1
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Prakash M, Rudharachari Maiyelvaganan K, Giri Lakshman N, Gopalakrishnan C, Hochlaf M. Microhydration of small protonated polyaromatic hydrocarbons: a first principles study. Phys Chem Chem Phys 2024; 26:17489-17503. [PMID: 38804893 DOI: 10.1039/d3cp06000d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Using first principles methodology, we investigate the microsolvation of protonated benzene (BzH+), protonated coronene (CorH+) and protonated dodecabenzocoronene (DbcH+). Gas phase complexes of these small protonated polyaromatic hydrocarbons (H+PAHs) with mono-, di-, and tri-hydrated water molecules are considered. Their most stable forms are presented, where we discuss their structural, energetic aromaticity and IR and UV spectral features. In particular, we focus on the analysis of the bonding and various non-bonded interactions between these protonated aromatics and water clusters. The strength of non-bonded interactions is quantified and correlated with their electron density profiles. Furthermore, insights into the interfacial interactions and stability of these complexes were obtained through non-covalent index and symmetry-adapted perturbation theory (SAPT0) analyses. We also discuss the effects of the extension of the π aromatic cloud on the water solvation of these protonated aromatics. In particular, we extended our predictions for the S0 → S1 and S0 → T1 wavelength transitions of micro hydrated H+PAHs to deduce those of these species solvated in aqueous solution. The present findings should be useful for understanding, at the microscopic level, the effects of water interacting with H+PAHs, which are relevant for organic chemistry, astrochemistry, atmospheric chemistry, combustion and materials science.
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Affiliation(s)
- Muthuramalingam Prakash
- Computational Chemistry Research Laboratory (CCRL), Department of Chemistry, SRM Institute of Science and Technology, Kattankulathur-603 203, Chengalpattu, Tamil Nadu, India.
| | - K Rudharachari Maiyelvaganan
- Computational Chemistry Research Laboratory (CCRL), Department of Chemistry, SRM Institute of Science and Technology, Kattankulathur-603 203, Chengalpattu, Tamil Nadu, India.
| | - N Giri Lakshman
- Computational Chemistry Research Laboratory (CCRL), Department of Chemistry, SRM Institute of Science and Technology, Kattankulathur-603 203, Chengalpattu, Tamil Nadu, India.
| | - C Gopalakrishnan
- Computational Chemistry Research Laboratory (CCRL), Department of Chemistry, SRM Institute of Science and Technology, Kattankulathur-603 203, Chengalpattu, Tamil Nadu, India.
| | - Majdi Hochlaf
- Université Gustave Eiffel, COSYS/IMSE, 5 Bd Descartes, 77454, Champs Sur Marne, France.
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2
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Marlton SJP, Liu C, Watkins P, Bieske EJ. Gas-phase electronic spectra of HC 2n+1H + ( n = 2-6) chains. Phys Chem Chem Phys 2024; 26:12306-12315. [PMID: 38623876 DOI: 10.1039/d4cp00625a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
Highly unsaturated carbon chains are generated in combustion processes and electrical discharges, and are confirmed constituents of the interstellar medium. In hydrogen-rich environments smaller carbon clusters tend to exist as linear chains, capped on each end by hydrogen atoms. Although the HC2nH+ polyacetylene chains have been extensively characterized spectroscopically, the corresponding odd HC2n+1H+ chains have received far less attention. Here we use two-colour resonance enhanced photodissociation spectroscopy to measure electronic spectra for HC2n+1H+ (n = 2-6) chains contained in a cryogenically cooled quadrupole ion trap. The HC2n+1H+ chains are formed either top-down by ionizing and fragmenting pyrene molecules using pulsed 266 nm radiation, or bottom-up by reacting cyclic carbon cluster cations with acetylene. Ion mobility measurements confirm that the HC2n+1H+ species are linear, consistent with predictions from electronic structure calculations. The HC2n+1H+ electronic spectra exhibit three band systems in the visible/near infrared spectral range, which each shifts progressively to longer wavelength by ≈90 nm with the addition of each additional CC subunit. The strongest visible HC11H+ band has a wavelength (λ = 545.1 nm) and width (1.5 nm) that match the strong λ 5450 diffuse interstellar band (DIB). However, other weaker HC11H+ bands do not correspond to catalogued DIBs, casting doubt on the role of HC11H+ as a carrier for the λ 5450 DIB. There are no identifiable correspondences between catalogued DIBs and bands for the other HC2n+1H+ chains, allowing upper limits to be established for their column densities in diffuse interstellar clouds.
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Affiliation(s)
- Samuel J P Marlton
- School of Chemistry, University of Melbourne, Parkville 3010, Australia.
| | - Chang Liu
- School of Chemistry, University of Melbourne, Parkville 3010, Australia.
| | - Patrick Watkins
- School of Chemistry, University of Melbourne, Parkville 3010, Australia.
| | - Evan J Bieske
- School of Chemistry, University of Melbourne, Parkville 3010, Australia.
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3
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Stoyanov ES, Bagryanskaya IY, Stoyanova IV. A new type of C +⋯H δ-(C=) bond in adducts of vinyl carbocations with alkenes. Sci Rep 2024; 14:8423. [PMID: 38600206 PMCID: PMC11006867 DOI: 10.1038/s41598-024-58109-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 03/25/2024] [Indexed: 04/12/2024] Open
Abstract
By X-ray diffraction analysis and IR spectroscopy, it was established here that vinyl carbocations C3H5+/C4H7+ with carborane counterion CHB11Cl11- form stable monosolvates C3H5+⋅C3H6/C4H7+⋅C4H8 with molecules of alkenes C3H6/C4H8. They contain molecular group =C+⋯Hδ--Cδ+= with a new type of bond formed by the H atom of the H-C= group of the alkene with the C atom of the C+=C group of the carbocation. The short C+----Cδ+ distance, equal to 2.44 Å, is typical of that of X----X in proton disolvates (L2H+) with an quasi-symmetrical X-H+⋯X moiety (where X = O or N) of basic molecule L. The nature of the discovered bond differs from that of the classic H-bond by an distribution of electron density: the electron-excessive Hδ- atom from the (=)C-H group of the alkene is attached to the C+ atom of the carbocation, on which the positive charge is predominantly concentrated. Therefore, it can be called an inverse hydrogen bond.
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Affiliation(s)
- Evgenii S Stoyanov
- Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences, Novosibirsk, 630090, Russia.
| | - Irina Yu Bagryanskaya
- Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | - Irina V Stoyanova
- Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences, Novosibirsk, 630090, Russia
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4
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Rioux B, Mouterde LMM, Alarcan J, Abiola TT, Vink MJA, Woolley JM, Peru AAM, Mention MM, Brunissen F, Berden G, Oomens J, Braeuning A, Stavros VG, Allais F. An expeditive and green chemo-enzymatic route to diester sinapoyl-l-malate analogues: sustainable bioinspired and biosourced UV filters and molecular heaters. Chem Sci 2023; 14:13962-13978. [PMID: 38075651 PMCID: PMC10699562 DOI: 10.1039/d3sc04836e] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 11/21/2023] [Indexed: 06/03/2024] Open
Abstract
Sinapoyl malate, naturally present in plants, has proved to be an exceptional UV filter and molecular heater for plants. Although there are nowadays industrially relevant sustainable synthetic routes to sinapoyl malate, its incorporation into certain cosmetic formulations, as well as its adsorption on plant leaves, is limited by its hydrophilicity. To overcome these obstacles, it is important to find a way to effectively control the hydrophilic-lipophilic balance of sinapoyl malate to make it readily compatible with the cosmetic formulations and stick on the waxy cuticle of leaves. To this end, herein, we describe a highly regioselective chemo-enzymatic synthesis of sinapoyl malate analogues possessing fatty aliphatic chains of variable length, enabling the lipophilicity of the compounds to be modulated. The potential toxicity (i.e., mutagenicity, carcinogenicity, endocrine disruption, acute and repeated-dose toxicity), bioaccumulation, persistence and biodegradability potential of these new analogues were evaluated in silico, along with the study of their transient absorption spectroscopy, their photostability as well as their photodegradation products.
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Affiliation(s)
- Benjamin Rioux
- URD Agro-Biotechnologies Industrielles (ABI), CEBB, AgroParisTech 51110 Pomacle France
| | - Louis M M Mouterde
- URD Agro-Biotechnologies Industrielles (ABI), CEBB, AgroParisTech 51110 Pomacle France
| | - Jimmy Alarcan
- Department of Food Safety, German Federal Institute for Risk Assessment Max-Dohrn-Str. 8-10 10589 Berlin Germany
| | - Temitope T Abiola
- Department of Chemistry, University of Warwick Gibbet Hill Road CV4 7AL Coventry UK
- Department of Chemistry, Lash Miller Chemical Laboratories 80 St. George Street Toronto ON M5S 3H6 Canada
| | - Matthias J A Vink
- Institute for Molecules and Materials, FELIX Laboratory, Radboud University Toernooiveld 7 6525ED Nijmegen Netherlands
| | - Jack M Woolley
- Department of Chemistry, University of Warwick Gibbet Hill Road CV4 7AL Coventry UK
| | - Aurélien A M Peru
- URD Agro-Biotechnologies Industrielles (ABI), CEBB, AgroParisTech 51110 Pomacle France
| | - Matthieu M Mention
- URD Agro-Biotechnologies Industrielles (ABI), CEBB, AgroParisTech 51110 Pomacle France
| | - Fanny Brunissen
- URD Agro-Biotechnologies Industrielles (ABI), CEBB, AgroParisTech 51110 Pomacle France
| | - Giel Berden
- Institute for Molecules and Materials, FELIX Laboratory, Radboud University Toernooiveld 7 6525ED Nijmegen Netherlands
| | - Jos Oomens
- Institute for Molecules and Materials, FELIX Laboratory, Radboud University Toernooiveld 7 6525ED Nijmegen Netherlands
| | - Albert Braeuning
- Department of Food Safety, German Federal Institute for Risk Assessment Max-Dohrn-Str. 8-10 10589 Berlin Germany
| | - Vasilios G Stavros
- Department of Chemistry, University of Warwick Gibbet Hill Road CV4 7AL Coventry UK
- School of Chemistry, University of Birmingham Edgbaston Birmingham B15 2TT UK
| | - Florent Allais
- URD Agro-Biotechnologies Industrielles (ABI), CEBB, AgroParisTech 51110 Pomacle France
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Moonkaen P, Finney JM, McCoy AB. Isotope Effects on Ground and Excited States of Ethyl Cation, H +(C 2H 4). J Phys Chem A 2023; 127:1196-1205. [PMID: 36705480 DOI: 10.1021/acs.jpca.2c07334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The structure and spectra of ethyl cation, H+(C2H4), and its deuterated analogues are investigated using diffusion Monte Carlo (DMC). These calculations all show that the ground state wave function for H+(C2H4) is localized near the minimum energy configuration in which the excess proton is in a bridging configuration, although the amplitude of the vibrational motions of the bridging proton is large. Deuteration of the bridging proton reduces the amplitude of this motion, while deuteration of only the ethylenic hydrogen atoms in H+(C2D4) has little effect on the amplitude of the motion of the bridging proton. Excited states that are accessed by spectroscopically observed transitions in H+(C2H4) are calculated using fixed-node DMC. The calculated and measured frequencies for the states with one quantum of excitation in the ethylenic CH stretching vibrations show good agreement. We also explore the excited state with one quantum of excitation in the proton transfer vibration of the bridging proton and obtain a frequency of 616 cm-1 for H+(C2H4). This frequency increases to 629 cm-1 in H+(C2D4). Deuteration decreases this frequency to 491 and 495 cm-1 in D+(C2H4) and D+(C2D4), respectively. The effects of partial deuteration on the frequencies of the CH stretching vibrations, and the corresponding probability amplitudes are also explored. Finally, we report the vibrationally averaged rotational constants for the four isotopologues of ethyl cation considered in this study.
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Affiliation(s)
- Pattarapon Moonkaen
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Jacob M Finney
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Anne B McCoy
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
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6
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Vink M, van Geenen FA, Berden G, O’Riordan TJC, Howe PW, Oomens J, Perry SJ, Martens J. Structural Elucidation of Agrochemicals and Related Derivatives Using Infrared Ion Spectroscopy. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:15563-15572. [PMID: 36214158 PMCID: PMC9671053 DOI: 10.1021/acs.est.2c03210] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 09/15/2022] [Accepted: 09/19/2022] [Indexed: 06/03/2023]
Abstract
Agrochemicals frequently undergo various chemical and metabolic transformation reactions in the environment that often result in a wide range of derivates that must be comprehensively characterized to understand their toxicity profiles and their persistence and outcome in the environment. In the development phase, this typically involves a major effort in qualitatively identifying the correct chemical isomer(s) of these derivatives from the many isomers that could potentially be formed. Liquid chromatography-mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy are often used in attempts to characterize such environment transformation products. However, challenges in confidently correlating chemical structures to detected compounds in mass spectrometry data and sensitivity/selectivity limitations of NMR frequently lead to bottlenecks in identification. In this study, we use an alternative approach, infrared ion spectroscopy, to demonstrate the identification of hydroxylated derivatives of two plant protection compounds (azoxystrobin and benzovindiflupyr) contained at low levels in tomato and spinach matrices. Infrared ion spectroscopy is an orthogonal tandem mass spectrometry technique that combines the sensitivity and selectivity of mass spectrometry with structural information obtained by infrared spectroscopy. Furthermore, IR spectra can be computationally predicted for candidate molecular structures, enabling the tentative identification of agrochemical derivatives and other unknowns in the environment without using physical reference standards.
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Affiliation(s)
- Matthias
J.A. Vink
- FELIX
Laboratory, Institute for Molecules and Materials, Radboud University, Toernooiveld 7, 6525ED Nijmegen, the Netherlands
| | - Fred A.M.G. van Geenen
- FELIX
Laboratory, Institute for Molecules and Materials, Radboud University, Toernooiveld 7, 6525ED Nijmegen, the Netherlands
| | - Giel Berden
- FELIX
Laboratory, Institute for Molecules and Materials, Radboud University, Toernooiveld 7, 6525ED Nijmegen, the Netherlands
| | - Timothy J. C. O’Riordan
- Syngenta,
Jealott’s Hill International Research Centre, RG42 6EY, Bracknell, Berkshire, United Kingdom
| | - Peter W.A. Howe
- Syngenta,
Jealott’s Hill International Research Centre, RG42 6EY, Bracknell, Berkshire, United Kingdom
| | - Jos Oomens
- FELIX
Laboratory, Institute for Molecules and Materials, Radboud University, Toernooiveld 7, 6525ED Nijmegen, the Netherlands
| | - Simon J. Perry
- Syngenta,
Jealott’s Hill International Research Centre, RG42 6EY, Bracknell, Berkshire, United Kingdom
| | - Jonathan Martens
- FELIX
Laboratory, Institute for Molecules and Materials, Radboud University, Toernooiveld 7, 6525ED Nijmegen, the Netherlands
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7
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Marlton SJP, Buntine JT, Liu C, Watkins P, Jacovella U, Carrascosa E, Bull JN, Bieske EJ. Disentangling Electronic Spectra of Linear and Cyclic Hydrogenated Carbon Cluster Cations, C 2n+1H + ( n = 3–10). J Phys Chem A 2022; 126:6678-6685. [DOI: 10.1021/acs.jpca.2c05051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Samuel J. P. Marlton
- School of Chemistry, The University of Melbourne, 3010 Parkville, Victoria, Australia
| | - Jack T. Buntine
- School of Chemistry, The University of Melbourne, 3010 Parkville, Victoria, Australia
| | - Chang Liu
- School of Chemistry, The University of Melbourne, 3010 Parkville, Victoria, Australia
| | - Patrick Watkins
- School of Chemistry, The University of Melbourne, 3010 Parkville, Victoria, Australia
| | - Ugo Jacovella
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d’Orsay, 91405 Orsay, France
| | - Eduardo Carrascosa
- Bruker Daltonics GmbH & Co. KG, Fahrenheitstrasse 4, 28359 Bremen, Germany
| | - James N. Bull
- School of Chemistry, University of East Anglia, Norwich Research Park, NR4 7TJ Norwich, U.K
| | - Evan J. Bieske
- School of Chemistry, The University of Melbourne, 3010 Parkville, Victoria, Australia
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8
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Stoyanov ES, Stoyanova IV. The Chloronium Cation [(C 2H 3) 2Cl +] and Unsaturated C 4-Carbocations with C=C and C≡C Bonds in Their Solid Salts and in Solutions: An H 1/C 13 NMR and Infrared Spectroscopic Study. Int J Mol Sci 2022; 23:ijms23169111. [PMID: 36012378 PMCID: PMC9409342 DOI: 10.3390/ijms23169111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/02/2022] [Accepted: 08/10/2022] [Indexed: 11/29/2022] Open
Abstract
Solid salts of the divinyl chloronium (C2H3)2Cl+ cation (I) and unsaturated C4H6Cl+ and C4H7+ carbocations with the highly stable CHB11Hal11− anion (Hal=F, Cl) were obtained for the first time. At 120 °C, the salt of the chloronium cation decomposes, yielding a salt of the C4H5+ cation. This thermally stable (up to 200 °C) carbocation is methyl propargyl, CH≡C-C+-H-CH3 (VI), which, according to quantum chemical calculations, should be energetically much less favorable than other isomers of the C4H7+ cations. Cation VI readily attaches HCl to the formal triple C≡C bond to form the CHCl=CH-C+H-CH3 cation (VII). In infrared spectra of cations I, VI, and VII, frequencies of C=C and C≡C stretches are significantly lower than those predicted by calculations (by 400–500 cm−1). Infrared and 1H/13C magic-angle spinning NMR spectra of solid salts of cations I and VI and high-resolution 1H/13C NMR spectra of VII in solution in SO2ClF were interpreted. On the basis of the spectroscopic data, the charge and electron density distribution in the cations are discussed.
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9
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Erukala S, Feinberg AJ, Moon CJ, Choi MY, Vilesov AF. Infrared spectroscopy of ions and ionic clusters upon ionization of ethane in helium droplets. J Chem Phys 2022; 156:204306. [DOI: 10.1063/5.0091819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Helium droplets are unique hosts for isolating diverse molecular ions for infrared spectroscopic experiments. Recently, it was found that electron impact ionization of ethylene clusters embedded in helium droplets produces diverse carbocations containing three and four carbon atoms, indicating effective ion–molecule reactions. In this work, similar experiments are reported but with the saturated hydrocarbon precursor of ethane. In distinction to ethylene, no characteristic bands of larger covalently bound carbocations were found, indicating inefficient ion–molecule reactions. Instead, the ionization in helium droplets leads to formation of weaker bound dimers, such as (C2H6)(C2H4)+, (C2H6)(C2H5)+, and (C2H6)(C2H6)+, as well as larger clusters containing several ethane molecules attached to C2H4+, C2H5+, and C2H6+ ionic cores. The spectra of larger clusters resemble those for neutral, neat ethane clusters. This work shows the utility of the helium droplets to study small ionic clusters at ultra-low temperatures.
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Affiliation(s)
- Swetha Erukala
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Alexandra J. Feinberg
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Cheol Joo Moon
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
- Research Institute for Green Energy Convergence Technology, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Myong Yong Choi
- Core‐Facility Center for Photochemistry and Nanomaterials, Department of Chemistry (BK21 FOUR), Research Institute of Natural Sciences, Gyeongsang National University, Jinju, Republic of Korea
| | - Andrey F. Vilesov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, USA
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Braak FT, Elferink H, Houthuijs KJ, Oomens J, Martens J, Boltje TJ. Characterization of Elusive Reaction Intermediates Using Infrared Ion Spectroscopy: Application to the Experimental Characterization of Glycosyl Cations. Acc Chem Res 2022; 55:1669-1679. [PMID: 35616920 PMCID: PMC9219114 DOI: 10.1021/acs.accounts.2c00040] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
![]()
A detailed
understanding of the reaction mechanism(s) leading to
stereoselective product formation is crucial to understanding and
predicting product formation and driving the development of new synthetic
methodology. One way to improve our understanding of reaction mechanisms
is to characterize the reaction intermediates involved in product
formation. Because these intermediates are reactive, they are often
unstable and therefore difficult to characterize using experimental
techniques. For example, glycosylation reactions are critical steps
in the chemical synthesis of oligosaccharides and need to be stereoselective
to provide the desired α- or β-diastereomer. It remains
challenging to predict and control the stereochemical outcome of glycosylation
reactions, and their reaction mechanisms remain a hotly debated topic.
In most cases, glycosylation reactions take place via reaction mechanisms
in the continuum between SN1- and SN2-like pathways.
SN2-like pathways proceeding via the displacement of a
contact ion pair are relatively well understood because the reaction
intermediates involved can be characterized by low-temperature NMR
spectroscopy. In contrast, the SN1-like pathways proceeding
via the solvent-separated ion pair, also known as the glycosyl cation,
are poorly understood. SN1-like pathways are more challenging
to investigate because the glycosyl cation intermediates involved
are highly reactive. The highly reactive nature of glycosyl cations
complicates their characterization because they have a short lifetime
and rapidly equilibrate with the corresponding contact ion pair. To
overcome this hurdle and enable the study of glycosyl cation stability
and structure, they can be generated in a mass spectrometer in the
absence of a solvent and counterion in the gas phase. The ease of
formation, stability, and fragmentation of glycosyl cations have been
studied using mass spectrometry (MS). However, MS alone provides little
information about the structure of glycosyl cations. By combining
mass spectrometry (MS) with infrared ion spectroscopy (IRIS), the
determination of the gas-phase structures of glycosyl cations has
been achieved. IRIS enables the recording of gas-phase infrared spectra
of glycosyl cations, which can be assigned by matching to reference
spectra predicted from quantum chemically calculated vibrational spectra.
Here, we review the experimental setups that enable IRIS of glycosyl
cations and discuss the various glycosyl cations that have been characterized
to date. The structure of glycosyl cations depends on the relative
configuration and structure of the monosaccharide substituents, which
can influence the structure through both steric and electronic effects.
The scope and relevance of gas-phase glycosyl cation structures in
relation to their corresponding condensed-phase structures are also
discussed. We expect that the workflow reviewed here to study glycosyl
cation structure and reactivity can be extended to many other reaction
types involving difficult-to-characterize ionic intermediates.
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Affiliation(s)
- Floor ter Braak
- Radboud University, Institute for Molecules and Materials, Synthetic Organic Chemistry, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Hidde Elferink
- Radboud University, Institute for Molecules and Materials, Synthetic Organic Chemistry, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Kas J. Houthuijs
- Radboud University, FELIX Laboratory, Institute of Molecules and Materials, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Jos Oomens
- Radboud University, FELIX Laboratory, Institute of Molecules and Materials, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Jonathan Martens
- Radboud University, FELIX Laboratory, Institute of Molecules and Materials, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Thomas J. Boltje
- Radboud University, Institute for Molecules and Materials, Synthetic Organic Chemistry, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
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11
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Dobulis MA, Thompson MC, Jarrold CC. Identification of Isoprene Oxidation Reaction Products via Anion Photoelectron Spectroscopy. J Phys Chem A 2021; 125:10089-10102. [PMID: 34755517 DOI: 10.1021/acs.jpca.1c08176] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present a study on the oxidation of isoprene under several different conditions that may model both atmospheric and combustion chemistry. Anions, formed by passing isoprene/oxidant gas mixtures through a pulsed discharge generating a range of species, are separated via mass spectrometry and characterized by anion photoelectron (PE) spectroscopy supported by computations. Specifically, a UV-irradiated isoprene/O2 mixture, which additionally produces O3, and an isoprene/O2/H2 mixture, which generates •OH when passed through the discharge, were sampled. The mass spectra of ions generated under both conditions show the production of intact molecular ions, ion-molecule complexes (e.g., O2-, O4-, and O2-·isoprene), and singly deprotonated species (e.g., deprotonated isoprene, C5H7-). In addition, both smaller and oxidized fragments are observed using both gas mixtures, though relative abundances differ. From the UV-irradiated isoprene/O2 gas mixture, additional intact molecular products of reactions initiated by ozonolysis of isoprene, methylglyoxal, and dimethylglyoxal were observed. Fragmentation and oxidation of isoprene observed in both gas mixtures included species with m/z 39, 53, 67, 69, and 83 that we attribute to a series of alkyl- and alkenoxide-based anions. The coexistence of intact molecules and complexes with fragments and reaction products demonstrates the versatility of this ion source as a simple and efficient anion formation method for studying species that may be relevant in atmospheric and combustion chemistry.
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Affiliation(s)
- Marissa A Dobulis
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Michael C Thompson
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Caroline Chick Jarrold
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
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12
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Kwasigroch B, Khuu T, Perez EH, Denton JK, Schneider EK, Straßner A, Theisen M, Kruppa SV, Weis P, Kappes MM, Riehn C, Johnson MA, Niedner-Schatteburg G. On the Hydrogen Oxalate Binding Motifs onto Dinuclear Cu and Ag Metal Phosphine Complexes. Chemistry 2021; 27:15136-15146. [PMID: 34632659 PMCID: PMC8597048 DOI: 10.1002/chem.202102768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Indexed: 11/23/2022]
Abstract
We report the binding geometries of the isomers that are formed when the hydrogen oxalate ((CO2)2H=HOx) anion attaches to dinuclear coinage metal phosphine complexes of the form [M1M2dcpm2(HOx)]+ with M=Cu, Ag and dcpm=bis(dicyclohexylphosphino)methane, abbreviated [MM]+. These structures are established by comparison of isomer‐selective experimental vibrational band patterns displayed by the cryogenically cooled and N2‐tagged cations with DFT calculations of the predicted spectra for various local minima. Two isomeric classes are identified that feature either attachment of the carboxylate oxygen atoms to the two metal centers (end‐on docking) or attachment of oxygen atoms on different carbon atoms asymmetrically to the metal ions (side‐on docking). Within each class, there are additional isomeric variations according to the orientation of the OH group. This behavior indicates that HOx undergoes strong and directional coordination to [CuCu]+ but adopts a more flexible coordination to [AgAg]+. Infrared spectra of the bare ions, fragmentation thresholds and ion mobility measurements are reported to explore the behaviors of the complexes at ambient temperature.
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Affiliation(s)
- Björn Kwasigroch
- Department of Chemistry, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 52, 67663, Kaiserslautern, Germany
| | - Thien Khuu
- Sterling Chemistry Laboratory, Yale University, 225 Prospect Str., New Haven, Connecticut, 06520, USA
| | - Evan H Perez
- Sterling Chemistry Laboratory, Yale University, 225 Prospect Str., New Haven, Connecticut, 06520, USA
| | - Joanna K Denton
- Sterling Chemistry Laboratory, Yale University, 225 Prospect Str., New Haven, Connecticut, 06520, USA
| | - Erik K Schneider
- Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber Weg 2, 76131, Karlsruhe, Germany
| | - Annika Straßner
- Department of Chemistry, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 52, 67663, Kaiserslautern, Germany
| | - Marvin Theisen
- Department of Chemistry, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 52, 67663, Kaiserslautern, Germany
| | - Sebastian V Kruppa
- Department of Chemistry, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 52, 67663, Kaiserslautern, Germany
| | - Patrick Weis
- Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber Weg 2, 76131, Karlsruhe, Germany
| | - Manfred M Kappes
- Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber Weg 2, 76131, Karlsruhe, Germany.,Institute for Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Christoph Riehn
- Department of Chemistry, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 52, 67663, Kaiserslautern, Germany.,Research Center OPTIMAS, Erwin-Schrödinger Str. 46, 67663, Kaiserslautern, Germany
| | - Mark A Johnson
- Sterling Chemistry Laboratory, Yale University, 225 Prospect Str., New Haven, Connecticut, 06520, USA
| | - Gereon Niedner-Schatteburg
- Department of Chemistry, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 52, 67663, Kaiserslautern, Germany.,Research Center OPTIMAS, Erwin-Schrödinger Str. 46, 67663, Kaiserslautern, Germany
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13
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Dobulis MA, McGee CJ, Sommerfeld T, Jarrold CC. Autodetachment over Broad Photon Energy Ranges in the Anion Photoelectron Spectra of [O 2- M] - ( M = Glyoxal, Methylglyoxal, or Biacetyl) Complex Anions. J Phys Chem A 2021; 125:9128-9142. [PMID: 34623818 DOI: 10.1021/acs.jpca.1c07163] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Complexes of anion-neutral pairs are prevalent in chemical and physical processes in the interstellar medium, the atmosphere, and biological systems, among others. However, bimolecular anionic species that cannot be described as simple ion-molecule complexes due to their competitive electron affinities have received less attention. In this study, the [O2-M]- (M = glyoxal, methylglyoxal, or biacetyl) anion photoelectron spectra obtained with several different photon energies are reported and interpreted in the context of ab initio calculations. The spectra do not resemble the photoelectron spectra of M- or O2- "solvated" by a neutral partner. Rather, all spectra are dominated by near-threshold autodetachment from what are likely transient dipole bound states of the cis conformers of the complex anions. Very low Franck-Condon overlap between the neutral M·O2 van der Waals clusters and the partial covalently bound complex anions results in low-intensity, broad direct detachment observed in the spectra. The [O2-glyoxal]- spectra measured with 2.88 and 3.495 eV photon energies additionally exhibit features at ∼0.5 eV electron kinetic energy, which is more difficult to explain, though there are numerous quasibound states of the anion that may be involved. Overall, these features point to the inadequacy of describing the complex anions as simple ion-molecule complexes.
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Affiliation(s)
- Marissa A Dobulis
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Conor J McGee
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Thomas Sommerfeld
- Department of Chemistry and Physics, Southeast Louisiana University, SLU 10878, Hammond, Louisiana 70402, United States
| | - Caroline Chick Jarrold
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
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14
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Wagner JP, McDonald DC, Colley JE, Franke PR, Duncan MA. Infrared spectroscopy of the protonated HCl dimer and trimer. J Chem Phys 2021; 155:134302. [PMID: 34624978 DOI: 10.1063/5.0065477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The protonated HCl dimer and trimer complexes were prepared by pulsed discharges in supersonic expansions of helium or argon doped with HCl and hydrogen. The ions were mass selected in a reflectron time-of-flight spectrometer and investigated with photodissociation spectroscopy in the IR and near-IR regions. Anharmonic vibrational frequencies were computed with VPT2 at the MP2/cc-pVTZ level of theory. The Cl-H stretching fundamentals and overtones were measured in addition to stretch-torsion combinations. VPT2 theory at this level confirms the proton-bound structure of the dimer complex and provides a reasonably good description of the anharmonic vibrations in this system. The trimer has a HCl-HClH+-ClH structure in which a central chloronium ion is solvated by two HCl molecules via hydrogen bonding. VPT2 reproduces anharmonic frequencies for this system, including several combinations involving core ion Cl-H stretches, but fails to describe the relative band intensities.
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Affiliation(s)
- J Philipp Wagner
- Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, Georgia 30602, USA
| | - David C McDonald
- Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, Georgia 30602, USA
| | - Jason E Colley
- Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, Georgia 30602, USA
| | - Peter R Franke
- Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, Georgia 30602, USA
| | - Michael A Duncan
- Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, Georgia 30602, USA
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15
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Stoyanov ES, Bagryanskaya IY, Stoyanova IV. Isomers of the Allyl Carbocation C 3H 5 + in Solid Salts: Infrared Spectra and Structures. ACS OMEGA 2021; 6:23691-23699. [PMID: 34568649 PMCID: PMC8459358 DOI: 10.1021/acsomega.1c01316] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 08/13/2021] [Indexed: 06/13/2023]
Abstract
Three isomers of the allyl cation C3H5 + were obtained in salts with the carborane anion CHB11Cl11 -. Two of them, angular CH3-CH=CH+ (I) and linear CH3-C+=CH2 (II), were characterized by X-ray crystallography, and the third one, (CH2CHCH2)+ (III), is formed in an amorphous salt. The stretch vibration of the charged double bond C=C+ of I and II is decreased by 162 cm-1 (I) or 76 cm-1 (II) as compared to that of neutral propene. This result contradicts the prediction of DFT and MP2 calculations with the 6-311G++(d,p) basis set that the appearance of the positive charge on the C=C bond should increase its stretch vibration by 200 cm-1 (I) or 210 cm-1 (II). According to infrared spectra, the CC bonds in isomer III have one-and-a-half bond status. Isomers I and II in the crystal lattice are stabilized due to uniform ionic interactions with neighboring anions with partial transfer of a positive charge to them. Additional stabilization of II is provided by a weak hyperconjugation effect. Isomer III is stabilized in the amorphous phase due to ion paring with a counterion and a strong intramolecular hyperconjugation effect.
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16
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Erukala S, Feinberg A, Singh A, Vilesov AF. Infrared spectroscopy of carbocations upon electron ionization of ethylene in helium nanodroplets. J Chem Phys 2021; 155:084306. [PMID: 34470362 DOI: 10.1063/5.0062171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The electron impact ionization of helium droplets doped with ethylene molecules and clusters yields diverse CXHY + cations embedded in the droplets. The ionization primarily produces C2H2 +, C2H3 +, C2H4 +, and CH2 +, whereas larger carbocations are produced upon the reactions of the primary ions with ethylene molecules. The vibrational excitation of the cations leads to the release of bare cations and cations with a few helium atoms attached. The laser excitation spectra of the embedded cations show well resolved vibrational bands with a few wavenumber widths-an order of magnitude less than those previously obtained in solid matrices or molecular beams by tagging techniques. Comparison with the previous studies of free and tagged CH2 +, CH3 +, C2H2 +, C2H3 +, and C2H4 + cations shows that the helium matrix typically introduces a shift in the vibrational frequencies of less than about 20 cm-1, enabling direct comparisons with the results of quantum chemical calculations for structure determination. This work demonstrates a facile technique for the production and spectroscopic study of diverse carbocations, which act as important intermediates in gas and condensed phases.
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Affiliation(s)
- Swetha Erukala
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Alexandra Feinberg
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Amandeep Singh
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Andrey F Vilesov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
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17
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Gorbachev VM, Miloglyadova L, Tsybizova A, Chen P. Application of continuous wave quantum cascade laser in combination with CIVP spectroscopy for investigation of large organic and organometallic ions. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:083002. [PMID: 34470415 DOI: 10.1063/5.0058625] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 07/24/2021] [Indexed: 06/13/2023]
Abstract
Rapidly developing mid-infrared quantum cascade laser (QCL) technology gives easy access to broadly tunable mid-IR laser radiation at a modest cost. Despite several applications of QCL in the industry, its usage for spectroscopic investigation of synthetically relevant organic compounds has been limited. Here, we report the application of an external cavity, continuous wave, mid-IR QCL to cryogenic ion vibrational predissociation spectroscopy to analyze a set of large organic molecules, organometallic complexes, and isotopically labeled compounds. The obtained spectra of test molecules are characterized by a high signal-to-noise ratio and low full width at half-maximum-values, allowing the assignment of two compounds with just a few wavenumber difference. Data generated by cw-QCL and spectra produced by another standard Nd:YAG difference-frequency generation system are compared and discussed.
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Affiliation(s)
| | | | | | - Peter Chen
- Laboratorium für Organische Chemie, ETH Zürich, CH-8093 Zürich, Switzerland
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18
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Stoyanov ES, Bagryanskaya IY, Stoyanova IV. Unsaturated Vinyl-Type Carbocation [(CH 3) 2C=CH] + in Its Carborane Salts. ACS OMEGA 2021; 6:15834-15843. [PMID: 34179627 PMCID: PMC8223440 DOI: 10.1021/acsomega.1c01297] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 06/01/2021] [Indexed: 06/13/2023]
Abstract
The isobutylene carbocation (CH3)2C=CH+ was obtained in amorphous and crystalline salts with the carborane anion CHB11Cl11 -. The cation was characterized by X-ray crystallography and IR spectroscopy. Its crystal structure shows a relatively uniform ionic interaction of the cation with the surrounding anions, with a slightly shortened distance between the C atom of the =CH group and the Cl atom of the anion, pointing to a higher positive charge on this group. In the amorphous phase, the asymmetric interaction of the cation with the anion increases, approaching ion pairing. This gives rise to a strong hyperconjugation between the two CH3 groups and the 2pz orbital of the central carbon sp2 atom (the red shift of the CH stretch is 150 cm-1); this effect stabilizes the cation. Over time, as the structure of the amorphous phase becomes more ordered, the hyperconjugation weakens and disappears in the crystalline phase with the disappearance of ion pairing. The carbocation stabilization in the crystalline phase is achieved due to the transfer of a portion of the charge to the neighboring anions, whereas the charge on the C=C bond becomes the strongest: the C=C stretch frequency drops to ∼160 cm-1 relative to neutral isobutylene. The collected IR spectra for the optimized cation under vacuum (in the 6-311G ++ (d, p) basis for all HF, MP2, and DFT calculations) predict that a positive charge on the C=C bond increases its stretching frequency; this computational result contradicts the experimental data, perhaps because it does not take into account the significant impact of the environment.
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Affiliation(s)
- Evgenii S. Stoyanov
- Vorozhtsov Novosibirsk Institute of
Organic Chemistry SB RAS, Prospect Lavrentieva 9, Novosibirsk 630090, Russia
| | - Irina Yu. Bagryanskaya
- Vorozhtsov Novosibirsk Institute of
Organic Chemistry SB RAS, Prospect Lavrentieva 9, Novosibirsk 630090, Russia
| | - Irina V. Stoyanova
- Vorozhtsov Novosibirsk Institute of
Organic Chemistry SB RAS, Prospect Lavrentieva 9, Novosibirsk 630090, Russia
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19
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Li W, Jin J, Wu X, Ding X, Wang G. Infrared photodissociation spectroscopic and theoretical study of H nC 4O + ( n = 1, 2) cation clusters in the gas phase. Mol Phys 2021. [DOI: 10.1080/00268976.2021.1879301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Wei Li
- School of Mathematics and Physics, North China Electric Power University, Beijing, People’s Republic of China
- Institute of clusters and low dimensional nanomaterials, North China Electric Power University, Beijing, People’s Republic of China
| | - Jiaye Jin
- Department of Chemistry, Fudan University, Shanghai, People’s Republic of China
| | - Xiaonan Wu
- Department of Chemistry, Fudan University, Shanghai, People’s Republic of China
| | - Xunlei Ding
- School of Mathematics and Physics, North China Electric Power University, Beijing, People’s Republic of China
- Institute of clusters and low dimensional nanomaterials, North China Electric Power University, Beijing, People’s Republic of China
| | - Guanjun Wang
- Department of Chemistry, Fudan University, Shanghai, People’s Republic of China
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20
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Marks JH, Miliordos E, Duncan MA. Infrared spectroscopy of RG-Co +(H 2O) complexes (RG = Ar, Ne, He): The role of rare gas "tag" atoms. J Chem Phys 2021; 154:064306. [PMID: 33588546 DOI: 10.1063/5.0041069] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
RGn-Co+(H2O) cation complexes (RG = Ar, Ne, He) are generated in a supersonic expansion by pulsed laser vaporization. Complexes are mass-selected using a time-of-flight spectrometer and studied with infrared laser photodissociation spectroscopy, measuring the respective mass channels corresponding to the elimination of the rare gas "tag" atom. Spectral patterns and theory indicate that the structures of the ions with a single rare gas atom have this bound to the cobalt cation opposite the water moiety in a near-C2v arrangement. The O-H stretch vibrations of the complex are shifted compared to those of water because of the metal cation charge-transfer interaction; these frequencies also vary systematically with the rare gas atom attached. The efficiencies of photodissociation also vary with the rare gas atoms because of their widely different binding energies to the cobalt cation. The spectrum of the argon complex could only be measured when at least three argon atoms were attached. In the case of the helium complex, the low binding energy allows the spectra to be measured for the low-frequency H-O-H scissors bending mode and for the O-D stretches of the deuterated analog. The partially resolved rotational structure for the antisymmetric O-H and O-D stretches reveals the temperature of these complexes (6 K) and establishes the electronic ground state. The helium complex has the same 3B1 ground state as the tag-free complex studied previously by Metz and co-workers ["Dissociation energy and electronic and vibrational spectroscopy of Co+(H2O) and its isotopomers," J. Phys. Chem. A 117, 1254 (2013)], but the A rotational constant is contaminated by vibrational averaging from the bending motion of the helium.
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Affiliation(s)
- Joshua H Marks
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
| | - Evangelos Miliordos
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, USA
| | - Michael A Duncan
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
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21
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Ouyang Z, Xie C. Reinterpreting the vibrational structure in the electronic spectrum of the propargyl cation (H 2C 3H +) using an efficient and accurate quantum model. J Chem Phys 2021; 154:044308. [PMID: 33514083 DOI: 10.1063/5.0037571] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The B̃1A1 ← X̃1A1 absorption spectra of propargyl cations H2C3H+ and D2C3D+ were simulated by an efficient two-dimensional (2D) quantum model, which includes the C-C stretch (v5) and the C≡C stretch (v3) vibrational modes. The choice of two modes was based on a scheme that can identify the active modes quantitively by examining the normal coordinate displacements (∆Q) directly based on the ab initio equilibrium geometries and frequencies of the X̃1A1 and B̃1A1 states of H2C3H+. The spectrum calculated by the 2D model was found to be very close to those calculated by all the higher three-dimensional (3D) quantum models (including v5, v3, and another one in 12 modes of H2C3H+), which validates the 2D model. The calculated B̃1A1 ← X̃1A1 absorption spectra of both H2C3H+ and D2C3D+ are in fairly good agreement with experimental results.
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Affiliation(s)
- Zheming Ouyang
- Institute of Modern Physics, Northwest University, Xian, Shaanxi 710127, China
| | - Changjian Xie
- Institute of Modern Physics, Northwest University, Xian, Shaanxi 710127, China
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22
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Rittgers BM, Leicht D, Duncan MA. Cation-π Complexes of Silver Studied with Photodissociation and Velocity-Map Imaging. J Phys Chem A 2020; 124:9166-9176. [PMID: 33103909 DOI: 10.1021/acs.jpca.0c08498] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Ag+(aromatic) ion-molecule complexes of benzene, toluene, or furan are generated in the gas phase by laser vaporization in a supersonic expansion. These ions are mass selected in a time-of-flight spectrometer and studied with ultraviolet laser photodissociation and photofragment imaging. UV laser excitation results in dissociative charge transfer (DCT) for these ions, producing neutral silver atom and the respective aromatic cation as the photofragments. Velocity-map imaging and slice imaging techniques are employed to investigate the kinetic energy release in these photodissociation processes. In each case, DCT produces significant kinetic energy, and evidence is also found for excitation of the internal rovibrational degrees of freedom for the molecular cations. Analysis of the kinetic energy release together with the known ionization energies of silver and the molecular ligands provides new information on the cation-π bond energies.
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Affiliation(s)
- Brandon M Rittgers
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Daniel Leicht
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Michael A Duncan
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
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23
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Tsybizova A, Paenurk E, Gorbachev V, Chen P. Perturbation of Pyridinium CIVP Spectra by N 2 and H 2 Tags: An Experimental and BOMD Study. J Phys Chem A 2020; 124:8519-8528. [PMID: 32954731 DOI: 10.1021/acs.jpca.0c06752] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In cryogenic ion vibrational predissociation (CIVP) spectroscopy, the influence of the tag on the spectrum is an important consideration. Whereas for small ions several studies have shown that the tag effects can be significant, these effects are less understood for large ions or for large numbers of tags. Nevertheless, it is commonly assumed that if the investigated molecular ion is large enough, the perturbations arising from the tag are small and can therefore be neglected in the interpretation. In addition, it is generally assumed that the more weakly bound the tag is, the less it perturbs the CIVP spectrum. Under these assumptions, CIVP spectra are claimed to be effectively IR absorption spectra of the free molecular ion. Having observed unexpected splittings in otherwise unproblematic CIVP spectra of some tagged ions, we report Born-Oppenheimer molecular dynamics (BOMD) simulations that strongly indicate that mobility among the more weakly bound tags leads to the surprising splittings. We compared the behavior of two tags commonly used in CIVP spectroscopy (H2 and N2) with a large pyridinium cation. Our experimental results surprisingly show that under the appropriate circumstances, the more weakly bound tag can perturb the CIVP spectra more than the more strongly bound tag by not just shifting but also splitting the observed bands. The more weakly bound tag had significant residence times at several spectroscopically distinct sites on the molecular ion. This indicates that the weakly bound tag is likely to sample several binding sites in the experiment, some of which involve interaction with the reporter chromophore.
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Affiliation(s)
- Alexandra Tsybizova
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
| | - Eno Paenurk
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
| | - Vladimir Gorbachev
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
| | - Peter Chen
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
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24
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McDonald DC, Rittgers BM, Theis RA, Fortenberry RC, Marks JH, Leicht D, Duncan MA. Infrared spectroscopy and anharmonic theory of H 3 +Ar 2,3 complexes: The role of symmetry in solvation. J Chem Phys 2020; 153:134305. [PMID: 33032436 DOI: 10.1063/5.0023205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The vibrational spectra of H3 +Ar2,3 and D3 +Ar2,3 are investigated in the 2000 cm-1 to 4500 cm-1 region through a combination of mass-selected infrared laser photodissociation spectroscopy and computational work including the effects of anharmonicity. In the reduced symmetry of the di-argon complex, vibrational activity is detected in the regions of both the symmetric and antisymmetric hydrogen stretching modes of H3 +. The tri-argon complex restores the D3h symmetry of the H3 + ion, with a concomitant reduction in the vibrational activity that is limited to the region of the antisymmetric stretch. Throughout these spectra, additional bands are detected beyond those predicted with harmonic vibrational theory. Anharmonic theory is able to reproduce some of the additional bands, with varying degrees of success.
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Affiliation(s)
- D C McDonald
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
| | - B M Rittgers
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
| | - R A Theis
- Department of Chemistry and Biochemistry, Georgia Southern University, Statesboro, Georgia 30460, USA
| | - R C Fortenberry
- Department of Chemistry and Biochemistry, University of Mississippi, University, Mississippi 38677, USA
| | - J H Marks
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
| | - D Leicht
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
| | - M A Duncan
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
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25
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Varras PC, Siskos MG, Gritzapis PS, Gerothanassis IP. The fleeting existence of the classical vinyl cation structure. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1752402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Panayiotis C. Varras
- Department of Chemistry, Section of Organic Chemistry & Biochemistry, University of Ioannina, Ioannina, Greece
| | - Michael G. Siskos
- Department of Chemistry, Section of Organic Chemistry & Biochemistry, University of Ioannina, Ioannina, Greece
| | | | - Ioannis P. Gerothanassis
- Department of Chemistry, Section of Organic Chemistry & Biochemistry, University of Ioannina, Ioannina, Greece
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26
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Leicht D, Rittgers BM, Douberly GE, Wagner JP, McDonald DC, Mauney DT, Tsuge M, Lee YP, Duncan MA. Infrared spectroscopy of H+(CO)2 in the gas phase and in para-hydrogen matrices. J Chem Phys 2020; 153:084305. [DOI: 10.1063/5.0019731] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Daniel Leicht
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
| | | | - Gary E. Douberly
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
| | - J. Philipp Wagner
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
| | - David C. McDonald
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
| | - Daniel T. Mauney
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
| | - Masashi Tsuge
- Department of Applied Chemistry, National Chiao Tung University, Hsinchu 30010, Taiwan
- Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan
| | - Yuan-Pern Lee
- Department of Applied Chemistry, National Chiao Tung University, Hsinchu 30010, Taiwan
- Center for Emergent Functional Matter Science, National Chiao Tung University, Hsinchu 30010, Taiwan
- Institute of Atomic and Molecular Sciences Academia Sinica, Taipei 10617, Taiwan
| | - Michael A. Duncan
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
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27
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Banik S, Sansi AK, Nandan S, Roy TK. On the Proton Shuttle Motion in Protonated Acetylene: An Electronic Structure Perspective. ChemistrySelect 2020. [DOI: 10.1002/slct.202002524] [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)
- Subrata Banik
- Department of ChemistrySchool of Chemical and BiotechnologySASTRA Deemed University Thanjavur 613401 Tamilnadu India
| | - Ankit Kumar Sansi
- Department of Chemistry and Chemical SciencesCentral University of Jammu, Rahya-Suchani (Bagla) Jammu 180011 India
| | - Shiv Nandan
- Department of Chemistry and Chemical SciencesCentral University of Jammu, Rahya-Suchani (Bagla) Jammu 180011 India
| | - Tapta Kanchan Roy
- Department of Chemistry and Chemical SciencesCentral University of Jammu, Rahya-Suchani (Bagla) Jammu 180011 India
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28
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Boyer MA, Chiu CS, McDonald DC, Wagner JP, Colley JE, Orr DS, Duncan MA, McCoy AB. The Role of Tunneling in the Spectra of H 5+ and D 5+ up to 7300 cm -1. J Phys Chem A 2020; 124:4427-4439. [PMID: 32392420 DOI: 10.1021/acs.jpca.0c02299] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The spectra for H5+ and D5+ are extended to cover the region between 4830 and 7300 cm-1. These spectra are obtained using mass-selected photodissociation spectroscopy. To understand the nature of the states that are accessed by the transitions in this and prior studies, we develop a four-dimensional model Hamiltonian. This Hamiltonian is expressed in terms of the two outer H2 stretches, the displacement of the shared proton from the center of mass of these two H2 groups, and the distance between the H2 groups. This choice is motivated by the large oscillator strength associated with the shared proton stretch and the fact that the spectral regions that have been probed correspond to zero, one, and two quanta of excitation in the H2 stretches. This model is analyzed using an adiabatic separation of the H2 stretches from the other two vibrations and includes the non-adiabatic couplings between H2 stretch states with the same total number of quanta of excitation in the H2 stretches. Based on the analysis of the energies and wave functions obtained from this model, we find that when there are one or more quanta of excitation in the H2 stretches the states come in pairs that reflect tunneling doublets. The states accessed by the transitions in the spectrum with the largest intensity are assigned to the members of the doublets with requisite symmetry that are localized on the lowest-energy adiabat for a given level of H2 excitation.
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Affiliation(s)
- Mark A Boyer
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Chloe S Chiu
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - David C McDonald
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - J Philipp Wagner
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Jason E Colley
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Dylan S Orr
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Michael A Duncan
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Anne B McCoy
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
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29
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Dobulis MA, Thompson MC, Sommerfeld T, Jarrold CC. Temporary anion states of fluorine substituted benzenes probed by charge transfer in O 2 -·C 6H 6-xF x (x = 0-5) ion-molecule complexes. J Chem Phys 2020; 152:204309. [PMID: 32486698 DOI: 10.1063/5.0011321] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The broadband photoelectron source realized by detaching O2 -·X (X = neutral unsaturated molecule) complexes offers a unique opportunity to probe temporary anion states of the unsaturated species. Detachment of the ion molecule complex typically accesses a dissociative portion of the neutral potential, creating a continuum electron source that can undergo scattering with X. We present the application of this new approach to electron-neutral scattering toward a study of the series of fluorinated benzenes via photoelectron spectroscopy of O2 -·C6H6-xFx (x = 0-6) measured with several photon energies. We compare these spectra to the reference O2 -·hexane spectrum and observe evidence of temporary anion states of C6H6-xFx for species with x = 0-5 in the form of enhanced signal intensity at electron kinetic energies coinciding with the energies of the temporary anions. Furthermore, we observe autodetachment features in the x = 3, 5 spectra. Results of calculations on the isolated symmetric isomer of C6H3F3 suggest that the molecule cannot support a weakly-bound non-valence state that could be associated with the observed autodetachment. However, C6HF5 - is predicted to support a valence bound state, which, if produced by charge transfer from O2 - with sufficient vibrational energy, may undergo autodetachment. Finally, the [O2·C6F6]- spectrum is unique insofar as the spectrum is substantially higher in binding energy and qualitatively different from the x = 0-5 spectra. This result suggests much stronger interactions and charge delocalization between O2 - and C6F6.
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Affiliation(s)
- Marissa A Dobulis
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, USA
| | - Michael C Thompson
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, USA
| | - Thomas Sommerfeld
- Department of Chemistry and Physics, Southeast Louisiana University, SLU 10878, Hammond, Louisiana 70402, USA
| | - Caroline Chick Jarrold
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, USA
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30
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Franke PR, Duncan MA, Douberly GE. Infrared photodissociation spectroscopy and anharmonic vibrational study of the HO 4 + molecular ion. J Chem Phys 2020; 152:174309. [PMID: 32384862 DOI: 10.1063/5.0005975] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Molecular cations of HO4 + and DO4 + are produced in a supersonic expansion. They are mass-selected, and infrared photodissociation spectra of these species are measured with the aid of argon-tagging. Although previous theoretical studies have modeled these systems as proton-bound dimers of molecular oxygen, infrared spectra have free OH stretching bands, suggesting other isomeric structures. As a consequence, we undertook extensive computational studies. Our conformer search used a composite method based on an economical combination of single- and multi-reference theories. Several conformers were located on the quintet, triplet, and singlet surfaces, spanning in energy of only a few thousand wavenumbers. Most of the singlet and triplet conformers have pronounced multiconfigurational character. Previously unidentified covalent-like structures (H-O-O-O-O) on the singlet and triplet surfaces likely represent the global minima. In our experiments, HO4 + is formed in a relatively hot environment, and similar experiments have been shown capable of producing multiple conformers in low-lying electronic states. None of the predicted HO4 + isomers can be ruled out a priori based on energetic arguments. We interpret our argon-tagged spectra with Second-Order Vibrational Perturbation Theory with Resonances (VPT2+K). The presence of one or more covalent-like isomers is the only reasonable explanation for the spectral features observed.
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Affiliation(s)
- Peter R Franke
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
| | - Michael A Duncan
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
| | - Gary E Douberly
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
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31
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Muller G, Jacovella U, Catani KJ, da Silva G, Bieske EJ. Electronic Spectrum and Photodissociation Chemistry of the 1-Butyn-3-yl Cation, H 3CCHCCH . J Phys Chem A 2020; 124:2366-2371. [PMID: 32119779 DOI: 10.1021/acs.jpca.9b11810] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The B̃1A' ← X̃1A' electronic spectra of the 1-butyn-3-yl cation (H3CCHCCH+) and the H3CCHCCH+-Ne and H3CCHCCH+-Ar complexes are measured using resonance enhanced photodissociation over the 245-285 nm range, with origin transitions occurring at 35936, 35930, and 35928 cm-1, respectively. Vibronic bands are assigned based on quantum chemical calculations and comparison of the spectra with those of the related linear methyl propargyl (H3C4H2+) and propargyl (H2C3H+) cations. The photofragment ions are C2H3+ (major) and C4H3+ (minor), with the preference for C2H3+ consistent with master equation simulations for a mechanism that involves rapid electronic deactivation and dissociation on the ground state potential energy surface.
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Affiliation(s)
- Giel Muller
- School of Chemistry, The University of Melbourne, Melbourne, Victoria, Australia 3010
| | - Ugo Jacovella
- School of Chemistry, The University of Melbourne, Melbourne, Victoria, Australia 3010
| | - Katherine J Catani
- School of Chemistry, The University of Melbourne, Melbourne, Victoria, Australia 3010
| | - Gabriel da Silva
- Department of Chemical Engineering, The University of Melbourne, Melbourne, Victoria, Australia 3010
| | - Evan J Bieske
- School of Chemistry, The University of Melbourne, Melbourne, Victoria, Australia 3010
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32
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Dobulis MA, Thompson MC, Patros KM, Sommerfeld T, Jarrold CC. Emerging Nonvalence Anion States of [Isoprene-H·]·H 2O Accessed via Detachment of OH -·Isoprene. J Phys Chem A 2020; 124:2279-2287. [PMID: 32091900 DOI: 10.1021/acs.jpca.0c01250] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The anion photoelectron imaging spectra of an ion with m/z 85, generated under ion source conditions that optimize •OH production in a coexpansion with isoprene, are presented and analyzed with supporting calculations. A spectroscopic feature observed at a vertical electron detachment energy of 2.45 eV, which dominates the photoelectron spectrum measured at 3.495 eV photon energy, is consistent with the OH-·isoprene ion-molecule complex, while additional signal observed at lower electron binding energy can be attributed to other constitutional isomers. However, spectra measured over a 2.2-2.6 eV photon energy range, i.e., from near threshold of the predominant OH-·isoprene detachment feature through the vertical detachment energy, exhibit sharp features with common electron kinetic energies, suggesting autodetachment from a temporary anion prepared by photoexcitation. The photon energy independence of the electron kinetic energy of these features along with the low dipole moment predicted for the neutral •OH·isoprene van der Waals complex, suggest a complex photon-driven process. We present calculations supporting a hypothesis that near-threshold production of the •OH···isoprene reactive complex results in hydrogen abstraction of the isoprene molecule. The newly formed activated complex anion supports a dipole bound state that temporarily traps the near zero-kinetic energy electron and then autodetaches, encoding the low-frequency modes of the dehydrogenated neutral isoprene radical in the electron kinetic energies.
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Affiliation(s)
- Marissa A Dobulis
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Michael C Thompson
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Kellyn M Patros
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Thomas Sommerfeld
- Department of Chemistry and Physics, Southeast Louisiana University, SLU 10878, Hammond, Louisiana 70402, United States
| | - Caroline Chick Jarrold
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
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33
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Li Y, Song W, Jiang N, Zhang Z, Xie M, Hu Y. Structural rearrangement of the acrylonitrile (AN) cluster in the gas phase under VUV one-photon radiation explored by mass-selected infrared spectroscopy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 226:117620. [PMID: 31610467 DOI: 10.1016/j.saa.2019.117620] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 07/27/2019] [Accepted: 10/06/2019] [Indexed: 06/10/2023]
Abstract
Acrylonitrile (AN), one of the most abundant nitriles in space, is considered to closely relate to the formation of interstellar prebiotic nitrogen-containing aromatics. Herein, we measured the vibrational spectra of acrylonitrile cluster cations (AN)2,3+ in a supersonic jet using infrared (IR) dissociation with vacuum-ultraviolet (VUV) photoionization and time-of-flight mass spectroscopy. Interestingly, the observed IR spectra demonstrate that a new molecular ion [Formula: see text] , is generated from the dimer and trimer of AN upon VUV single-photo ionization. Calculation results reveal that the new molecular cations can be generated through a relative low energy barrier after ionization of the neutral (AN)2. However, the reaction pathways are barrierless for the trimer, in which the third solvent AN acts as a catalyst. The mechanisms of those reactions also have been discussed in detail. This study contributes to a deeper understanding of ion-molecule reaction in gas-phase and the quest for the formation of prebiotic N -containing molecules in the outer space.
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Affiliation(s)
- Yujian Li
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, Guangzhou Key Laboratory of Spectral Analysis and Functional Probes, South China Normal University, Guangzhou, 510631, PR China
| | - Wentao Song
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, Guangzhou Key Laboratory of Spectral Analysis and Functional Probes, South China Normal University, Guangzhou, 510631, PR China
| | - Ningjing Jiang
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, Guangzhou Key Laboratory of Spectral Analysis and Functional Probes, South China Normal University, Guangzhou, 510631, PR China
| | - Zhaoli Zhang
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, Guangzhou Key Laboratory of Spectral Analysis and Functional Probes, South China Normal University, Guangzhou, 510631, PR China
| | - Min Xie
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, Guangzhou Key Laboratory of Spectral Analysis and Functional Probes, South China Normal University, Guangzhou, 510631, PR China.
| | - Yongjun Hu
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, Guangzhou Key Laboratory of Spectral Analysis and Functional Probes, South China Normal University, Guangzhou, 510631, PR China.
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34
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Varras PC, Siskos MG, Gritzapis PS. A quantum mechanical explanation of the structure of vinyl cation based on a CASSCF/CASMP2 study. Mol Phys 2019. [DOI: 10.1080/00268976.2019.1706778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Panayiotis C. Varras
- Department of Chemistry, Section of Organic Chemistry & Biochemistry, University of Ioannina, Ioannina, Greece
| | - Michael G. Siskos
- Department of Chemistry, Section of Organic Chemistry & Biochemistry, University of Ioannina, Ioannina, Greece
| | - Panagiotis S. Gritzapis
- Molecular Biology and Genetics Department, Democritus University of Thrace, Alexandroupolis, Greece
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35
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Maitre P, Scuderi D, Corinti D, Chiavarino B, Crestoni ME, Fornarini S. Applications of Infrared Multiple Photon Dissociation (IRMPD) to the Detection of Posttranslational Modifications. Chem Rev 2019; 120:3261-3295. [PMID: 31809038 DOI: 10.1021/acs.chemrev.9b00395] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Infrared multiple photon dissociation (IRMPD) spectroscopy allows for the derivation of the vibrational fingerprint of molecular ions under tandem mass spectrometry (MS/MS) conditions. It provides insight into the nature and localization of posttranslational modifications (PTMs) affecting single amino acids and peptides. IRMPD spectroscopy, which takes advantage of the high sensitivity and resolution of MS/MS, relies on a wavelength specific fragmentation process occurring on resonance with an IR active vibrational mode of the sampled species and is well suited to reveal the presence of a PTM and its impact in the molecular environment. IRMPD spectroscopy is clearly not a proteomics tool. It is rather a valuable source of information for fixed wavelength IRMPD exploited in dissociation protocols of peptides and proteins. Indeed, from the large variety of model PTM containing amino acids and peptides which have been characterized by IRMPD spectroscopy, specific signatures of PTMs such as phosphorylation or sulfonation can be derived. High throughput workflows relying on the selective fragmentation of modified peptides within a complex mixture have thus been proposed. Sequential fragmentations can be observed upon IR activation, which do not only give rise to rich fragmentation patterns but also overcome low mass cutoff limitations in ion trap mass analyzers. Laser-based vibrational spectroscopy of mass-selected ions holding various PTMs is an increasingly expanding field both in the variety of chemical issues coped with and in the technological advancements and implementations.
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Affiliation(s)
- Philippe Maitre
- Laboratoire de Chimie Physique (UMR8000), Université Paris-Sud, CNRS, Université Paris Saclay, 91405, Orsay, France
| | - Debora Scuderi
- Laboratoire de Chimie Physique (UMR8000), Université Paris-Sud, CNRS, Université Paris Saclay, 91405, Orsay, France
| | - Davide Corinti
- Dipartimento di Chimica e Tecnologie del Farmaco, Università di Roma "La Sapienza", I-00185 Roma, Italy
| | - Barbara Chiavarino
- Dipartimento di Chimica e Tecnologie del Farmaco, Università di Roma "La Sapienza", I-00185 Roma, Italy
| | - Maria Elisa Crestoni
- Dipartimento di Chimica e Tecnologie del Farmaco, Università di Roma "La Sapienza", I-00185 Roma, Italy
| | - Simonetta Fornarini
- Dipartimento di Chimica e Tecnologie del Farmaco, Università di Roma "La Sapienza", I-00185 Roma, Italy
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36
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Martens J, van Outersterp RE, Vreeken RJ, Cuyckens F, Coene KLM, Engelke UF, Kluijtmans LAJ, Wevers RA, Buydens LMC, Redlich B, Berden G, Oomens J. Infrared ion spectroscopy: New opportunities for small-molecule identification in mass spectrometry - A tutorial perspective. Anal Chim Acta 2019; 1093:1-15. [PMID: 31735202 DOI: 10.1016/j.aca.2019.10.043] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 10/19/2019] [Accepted: 10/21/2019] [Indexed: 01/21/2023]
Abstract
Combining the individual analytical strengths of mass spectrometry and infrared spectroscopy, infrared ion spectroscopy is increasingly recognized as a powerful tool for small-molecule identification in a wide range of analytical applications. Mass spectrometry is itself a leading analytical technique for small-molecule identification on the merit of its outstanding sensitivity, selectivity and versatility. The foremost shortcoming of the technique, however, is its limited ability to directly probe molecular structure, especially when contrasted against spectroscopic techniques. In infrared ion spectroscopy, infrared vibrational spectra are recorded for mass-isolated ions and provide a signature that can be matched to reference spectra, either measured from standards or predicted using quantum-chemical calculations. Here we present an overview of the potential for this technique to develop into a versatile analytical method for identifying molecular structures in mass spectrometry-based analytical workflows. In this tutorial perspective, we introduce the reader to the technique of infrared ion spectroscopy and highlight a selection of recent experimental advances and applications in current analytical challenges, in particular in the field of untargeted metabolomics. We report on the coupling of infrared ion spectroscopy with liquid chromatography and present experiments that serve as proof-of-principle examples of strategies to address outstanding challenges.
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Affiliation(s)
- Jonathan Martens
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED, Nijmegen, the Netherlands.
| | - Rianne E van Outersterp
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED, Nijmegen, the Netherlands
| | - Rob J Vreeken
- Drug Metabolism & Pharmacokinetics, Janssen R&D, Beerse, Belgium
| | - Filip Cuyckens
- Drug Metabolism & Pharmacokinetics, Janssen R&D, Beerse, Belgium
| | - Karlien L M Coene
- Department of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Udo F Engelke
- Department of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Leo A J Kluijtmans
- Department of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Ron A Wevers
- Department of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Lutgarde M C Buydens
- Radboud University, Institute for Molecules and Materials, Chemometrics, Heyendaalseweg 135, 6525AJ, Nijmegen, the Netherlands
| | - Britta Redlich
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED, Nijmegen, the Netherlands
| | - Giel Berden
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED, Nijmegen, the Netherlands
| | - Jos Oomens
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED, Nijmegen, the Netherlands; van't Hoff Institute for Molecular Sciences, University of Amsterdam, 1098XH, Amsterdam, Science Park 908, the Netherlands.
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37
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Brünken S, Lipparini F, Stoffels A, Jusko P, Redlich B, Gauss J, Schlemmer S. Gas-Phase Vibrational Spectroscopy of the Hydrocarbon Cations l-C 3H +, HC 3H +, and c-C 3H 2+: Structures, Isomers, and the Influence of Ne-Tagging. J Phys Chem A 2019; 123:8053-8062. [PMID: 31422660 PMCID: PMC6755619 DOI: 10.1021/acs.jpca.9b06176] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
![]()
We
report the first gas-phase vibrational spectra of the hydrocarbon
ions C3H+ and C3H2+. The ions were produced by electron impact ionization of
allene. Vibrational spectra of the mass-selected ions tagged with
Ne were recorded using infrared predissociation spectroscopy in a
cryogenic ion trap instrument using the intense and widely tunable
radiation of a free electron laser. Comparison of high-level quantum
chemical calculations and resonant depletion measurements revealed
that the C3H+ ion is exclusively formed in its
most stable linear isomeric form, whereas two isomers were observed
for C3H2+. Bands of the energetically
favored cyclic c-C3H2+ are in excellent
agreement with calculated anharmonic frequencies, whereas for the
linear open-shell HCCCH+ (2Πg) a detailed theoretical description of the spectrum remains challenging
because of Renner–Teller and spin–orbit interactions.
Good agreement between theory and experiment, however, is observed
for the frequencies of the stretching modes for which an anharmonic
treatment was possible. In the case of linear l-C3H+, small but non-negligible effects of the attached Ne on the
ion fundamental band positions and the overall spectrum were found.
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Affiliation(s)
- Sandra Brünken
- FELIX Laboratory, Institute for Molecules and Materials , Radboud University , Toernooiveld 7c , NL-6525ED Nijmegen , The Netherlands.,I. Physikalisches Institut , Universität zu Köln , Zülpicher Str. 77 , D-50937 Köln , Germany
| | - Filippo Lipparini
- Institut für Physikalische Chemie , Johannes Gutenberg-Universität Mainz , Duesbergweg 10-14 , D-55128 Mainz , Germany.,Dipartimento di Chimica e Chimica Industriale , Università di Pisa , Via G. Moruzzi 13 , I-56124 Pisa , Italy
| | - Alexander Stoffels
- FELIX Laboratory, Institute for Molecules and Materials , Radboud University , Toernooiveld 7c , NL-6525ED Nijmegen , The Netherlands.,I. Physikalisches Institut , Universität zu Köln , Zülpicher Str. 77 , D-50937 Köln , Germany
| | - Pavol Jusko
- I. Physikalisches Institut , Universität zu Köln , Zülpicher Str. 77 , D-50937 Köln , Germany
| | - Britta Redlich
- FELIX Laboratory, Institute for Molecules and Materials , Radboud University , Toernooiveld 7c , NL-6525ED Nijmegen , The Netherlands
| | - Jürgen Gauss
- Institut für Physikalische Chemie , Johannes Gutenberg-Universität Mainz , Duesbergweg 10-14 , D-55128 Mainz , Germany
| | - Stephan Schlemmer
- I. Physikalisches Institut , Universität zu Köln , Zülpicher Str. 77 , D-50937 Köln , Germany
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38
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Császár AG, Fábri C, Sarka J. Quasistructural molecules. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2019. [DOI: 10.1002/wcms.1432] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Attila G. Császár
- Laboratory of Molecular Structure and Dynamics, Institute of Chemistry ELTE Eötvös Loránd University Budapest Hungary
- MTA‐ELTE Complex Chemical Systems Research Group Budapest Hungary
| | - Csaba Fábri
- Laboratory of Molecular Structure and Dynamics, Institute of Chemistry ELTE Eötvös Loránd University Budapest Hungary
- MTA‐ELTE Complex Chemical Systems Research Group Budapest Hungary
| | - János Sarka
- Department of Chemistry and Biochemistry Texas Tech University Lubbock Texas USA
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39
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Wagner JP, Giles SM, Duncan MA. Gas phase infrared spectroscopy of the H2C NH2+ methaniminium cation. Chem Phys Lett 2019. [DOI: 10.1016/j.cplett.2019.04.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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40
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Puzzarini C, Tasinato N, Bloino J, Spada L, Barone V. State-of-the-art computation of the rotational and IR spectra of the methyl-cyclopropyl cation: hints on its detection in space. Phys Chem Chem Phys 2019; 21:3431-3439. [PMID: 30110028 DOI: 10.1039/c8cp04629h] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recent measurements by the Cassini Ion Neutral Mass Spectrometer demonstrated the presence of numerous carbocations in Titan's upper atmosphere. In [Ali et al., Planet. Space Sci., 2013, 87, 96], an analysis of these measurements revealed the formation of the three-membered cyclopropenyl cation and its methyl derivatives. As a starting point of a future coordinated effort of laboratory experiments, quantum-chemical calculations, and astronomical observations, in the present work the molecular structure and spectroscopic properties of the methyl-cyclopropenyl cation have been investigated by means of state-of-the-art computational approaches in order to simulate its rotational and infrared spectra. Rotational parameters have been predicted with an expected accuracy better than 0.1% for rotational constants and on the order of 1-2% for centrifugal-distortion terms. As for the infrared spectrum, despite the challenge of a large amplitude motion, fundamental transitions have been computed to a good accuracy, i.e., the uncertainties are expected to be smaller than 5-10 wavenumbers.
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Affiliation(s)
- Cristina Puzzarini
- Dipartimento di Chimica "Giacomo Ciamician", University of Bologna, via F. Selmi 2, I-40126 Bologna, Italy.
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41
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Li W, Jin JY, Qu H, Wang GJ, Zhou MF. Infrared photodissociation spectroscopic and theoretical study of the HC2nO+ (n=3−6) cations. CHINESE J CHEM PHYS 2019. [DOI: 10.1063/1674-0068/cjcp1811254] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Wei Li
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University, Shanghai 200433, China
| | - Jia-ye Jin
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University, Shanghai 200433, China
| | - Hui Qu
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University, Shanghai 200433, China
| | - Guan-jun Wang
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University, Shanghai 200433, China
| | - Ming-fei Zhou
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University, Shanghai 200433, China
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42
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Schwarz H, Asmis KR. Identification of Active Sites and Structural Characterization of Reactive Ionic Intermediates by Cryogenic Ion Trap Vibrational Spectroscopy. Chemistry 2019; 25:2112-2126. [PMID: 30623993 DOI: 10.1002/chem.201805836] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 01/07/2019] [Indexed: 01/02/2023]
Abstract
Cryogenic ion trap vibrational spectroscopy paired with quantum chemistry currently represents the most generally applicable approach for the structural investigation of gaseous cluster ions that are not amenable to direct absorption spectroscopy. Here, we give an overview of the most popular variants of infrared action spectroscopy and describe the advantages of using cryogenic ion traps in combination with messenger tagging and vibrational predissociation spectroscopy. We then highlight a few recent studies that apply this technique to identify highly reactive ionic intermediates and to characterize their reactive sites. We conclude by commenting on future challenges and potential developments in the field.
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Affiliation(s)
- Helmut Schwarz
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Knut R Asmis
- Wilhelm-Ostwald Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstr. 2, 04103, Leipzig, Germany
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43
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Patros KM, Mann JE, Dobulis MA, Thompson MC, Jarrold CC. Probing alkenoxy radical electronic structure using anion PEI spectroscopy. J Chem Phys 2019; 150:034302. [PMID: 30660161 DOI: 10.1063/1.5064795] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Photoelectron imaging spectra of three alkenoxide radical anions (3-buten-1-oxide, 3-buten-2-oxide, and 2-propenoxide) are presented and analyzed with supporting results of density functional theory calculations. In all spectra, intense detachment features are observed at approximately 2 eV electron binding energy, which is similar to the electron affinities of saturated neutral alkoxy radicals [Ramond et al., J. Chem. Phys. 112, 1158 (2000)]. Photoelectron angular distributions suggest the presence of several overlapping transitions which are assigned to the X̃ and à states of multiple energetically competitive conformers. The term energy of the à state of the 2-propenoxy radical, 0.17 eV, is higher than that of 3-buten-2-oxy (0.13 eV) and 3-buten-1-oxy (0.05 eV) radicals. Comparing the butenoxy radicals, we infer that stronger interactions between the non-bonding O 2p orbitals and the π bond increase the splitting between the ground and the first excited state in the 3-buten-2-oxy radical relative to the 3-buten-1-oxy radical.
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Affiliation(s)
- Kellyn M Patros
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, USA
| | - Jennifer E Mann
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, USA
| | - Marissa A Dobulis
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, USA
| | - Michael C Thompson
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, USA
| | - Caroline Chick Jarrold
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, USA
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44
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Chin CH, Lin MY, Huang TP, Wu PZ, Wu YJ. Direct IR Absorption Spectra of Propargyl Cation Isolated in Solid Argon. Sci Rep 2018; 8:14392. [PMID: 30258064 PMCID: PMC6158168 DOI: 10.1038/s41598-018-32644-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 09/12/2018] [Indexed: 11/12/2022] Open
Abstract
The direct infrared (IR) absorption spectra of propargyl cations were recorded. These cations were generated via the electron bombardment of a propyne/Ar matrix sample during matrix deposition. Secondary photolysis with selected ultraviolet (UV) light was used for grouping the observed bands of various products. The band assignment of the propargyl cation in solid Ar was performed according by referring to the previous infrared photodissociation (IRPD) and velocity-map imaging photoelectron (VMI-PE) data, and via theoretical predictions of the anharmonic vibrational wavenumbers, band intensities, and deuterium-substituted isotopic ratios. Almost all the IR active bands with an observable intensity were recorded and the ν11 mode was reported for the first time.
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Affiliation(s)
- Chih-Hao Chin
- National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu, 30076, Taiwan
| | - Meng-Yeh Lin
- National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu, 30076, Taiwan
| | - Tzu-Ping Huang
- National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu, 30076, Taiwan
| | - Pei-Zhen Wu
- National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu, 30076, Taiwan
| | - Yu-Jong Wu
- National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu, 30076, Taiwan. .,Department of Applied Chemistry, National Chiao Tung University, 1001, Ta-Hsueh Road, Hsinchu, 30010, Taiwan.
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45
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Wagner JP, McDonald DC, Duncan MA. Mid-Infrared Spectroscopy of C 7H 7+ Isomers in the Gas Phase: Benzylium and Tropylium. J Phys Chem Lett 2018; 9:4591-4595. [PMID: 30059230 DOI: 10.1021/acs.jpclett.8b02121] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Both prominent C7H7+ isomers, the benzylium and the tropylium cations, were generated in an electrical discharge/supersonic expansion from toluene and cycloheptatriene precursors. Their infrared spectra were measured in the region of 1000-3500 cm-1 using photodissociation of the respective argon- and nitrogen-tagged complexes with a broadly tunable OPO/OPA laser system. Spectral signatures of both isomers were observed independent of the precursor, albeit in different relative intensities. The spectra were assigned based on scaled harmonic B3LYP-D3/cc-pVTZ frequency computations and comparisons to previous experimental studies. Consistent with its high symmetry, only two bands were observed for the (nitrogen-tagged) tropylium ion at 3036 and 1477 cm-1, corresponding to C-H stretching and C-C-H deformation/C═C stretching vibrations, respectively. Furthermore, the C-H stretching region of the benzylium ion is reported for the first time.
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Affiliation(s)
- J Philipp Wagner
- Department of Chemistry , University of Georgia , 140 Cedar Street , Athens , Georgia 30602 , United States
| | - David C McDonald
- Department of Chemistry , University of Georgia , 140 Cedar Street , Athens , Georgia 30602 , United States
| | - Michael A Duncan
- Department of Chemistry , University of Georgia , 140 Cedar Street , Athens , Georgia 30602 , United States
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46
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McDonald DC, Wagner JP, Duncan MA. Communication: Infrared photodissociation spectroscopy of the H 6+ cation in the gas phase. J Chem Phys 2018; 149:031105. [PMID: 30037249 DOI: 10.1063/1.5043425] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The H6+ cation was generated in a pulsed-discharge supersonic expansion of hydrogen and mass-selected in a time-of-flight spectrometer. Its vibrational spectrum was measured in the region of 2050-4550 cm-1 using infrared photodissociation with a tunable OPO/OPA laser system. The H6+ photodissociates, producing H5+, H4+, and H3+ fragments; each of these fragment channels has a different spectrum. Computational studies identify two low-lying isomers described in previous work, whose energies were evaluated at the CCSD(T)/cc-pVTZ//MP2/cc-pVTZ level of theory. A D2d species having an H2+ cation bridging between two perpendicular H2 molecules is the global minimum structure. A Cs structure with an H3+ core ion bound to both H2 and an H atom lies 4.0 kcal mol-1 higher in energy. Anharmonic vibrational spectra were computed for each of these isomers with second-order vibrational perturbation theory (VPT2) in combination with density functional theory at the B2PLYP/cc-pVTZ level. The comparison between experimental and predicted spectra confirms the presence of both the D2d and Cs structures and explains the spectra in different fragmentation channels. Although we find reasonable agreement between the experiment and the spectra predicted by VPT2 computations, a more sophisticated computational approach is needed to better understand this complex system.
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Affiliation(s)
- David C McDonald
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
| | - J Philipp Wagner
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
| | - Michael A Duncan
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
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47
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Katada M, Fujii A. Infrared Spectroscopy of Protonated Phenol–Water Clusters. J Phys Chem A 2018; 122:5822-5831. [DOI: 10.1021/acs.jpca.8b04446] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Marusu Katada
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Asuka Fujii
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
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48
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Wagner JP, McDonald DC, Duncan MA. Spectroscopy of Proton Coordination with Ethylenediamine. J Phys Chem A 2018; 122:5168-5176. [PMID: 29771517 DOI: 10.1021/acs.jpca.8b03592] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Protonated ethylenediamine monomer, dimer, and trimer were produced in the gas phase by an electrical discharge/supersonic expansion of argon seeded with ethylenediamine (C2H8N2, en) vapor. Infrared spectra of these ions were measured in the region from 1000 to 4000 cm-1 using laser photodissociation and argon tagging. Computations at the CBS-QB3 level were performed to explore possible isomers and understand the infrared spectra. The protonated monomer exhibits a gauche conformation and an intramolecular hydrogen bond. Its parallel shared proton vibration occurs as a broad band around 2785 cm-1, despite the formally equivalent proton affinities of the two amino groups involved, which usually leads to low frequency bands. The barrier to intramolecular proton transfer is 2.2 kcal mol-1 and does not vanish upon addition of the zero-point energy, unlike the related protonated ammonia dimer. The structure of the dimer is formed by chelation of the monomer's NH3+ group, thereby localizing the excess proton and increasing the frequency of the intramolecular shared proton vibration to 3157 cm-1. Other highly fluxional dimer structures with facile intermolecular proton transfer and concomitant structural reorganization were computed to lie within 2 kcal mol-1 of the experimentally observed structure. The spectrum of the trimer is rather diffuse, and a clear assignment is not possible. However, an isomer with an intramolecular proton transfer like that of the monomer is most consistent with the experimental spectrum.
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Affiliation(s)
- J Philipp Wagner
- Department of Chemistry , University of Georgia , 140 Cedar Street , Athens , Georgia 30602 , United States
| | - David C McDonald
- Department of Chemistry , University of Georgia , 140 Cedar Street , Athens , Georgia 30602 , United States
| | - Michael A Duncan
- Department of Chemistry , University of Georgia , 140 Cedar Street , Athens , Georgia 30602 , United States
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49
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Wagner JP, McDonald DC, Duncan MA. An Argon–Oxygen Covalent Bond in the ArOH
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Molecular Ion. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201802093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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50
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Wagner JP, McDonald DC, Duncan MA. An Argon–Oxygen Covalent Bond in the ArOH
+
Molecular Ion. Angew Chem Int Ed Engl 2018; 57:5081-5085. [DOI: 10.1002/anie.201802093] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Indexed: 11/11/2022]
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