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Jeong C, Yun J, Heo J, Kim NJ. Anisotropic circular dichroism of jet-cooled chiral molecules. Phys Chem Chem Phys 2023; 25:22644-22649. [PMID: 37591819 DOI: 10.1039/d3cp03074a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/19/2023]
Abstract
Anisotropic circular dichroism (CD) refers to the CD of oriented molecules, which varies with the direction of light propagation toward the molecules. Thus, anisotropic CD spectroscopy has been used to investigate the orientations of molecules in anisotropic media such as liquid crystals and thin films. However, it is unclear whether anisotropic CD results from isolated chromophores or their intermolecular interactions with other atoms or molecules that form anisotropically aligned structures. Herein, anisotropic CD of isolated chiral molecules was observed for the first time. The resonant two-photon ionization CD spectra of jet-cooled pseudoephedrine and styrene oxide indicated a difference between the CD values of the P/R and Q branches of the origin bands of the S0-S1 transition. This difference may have resulted from the anisotropic CD phenomena of these molecules, which are oriented via photoselection. Although jet-cooled molecules may have nearly random orientations, those excited to the P/R or Q branch become oriented because the transition probability to these branches depends on the molecular orientation relative to the direction of light propagation. These results demonstrate that the CD spectra of cold, isolated molecules, such as those in an interstellar medium, may exhibit anisotropic CD values.
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Affiliation(s)
- Changseop Jeong
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea.
| | - Jiyeon Yun
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea.
| | - Jiyoung Heo
- Department of Green Chemical Engineering, Sangmyung University, Chungnam 31066, Korea.
| | - Nam Joon Kim
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea.
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2
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Jeong C, Eun HJ, Yun J, Kim NJ. Dual-Beam Circular Dichroism Spectroscopy of Jet-Cooled Chiral Molecules. J Phys Chem A 2022; 126:4295-4299. [PMID: 35758322 DOI: 10.1021/acs.jpca.2c02745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Circular dichroism (CD) spectroscopy of jet-cooled molecules provides conformation-specific CD spectra. However, its widespread utilization has been limited by the weak CD effects and the low density of gas-phase molecules. Here, we developed a dual-beam method to improve the sensitivity and accuracy of gas-phase CD measurements. Circularly and linearly polarized pulses were generated from a single laser pulse and used to irradiate a single molecular-beam pulse to produce two ion peaks. The ion peaks induced by linearly polarized pulses were subtracted from those induced by circularly polarized pulses to correct the CD values for the pulse-to-pulse fluctuations in laser power and gas density. The resonant two-photon ionization CD spectrum of (1R,2R)-(-)-pseudoephedrine revealed that the standard deviations of CD values measured using the dual-beam method were three times lower than those measured using a single-beam method. The dual-beam method provides an effective, accurate, and easy-to-use tool to obtain gas-phase CD spectra.
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Affiliation(s)
- Changseop Jeong
- Department of Chemistry, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea
| | - Han Jun Eun
- Department of Chemistry, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea
| | - Jiyeon Yun
- Department of Chemistry, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea
| | - Nam Joon Kim
- Department of Chemistry, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea
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3
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Mondelo-Martell M, Basilewitsch D, Braun H, Koch CP, Reich DM. Increasing ion yield circular dichroism in femtosecond photoionisation using optimal control theory. Phys Chem Chem Phys 2022; 24:9286-9297. [PMID: 35411352 DOI: 10.1039/d1cp05239j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We investigate how optimal control theory can be used to improve Circular Dichroism (CD) signals for the A-band of fenchone measured via the photoionization yield upon further excitation. These transitions are electric dipole forbidden to first order, which translates into low population transfer to the excited state but allows for a clearer interplay between electric and magnetic transition dipole moments, which are of the same order of magnitude. Using a model including the electronic ground and excited A state as well as all permanent and transition multipole moments up to the electric quadrupole, we find that the absolute CD signal of randomly oriented molecules can be increased by a factor of 2.5 when using shaped laser pulses, with the anisotropy parameter g increasing from 0.06 to 1. We find that this effect is caused by the interference between the excitation pathways prompted by the different multipole moments of the molecule.
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Affiliation(s)
- Manel Mondelo-Martell
- Dahlem Center of Complex Quantum Systems & Department of Physics, Freie Universität Berlin, Berlin, Germany.
| | - Daniel Basilewitsch
- Dahlem Center of Complex Quantum Systems & Department of Physics, Freie Universität Berlin, Berlin, Germany.
| | - Hendrike Braun
- Institute of Physics, Universität Kassel, Kassel, Germany.
| | - Christiane P Koch
- Dahlem Center of Complex Quantum Systems & Department of Physics, Freie Universität Berlin, Berlin, Germany.
| | - Daniel M Reich
- Dahlem Center of Complex Quantum Systems & Department of Physics, Freie Universität Berlin, Berlin, Germany.
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5
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Lehmann CS, Botros D, Weitzel KM. Coincident measurement of photo-ion circular dichroism and photo-electron circular dichroism on 1-Phenylethylamine. Phys Chem Chem Phys 2022; 24:15904-15911. [DOI: 10.1039/d2cp01418a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Here we report the coincident measurement of the PICD and PECD effect in 1-Phenylethylamine upon multiphoton ionisation. Photo-ion circular dichroism (PICD) and photo-electron circular dichroism (PECD) are both methods to...
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6
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Yoo IT, Eun HJ, Min A, Jeon CW, Jeong J, Heo J, Kim NJ. Ultraviolet photodissociation circular dichroism spectroscopy of protonated L-phenylalanyl-L-alanine in a cryogenic ion trap. Phys Chem Chem Phys 2021; 23:24180-24186. [PMID: 34676382 DOI: 10.1039/d1cp04030h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We obtained ultraviolet photodissociation (UVPD) circular dichroism (CD) spectra of protonated L-phenylalanyl-L-alanine (L-H+PheAla) near the origin band of the S0-S1 transition using cryogenic ion spectroscopy. Infrared (IR) ion-dip, IR-UV hole burning (HB) and UV-UV HB spectra showed that L-H+PheAla existed as two different conformers in a cryogenic ion trap, and they had nearly identical peptide backbones but different conformations in the Phe side chain. The UVPD CD spectra revealed that the two conformers had opposite CD signs and significantly different CD magnitudes from each other. These results demonstrate that the CD value of L-H+PheAla near the origin band is strongly influenced by the conformation of the Phe side chain.
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Affiliation(s)
- Il Tae Yoo
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea.
| | - Han Jun Eun
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea.
| | - Ahreum Min
- Department of Chemistry (BK21 +) and Research Institute of Natural Science, Gyeongsang National University, Jinju 52828, Korea
| | - Chang Wook Jeon
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea.
| | - Jinho Jeong
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea.
| | - Jiyoung Heo
- Department of Green Chemical Engineering, Sangmyung University, Chungnam 31066, Korea
| | - Nam Joon Kim
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea.
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7
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Krüger P, Weitzel K. Photoelektronen‐Zirkulardichroismus im Photodetachment von Aminosäuren‐Anionen. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202107150] [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]
Affiliation(s)
- Peter Krüger
- Fachbereich Chemie Philipps-Universität Marburg 35032 Marburg Deutschland
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Krüger P, Weitzel KM. Photoelectron Circular Dichroism in the Photodetachment of Amino Acid Anions. Angew Chem Int Ed Engl 2021; 60:17861-17865. [PMID: 34137142 PMCID: PMC8457165 DOI: 10.1002/anie.202107150] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Indexed: 01/31/2023]
Abstract
The chirality of chemical compounds is of undisputed importance in science and technology. In particular with respect to pharmacological application most molecules of interest cannot be accessed by the powerful techniques developed in recent years for gas phase analytes. Here, we demonstrate that the combination of electrospray ionization (ESI) with the detection of photoelectron circular dichroism (PECD) provides access to chirality information applicable to molecular materials with negligible vapor pressure, for example, amino acids. To this end, glutamic acid and 3,4‐dihydroxyphenylalanine (DOPA) have been electrosprayed into the source of a chirality spectrometer, where photodetachment is enforced and the PECD is detected. The technique can be expected to be conceptually applicable to all chemical systems with chirality based on molecular properties.
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Affiliation(s)
- Peter Krüger
- Fachbereich Chemie, Philipps-Universität Marburg, 35032, Marburg, Germany
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9
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Ring T, Witte C, Vasudevan S, Das S, Ranecky ST, Lee H, Ladda N, Senftleben A, Braun H, Baumert T. Self-referencing circular dichroism ion yield measurements for improved statistics using femtosecond laser pulses. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:033001. [PMID: 33820110 DOI: 10.1063/5.0036344] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 02/18/2021] [Indexed: 06/12/2023]
Abstract
The combination of circular dichroism with laser mass spectrometry via the measurement of ion yields is a powerful tool in chiral recognition, but the measured anisotropies are generally weak. The method presented in this contribution reduces the measurement error significantly. A common path optical setup generates a pair of counter-rotating laser foci in the interaction region of a time-of-flight spectrometer. As the space focus condition is fulfilled for both foci individually, this becomes a twin-peak ion source with well separated and sufficiently resolved mass peaks. The individual control of polarization allows for in situ correction of experimental fluctuations measuring circular dichroism. Our robust optical setup produces reliable and reproducible results and is applicable for dispersion sensitive femtosecond laser pulses. In this contribution, we use 3-methyl-cyclopentanone as a prototype molecule to illustrate the evaluation procedure and the measurement principle.
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Affiliation(s)
- T Ring
- Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - C Witte
- Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - S Vasudevan
- Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - S Das
- Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - S T Ranecky
- Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - H Lee
- Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - N Ladda
- Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - A Senftleben
- Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - H Braun
- Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - T Baumert
- Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
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Bégin JL, Alsaawy M, Bhardwaj R. Chiral discrimination by recollision enhanced femtosecond laser mass spectrometry. Sci Rep 2020; 10:14074. [PMID: 32826912 PMCID: PMC7442795 DOI: 10.1038/s41598-020-71069-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 08/05/2020] [Indexed: 11/09/2022] Open
Abstract
Chiral molecules and their interactions are critical in a variety of chemical and biological processes. Circular dichroism (CD) is the most widely used optical technique to study chirality, often performed in a solution phase. However, CD has low-efficiency on the order of 0.01-1[Formula: see text]. Therefore, there is a growing need to develop high-efficiency chiroptical techniques, especially in gas-phase, to gain background-free in-depth insight into chiral interactions. By using mass spectrometry and strong-field ionization of limonene with elliptically polarized light, we demonstrate an efficient chiral discrimination method that produces a chiral signal of one to two orders of magnitude higher than the conventional CD. The chiral response exhibits a strong dependence on wavelength in the range of 1,300-2,400 nm, where the relative abundance of the ion yields alternates between the two enantiomers. The origin of enhanced enantio-sensitivity in intense laser fields is attributed to two mechanisms that rely on the recollision dynamics in a chiral system: (1) the excited ionic state dynamics mediated either by the laser field or by the recollision process, and (2) non-dipole effects that alter the electron's trajectories. Our results can serve as a benchmark for testing and developing theoretical tools involving non-dipole effects in strong-field ionization of molecules.
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Affiliation(s)
- Jean-Luc Bégin
- Department of Physics, University of Ottawa, Ottawa, ON, K1N 6N5, Canada
| | - Maye Alsaawy
- Department of Physics, University of Ottawa, Ottawa, ON, K1N 6N5, Canada
| | - Ravi Bhardwaj
- Department of Physics, University of Ottawa, Ottawa, ON, K1N 6N5, Canada.
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11
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Daly S, Rosu F, Gabelica V. Mass-resolved electronic circular dichroism ion spectroscopy. Science 2020; 368:1465-1468. [PMID: 32587016 DOI: 10.1126/science.abb1822] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 04/27/2020] [Indexed: 12/15/2022]
Abstract
DNA and proteins are chiral: Their three-dimensional structures cannot be superimposed with their mirror images. Circular dichroism spectroscopy is widely used to characterize chiral compounds, but data interpretation is difficult in the case of mixtures. We recorded the electronic circular dichroism spectra of DNA helices separated in a mass spectrometer. We studied guanine-rich strands having various secondary structures, electrosprayed them as negative ions, irradiated them with an ultraviolet nanosecond optical parametric oscillator laser, and measured the difference in electron photodetachment efficiency between left and right circularly polarized light. The reconstructed circular dichroism ion spectra resembled those of their solution-phase counterparts, thereby allowing us to assign the DNA helical topology. The ability to measure circular dichroism directly on biomolecular ions expands the capabilities of mass spectrometry for structural analysis.
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Affiliation(s)
- Steven Daly
- Université de Bordeaux, Inserm & CNRS, Laboratoire Acides Nucléiques: Régulations Naturelle et Artificielle (ARNA, U1212, UMR5320), IECB, 33607 Pessac, France
| | - Frédéric Rosu
- Université de Bordeaux, CNRS & Inserm, Institut Européen de Chimie et Biologie (IECB, UMS3033, US001), 33607 Pessac, France
| | - Valérie Gabelica
- Université de Bordeaux, Inserm & CNRS, Laboratoire Acides Nucléiques: Régulations Naturelle et Artificielle (ARNA, U1212, UMR5320), IECB, 33607 Pessac, France.
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12
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Eun HJ, Min A, Jeon CW, Yoo IT, Heo J, Kim NJ. Chiral and Isomeric Discrimination of Chiral Molecular Ions by Cold Ion Circular Dichroism Spectroscopy. J Phys Chem Lett 2020; 11:4367-4371. [PMID: 32396359 DOI: 10.1021/acs.jpclett.0c01081] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Circular dichroism (CD) spectra contain information about absolute configurations and conformations of chiral compounds. However, extracting this information from CD spectra in solution is challenging, because the spectra exhibit only the averaged CD values of all different conformers. CD spectroscopy of jet-cooled molecules can provide conformation-specific CD spectra, but its application to biomolecules has been limited due to the difficulty of their production in the gas phase. Here, we obtained the first CD spectra of chiral molecular ions produced by electrospray ionization (ESI) using cold ion CD spectroscopy. Protonated l- or d-phenylalanine ions produced by ESI were stored in a cold quadrupole ion trap and irradiated by multiple laser pulses with left or right circular polarization. The CD spectra exhibited well-resolved CD bands of two conformers, whose signs were opposite to each other. This study will broaden the scope of conformation-resolved CD spectroscopy to large molecular ions without size limitations.
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Affiliation(s)
- Han Jun Eun
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea
| | - Ahreum Min
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea
| | - Chang Wook Jeon
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea
| | - Il Tae Yoo
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea
| | - Jiyoung Heo
- Department of Green Chemical Engineering, Sangmyung University, Chungnam 31066, Korea
| | - Nam Joon Kim
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea
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13
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Kastner A, Koumarianou G, Glodic P, Samartzis PC, Ladda N, Ranecky ST, Ring T, Vasudevan S, Witte C, Braun H, Lee HG, Senftleben A, Berger R, Park GB, Schäfer T, Baumert T. High-resolution resonance-enhanced multiphoton photoelectron circular dichroism. Phys Chem Chem Phys 2020; 22:7404-7411. [PMID: 32215414 DOI: 10.1039/d0cp00470g] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photoelectron circular dichroism (PECD) is a highly sensitive enantiospecific spectroscopy for studying chiral molecules in the gas phase using either single-photon ionization or multiphoton ionization. In the short pulse limit investigated with femtosecond lasers, resonance-enhanced multiphoton ionization (REMPI) is rather instantaneous and typically occurs simultaneously via more than one vibrational or electronic intermediate state due to limited frequency resolution. In contrast, vibrational resolution in the REMPI spectrum can be achieved using nanosecond lasers. In this work, we follow the high-resolution approach using a tunable narrow-band nanosecond laser to measure REMPI-PECD through distinct vibrational levels in the intermediate 3s and 3p Rydberg states of fenchone. We observe the PECD to be essentially independent of the vibrational level. This behaviour of the chiral sensitivity may pave the way for enantiomer specific molecular identification in multi-component mixtures: one can specifically excite a sharp, vibrationally resolved transition of a distinct molecule to distinguish different chiral species in mixtures.
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Affiliation(s)
| | - Greta Koumarianou
- Institute of Electronic Structure and Lasers, Foundation for Research and Technology - Hellas (FORTH), P. O. Box 1527, 71110 Heraklion, Greece
| | - Pavle Glodic
- Institute of Electronic Structure and Lasers, Foundation for Research and Technology - Hellas (FORTH), P. O. Box 1527, 71110 Heraklion, Greece
| | - Peter C Samartzis
- Institute of Electronic Structure and Lasers, Foundation for Research and Technology - Hellas (FORTH), P. O. Box 1527, 71110 Heraklion, Greece
| | - Nicolas Ladda
- Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Simon T Ranecky
- Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Tom Ring
- Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | | | - Constantin Witte
- Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Hendrike Braun
- Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Han-Gyeol Lee
- Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Arne Senftleben
- Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Robert Berger
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany
| | - G Barratt Park
- Georg-August-Universität Göttingen, Tammannstr. 6, 37077 Göttingen, Germany. and Max Planck Institut für Biophysikalische Chemie, Am Fassberg 11, 37077 Göttingen, Germany
| | - Tim Schäfer
- Georg-August-Universität Göttingen, Tammannstr. 6, 37077 Göttingen, Germany. and Max Planck Institut für Biophysikalische Chemie, Am Fassberg 11, 37077 Göttingen, Germany
| | - Thomas Baumert
- Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
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14
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Lehmann CS, Weitzel KM. Coincident measurement of photo-ion circular dichroism and photo-electron circular dichroism. Phys Chem Chem Phys 2020; 22:13707-13712. [DOI: 10.1039/d0cp01376e] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photo-ion circular dichroism (PICD) and photo-electron circular dichroism (PECD) have been measured for the first time simultaneously in a coincidence experiment detecting the chirality of R- and S-Methyloxirane.
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15
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Abstract
Chiral molecules interact and react differently, depending on their handedness (left vs. right). This chiral recognition is the principle governing most biomolecular interactions, such as the activity of drugs or our perception of scents. In spite of this fundamental importance, a real-time (femtosecond) observation of chirality during a chemical reaction has remained out of reach in the gas phase. In the present work, we report this breakthrough with a seemingly unlikely technique: high-harmonic generation (HHG) in tailored intense near-infrared laser fields. Combining the transient-grating technique with HHG in counterrotating circularly polarized laser fields, we follow the temporal evolution of molecular chirality during a chemical reaction from the unexcited electronic ground state through the transition-state region to the final achiral products. Chiral molecules interact and react differently with other chiral objects, depending on their handedness. Therefore, it is essential to understand and ultimately control the evolution of molecular chirality during chemical reactions. Although highly sophisticated techniques for the controlled synthesis of chiral molecules have been developed, the observation of chirality on the natural femtosecond time scale of a chemical reaction has so far remained out of reach in the gas phase. Here, we demonstrate a general experimental technique, based on high-harmonic generation in tailored laser fields, and apply it to probe the time evolution of molecular chirality during the photodissociation of 2-iodobutane. These measurements show a change in sign and a pronounced increase in the magnitude of the chiral response over the first 100 fs, followed by its decay within less than 500 fs, revealing the photodissociation to achiral products. The observed time evolution is explained in terms of the variation of the electric and magnetic transition-dipole moments between the lowest electronic states of the cation as a function of the reaction coordinate. These results open the path to investigations of the chirality of molecular-reaction pathways, light-induced chirality in chemical processes, and the control of molecular chirality through tailored laser pulses.
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16
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Hong A, Min A, Jang H, Moon CJ, Jeong C, Choi MY, Heo J, Kim NJ. Induced Circular Dichroism of Jet-Cooled Phenol Complexes with ( R)-(-)-2-Butanol. J Phys Chem A 2019; 123:8913-8920. [PMID: 31549840 DOI: 10.1021/acs.jpca.9b07237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The induced circular dichroism (ICD) of phenol complexed with (R)-(-)-2-butanol [PhOH-(-)BOH] in a supersonic jet is investigated using resonant two-photon ionization circular dichroism (R2PICD) spectroscopy. The R2PICD spectrum of PhOH-(-)BOH exhibits nonzero ICD bands near the absorption region of bare PhOH, where (-)BOH is transparent. Two different conformers containing a single hydrogen bond between PhOH and (-)BOH are identified using ultraviolet-ultraviolet hole-burning and infrared ion-dip spectroscopy combined with quantum theoretical calculations. The ICD values of the two conformers are similar to each other. To understand these similar ICD effects of the conformers, the geometrical asymmetry of the PhOH moiety bound to (-)BOH and the coupling strength of the electric transition dipole moments between PhOH and (-)BOH are estimated. Comparing the ICD values of PhOH-(-)BOH with those of PhOH-(-)-l-methyl lactate in the previous report [ Hong , A. ; J. Phys. Chem. Lett. 2018 , 9 , 476 -480 ], we investigate the physical properties that may govern the differences of the ICD values between the two complexes.
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Affiliation(s)
- Aram Hong
- Department of Chemistry , Chungbuk National University , Cheongju , Chungbuk 28644 , Korea
| | - Ahreum Min
- Department of Chemistry , Chungbuk National University , Cheongju , Chungbuk 28644 , Korea
| | - Heeseon Jang
- Department of Chemistry , Chungbuk National University , Cheongju , Chungbuk 28644 , Korea
| | - Cheol Joo Moon
- Department of Chemistry (BK21+) and Research Institute of Natural Science , Gyeongsang National University , Jinju 52828 , Korea
| | - Changseop Jeong
- Department of Chemistry , Chungbuk National University , Cheongju , Chungbuk 28644 , Korea
| | - Myong Yong Choi
- Department of Chemistry (BK21+) and Research Institute of Natural Science , Gyeongsang National University , Jinju 52828 , Korea
| | - Jiyoung Heo
- Department of Green Chemical Engineering , Sangmyung University , Cheonan , Chungnam 31066 , Korea
| | - Nam Joon Kim
- Department of Chemistry , Chungbuk National University , Cheongju , Chungbuk 28644 , Korea
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17
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Kartouzian A. Spectroscopy for model heterogeneous asymmetric catalysis. Chirality 2019; 31:641-657. [PMID: 31318108 DOI: 10.1002/chir.23113] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 07/02/2019] [Indexed: 12/31/2022]
Abstract
Heterogeneous catalysis has vastly benefited from investigations performed on model systems under well-controlled conditions. The application of most of the techniques utilized for such studies is not feasible for asymmetric reactions as enantiomers possess identical physical and chemical properties unless while interacting with polarized light and other chiral entities. A thorough investigation of a heterogeneous asymmetric catalytic process should include probing the catalyst prior to, during, and after the reaction as well as the analysis of reaction products to evaluate the achieved enantiomeric excess. I present recent studies that demonstrate the strength of chiroptical spectroscopic methods to tackle the challenges in investigating model heterogeneous asymmetric catalysis covering all the abovementioned aspects.
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Affiliation(s)
- Aras Kartouzian
- Lehrstuhl für physikalische Chemie, Catalysis Research Center, Technische Universität München, Garching bei München, Germany
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18
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Lepelmeier J, Alonso-Gómez JL, Mortaheb F, Boesl U, Heiz U, Kartouzian A. Chiroptical inversion for isolated vibronic transitions of supersonic beam-cooled molecules. Phys Chem Chem Phys 2018. [PMID: 28650046 DOI: 10.1039/c7cp02596c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Circular dichroism-resonance-enhanced multiphoton ionization (CD-REMPI) was used for CD measurements on several single vibronic transitions of supersonic beam-cooled (R)-(+)-1-phenylethanol. Due to the low molecular densities within a supersonic beam and the expected small anisotropy factor of 1-phenylethanol in the permille region, the precision of the experimental method had to be significantly improved. Therefore, a single laser pulse evaluation combined with a twin-peak technique enabled within the used supersonic beam setup is presented. For the electronic transition S0 → S1 of (R)-(+)-1-phenylethanol (π → π* transition of the phenyl ring at 266 nm) ten different vibrational modes as well as the 0-transition were investigated with one-color (1 + 1) CD-REMPI. The results deliver new experimental insights on the influence of molecular vibrations on the anisotropy factor. TD-DFT theoretical predictions show how the angle between the electronic and magnetic transition dipole moments of the electronic transition can be modified by different vibrational modes, making even a flip of the sign of the anisotropy factor possible.
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Affiliation(s)
- Jörn Lepelmeier
- Technical University of Munich, Lichtenbergstraße 4, 85748 Garching, Germany.
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19
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Hong A, Moon CJ, Jang H, Min A, Choi MY, Heo J, Kim NJ. Isomer-Specific Induced Circular Dichroism Spectroscopy of Jet-Cooled Phenol Complexes with (-)-Methyl l-Lactate. J Phys Chem Lett 2018; 9:476-480. [PMID: 29309156 DOI: 10.1021/acs.jpclett.7b03241] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Induced circular dichroism (ICD) is the CD observed in the absorption of an achiral molecule bound to a transparent chiral molecule through noncovalent interactions. ICD spectroscopy has been used to probe the binding between molecules, such as protein-ligand interactions. However, most ICD spectra have been measured in solution, which only exhibit the averaged CD values of all conformational isomers in solution. Here, we obtained the first isomer-selective ICD spectra by applying resonant two-photon ionization CD spectroscopy to jet-cooled phenol complexes with (-)-methyl l-lactate (PhOH-(-)ML). The well-resolved CD bands in the spectra were assigned to two conformers, which contained different types of hydrogen-bonding interactions between PhOH and (-)ML. The ICD values of the two conformers have different signs and magnitudes, which were explained by differences both in the geometrical asymmetries of PhOH bound to (-)ML and in the electronic coupling strengths between PhOH and (-)ML.
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Affiliation(s)
- Aram Hong
- Department of Chemistry, Chungbuk National University , Chungbuk 28644, Korea
| | - Cheol Joo Moon
- Department of Chemistry (BK21+) and Research Institute of Natural Science, Gyeongsang National University , Jinju 52828, Korea
| | - Heeseon Jang
- Department of Chemistry, Chungbuk National University , Chungbuk 28644, Korea
| | - Ahreum Min
- Department of Chemistry, Chungbuk National University , Chungbuk 28644, Korea
| | - Myong Yong Choi
- Department of Chemistry (BK21+) and Research Institute of Natural Science, Gyeongsang National University , Jinju 52828, Korea
| | - Jiyoung Heo
- Department of Green Chemical Engineering, Sangmyung University , Chungnam 31066, Korea
| | - Nam Joon Kim
- Department of Chemistry, Chungbuk National University , Chungbuk 28644, Korea
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20
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Alenaizan A, Al-Basheer W, Musa MM. Solvent, temperature and concentration effects on the optical rotatory dispersion of (R)-3-methylcyclohexanone. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2016.10.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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21
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Goetz RE, Isaev TA, Nikoobakht B, Berger R, Koch CP. Theoretical description of circular dichroism in photoelectron angular distributions of randomly oriented chiral molecules after multi-photon photoionization. J Chem Phys 2017; 146:024306. [DOI: 10.1063/1.4973456] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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22
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Abstract
We introduce a general theoretical approach for the simulation of photochemical dynamics under the influence of circularly polarized light to explore the possibility of generating enantiomeric enrichment through polarized-light-selective photochemistry. The method is applied to the simulation of the photolysis of alanine, a prototype chiral amino acid. We show that a systematic enantiomeric enrichment can be obtained depending on the helicity of the circularly polarized light that induces the excited-state photochemistry of alanine. By analyzing the patterns of the photoinduced fragmentation of alanine we find an inducible enantiomeric enrichment up to 1.7%, which is also in good correspondence to the experimental findings. Our method is generally applicable to complex systems and might serve to systematically explore the photochemical origin of homochirality.
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Affiliation(s)
- Matthias Wohlgemuth
- Institute for Physical and Theoretical Chemistry, Julius Maximilians University Würzburg , Emil-Fischer-Str. 42, 97074 Würzburg, Germany
| | - Roland Mitrić
- Institute for Physical and Theoretical Chemistry, Julius Maximilians University Würzburg , Emil-Fischer-Str. 42, 97074 Würzburg, Germany
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23
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Lepelmeier J, Titze K, Kartouzian A, Boesl U, Heiz U. Mass-Selected Circular Dichroism of Supersonic-Beam-Cooled [D 4 ]-(R)-(+)-3-Methylcyclopentanone. Chemphyschem 2016; 17:4052-4058. [PMID: 27809379 DOI: 10.1002/cphc.201600811] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 10/05/2016] [Indexed: 11/06/2022]
Abstract
UV spectroscopy and electronic circular dichroism (ECD) experiments on supersonic-beam-cooled deuterated (R)-(+)-3-methylcyclopentanone ([D4 ]-(R)-(+)-3-MCP) have been performed by using a laser mass spectrometer. The spectral resolution not only allowed excitation and CD measurements for single vibronic transitions but also for the rotational P, Q, and R branches of these transitions. The investigated n→π*18042501 transition showed the largest anisotropy factor ever observed for chiral molecules in the gas phase, which, due to residual saturation of the excited transition, represents only a lower limit for the real anisotropy factor. Furthermore, one-color (1+1+1) and two-color (1+1') resonance-enhanced multiphoton ionization (REMPI) measurements were performed and the effusive-beam (room temperature) and supersonic-beam results for [D4 ]-(R)-(+)-3-MCP were compared. These results allowed a differentiation between single-step ECD (comparable to conventional ECD) and cumulative ECD (only possible in multiphoton excitation) under supersonic-beam conditions.
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Affiliation(s)
- Jörn Lepelmeier
- Technische Universität München, Lehrstuhl für Physikalische Chemie, Lichtenbergstr. 4, 85748, Garching, Germany
| | - Katharina Titze
- Technische Universität München, Lehrstuhl für Physikalische Chemie, Lichtenbergstr. 4, 85748, Garching, Germany
| | - Aras Kartouzian
- Technische Universität München, Lehrstuhl für Physikalische Chemie, Lichtenbergstr. 4, 85748, Garching, Germany
| | - Ulrich Boesl
- Technische Universität München, Lehrstuhl für Physikalische Chemie, Lichtenbergstr. 4, 85748, Garching, Germany
| | - Ulrich Heiz
- Technische Universität München, Lehrstuhl für Physikalische Chemie, Lichtenbergstr. 4, 85748, Garching, Germany
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24
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Hong A, Jang H, Jeong C, Choi MC, Heo J, Kim NJ. Electronic Circular Dichroism Spectroscopy of Jet-Cooled Phenylalanine and Its Hydrated Clusters. J Phys Chem Lett 2016; 7:4385-4390. [PMID: 27766866 DOI: 10.1021/acs.jpclett.6b01894] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We obtained resonant two-photon ionization circular dichroism (R2PICD) spectra of jet-cooled phenylalanine (Phe) and its hydrated clusters (Phe(H2O)n, n = 1-2) near the origin band of the S0-S1 transition. The R2PICD spectra of Phe exhibit well-resolved CD bands of six different conformers present in the jet, which vary in sign and magnitude depending on their conformations. We revised the previous structural assignments of the Phe conformers based on the comparison between the experimental and theoretical CD signs, infrared spectra, and rotational band contours. The R2PICD spectra of Phe(H2O)n reveal that hydration with one or two water molecule(s) does not affect the CD signs of Phe conformers but significantly increases their CD magnitudes. Furthermore, conformational selection by solvation alters relative populations of Phe conformers, leading to a sign inversion in the CD spectra of Phe(H2O)n compared with that of Phe monomer.
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Affiliation(s)
- Aram Hong
- Department of Chemistry, Chungbuk National University , Chungbuk 28644, Korea
| | - Heeseon Jang
- Department of Chemistry, Chungbuk National University , Chungbuk 28644, Korea
| | - Changseop Jeong
- Department of Chemistry, Chungbuk National University , Chungbuk 28644, Korea
| | - Myoung Choul Choi
- Mass Spectrometry & Advanced Instrument Group, Korea Basic Science Institute , Ochang Center, Chungbuk 28119, Korea
| | - Jiyoung Heo
- Department of Biomedical Technology, Sangmyung University , Chungnam 31066, Korea
| | - Nam Joon Kim
- Department of Chemistry, Chungbuk National University , Chungbuk 28644, Korea
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25
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Boesl U, Kartouzian A. Mass-Selective Chiral Analysis. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2016; 9:343-364. [PMID: 27070181 DOI: 10.1146/annurev-anchem-071015-041658] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Three ways of realizing mass-selective chiral analysis are reviewed. The first is based on the formation of diastereomers that are of homo- and hetero- type with respect to the enantiomers of involved chiral molecules. This way is quite well-established with numerous applications. The other two ways are more recent developments, both based on circular dichroism (CD). In one, conventional or nonlinear electronic CD is linked to mass spectrometry (MS) by resonance-enhanced multiphoton ionization. The other is based on CD in the angular distribution of photoelectrons, which is measured in combination with MS via photoion photoelectron coincidence. Among the many important applications of mass-selective chiral analysis, this review focuses on its use as an analytical tool for the development of heterogeneous enantioselective chemical catalysis. There exist other approaches to combine chiral analysis and mass-selective detection, such as chiral chromatography MS, which are not discussed here.
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Affiliation(s)
- Ulrich Boesl
- Department of Chemistry, Technische Universität München, 85747 Garching, Germany; ,
| | - Aras Kartouzian
- Department of Chemistry, Technische Universität München, 85747 Garching, Germany; ,
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26
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Hong A, Jeong C, Jang H, Choi MC, Heo J, Kim NJ. Fluorescence-detected circular dichroism spectroscopy of jet-cooled ephedrine. Phys Chem Chem Phys 2016; 18:7762-7. [PMID: 26910410 DOI: 10.1039/c5cp07438j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The resonant two-photon ionization circular dichroism (R2PICD) spectrum represents the cumulative circular dichroism (CD) of one-photon excitation and the subsequent one-photon ionization, whereas the fluorescence-detected circular dichroism (FDCD) spectra exhibit only the CD of one-photon excitation, similar to conventional CD spectra. We obtained the FDCD spectra of jet-cooled ephedrine (EPD) near the origin band of the S0-S1 transition to measure the CD of one-photon absorption and thus the CD of the ionization process in R2PI in comparison with the R2PICD spectra. The CD effects of the ionization following excitation of the A (0-0) and C (930 cm(-1)) bands in the spectrum are small, whereas those of the B band (530 cm(-1)) are anomalously large, leading to opposite CD signs for the FDCD and R2PICD spectra. Based on the intermediate state-selective fragmentation patterns in the R2PI spectra, this large CD effect is attributed to the state-selective isomerization that occurs after excitation of the B band. By comparing the experimental and theoretical spectra, we determined that the B band corresponds to an asymmetric ring distortion mode that involves torsional motions of the side chain, which may facilitate the isomerization process. This study demonstrates that FDCD spectroscopy combined with R2PICD spectroscopy provides a powerful tool to measure the CD effects of the excitation and ionization processes separately in R2PI and thus probe the structural changes that occur during the ionization process following excitation to an intermediate state.
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Affiliation(s)
- Aram Hong
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea.
| | - Changseop Jeong
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea.
| | - Heeseon Jang
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea.
| | - Myoung Choul Choi
- Mass Spectrometry & Advanced Instrument Group, Korea Basic Science Institute, Ochang Center, Chungbuk 28119, Korea
| | - Jiyoung Heo
- Department of Biomedical Technology, Sangmyung University, Chungnam 31066, Korea.
| | - Nam Joon Kim
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea.
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27
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Kröner D, Gaebel T. Circular Dichroism in Mass Spectrometry: Quantum Chemical Investigations for the Differences between (R)-3-Methylcyclopentanone and Its Cation. J Phys Chem A 2015. [PMID: 26214257 DOI: 10.1021/acs.jpca.5b05247] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In mass spectrometry enantiomers can be distinguished by multiphoton ionization employing circular polarized laser pulses. The circular dichroism (CD) is detected from the normalized difference in the ion yield after excitation with light of opposite handedness. While there are cases in which fragment and parent ions exhibit the same sign of the CD in the ion yield, several experiments show that they might also differ in sign and magnitude. Supported by experimental observations it has been proposed that the parent ion, once it has been formed, is further excited by the laser, which may result in a change of the CD in the ion yield of the formed fragments compared to the parent ion. To gain a deeper insight in possible excitation pathways we calculated and compared the electronic CD absorption spectra of neutral and cationic (R)-3-methylcyclopentanone, applying density functional theory. In addition, electron wavepacket dynamics were used to compare the CD of one- and two-photon transitions. Our results support the proposed subsequent excitation of the parent ion as a possible origin of the difference of the CD in the ion yield between parent ion and fragments.
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28
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Kröner D. Laser-driven electron dynamics for circular dichroism in mass spectrometry: from one-photon excitations to multiphoton ionization. Phys Chem Chem Phys 2015; 17:19643-55. [PMID: 26151731 DOI: 10.1039/c5cp02193f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The distinction of enantiomers is a key aspect of chemical analysis. In mass spectrometry the distinction of enantiomers has been achieved by ionizing the sample with circularly polarized laser pulses and comparing the ion yields for light of opposite handedness. While resonant excitation conditions are expected to be most efficient, they are not required for the detection of a circular dichroism (CD) in the ion yield. However, the prediction of the size and sign of the circular dichroism becomes challenging if non-resonant multiphoton excitations are used to ionize the sample. Employing femtosecond laser pulses to drive electron wavepacket dynamics based on ab initio calculations, we attempt to reveal underlying mechanisms that determine the CD under non-resonant excitation conditions. Simulations were done for (R)-1,2-propylene oxide, using time-dependent configuration interaction singles with perturbative doubles (TD-CIS(D)) and the aug-cc-pVTZ basis set. Interactions between the electric field and the electric dipole and quadrupole as well as between the magnetic field and the magnetic dipole were explicitly accounted for. The ion yield was determined by treating states above the ionization potential as either stationary or non-stationary with energy-dependent lifetimes based on an approved heuristic approach. The observed population dynamics do not allow for a simple interpretation, because of highly non-linear interactions. Still, the various transition pathways are governed by resonant enantiospecific n-photon excitation, with preferably high transition dipole moments, which eventually dominate the CD in the ionized population.
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Affiliation(s)
- Dominik Kröner
- Chemistry Department - Theoretical Chemistry, Universität Potsdam, Karl-Liebknecht-Straße 24-25, D-14476 Potsdam, Germany.
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29
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Fanood MMR, Ram NB, Lehmann CS, Powis I, Janssen MHM. Enantiomer-specific analysis of multi-component mixtures by correlated electron imaging-ion mass spectrometry. Nat Commun 2015; 6:7511. [PMID: 26104140 PMCID: PMC4491818 DOI: 10.1038/ncomms8511] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 05/14/2015] [Indexed: 11/09/2022] Open
Abstract
Simultaneous, enantiomer-specific identification of chiral molecules in multi-component mixtures is extremely challenging. Many established techniques for single-component analysis fail to provide selectivity in multi-component mixtures and lack sensitivity for dilute samples. Here we show how enantiomers may be differentiated by mass-selected photoelectron circular dichroism using an electron-ion coincidence imaging spectrometer. As proof of concept, vapours containing ∼1% of two chiral monoterpene molecules, limonene and camphor, are irradiated by a circularly polarized femtosecond laser, resulting in multiphoton near-threshold ionization with little molecular fragmentation. Large chiral asymmetries (2-4%) are observed in the mass-tagged photoelectron angular distributions. These asymmetries switch sign according to the handedness (R- or S-) of the enantiomer in the mixture and scale with enantiomeric excess of a component. The results demonstrate that mass spectrometric identification of mixtures of chiral molecules and quantitative determination of enantiomeric excess can be achieved in a table-top instrument.
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Affiliation(s)
- Mohammad M Rafiee Fanood
- LaserLaB Amsterdam and Department of Physics and Astronomy, VU University Amsterdam, De Boelelaan 1081, Amsterdam 1081 HV, The Netherlands
| | - N Bhargava Ram
- LaserLaB Amsterdam and Department of Physics and Astronomy, VU University Amsterdam, De Boelelaan 1081, Amsterdam 1081 HV, The Netherlands
| | - C Stefan Lehmann
- LaserLaB Amsterdam and Department of Physics and Astronomy, VU University Amsterdam, De Boelelaan 1081, Amsterdam 1081 HV, The Netherlands
| | - Ivan Powis
- School of Chemistry, University Park, University of Nottingham, Nottingham NG7 2RD, UK
| | - Maurice H M Janssen
- LaserLaB Amsterdam and Department of Physics and Astronomy, VU University Amsterdam, De Boelelaan 1081, Amsterdam 1081 HV, The Netherlands
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30
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Photoelectron Circular Dichroism of Bicyclic Ketones from Multiphoton Ionization with Femtosecond Laser Pulses. Chemphyschem 2014; 16:115-37. [DOI: 10.1002/cphc.201402643] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Indexed: 11/07/2022]
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31
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Rafiee Fanood MM, Powis I, Janssen MHM. Chiral Asymmetry in the Multiphoton Ionization of Methyloxirane Using Femtosecond Electron–Ion Coincidence Imaging. J Phys Chem A 2014; 118:11541-6. [DOI: 10.1021/jp5113125] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Ivan Powis
- School
of Chemistry, University of Nottingham, Nottingham NG7 2RD, U.K
| | - Maurice H. M. Janssen
- LaserLaB
Amsterdam, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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32
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Titze K, Zollitsch T, Heiz U, Boesl U. Laser mass spectrometry with circularly polarized light: circular dichroism of cold molecules in a supersonic gas beam. Chemphyschem 2014; 15:2762-7. [PMID: 25044352 DOI: 10.1002/cphc.201402270] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Indexed: 11/12/2022]
Abstract
An experiment on chiral molecules that combines circular dichroism (CD) spectroscopy, mass-selective detection by laser mass spectrometry (MS), and cooling of molecules by using a supersonic beam is presented. The combination of the former two techniques (CD-laser-MS) is a new method to investigate chiral molecules and is now used by several research groups. Cooling in a supersonic beam supplies a substantial increase in spectroscopic resolution, a feature that has not yet been used in CD spectroscopy. In the experiments reported herein, a large variation in the electronic CD of carbonyl 3-methylcyclopentanone was observed depending on the excited vibrational modes in the n → π* transition. This finding should be of interest for the detection of chiral molecules and for the theoretical understanding of the CD of vibronic bands. It is expected that this effect will show up in other chiral carbonyls because the n → π* transition is typical for the carbonyl group.
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Affiliation(s)
- Katharina Titze
- Chemistry Department, Physical Chemistry Chair, Technische Universität München, Lichtenbergstr. 4, 85748 Garching (Germany), Fax: (+49) 89 289 13389
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33
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Hong A, Choi CM, Eun HJ, Jeong C, Heo J, Kim NJ. Conformation-Specific Circular Dichroism Spectroscopy of Cold, Isolated Chiral Molecules. Angew Chem Int Ed Engl 2014; 53:7805-8. [DOI: 10.1002/anie.201403916] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Indexed: 11/08/2022]
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34
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Hong A, Choi CM, Eun HJ, Jeong C, Heo J, Kim NJ. Conformation-Specific Circular Dichroism Spectroscopy of Cold, Isolated Chiral Molecules. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201403916] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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35
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Patterson D, Schnell M. New studies on molecular chirality in the gas phase: enantiomer differentiation and determination of enantiomeric excess. Phys Chem Chem Phys 2014; 16:11114-23. [DOI: 10.1039/c4cp00417e] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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36
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Turchini S, Catone D, Zema N, Contini G, Prosperi T, Decleva P, Stener M, Rondino F, Piccirillo S, Prince KC, Speranza M. Conformational Sensitivity in Photoelectron Circular Dichroism of 3-Methylcyclopentanone. Chemphyschem 2013; 14:1723-32. [DOI: 10.1002/cphc.201200975] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 02/13/2013] [Indexed: 11/08/2022]
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37
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Wollenhaupt M, Lux C, Krug M, Baumert T. Tomographic Reconstruction of Designer Free-Electron Wave Packets. Chemphyschem 2013; 14:1341-9. [DOI: 10.1002/cphc.201200968] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Indexed: 11/07/2022]
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38
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Resonance-enhanced multiphoton ionization with circularly polarized light: chiral carbonyls. Anal Bioanal Chem 2013; 405:6913-24. [DOI: 10.1007/s00216-012-6666-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 12/11/2012] [Accepted: 12/13/2012] [Indexed: 10/27/2022]
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39
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Logé C, Boesl U. Laser Mass Spectrometry with Circularly Polarized Light: Circular Dichroism of Molecular Ions. Chemphyschem 2012; 13:4218-23. [DOI: 10.1002/cphc.201200614] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 10/02/2012] [Indexed: 11/09/2022]
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40
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Horsch P, Urbasch G, Weitzel KM. Analysis of Chirality by Femtosecond Laser Ionization Mass Spectrometry. Chirality 2012; 24:684-90. [DOI: 10.1002/chir.22037] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Accepted: 02/15/2012] [Indexed: 01/05/2023]
Affiliation(s)
- Philipp Horsch
- Philipps-Universität Marburg; Fachbereich Chemie; Hans-Meerweinstraβe; Marburg; Germany
| | - Gunter Urbasch
- Philipps-Universität Marburg; Fachbereich Chemie; Hans-Meerweinstraβe; Marburg; Germany
| | - Karl-Michael Weitzel
- Philipps-Universität Marburg; Fachbereich Chemie; Hans-Meerweinstraβe; Marburg; Germany
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41
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Logé C, Boesl U. Laser mass spectrometry with circularly polarized light: two-photon circular dichroism. Phys Chem Chem Phys 2012; 14:11981-9. [DOI: 10.1039/c2cp41405h] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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42
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Kröner D. Chiral distinction by ultrashort laser pulses: electron wavepacket dynamics incorporating magnetic interactions. J Phys Chem A 2011; 115:14510-8. [PMID: 22010997 DOI: 10.1021/jp207270s] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The qualitative and quantitative distinction of enantiomers is one of the key issues in chemical analysis. In the last years, circular dichroism (CD) has been combined with laser ionization mass spectrometry (LIMS), applying resonance enhanced multiphoton ionization (REMPI) with ultrashort laser pulses. We present theoretical investigations on the CD in the populations of the first electronic excited state of the REMPI process, caused by the interaction of 3-methyl-cyclopentanone with either left or right circular polarized fs-laser pulses. For this we performed multistate laser driven many electron dynamics based on ab initio electronic structure calculations, namely, TD-CIS(D)/6-311++(2d,2p). For a theoretical description of these experiments, a complete description of the field-dipole correlation is mandatory, including both electric field-electric dipole and magnetic field-magnetic dipole interactions. The effect of various pulse parameters on the CD are analyzed and compared with experimental results to gain further understanding of the key elements for an optimal distinction of enantiomers.
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Affiliation(s)
- Dominik Kröner
- Chemistry Department-Theoretical Chemistry, Universität Potsdam, Potsdam, Germany.
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Rizzo A, Vahtras O. Ab initio study of excited state electronic circular dichroism. Two prototype cases: Methyl oxirane and R-(+)-1,1′-bi(2-naphthol). J Chem Phys 2011; 134:244109. [DOI: 10.1063/1.3602219] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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Logé C, Boesl U. Multiphoton Ionization and Circular Dichroism: New Experimental Approach and Application to Natural Products. Chemphyschem 2011; 12:1940-7. [DOI: 10.1002/cphc.201100035] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Indexed: 11/09/2022]
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Hernández FE, Rizzo A. Two-photon polarization dependent spectroscopy in chirality: a novel experimental-theoretical approach to study optically active systems. Molecules 2011; 16:3315-37. [PMID: 21512440 PMCID: PMC6260626 DOI: 10.3390/molecules16043315] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 04/07/2011] [Accepted: 04/12/2011] [Indexed: 11/16/2022] Open
Abstract
Many phenomena, including life itself and its biochemical foundations are fundamentally rooted in chirality. Combinatorial methodologies for catalyst discovery and optimization remain an invaluable tool for gaining access to enantiomerically pure compounds in the development of pharmaceuticals, agrochemicals, and flavors. Some exotic metamaterials exhibiting negative refractive index at optical frequencies are based on chiral structures. Chiroptical activity is commonly quantified in terms of circular dichroism (CD) and optical rotatory dispersion (ORD). However, the linear nature of these effects limits their application in the far and near-UV region in highly absorbing and scattering biological systems. In order to surmount this barrier, in recent years we made important advancements on a novel non linear, low-scatter, long-wavelength CD approach called two-photon absorption circular dichroism (TPACD). Herein we present a descriptive analysis of the optics principles behind the experimental measurement of TPACD, i.e., the double L-scan technique, and its significance using pulsed lasers. We also make an instructive examination and discuss the reliability of our theoretical-computational approach, which uses modern analytical response theory, within a Time-Dependent Density Functional Theory (TD-DFT) approach. In order to illustrate the potential of this novel spectroscopic tool, we first present the experimental and theoretical results obtained in C(2)-symmetric, axially chiral R-(+)-1,1'-bi(2-naphthol), R-BINOL, a molecule studied at the beginning of our investigation in this field. Next, we reveal some preliminary results obtained for (R)-3,3'-diphenyl-2,2'-bi-1-naphthol, R-VANOL, and (R)-2,2'-diphenyl-3,3'-(4-biphenanthrol), R-VAPOL. This family of optically active compounds has been proven to be a suitable model for the structure-property relationship study of TPACD, because its members are highly conjugated yet photo-stable, and easily derivatized at the 5- and 6-positions. With the publication of these outcomes we hope to motivate more members of the scientist community to engage in state-of-the-art TPACD spectroscopy.
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Affiliation(s)
- Florencio E. Hernández
- Department of Chemistry, University of Central Florida, P. O. Box 162366, Orlando, FL 382616, USA
- The College of Optics and Photonics, CREOL University of Central Florida, P. O. Box 162366, Orlando, FL 382616, USA
| | - Antonio Rizzo
- Consiglio Nazionale delle Ricerche (CNR), Istituto per i Processi Chimico Fisici (IPCF-CNR), UoS di Pisa, Area della Ricerca, Via G. Moruzzi 1, I-56124 Pisa, Italy
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Horsch P, Urbasch G, Weitzel KM. Circular Dichroism in Ion Yields in Multiphoton Ionization of (R)-Propylene Oxide Employing Femtosecond Laser Pulses. Z PHYS CHEM 2011. [DOI: 10.1524/zpch.2011.0103] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract
The feasibility of measuring circular dichroism (CD) in ion yields is demonstrated in multiphoton ionization employing femtosecond laser radiation for the first time. CD values for (R)-propylene oxide are reported at 738 nm, 810 nm and 878 nm. The data suggest the possibility of resonance contributions at 810 nm. At the other wavelengths the CD appears to originate from non-resonant multiphoton ionization. Possible implications of measuring non-resonant CD are discussed.
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Affiliation(s)
- Philipp Horsch
- Philipps-Universität Marburg, Fachbereich Chemie, Marburg, Deutschland
| | - Gunter Urbasch
- Philipps-Universität Marburg, Fachbereich Chemie, Marburg, Deutschland
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Horsch P, Urbasch G, Weitzel KM, Kröner D. Circular dichroism in ion yields employing femtosecond laser ionization—the role of laser pulse duration. Phys Chem Chem Phys 2011; 13:2378-86. [DOI: 10.1039/c0cp01903h] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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48
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Toro C, De Boni L, Lin N, Santoro F, Rizzo A, Hernandez F. Two-Photon Absorption Circular Dichroism: A New Twist in Nonlinear Spectroscopy. Chemistry 2010; 16:3504-9. [DOI: 10.1002/chem.200902286] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Progress in circular dichroism laser mass spectrometry. Anal Bioanal Chem 2009; 395:1631-9. [PMID: 19636544 DOI: 10.1007/s00216-009-2956-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Revised: 06/26/2009] [Accepted: 07/06/2009] [Indexed: 10/20/2022]
Abstract
Circular dichroism in ion yield has promising new potentials for chiral analysis. Our progress of its development is described here. Circular dichroism in ion yield is achieved by resonance-enhanced multiphoton ionization. The feasibility of circular dichroism spectroscopy and quantitative determination of circular dichroism by this method is demonstrated. Several excitation schemes have been applied using different types of lasers, which vary in wavelength and repetition rate. Progress to improve the statistical error and thus the lower limit of measurable circular dichroism is described. This is achieved by adding achiral compounds or racemic mixtures of chiral compounds to the sample gas as reference substances and ionizing them by the same laser pulse. Therefore, in the mass spectrum of every single laser pulse, ion signals of sample and reference species appear both being subject to the same kind of instrumental fluctuations (in particular of laser pulse energy). In another approach, a laser repetition rate of 200 Hz allowed averaging of large numbers of laser pulses.
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Breunig HG, Urbasch G, Horsch P, Cordes J, Koert U, Weitzel KM. Circular Dichroism in Ion Yields of Femtosecond-Laser Mass Spectrometry. Chemphyschem 2009; 10:1199-202. [DOI: 10.1002/cphc.200900103] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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