID: PMC9737189 DOI: 10.3390/ijms232315118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 11/24/2022] [Accepted: 11/25/2022] [Indexed: 12/05/2022] Open
Abstract
An unusual residual dipolar coupling of methylene protons was recorded in NMR spectra because aromatic zephycandidine has preferential orientation at the external magnetic field. The observed splitting contains contribution from the dipole-dipole D-coupling and the anisotropic component of J-coupling. Absolute values of the anisotropy of magnetic susceptibility |Δχax| are larger for protic solvents because of the hydrogen-bonding compared to aprotic solvents for which polar and dispersion forces are more important. The energy barrier for the reorientation due to hydrogen-bonding is 1.22 kJ/mol in methanol-d4, 0.85 kJ/mol in ethanol-d6 and 0.87 kJ/mol in acetic acid-d6. In dimethyl sulfoxide-d6, 1.08 kJ/mol corresponds to the interaction of solvent lone pair electrons with π-electrons of zephycandidine. This energy barrier decreases for acetone-d6 which has smaller electric dipole moment. In acetonitrile-d3, there is no energy barrier which suggests solvent ordering around the solute due to the solvent-solvent interactions. The largest absolute values of the magnetic anisotropy are observed for aromatic benezene-d6 and tolune-d8 which have their own preferential orientation and enhance the order in the solution. The magnetic anisotropy of "isolated" zephycandidine, not hindered by intermolecular interaction could be estimated from the correlation between Δχax and cohesion energy density.
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Grills DC, Lymar SV. Solvated Electron in Acetonitrile: Radiation Yield, Absorption Spectrum, and Equilibrium between Cavity- and Solvent-Localized States. J Phys Chem B 2021; 126:262-269. [PMID: 34931828 DOI: 10.1021/acs.jpcb.1c08946] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The equilibrium between a solvent cavity-localized electron, ecav-, and a dimeric solvent anion, (CH3CN)2•-, which are the two lowest energy states of the solvated electron in acetonitrile, has been investigated by pulse radiolysis at 233-353 K. The enthalpy and entropy for the ecav- to (CH3CN)2•- conversion amount to -11.2 ± 0.3 kcal/mol and -39.3 ± 1.2 cal/(mol K), corresponding to a 0.44 ± 0.35 equilibrium constant at 25 °C. The radiation yield of the solvated electron has been quantified using a Co(II) macrocycle that scavenges electrons with a 1.55 × 1011 M-1 s-1 rate constant. The apparent yield increases without saturation over the attainable scavenger concentration range, reaching 2.8 per 100 eV; this value represents the lower limit for the acetonitrile ionization yield in pulse radiolysis. The apparent molar absorption coefficient of (20.8 ± 1.5) × 103 M-1 cm-1 at 1450 nm and 20 °C for the solvated electron and individual vis-near-infrared (NIR) absorption spectra of ecav- and (CH3CN)2•- are derived from the data. Variances with previous reports are thoroughly discussed. Collectively, these results resolve several controversies concerning the solvated electron properties in acetonitrile and furnish requisite data for quantitative pulse radiolysis investigations in this commonly used solvent.
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Affiliation(s)
- David C Grills
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Sergei V Lymar
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
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Jański JJ, Roszak S, Orzechowski K, Sobczyk L. The electron attachment effect on the structure and properties of ortho-hydroxyaryl Schiff and Mannich bases - the hydrogen/proton transfer processes. Phys Chem Chem Phys 2021; 24:1338-1344. [PMID: 34812832 DOI: 10.1039/d1cp03723d] [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
The attachment of electrons is known to significantly influence some chemical and biological processes. The chemical differences between Schiff and Mannich bases are characterized by strong intramolecular hydrogen bonds, resulting from the presence of, respectively, single or double carbon-nitrogen bonds in the chelate rings. Differences are especially visible in the hydrogen transfer processes from molecular (O-H⋯N) to the proton transfer (O⋯H-N) forms. The reaction in a Schiff base occurs as an ordinary hydrogen transfer from a donor to an acceptor, while in a Mannich base the transfer of hydrogen occurs simultaneously with a C-N bond scission leading to an intermolecular complex. The attachment of electrons preserves the overall structural topology of the reactants; however, due to differences in electron affinities, reactions switch from endothermic to exothermic and reaction rates in the anionic systems are significantly higher. The difference in electron affinities for particular reactants comes from the fundamental differences in electron binding mechanisms, leading to the valence-bound or dipole-bound states. The observed mechanisms are closely related to the nature and size of the LUMOs of the parent molecules. The transition state of the Mannich base corresponds to the σ and π orbital conversion and possesses the characteristics of the valence-bound state and the dipole-bound electronic state.
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Affiliation(s)
- Jerzy J Jański
- Faculty of Chemistry, University of Wrocław, 50-370 Wrocław, Poland.
| | - Szczepan Roszak
- Faculty of Chemistry, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland.
| | | | - Lucjan Sobczyk
- Faculty of Chemistry, University of Wrocław, 50-370 Wrocław, Poland.
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Narvaez WA, Schwartz BJ. Ab Initio Simulations of Poorly and Well Equilibrated (CH 3CN) n- Cluster Anions: Assigning Experimental Photoelectron Peaks to Surface-Bound Electrons and Solvated Monomer and Dimer Anions. J Phys Chem A 2021; 125:7685-7693. [PMID: 34432443 DOI: 10.1021/acs.jpca.1c05855] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Excess electrons in liquid acetonitrile are of particular interest because they exist in two different forms in equilibrium: they can be present as traditional solvated electrons in a cavity, and they can form some type of solvated molecular anion. Studies of small acetonitrile cluster anions in the gas phase show two isomers with distinct vertical detachment energies, and it is tempting to presume that the two gas-phase cluster anion isomers are precursors of the two excess electron species present in bulk solution. In this paper, we perform DFT-based ab initio molecular dynamics simulations of acetonitrile cluster anions to understand the electronic species that are present and why they have different binding energies. Using a long-range-corrected density functional that was optimally tuned to describe acetonitrile cluster anion structures, we have theoretically explored the chemistry of (CH3CN)n- cluster anions with sizes n = 5, 7, and 10. Because the temperature of the experimental cluster anions is not known, we performed two sets of simulations that investigated how the way in which the cluster anions are prepared affects the excess electron binding motif: one set of simulations simply attached excess electrons to neutral (CH3CN)n clusters, providing little opportunity for the clusters to relax in the presence of the excess electron, while the other set allowed the cluster anions to thermally equilibrate near room temperature. We find that both sets of simulations show three distinct electron binding motifs: electrons can attach to the surface of the cluster (dipole-bound) or be present either as solvated monomer anions, CH3CN-, or as solvated molecular dimer anions, (CH3CN)2-. All three species have higher binding energies at larger cluster sizes. Thermal equilibration strongly favors the formation of the valence-bound molecular anions relative to surface-bound excess electrons, and the dimer anion becomes more stable than the monomer anion and surface-bound species as the cluster size increases. The calculated photoelectron spectra from our simulations in which there was poor thermal equilibration are in good agreement with experiment, suggesting assignment of the two experimental cluster anion isomers as the surface-bound electron and the solvated molecular dimer anion. The simulations also suggest that the shoulder seen experimentally on the low-energy isomer's detachment peak is not part of a vibronic progression but instead results from molecular monomer anions. Nowhere in the size range that we explore do we see evidence for a nonvalence, cavity-bound interior-solvated electron, indicating that this species is likely only accessible at larger sizes with good thermal equilibration.
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Affiliation(s)
- Wilberth A Narvaez
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States
| | - Benjamin J Schwartz
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States
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Sidorkin VF, Belogolova EF, Doronina EP, Liu G, Ciborowski SM, Bowen KH. “Outlaw” Dipole-Bound Anions of Intra-Molecular Complexes. J Am Chem Soc 2020; 142:2001-2011. [DOI: 10.1021/jacs.9b11694] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Valery F. Sidorkin
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences Favorsky, 1, Irkutsk 664033, Russian Federation
| | - Elena F. Belogolova
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences Favorsky, 1, Irkutsk 664033, Russian Federation
| | - Evgeniya P. Doronina
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences Favorsky, 1, Irkutsk 664033, Russian Federation
| | - Gaoxiang Liu
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Sandra M. Ciborowski
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Kit H. Bowen
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
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Naskar P, Talukder S, Ghosh S, Chaudhury P. Controlling the isomerization dynamics of iodide acetonitrile dimer complex by optimally designed electromagnetic field: A wave packet based approach. INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY 2019; 119:e25927. [DOI: 10.1002/qua.25927] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/19/2023]
Affiliation(s)
- Pulak Naskar
- Department of ChemistryUniversity of Calcutta Kolkata India
| | - Srijeeta Talukder
- School of Chemical SciencesIndian Association for the Cultivation of Science Kolkata India
| | - Subhasree Ghosh
- Department of ChemistrySerampore College Serampore West Bengal India
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9
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Kowsari MH, Tohidifar L. Systematic evaluation and refinement of existing all‐atom force fields for the simulation of liquid acetonitrile. J Comput Chem 2018; 39:1843-1853. [DOI: 10.1002/jcc.25337] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 04/08/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Mohammad H. Kowsari
- Department of ChemistryInstitute for Advanced Studies in Basic Sciences (IASBS)Zanjan45137‐66731 Iran
- Center for Research in Climate Change and Global Warming (CRCC), Institute for Advanced Studies in Basic Sciences (IASBS)Zanjan45137‐66731 Iran
| | - Leila Tohidifar
- Department of ChemistryInstitute for Advanced Studies in Basic Sciences (IASBS)Zanjan45137‐66731 Iran
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Skotnicki K, De la Fuente JR, Cañete Á, Berrios E, Bobrowski K. Radical Ions of 3-Styryl-quinoxalin-2-one Derivatives Studied by Pulse Radiolysis in Organic Solvents. J Phys Chem B 2018. [PMID: 29533616 DOI: 10.1021/acs.jpcb.8b01004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The absorption-spectral and kinetic behaviors of radical ions and neutral hydrogenated radicals of seven 3-styryl-quinoxalin-2(1 H)-one (3-SQ) derivatives, one without substituents in the styryl moiety, four others with electron-donating (R = -CH3, -OCH3, and -N(CH3)2) or electron-withdrawing (R = -OCF3) substituents in the para position in their benzene ring, and remaining two with double methoxy substituents (-OCH3), however, at different positions (meta/para and ortho/meta) have been studied by UV-vis spectrophotometric pulse radiolysis in neat acetonitrile saturated with argon (Ar) and oxygen (O2) and in 2-propanol saturated with Ar, at room temperature. In acetonitrile solutions, the radical anions (4R-SQ•-) are characterized by two absorption maxima located at λmax = 470-490 nm and λmax = 510-540 nm, with the respective molar absorption coefficients ε470-490 = 8500-13 100 M-1 cm-1 and ε510-540 = 6100-10 300 M-1 cm-1, depending on the substituent (R). All 4R-SQ•- decay in acetonitrile via first-order kinetics, with the rate constants in the range (1.2-1.5) × 106 s-1. In 2-propanol solutions, they decay predominantly through protonation by the solvent, forming neutral hydrogenated radicals (4R-SQH•), which are characterized by weak absorption bands with λmax = 480-490 nm. Being oxygen-insensitive, the radical cations (4R-SQ•+) are characterized by a strong absorption with λmax = 450-630 nm, depending on the substituent (R). They are formed in a charge-transfer reaction between a radical cation derived from acetonitrile (ACN•+) and substituted 3-styryl-quinoxalin-2-one derivatives (4R-SQ) with a pseudo-first-order rate constant k = (2.7-4.7) × 105 s-1 measured in solutions containing 0.1 mM 4R-3-SQ. The Hammett equation plot gave a very small negative slope (ρ = -0.08), indicating a very weak influence of the substituents in the benzene ring on the rate of charge-transfer reaction. The decay of 4R-SQ•+ in Ar-saturated acetonitrile solutions occurs with a pseudo-first-order rate constant k = (1.6-6.2) × 104 s-1 and, in principle, is not affected by the presence of O2, suggesting charge-spin delocalization over the whole 3-SQ molecule. Most of the radiolytically generated transient spectra are reasonably well-reproduced by semiempirical PM3-ZINDO/S (for 4R-SQ•-) and density functional theory quantum mechanics calculations employing M06-2x hybrid functional together with the def2-TZVP basis set (for 4R-SQ•+).
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Affiliation(s)
- Konrad Skotnicki
- Institute of Nuclear Chemistry and Technology , 03-195 Warsaw , Poland
| | - Julio R De la Fuente
- Departamento de Química Orgánica y Fisicoquímica, Facultad de Ciencias Químicas y Farmacéuticas , Universidad de Chile , Casilla 223 , Santiago 1 8380492 , Chile
| | - Álvaro Cañete
- Departamento de Química Orgánica, Facultad de Química , Pontificia Universidad Católica de Chile , Casilla 306, Correo 22 , Santiago 7820436 , Chile
| | - Eduardo Berrios
- Departamento de Química Orgánica y Fisicoquímica, Facultad de Ciencias Químicas y Farmacéuticas , Universidad de Chile , Casilla 223 , Santiago 1 8380492 , Chile
| | - Krzysztof Bobrowski
- Institute of Nuclear Chemistry and Technology , 03-195 Warsaw , Poland.,Notre Dame Radiation Laboratory , University of Notre Dame , Notre Dame , Indiana 46556 , United States
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Takeshita T, Hara M. Photoionization and trans-to-cis isomerization of β-cyclodextrin-encapsulated azobenzene induced by two-color two-laser-pulse excitation. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 193:475-479. [PMID: 29289746 DOI: 10.1016/j.saa.2017.12.061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 12/19/2017] [Accepted: 12/20/2017] [Indexed: 06/07/2023]
Abstract
Azobenzene (1) and the complex resulting from the incorporation of 1 with cyclodextrin (1/CD) are attractive for light-driven applications such as micromachining and chemical biology tools. The highly sensitive photoresponse of 1 is crucial for light-driven applications containing both 1 and 1/CD to reach their full potential. In this study, we investigated the photoionization and trans-to-cis isomerization of 1/CD induced by one- and two-color two-laser pulse excitation. Photoionization of 1/CD, which was induced by stepwise two-photon absorption, was observed using laser pulse excitation at 266nm. Additionally, simultaneous irradiation with 266 and 532nm laser pulses increased the trans-to-cis isomerization yield (Υt→c) by 27%. It was concluded that the increase in Υt→c was caused by the occurrence of trans-to-cis isomerization in the higher-energy singlet state (Sn), which was reached by S1→Sn transition induced by laser pulse excitation at 532nm. The results of this study are potentially applicable in light-driven applications such as micromachining and chemical biology tools.
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Affiliation(s)
- Tatsuya Takeshita
- Department of Environmental and Food Sciences, Fukui University of Technology, Fukui, Japan
| | - Michihiro Hara
- Department of Environmental and Food Sciences, Fukui University of Technology, Fukui, Japan.
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12
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Takeshita T, Kurata H, Hara M. Improvement of photoionization efficiency of diarylethene-cyclodextrin complexes by using multi-laser pulse excitation. J Photochem Photobiol A Chem 2017. [DOI: 10.1016/j.jphotochem.2017.04.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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13
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Ingenmey J, von Domaros M, Kirchner B. Predicting miscibility of binary liquids from small cluster QCE calculations. J Chem Phys 2017; 146:154502. [PMID: 28433040 DOI: 10.1063/1.4980032] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- Johannes Ingenmey
- Mulliken Center for Theoretical Chemistry, Universität Bonn, Beringstr. 4, D-53115 Bonn, Germany
| | - Michael von Domaros
- Mulliken Center for Theoretical Chemistry, Universität Bonn, Beringstr. 4, D-53115 Bonn, Germany
| | - Barbara Kirchner
- Mulliken Center for Theoretical Chemistry, Universität Bonn, Beringstr. 4, D-53115 Bonn, Germany
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14
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Resonant two-photon ionization of aromatic hydrocarbons included in cyclodextrins. J Photochem Photobiol A Chem 2016. [DOI: 10.1016/j.jphotochem.2016.01.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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15
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Tang WK, Leong CP, Hao Q, Siu CK. Theoretical examination of competitive β-radical-induced cleavages of N–Cα and Cα–C bonds of peptides. CAN J CHEM 2015. [DOI: 10.1139/cjc-2015-0208] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Selective cleavages of N–Cα and Cα–C bonds of β-radical tautomers of amino acid residues in radical peptides have been examined theoretically by means of the density functional theory at the M06-2X/6-311++G(d,p) level. The majority of the bond cleavages are homolytic via β-scission. Their energy barriers depend largely on the ability of the radical being stabilized in the transition structures and the availability of a mobile proton in the vicinity of the β-radical center. The N–Cα bond is less favorably cleaved than the Cα–C bond (except Ser and Thr) for systems without a mobile proton. It is because, firstly, the homolytic cleavage is less favorable for the more polar N–Cα bond than for the less polar Cα–C bond. Secondly, a less stable σ-radical localized on the amide nitrogen atom of the incipient N-terminal fragment is formed for the former, while a more stable radical delocalized in a π*(CO)-like orbital of the incipient C-terminal fragment is formed for the latter. In the presence of a mobile proton N-terminal to the β-radical center, some degrees of heterolytic cleavage character, as preferred by the polar N–Cα bond, are observed. Consequently, its barrier is reduced. If the mobile proton is located at the C-terminal amide oxygen of the β-radical center, the Cα–C bond cleavage will be significantly suppressed. It is because the radical in the incipient C-terminal fragment becomes more localized as a σ-radical on the carbon atom of its protonated amide group. With basic amino acid residues, the Cα–C bond cleavage can be reactivated. Heterolytic cleavage of the polar N–Cα bond can be largely facilitated if a mobile proton N-terminal to the β-radical center is available and the radical in the incipient C-terminal fragment is sufficiently stabilized, for instance, by the aromatic side chain of Trp and Tyr. Therefore, cleavages of the N–Cα bond induced by the β-radical tautomer of Trp and Tyr are often preferred as compared with cleavages of the Cα–C bond in peptide radical cations containing mobile protons.
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Affiliation(s)
- Wai-Kit Tang
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong SAR, P.R. China
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong SAR, P.R. China
| | - Chun-Ping Leong
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong SAR, P.R. China
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong SAR, P.R. China
| | - Qiang Hao
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong SAR, P.R. China
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong SAR, P.R. China
| | - Chi-Kit Siu
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong SAR, P.R. China
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong SAR, P.R. China
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Herber I, Tang WK, Wong HY, Lam TW, Siu CK, Beyer MK. Reactivity of Hydrated Monovalent First Row Transition Metal Ions [M(H2O)n]+, M = Cr, Mn, Fe, Co, Ni, Cu, and Zn, n < 50, Toward Acetonitrile. J Phys Chem A 2015; 119:5566-78. [DOI: 10.1021/acs.jpca.5b02946] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ina Herber
- Institut
für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstrasse
40, 24098 Kiel, Germany
- Institut
für Ionenphysik und Angewandte Physik, Leopold-Franzens-Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| | - Wai-Kit Tang
- Department
of Biology and Chemistry, City University of Hong Kong, 83 Tat
Chee Avenue, Kowloon Tong, Hong Kong SAR, People’s Republic of China
| | - Ho-Yin Wong
- Department
of Biology and Chemistry, City University of Hong Kong, 83 Tat
Chee Avenue, Kowloon Tong, Hong Kong SAR, People’s Republic of China
| | - Tim-Wai Lam
- Department
of Biology and Chemistry, City University of Hong Kong, 83 Tat
Chee Avenue, Kowloon Tong, Hong Kong SAR, People’s Republic of China
| | - Chi-Kit Siu
- Department
of Biology and Chemistry, City University of Hong Kong, 83 Tat
Chee Avenue, Kowloon Tong, Hong Kong SAR, People’s Republic of China
| | - Martin K. Beyer
- Institut
für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstrasse
40, 24098 Kiel, Germany
- Institut
für Ionenphysik und Angewandte Physik, Leopold-Franzens-Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
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Wang S, Liu J, Zhang C, Guo L, Bu Y. Crucial role of solvent-impacted molecular anionic resonances in controlling protonation modes in the acetonitrile-water anionic cluster revealed by ab initio molecular dynamics simulations. J Phys Chem A 2014; 118:9212-9. [PMID: 24831567 DOI: 10.1021/jp5030284] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present an ab initio molecular dynamics simulation study of a CH3CN-(H2O)40 cluster with an excess electron (EE) injected vertically in this work. Instead of surface bound or internally solvated electron, a hydrated CH3CN(-) is first formed as the CN transient after geometrical relaxation. The driving forces for the formation of CH3CN(-) are bending vibration of ∠CCN angle, which initiates transfer of an extra charge to the CH3CN LUMO, and hydration effect of the immediate water molecules, which plays a stabilizing role. Solvent thermal fluctuation can lead to different resonances (the quasi-C2-resonance versus quasi-N-resonance) from the CN transient and further cause the hydrated CH3CN(-) system to evolve via two distinctly different pathways featuring spontaneous proton transfer to the central C and N sites, producing two different protonation products, respectively. The solvent thermal fluctuation induced formation of hydrogen bonding with the corresponding sites (C2 versus N) is responsible for the quasi-resonances and interconversion between three resonant structures and further proton transfers featuring spontaneous transfer of a proton to C2 or to N from its interacting water molecule. The duration of CH3CN(-) for either of the two proton transfer processes is less than 200 fs. On the basis of experimental ESR results in which only the CH3CHN radical was found and present theoretical calculations, it is suggested that the trans-CH3CNH radical can be further converted to the CH3CHN radical via a water-mediated hydrogen atom transfer path.
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Affiliation(s)
- Shoushan Wang
- School of Chemistry and Chemical Engineering, Institute of Theoretical Chemistry, Shandong University , Jinan 250100, P. R. China
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Mbaiwa F, Holtgrewe N, Dao DB, Lasinski J, Mabbs R. Photoelectron Angular Distributions as Probes of Cluster Anion Structure: I–·(H2O)2 and I–·(CH3CN)2. J Phys Chem A 2014; 118:7249-54. [DOI: 10.1021/jp4104596] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Foster Mbaiwa
- Department
of Chemistry, University of Botswana, Private Bag UB00704, Gaborone, Botswana
| | - Nicholas Holtgrewe
- Department
of Chemistry, Washington University in St. Louis, One Brookings
Drive, St. Louis, Missouri 63130, United States
| | - Diep Bich Dao
- Department
of Chemistry, Washington University in St. Louis, One Brookings
Drive, St. Louis, Missouri 63130, United States
| | - Joshua Lasinski
- Department
of Chemistry, Washington University in St. Louis, One Brookings
Drive, St. Louis, Missouri 63130, United States
| | - Richard Mabbs
- Department
of Chemistry, Washington University in St. Louis, One Brookings
Drive, St. Louis, Missouri 63130, United States
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Lam TW, van der Linde C, Akhgarnusch A, Hao Q, Beyer MK, Siu CK. Reduction of Acetonitrile by Hydrated Magnesium Cations Mg + (H 2 O) n (n≈20-60) in the Gas Phase. Chempluschem 2013; 78:1040-1048. [PMID: 31986721 DOI: 10.1002/cplu.201300170] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Indexed: 11/09/2022]
Abstract
Ion-molecule reactions of Mg+ (H2 O)n (n≈20-60) with CH3 CN are studied by Fourier-transform ion-cyclotron resonance mass spectrometry. Collision with CH3 CN initiates the formation of MgOH+ (H2 O)n-1 together with CH3 CHN. or CH3 CNH. , which is similar to the reaction of hydrated electrons (H2 O)n - with CH3 CN. In subsequent reaction steps, three more CH3 CN molecules are taken up by the clusters, to form MgOH+ (CH3 CN)3 after a reaction delay of 60 seconds. Density functional theory (DFT) calculations at the M06/6-31++G(d,p) level of theory suggest that the bending motion of CH3 CN allows the unpaired electron that is solvated out from the Mg center to localize in a π*(CN)-like orbital of the bent CH3 CN.- , which undergoes spontaneous proton transfer to form CH3 CNH. or CH3 CHN. , with the former being kinetically more favorable. The reaction energy for a cluster with the hexacoordinated Mg center is more exothermic than that with the pentacoordinated Mg. The CH3 CNH. or CH3 CHN. is preferentially solvated on the cluster surface rather than at the first solvation shell of the Mg center. By contrast, the three additional CH3 CN molecules taken up by the resulting MgOH+ (H2 O)n clusters coordinate directly to the first solvation shell of the MgOH+ core, as revealed by DFT calculations.
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Affiliation(s)
- Tim-Wai Lam
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong (P. R. China), Fax: (+852) 3442-0522
| | - Christian van der Linde
- Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstraße 40, 24098 Kiel (Germany), Fax: (+49) 431-880-2830
| | - Amou Akhgarnusch
- Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstraße 40, 24098 Kiel (Germany), Fax: (+49) 431-880-2830
| | - Qiang Hao
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong (P. R. China), Fax: (+852) 3442-0522
| | - Martin K Beyer
- Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstraße 40, 24098 Kiel (Germany), Fax: (+49) 431-880-2830
| | - Chi-Kit Siu
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong (P. R. China), Fax: (+852) 3442-0522
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Doan SC, Schwartz BJ. Nature of Excess Electrons in Polar Fluids: Anion-Solvated Electron Equilibrium and Polarized Hole-Burning in Liquid Acetonitrile. J Phys Chem Lett 2013; 4:1471-1476. [PMID: 26282301 DOI: 10.1021/jz400621m] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Affiliation(s)
- Stephanie C Doan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States
| | - Benjamin J Schwartz
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States
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Cahill KJ, Johnson RP. Beyond Frontier Molecular Orbital Theory: A Systematic Electron Transfer Model (ETM) for Polar Bimolecular Organic Reactions. J Org Chem 2012; 78:1864-73. [DOI: 10.1021/jo301731v] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Katharine J. Cahill
- Department of Chemistry, University of New Hampshire, Durham, New Hampshire 03824, United States
| | - Richard P. Johnson
- Department of Chemistry, University of New Hampshire, Durham, New Hampshire 03824, United States
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23
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Doan SC, Schwartz BJ. Ultrafast Studies of Excess Electrons in Liquid Acetonitrile: Revisiting the Solvated Electron/Solvent Dimer Anion Equilibrium. J Phys Chem B 2012; 117:4216-21. [DOI: 10.1021/jp303591h] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Stephanie C. Doan
- Department of Chemistry
and Biochemistry, University of California, Los Angeles, Los Angeles,
California 90095, United States
| | - Benjamin J. Schwartz
- Department of Chemistry
and Biochemistry, University of California, Los Angeles, Los Angeles,
California 90095, United States
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Affiliation(s)
- Ryan M. Young
- Department of Chemistry, University of California, Berkeley, California 94720,
United States
| | - Daniel M. Neumark
- Department of Chemistry, University of California, Berkeley, California 94720,
United States
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
94720, United States
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Varadwaj PR, Varadwaj A, Peslherbe GH. An electronic structure theory investigation of the physical chemistry of the intermolecular complexes of cyclopropenylidene with hydrogen halides. J Comput Chem 2012; 33:2073-82. [DOI: 10.1002/jcc.23043] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 05/04/2012] [Accepted: 05/07/2012] [Indexed: 01/30/2023]
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Shkrob IA, Marin TW. Electron Localization and Radiation Chemistry of Amides. J Phys Chem A 2012; 116:1746-57. [DOI: 10.1021/jp2115687] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ilya A. Shkrob
- Chemical Sciences
and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States
| | - Timothy W. Marin
- Chemical Sciences
and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States
- Chemistry Department, Benedictine University, 5700 College Road, Lisle, Illinois
60532, United States
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Timerghazin QK, Rizvi I, Peslherbe GH. Can a Dipole-Bound Electron Form a Pseudo-Atom? An Atoms-In-Molecules Study of the Hydrated Electron. J Phys Chem A 2011; 115:13201-9. [DOI: 10.1021/jp207381t] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Qadir K. Timerghazin
- Department of Chemistry, Marquette University, P.O. Box 1881, Milwaukee, Wisconsin, 53201
| | - Inessa Rizvi
- Centre for Research in Molecular Modeling and Department of Chemistry & Biochemistry, Concordia University, Montréal, QC, Canada H4B 1R6
| | - Gilles H. Peslherbe
- Centre for Research in Molecular Modeling and Department of Chemistry & Biochemistry, Concordia University, Montréal, QC, Canada H4B 1R6
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28
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Azar J, Kurlancheek W, Head-Gordon M. Characterization of electronically excited states in anionic acetonitrile clusters. Phys Chem Chem Phys 2011; 13:9147-54. [DOI: 10.1039/c1cp20089e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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Intra- and intermolecular quenching of carbazole photoluminescence by imidazolidine radicals. Russ Chem Bull 2010. [DOI: 10.1007/s11172-010-0160-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Young RM, Griffin GB, Kammrath A, Ehrler OT, Neumark DM. Time-resolved dynamics in acetonitrile cluster anions (CH3CN)n-. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2009.12.058] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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31
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Ehrler OT, Griffin GB, Young RM, Neumark DM. Photoinduced Electron Transfer and Solvation in Iodide-doped Acetonitrile Clusters. J Phys Chem B 2008; 113:4031-7. [DOI: 10.1021/jp806856m] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Oli T. Ehrler
- Department of Chemistry, University of California, Berkeley, California 94720 and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Graham B. Griffin
- Department of Chemistry, University of California, Berkeley, California 94720 and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Ryan M. Young
- Department of Chemistry, University of California, Berkeley, California 94720 and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Daniel M. Neumark
- Department of Chemistry, University of California, Berkeley, California 94720 and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
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Olejniczak A, Katrusiak A. Supramolecular Reaction between Pressure-Frozen Acetonitrile Phases α and β. J Phys Chem B 2008; 112:7183-90. [DOI: 10.1021/jp800753n] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anna Olejniczak
- Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznań, Poland
| | - Andrzej Katrusiak
- Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznań, Poland
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