1
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Forjan M, Zgrablić G, Vdović S, Šekutor M, Basarić N, Kabacinski P, Nazari Haghighi Pashaki M, Frey HM, Cannizzo A, Cerullo G. Photogeneration of quinone methide from adamantylphenol in an ultrafast non-adiabatic dehydration reaction. Phys Chem Chem Phys 2022; 24:4384-4393. [PMID: 35112685 PMCID: PMC8849006 DOI: 10.1039/d1cp05690e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 01/24/2022] [Indexed: 01/23/2023]
Abstract
The ultrafast photochemical reaction of quinone methide (QM) formation from adamantylphenol was monitored in real time using femtosecond transient absorption spectroscopy and fluorescence upconversion in solution at room temperature. Experiments were complemented by theoretical studies simulating the reaction pathway and elucidating its mechanism. Excitation with sub-20 fs UV pulses and broadband probing revealed ultrafast formation of the long-lived QM intermediate directly in the ground state, occurring with a time constant of around 100 fs. UV-vis transient absorption data covering temporal dynamics from femtoseconds to hundreds of milliseconds revealed persistence of the absorption band assigned to QM and partially overlapped with other contributions tentatively assigned to triplet excited states of the adamantyl derivative and the phenoxyl radical that are clearly distinguished by their evolution on different time scales. Our data, together with the computations, provide evidence of a non-adiabatic photodehydration reaction, which leads to the formation of QM in the ground state via a conical intersection, circumventing the generation of a transient QM excited state.
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Affiliation(s)
- Mateo Forjan
- Institute of Physics, Bijenička cesta 46, 10 000 Zagreb, Croatia.
| | - Goran Zgrablić
- Institute of Physics, Bijenička cesta 46, 10 000 Zagreb, Croatia.
| | - Silvije Vdović
- Institute of Physics, Bijenička cesta 46, 10 000 Zagreb, Croatia.
| | - Marina Šekutor
- Department of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10 000 Zagreb, Croatia
| | - Nikola Basarić
- Department of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10 000 Zagreb, Croatia
| | - Piotr Kabacinski
- IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | | | - Hans-Martin Frey
- Institute of Applied Physics, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - Andrea Cannizzo
- Institute of Applied Physics, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - Giulio Cerullo
- IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
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2
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Kajita M, Takaya T, Iwata K. Dynamics of electron ejection on photoionization of trans-stilbene and biphenyl in acetonitrile as observed with femtosecond time-resolved near-IR absorption spectroscopy. Phys Chem Chem Phys 2022; 24:5411-5418. [DOI: 10.1039/d1cp05533j] [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
Photoionization in solution is a basic but complex phenomenon involving a solute, an ejected electron and surrounding solvent molecules. It may seem obvious that an electron is released immediately after...
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3
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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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4
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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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5
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Liu G, Díaz-Tinoco M, Ciborowski SM, Martinez-Martinez C, Lyapustina S, Hendricks JH, Ortiz JV, Bowen KH. Excess electrons bound to H2S trimer and tetramer clusters. Phys Chem Chem Phys 2020; 22:3273-3280. [DOI: 10.1039/c9cp06872d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We have prepared the hydrogen sulfide trimer and tetramer anions, (H2S)3− and (H2S)4−, measured their anion photoelectron spectra, and applied high-level quantum chemical calculations to interpret the results.
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Affiliation(s)
- Gaoxiang Liu
- Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Manuel Díaz-Tinoco
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849, USA
| | | | | | | | - Jay H. Hendricks
- Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Joseph Vincent Ortiz
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849, USA
| | - Kit H. Bowen
- Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA
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6
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Ye M, Iwata K. Ultrafast Electron Solvation in Room Temperature Ionic Liquid Observed by Femtosecond Time-resolved Near-IR Spectroscopy. CHEM LETT 2019. [DOI: 10.1246/cl.181043] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Manping Ye
- College of Optical and Electronic Technology, China Jiliang University, Hangzhou 310018, P. R. China
- Department of Chemistry, Faculty of Science, Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588, Japan
| | - Koichi Iwata
- Department of Chemistry, Faculty of Science, Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588, Japan
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7
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Sciortino A, Gazzetto M, Buscarino G, Popescu R, Schneider R, Giammona G, Gerthsen D, Rohwer EJ, Mauro N, Feurer T, Cannizzo A, Messina F. Disentangling size effects and spectral inhomogeneity in carbon nanodots by ultrafast dynamical hole-burning. NANOSCALE 2018; 10:15317-15323. [PMID: 30069566 DOI: 10.1039/c8nr02953a] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Carbon nanodots (CDs) are a novel family of nanomaterials exhibiting unique optical properties. In particular, their bright and tunable fluorescence redefines the paradigm of carbon as a "black" material and is considered very appealing for many applications. While the field keeps growing, understanding CDs fundamental properties and relating them to their variable structures becomes more and more critical. Two crucial problems concern the effect of size on the electronic structure of CDs, and to what extent their optical properties are influenced by structural disorder. Furthermore, it remains largely unclear whether traditional concepts borrowed from the photo-physics of semiconductor quantum dots can be applied to any type of CDs. We used femtosecond optical hole burning to address the excited-state properties of a family of CDs with the specific structure of β-C3N4. The experiments provide compelling evidence of the dramatic effects of structural heterogeneity on the optical spectra, and reveal the remarkably simple pattern of the electronic transitions of these CDs, normally obscured by disorder. Moreover, the data conclusively clarify the different effects of the nanometric size and of the disordered surface structure on the fluorescence tunability, ruling out for these CDs any quantum confinement effect comparable to semiconductor quantum dots.
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Affiliation(s)
- Alice Sciortino
- Dipartimento di Fisica e Chimica, Università degli Studi di Palermo, Via Archirafi 36, 90123 Palermo, Italy.
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8
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Wang Y, Guo H, Zheng Q, Saidi WA, Zhao J. Tuning Solvated Electrons by Polar-Nonpolar Oxide Heterostructure. J Phys Chem Lett 2018; 9:3049-3056. [PMID: 29767527 DOI: 10.1021/acs.jpclett.8b00938] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Solvated electron states at the oxide/aqueous interface represent the lowest energy charge-transfer pathways, thereby playing an important role in photocatalysis and electronic device applications. However, their energies are usually higher than the conduction band minimum (CBM), which makes the solvated electrons difficult to utilize in charge-transfer processes. Thus it is essential to stabilize the energy of the solvated electron states. Taking LaAlO3/SrTiO3 (LAO/STO) oxide heterostructure with H2O-adsorbed monolayer as a prototypical system, we show using DFT and ab initio time-dependent nonadiabatic molecular dynamics simulation that the energy and dynamics of solvated electrons can be tuned by the electric field in the polar-nonpolar oxide heterostructure. In particular, for LAO/STO with p-type interface, the CBM is contributed by the solvated electron state when LAO is thicker than four unit cells. Furthermore, the solvated electron band minimum can be partially occupied when LAO is thicker than eight unit cells. We propose that the tunability of solvated electron states can be achieved on polar-nonpolar oxide heterostructure surfaces as well as on ferroelectric oxides, which is important for charge and proton transfer at oxide/aqueous interfaces.
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Affiliation(s)
- Yanan Wang
- ICQD/Hefei National Laboratory for Physical Sciences at Microscale and Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences and Department of Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Hongli Guo
- ICQD/Hefei National Laboratory for Physical Sciences at Microscale and Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences and Department of Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education , Wuhan University , Wuhan 430072 , China
| | - Qijing Zheng
- ICQD/Hefei National Laboratory for Physical Sciences at Microscale and Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences and Department of Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Wissam A Saidi
- Department of Mechanical Engineering and Materials Science , University of Pittsburgh , Pittsburgh , Pennsylvania 15261 , United States
| | - Jin Zhao
- ICQD/Hefei National Laboratory for Physical Sciences at Microscale and Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences and Department of Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China
- Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh , Pennsylvania 15260 , United States
- Synergetic Innovation Center of Quantum Information & Quantum Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China
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9
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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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10
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Grills DC, Lymar SV. Radiolytic formation of the carbon dioxide radical anion in acetonitrile revealed by transient IR spectroscopy. Phys Chem Chem Phys 2018; 20:10011-10017. [DOI: 10.1039/c8cp00977e] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
First IR detection of CO2˙− in acetonitrile, produced by radiation-induced CO2 reduction and oxidation of formate.
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11
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Borovkov VI. Unexpectedly Large Spin Coherence Effects in the Recombination Fluorescence from Irradiated Highly Polar Solutions on a Nanosecond Time Scale. J Phys Chem B 2017; 121:9422-9428. [PMID: 28915031 DOI: 10.1021/acs.jpcb.7b08813] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Spin correlation effects in the geminate recombination of radical ion pairs in irradiated highly polar liquids are typically believed to be negligible due to a high escape probability for the ions. This report presents the results of an exploratory study of organic polar solvents aimed at the searching for, and estimating the magnitude of, the time-resolved magnetic field effects (TR MFEs) in the delayed radiation-induced fluorescence from diluted solutions of a luminophore. It has been found that upon the high-energy irradiation of the solutions in polar liquids, such as dichloroethane (ε ≈ 10), methanol (ε ≈ 33), acetonitrile (ε ≈ 37), dimethylformamide (ε ≈ 37), dimethyl sulfoxide (ε ≈ 47), ethylene carbonate (ε ≈ 89), substantial spin coherence effects in the delayed fluorescence can be observed within a time range up to ∼100 ns. In most of the cases studied, magnetic resonance characteristics of primary or very early solvent-related radical ions were evaluated from the TR MFE curves. This approach can, therefore, be widely used to complement results obtained by the pulse radiolysis technique with structural and kinetic data extracted from the magnetic resonance characteristics of the short-lived radical ions formed in irradiated media.
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Affiliation(s)
- Vsevolod I Borovkov
- Voevodsky Institute of Chemical Kinetics and Combustion, Siberian Branch of the Russian Academy of Science , 3 Institutskaya Street, Novosibirsk 630090, Russia.,Novosibirsk State University , 2 Pirogova Street, Novosibirsk 630090, Russia
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12
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Chaban VV, Prezhdo OV. Electron Solvation in Liquid Ammonia: Lithium, Sodium, Magnesium, and Calcium as Electron Sources. J Phys Chem B 2016; 120:2500-6. [PMID: 26886153 DOI: 10.1021/acs.jpcb.6b00412] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A free electron in solution, known as a solvated electron, is the smallest possible anion. Alkali and alkaline earth atoms serve as electron donors in solvents that mediate outer-sphere electron transfer. We report herein ab initio molecular dynamics simulations of lithium, sodium, magnesium, and calcium in liquid ammonia at 250 K. By analyzing the electronic properties and the ionic and solvation structures and dynamics, we systematically characterize these metals as electron donors and ammonia molecules as electron acceptors. We show that the solvated metal strongly modifies the properties of its solvation shells and that the observed effect is metal-specific. Specifically, the radius and charge exhibit major impacts. The single solvated electron present in the alkali metal systems is distributed more uniformly among the solvent molecules of each metal's two solvation shells. In contrast, alkaline earth metals favor a less uniform distribution of the electron density. Alkali and alkaline earth atoms are coordinated by four and six NH3 molecules, respectively. The smaller atoms, Li and Mg, are stronger electron donors than Na and Ca. This result is surprising, as smaller atoms in a column of the periodic table have higher ionization potentials. However, it can be explained by stronger electron donor-acceptor interactions between the smaller atoms and the solvent molecules. The structure of the first solvation shell is sharpest for Mg, which has a large charge and a small radius. Solvation is weakest for Na, which has a small charge and a large radius. Weak solvation leads to rapid dynamics, as reflected in the diffusion coefficients of NH3 molecules of the first two solvation shells and the Na atom. The properties of the solvated electrons established in the present study are important for radiation chemistry, synthetic chemistry, condensed-matter charge transfer, and energy sources.
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Affiliation(s)
- Vitaly V Chaban
- Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo , 12231-280 São José dos Campos, SP Brazil
| | - Oleg V Prezhdo
- Department of Chemistry, University of Southern California , Los Angeles, California 90089, United States
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13
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Weinert C, Wezisla B, Lindner J, Vöhringer P. Ultrafast primary processes of the stable neutral organic radical, 1,3,5-triphenylverdazyl, in liquid solution. Phys Chem Chem Phys 2015; 17:13659-71. [DOI: 10.1039/c5cp01383f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Femtosecond pump–probe spectroscopy reveals ultrafast photochemical processes of a stable neutral organic radical in solution.
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Affiliation(s)
- Christoph Weinert
- Lehrstuhl für Molekulare Physikalische Chemie
- Institut für Physikalische und Theoretische Chemie
- Rheinische Friedrich-Wilhelms-Universität
- 53115 Bonn
- Germany
| | - Boris Wezisla
- Lehrstuhl für Molekulare Physikalische Chemie
- Institut für Physikalische und Theoretische Chemie
- Rheinische Friedrich-Wilhelms-Universität
- 53115 Bonn
- Germany
| | - Jörg Lindner
- Lehrstuhl für Molekulare Physikalische Chemie
- Institut für Physikalische und Theoretische Chemie
- Rheinische Friedrich-Wilhelms-Universität
- 53115 Bonn
- Germany
| | - Peter Vöhringer
- Lehrstuhl für Molekulare Physikalische Chemie
- Institut für Physikalische und Theoretische Chemie
- Rheinische Friedrich-Wilhelms-Universität
- 53115 Bonn
- Germany
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14
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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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15
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Redeckas K, Voiciuk V, Steponavičiu̅tė R, Martynaitis V, Šačkus A, Vengris M. Optically Controlled Molecular Switching of an Indolobenzoxazine-Type Photochromic Compound. J Phys Chem A 2014; 118:5642-51. [DOI: 10.1021/jp505723q] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Kipras Redeckas
- Quantum
Electronics Department, Vilnius University, Saulėtekio 10, LT-10223 Vilnius, Lithuania
| | - Vladislava Voiciuk
- Quantum
Electronics Department, Vilnius University, Saulėtekio 10, LT-10223 Vilnius, Lithuania
| | - Rasa Steponavičiu̅tė
- Department
of Organic Chemistry, Kaunas University of Technology, Radvilėnų
19, LT-50254 Kaunas, Lithuania
| | - Vytas Martynaitis
- Department
of Organic Chemistry, Kaunas University of Technology, Radvilėnų
19, LT-50254 Kaunas, Lithuania
| | - Algirdas Šačkus
- Department
of Organic Chemistry, Kaunas University of Technology, Radvilėnų
19, LT-50254 Kaunas, Lithuania
| | - Mikas Vengris
- Quantum
Electronics Department, Vilnius University, Saulėtekio 10, LT-10223 Vilnius, Lithuania
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16
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Narra S, Nishimura Y, Witek HA, Shigeto S. Mechanism of Back Electron Transfer in an Intermolecular Photoinduced Electron Transfer Reaction: Solvent as a Charge Mediator. Chemphyschem 2014; 15:2945-50. [DOI: 10.1002/cphc.201402411] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Indexed: 11/12/2022]
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17
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Liu J, Cukier RI, Bu Y. Bending Vibration-Governed Solvation Dynamics of an Excess Electron in Liquid Acetonitrile Revealed by Ab Initio Molecular Dynamics Simulation. J Chem Theory Comput 2013; 9:4727-34. [DOI: 10.1021/ct4002174] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jinxiang Liu
- School
of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100 Shandong, P. R. China
| | - Robert I. Cukier
- Department of Chemistry, Michigan State University, East Lansing, 48824 Michigan, United States
| | - Yuxiang Bu
- School
of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100 Shandong, P. R. China
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18
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Casey JR, Kahros A, Schwartz BJ. To be or not to be in a cavity: the hydrated electron dilemma. J Phys Chem B 2013; 117:14173-82. [PMID: 24160853 DOI: 10.1021/jp407912k] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The hydrated electron-the species that results from the addition of a single excess electron to liquid water-has been the focus of much interest both because of its role in radiation chemistry and other chemical reactions, and because it provides for a deceptively simple system that can serve as a means to confront the predictions of quantum molecular dynamics simulations with experiment. Despite all this interest, there is still considerable debate over the molecular structure of the hydrated electron: does it occupy a cavity, have a significant number of interior water molecules, or have a structure somewhere in between? The reason for all this debate is that different computer simulations have produced each of these different structures, yet the predicted properties for these different structures are still in reasonable agreement with experiment. In this Feature Article, we explore the reasons underlying why different structures are produced when different pseudopotentials are used in quantum simulations of the hydrated electron. We also show that essentially all the different models for the hydrated electron, including those from fully ab initio calculations, have relatively little direct overlap of the electron's wave function with the nearby water molecules. Thus, a non-cavity hydrated electron is better thought of as an "inverse plum pudding" model, with interior waters that locally expel the surrounding electron's charge density. Finally, we also explore the agreement between different hydrated electron models and certain key experiments, such as resonance Raman spectroscopy and the temperature dependence and degree of homogeneous broadening of the optical absorption spectrum, in order to distinguish between the different simulated structures. Taken together, we conclude that the hydrated electron likely has a significant number of interior water molecules.
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Affiliation(s)
- Jennifer R Casey
- Department of Chemistry and Biochemistry, University of California, Los Angeles , Los Angeles, California 90095-1569, United States
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19
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Shkrob IA, Marin TW, Crowell RA, Wishart JF. Photo- and Radiation-Chemistry of Halide Anions in Ionic Liquids. J Phys Chem A 2013; 117:5742-56. [DOI: 10.1021/jp4042793] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [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
| | - R. A. Crowell
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973-5000,
United States
| | - James F. Wishart
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973-5000,
United States
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