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Auvil NC, Bier ME. Nanoelectrode Atmospheric Pressure Chemical Ionization Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024. [PMID: 38917028 DOI: 10.1021/jasms.4c00117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/27/2024]
Abstract
A small ionization needle with an ultrasharp, ultrafine tip is introduced. It is lab-fabricated from tungsten wire and serves as a corona discharge emitter in nanoelectrode atmospheric pressure chemical ionization mass spectrometry (nAPCI-MS). Tip radii ranged from 8 to 44 nm, up to 44× smaller than the sharpest previously reported corona needle. Because of this, nAPCI was able to operate at +1.0 kV with no auxiliary counter electrode. Alternatively, at +1.2 kV, nAPCI could be enclosed in a small plastic assembly for headspace analysis with a sampling tube attachment as long as 15 m. No added heat or gas flow was necessary. The efficacy of nAPCI-MS was demonstrated through needle durability studies and direct analysis of vapors from real-world samples. Provisional identifications include ibuprofen from a pharmaceutical tablet, albuterol aerosol sprayed from a medical inhaler, cocaine from paper currency, caffeine from a fingertip, and bisphenol E from a paper receipt.
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Affiliation(s)
- Nicole C Auvil
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Mark E Bier
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
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2
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Calderón-Santoyo M, Calderón-Chiu C, Ragazzo-Calderón FZ, Barros-Castillo JC, Ragazzo-Sánchez JA. Mexican Coccoloba uvifera L. Leaf and Fruit Extracts: Identification of Pentacyclic Triterpenes and Volatile Profile by GC-MS. PLANT FOODS FOR HUMAN NUTRITION (DORDRECHT, NETHERLANDS) 2024:10.1007/s11130-024-01186-7. [PMID: 38795268 DOI: 10.1007/s11130-024-01186-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/23/2024] [Indexed: 05/27/2024]
Abstract
Mexican Coccoloba uvifera fruit contains polyphenols, flavonoids, and anthocyanins, while in the leaves, lupeol, α- and β-amyrin have been previously identified by HPLC. However, the low resolution by HPLC of pentacyclic triterpenes (PTs) is a limitation. Moreover, the volatile profile of C. uvifera fruit is still unknown. Therefore, this study aimed to identify PTs in C. uvifera leaf and fruit extracts by CG-MS analysis and to determine the volatile profile of C. uvifera pulp by headspace solid-phase microextraction. The results showed trimethylsilylated compounds of standards lupeol, α- and β-amyrin, indicating that the silylation reaction was suitable. These trimethylsilylated compounds were identified in leaf and fruit extracts. The fruit volatile profile revealed the presence of 278 esters, 20 terpenes, 9 aldehydes, 5 alcohols, and 4 ketones. The fruit showed a high content of esters and terpenes. Due to their flavour properties, esters are essential for the food, cosmetics, and pharmaceutics industries. Moreover, terpenes in the fruit, such as menthone, β-elemene, junipene, and β-caryophyllene have the potential as anticancer and phytopathogen agents. The results indicated that GC-MS is an alternative to HPLC approaches for identifying PTs. Besides, identifying volatile compounds in the fruit will increase the value of this plant and expand its application. Identifying PTs and volatile compounds in Mexican C. uvifera leads to a better understanding of the potential benefits of this plant. This would increase the consumption of Mexican C. uvifera fresh or as functional ingredients in nutraceutical or pharmaceutical products.
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Affiliation(s)
- Montserrat Calderón-Santoyo
- Laboratorio Integral de Investigación en Alimentos, Tecnológico Nacional de México, Instituto Tecnológico de Tepic, Tepic, Nayarit, México
| | - Carolina Calderón-Chiu
- Laboratorio Integral de Investigación en Alimentos, Tecnológico Nacional de México, Instituto Tecnológico de Tepic, Tepic, Nayarit, México
| | - Frida Zoé Ragazzo-Calderón
- Laboratorio Integral de Investigación en Alimentos, Tecnológico Nacional de México, Instituto Tecnológico de Tepic, Tepic, Nayarit, México
| | - Julio César Barros-Castillo
- Laboratorio Integral de Investigación en Alimentos, Tecnológico Nacional de México, Instituto Tecnológico de Tepic, Tepic, Nayarit, México
| | - Juan Arturo Ragazzo-Sánchez
- Laboratorio Integral de Investigación en Alimentos, Tecnológico Nacional de México, Instituto Tecnológico de Tepic, Tepic, Nayarit, México.
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Menthol and Fatty Acid-Based Hydrophobic Deep Eutectic Solvents as Media for Enzyme Activation. Processes (Basel) 2023. [DOI: 10.3390/pr11020547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
This research aims to provide insights into the biological efficacy of a newly formed hydrophobic deep eutectic solvent (DES). A DES based on menthol was successfully synthesized with fatty acids. The DESs’ properties as enzyme activators were examined against a neat counterpart. The menthol:decanoic acid (1:1) combination showed improved thermal stability, strong catalytic activity, and reusability for up to four subsequent cycles under ideal conditions (pH 7.0, 40 °C for 2 h). The hydrophobic DES replaced hexane in ester synthesis, where RNL@DES5 showed better fatty acid conversion compared to neat RNL. This study demonstrated promising applications of hydrophobic DESs in non-aqueous organic reactions.
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4
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Triptow J, Meijer G, Fielicke A, Dopfer O, Green M. Comparison of Conventional and Nonconventional Hydrogen Bond Donors in Au - Complexes. J Phys Chem A 2022; 126:3880-3892. [PMID: 35687835 PMCID: PMC9234979 DOI: 10.1021/acs.jpca.2c02725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Although gold has become a well-known nonconventional hydrogen bond acceptor, interactions with nonconventional hydrogen bond donors have been largely overlooked. In order to provide a better understanding of these interactions, two conventional hydrogen bonding molecules (3-hydroxytetrahydrofuran and alaninol) and two nonconventional hydrogen bonding molecules (fenchone and menthone) were selected to form gas-phase complexes with Au-. The Au-[M] complexes were investigated using anion photoelectron spectroscopy and density functional theory. Au-[fenchone], Au-[menthone], Au-[3-hydroxyTHF], and Au-[alaninol] were found to have vertical detachment energies of 2.71 ± 0.05, 2.76 ± 0.05, 3.01 ± 0.03, and 3.02 ± 0.03 eV, respectively, which agree well with theory. The photoelectron spectra of the complexes resemble the spectrum of Au- but are blueshifted due to the electron transfer from Au- to M. With density functional theory, natural bond orbital analysis, and atoms-in-molecules analysis, we were able to extend our comparison of conventional and nonconventional hydrogen bonding to include geometric and electronic similarities. In Au-[3-hydroxyTHF] and Au-[alaninol], the hydrogen bonding comprised of Au-···HO as a strong, primary hydrogen bond, with secondary stabilization by weaker Au-···HN or Au-···HC hydrogen bonds. Interestingly, the Au-···HC bonds in Au-[fenchone] and Au-[menthone] can be characterized as hydrogen bonds, despite their classification as nonconventional hydrogen bond donors.
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Affiliation(s)
- Jenny Triptow
- Fritz-Haber-Institut der Max-Planck Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.,Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
| | - Gerard Meijer
- Fritz-Haber-Institut der Max-Planck Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - André Fielicke
- Fritz-Haber-Institut der Max-Planck Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.,Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
| | - Otto Dopfer
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
| | - Mallory Green
- Fritz-Haber-Institut der Max-Planck Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
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5
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A Scent of Peppermint—A Microwave Spectroscopy Analysis on the Composition of Peppermint Oil. Symmetry (Basel) 2022. [DOI: 10.3390/sym14061262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Essential oils have a vast number of applications in different areas of our daily life. Detailed chiral analysis and structural characterization of their constituents remains an important subject in analytical chemistry. Here, we report on a broadband rotational spectroscopy study of peppermint oil in the frequency range 2–8 GHz. We focus on an unambiguous determination of the excess enantiomers of the oil constituents menthone and isomenthone in the oil by applying chirality-sensitive rotational spectroscopy, the so-called microwave three-wave mixing (M3WM) technique. Additionally, a new menthol conformer, not previously characterized, was experimentally observed, and the gas-phase structures of the two conformers of menthol and menthone were determined experimentally based on the assignment of their 13C-isotopologues in natural abundance.
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Chiral Analysis of Linalool, an Important Natural Fragrance and Flavor Compound, by Molecular Rotational Resonance Spectroscopy. Symmetry (Basel) 2022. [DOI: 10.3390/sym14050917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The chiral analysis of terpenes in complex mixtures of essential oils, necessary for authentication, has been further developed using chiral tagging molecular rotational resonance (MRR) spectroscopy. One analyte that is of particular interest is linalool (3,7-dimethyl-1,6-octadien-3-ol), a common natural chiral terpene found in botanicals with its enantiomers having unique flavor, fragrance, and aromatherapy characteristics. In this MRR demonstration, resolution of the enantiomers is achieved through the addition of a chiral tag, which creates non-covalent diastereomeric complexes with distinct spectral signatures. The relative stereochemistry of the complexes is identified by the comparison of calculated spectroscopic parameters with experimentally determined parameters of the chiral complexes with high accuracy. The diastereomeric complex intensities are analyzed to determine the absolute configuration (AC) and enantiomeric excess (EE) in each sample. Here, we demonstrate the use of chiral tagging MRR spectroscopy to perform a quantitative routine enantiomer analysis of linalool in complex essential oil mixtures, without the need for reference samples or chromatographic separation.
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Buschmann P, Lengsfeld KG, Djahandideh J, Grabow JU. From rotational resolved spectra to an extended increment system of planar moments allowing ad-hoc conformational identification – Exemplification by the broadband microwave spectrum of α-hydroxyisobutyric acid. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2021.131805] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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9
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Singh H, Pinacho P, Obenchain DA, Quesada-Moreno MM, Schnell M. The many forms of alpha-methoxy phenylacetic acid in the gas phase: flexibility, internal dynamics, and their intramolecular interactions. Phys Chem Chem Phys 2022; 24:27312-27320. [DOI: 10.1039/d2cp03962a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Five conformers of the flexible molecule alpha-methoxy phenylacetic acid were identified using rotational spectroscopy. The conformational landscape, internal dynamics, and intramolecular interactions were investigated.
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Affiliation(s)
- Himanshi Singh
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
- Institute of Physical Chemistry, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Str. 1, 24118 Kiel, Germany
| | - Pablo Pinacho
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Daniel A. Obenchain
- Institut fur Physikalische Chemie, Universität Göttingen, Tammannstr. 6, 37077 Göttingen, Germany
| | - María Mar Quesada-Moreno
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva s/n, 18071 Granada, Spain
| | - Melanie Schnell
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
- Institute of Physical Chemistry, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Str. 1, 24118 Kiel, Germany
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10
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Wang G. Ligand-stereoselective allosteric activation of cold-sensing TRPM8 channels by an H-bonded homochiral menthol dimer with head-to-head or head-to-tail. Chirality 2021; 33:783-796. [PMID: 34596287 DOI: 10.1002/chir.23364] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 09/01/2021] [Accepted: 09/02/2021] [Indexed: 11/07/2022]
Abstract
Both menthol and its analog WS-12 share the same hydrophobic intra-subunit binding pocket between a voltage-sensor-like domain and a TRP domain in a cold-sensing TRPM8 channel. However, unlike WS-12, menthol upregulates TRPM8 with a low efficacy but a high coefficient of a dose response at membrane hyperpolarization and with ligand stereoselectivity at membrane depolarization. The underlying mechanisms are unknown. Here, this in silico research suggested that the ligand-stereoselective sequential cooperativity between two menthol molecules in the WS-12 pocket is required for allosteric activation of TRPM8. Furthermore, two H-bonded homochiral menthol dimers with both head-to-head and head-to-tail can compete for the WS-12 site via non-covalent interactions. Although both dimers can form an H-bonding network with a voltage sensor S4 to disrupt a S3-S4 salt bridge in the voltage-sensor-like domain to release a "parking brake," only one dimer may drive channel opening by pushing a "gas pedal" in the TRP domain away from the S6 gate against S4. In this way, the efficacy is decreased, but the cooperativity is increased for the menthol effect at membrane hyperpolarization. Therefore, this review may extend a new pathway for ligand-stereoselective allosteric regulation of other voltage- and ligand-gated ion channels by menthol.
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Affiliation(s)
- Guangyu Wang
- Department of Drug Research and Development, Institute of Biophysical Medico-chemistry, Reno, NV, USA
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11
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Testing the Scalability of the HS-AUTOFIT Tool in a High-Performance Computing Environment. ELECTRONICS 2021. [DOI: 10.3390/electronics10182251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In the last years, the development of broadband chirped-pulse Fourier transform microwave spectrometers has revolutionized the field of rotational spectroscopy. Currently, it is possible to experimentally obtain a large quantity of spectra that would be difficult to analyze manually due to two main reasons. First, recent instruments allow obtaining a considerable amount of data in very short times, and second, it is possible to analyze complex mixtures of molecules that all contribute to the density of the spectra. AUTOFIT is a spectral assignment software application that was developed in 2013 to support and facilitate the analysis. Notwithstanding the benefits AUTOFIT brings in terms of automation of the analysis of the accumulated data, it still does not guarantee a good performance in terms of execution time because it leverages the computing power of a single computing machine. To cater to this requirement, we developed a parallel version of AUTOFIT, called HS-AUTOFIT, capable of running on high-performance computing (HPC) clusters to shorten the time to explore and analyze spectral big data. In this paper, we report some tests conducted on a real HPC cluster aimed at providing a quantitative assessment of HS-AUTOFIT’s scaling capabilities in a multi-node computing context. The collected results demonstrate the benefits of the proposed approach in terms of a significant reduction in computing time.
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12
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Medel R, Suhm MA. Predicting OH stretching fundamental wavenumbers of alcohols for conformational assignment: different correction patterns for density functional and wave-function-based methods. Phys Chem Chem Phys 2021; 23:5629-5643. [PMID: 33656038 DOI: 10.1039/d1cp00342a] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A model is presented for the prediction of OH stretching fundamental wavenumbers of alcohol conformers in the gas phase by application of a small set of empirical anharmonicity corrections to calculations in the harmonic approximation. In contrast to the popular application of a uniform scaling factor, the local chemical structure of the alcohol is taken into account to greatly improve accuracy. Interestingly, different correction patterns emerge for results of hybrid density functional (B3LYP-D3 and PBE0-D3) and wave-function-based methods (SCS-LMP2, LCCSD(T*)-F12a and CCSD(T)-F12a 1D). This raises questions about electronic structure deficiencies in these methods and differences in anharmonicity between alcohols. After its initial construction on the basis of literature assignments the model is tested with Raman jet spectroscopy of propargyl alcohol, cyclohexanol, borneol, isopinocampheol and 2-methylbutan-2-ol. For propargyl alcohol a spectral splitting attributed to tunneling is resolved. PBE0-D3 is identified as a well performing and broadly affordable electronic structure method for this model. A mean absolute error of 1.3 cm-1 and a maximum absolute error of 3 cm-1 result for 46 conformers of 24 alcohols in a 60 cm-1 range, when a single parameter is adjusted separately for each alcohol substitution class (methanol, primary, secondary, tertiary).
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Affiliation(s)
- Robert Medel
- Institute of Physical Chemistry, University of Goettingen, Tammannstr. 6, 37077 Goettingen, Germany.
| | - Martin A Suhm
- Institute of Physical Chemistry, University of Goettingen, Tammannstr. 6, 37077 Goettingen, Germany.
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13
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Chrayteh M, Huet TR, Dréan P. Microsolvation of myrtenal studied by microwave spectroscopy highlights the role of quasi-hydrogen bonds in the stabilization of its hydrates. J Chem Phys 2020; 153:104304. [DOI: 10.1063/5.0019957] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Mhamad Chrayteh
- University of Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers, Atomes et Molécules, F-59000 Lille, France
| | - Thérèse R. Huet
- University of Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers, Atomes et Molécules, F-59000 Lille, France
| | - Pascal Dréan
- University of Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers, Atomes et Molécules, F-59000 Lille, France
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14
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Bartolo ND, Read JA, Valentín EM, Woerpel KA. Reactions of Allylmagnesium Reagents with Carbonyl Compounds and Compounds with C═N Double Bonds: Their Diastereoselectivities Generally Cannot Be Analyzed Using the Felkin-Anh and Chelation-Control Models. Chem Rev 2020; 120:1513-1619. [PMID: 31904936 PMCID: PMC7018623 DOI: 10.1021/acs.chemrev.9b00414] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
This review describes the additions of allylmagnesium reagents to carbonyl compounds and to imines, focusing on the differences in reactivity between allylmagnesium halides and other Grignard reagents. In many cases, allylmagnesium reagents either react with low stereoselectivity when other Grignard reagents react with high selectivity, or allylmagnesium reagents react with the opposite stereoselectivity. This review collects hundreds of examples, discusses the origins of stereoselectivities or the lack of stereoselectivity, and evaluates why selectivity may not occur and when it will likely occur.
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Affiliation(s)
- Nicole D. Bartolo
- Department of Chemistry, New York University, 100
Washington Square East, New York, NY 10003, USA
| | - Jacquelyne A. Read
- Department of Chemistry, New York University, 100
Washington Square East, New York, NY 10003, USA
- Department of Chemistry, University of Utah, 315 South 1400
East, Salt Lake City, UT 84112, USA
| | - Elizabeth M. Valentín
- Department of Chemistry, New York University, 100
Washington Square East, New York, NY 10003, USA
- Department of Chemistry, Susquehanna University, 514
University Avenue, Selinsgrove, PA 17870, USA
| | - K. A. Woerpel
- Department of Chemistry, New York University, 100
Washington Square East, New York, NY 10003, USA
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Leibscher M, Giesen TF, Koch CP. Principles of enantio-selective excitation in three-wave mixing spectroscopy of chiral molecules. J Chem Phys 2019; 151:014302. [DOI: 10.1063/1.5097406] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
- Monika Leibscher
- Theoretische Physik, Universität Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Thomas F. Giesen
- Experimentalphysik, Universität Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Christiane P. Koch
- Theoretische Physik, Universität Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
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Yeh L, Satterthwaite L, Patterson D. Automated, context-free assignment of asymmetric rotor microwave spectra. J Chem Phys 2019; 150:204122. [PMID: 31153211 DOI: 10.1063/1.5085794] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
We present a new algorithm, Robust Automated Assignment of Rigid Rotors (RAARR), for assigning rotational spectra of asymmetric tops. The RAARR algorithm can automatically assign experimental spectra under a broad range of conditions, including spectra comprised of multiple mixture components, in ≲100 s. The RAARR algorithm exploits constraints placed by the conservation of energy to find sets of connected lines in an unassigned spectrum. The highly constrained structure of these sets eliminates all but a handful of plausible assignments for a given set, greatly reducing the number of potential assignments that must be evaluated. We successfully apply our algorithm to automatically assign 15 experimental spectra, including 5 previously unassigned species, without prior estimation of molecular rotational constants. In 9 of the 15 cases, the RAARR algorithm successfully assigns two or more mixture components.
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Affiliation(s)
- Lia Yeh
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - Lincoln Satterthwaite
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - David Patterson
- Department of Physics, University of California, Santa Barbara, California 93106, USA
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17
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Riffe EJ, Shipman ST, Gaster SA, Funderburk CM, Brown GG. Rotational Spectrum of Eugenol As Analyzed with Double Resonance and Grid-Based Autofit. J Phys Chem A 2019; 123:1091-1099. [DOI: 10.1021/acs.jpca.8b09169] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Erika J. Riffe
- Division of Natural Sciences, New College of Florida, Sarasota, Florida 34243, United States
| | - Steven T. Shipman
- Division of Natural Sciences, New College of Florida, Sarasota, Florida 34243, United States
| | - Sydney A. Gaster
- Department of Science and Mathematics, Coker College, Hartsville, South Carolina 29550, United States
| | - Cameron M. Funderburk
- Department of Science and Mathematics, Coker College, Hartsville, South Carolina 29550, United States
| | - Gordon G. Brown
- Department of Science and Mathematics, Coker College, Hartsville, South Carolina 29550, United States
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Štejfa V, Bazyleva A, Fulem M, Rohlíček J, Skořepová E, Růžička K, Blokhin AV. Polymorphism and thermophysical properties of L- and DL-menthol. THE JOURNAL OF CHEMICAL THERMODYNAMICS 2019; 131:10.1016/j.jct.2018.11.004. [PMID: 32165766 PMCID: PMC7067000 DOI: 10.1016/j.jct.2018.11.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The thermodynamic properties, phase behavior, and kinetics of polymorphic transformations of racemic (DL-) and enantiopure (L-) menthol were studied using a combination of advanced experimental techniques, including static vapor pressure measurements, adiabatic calorimetry, Tian-Calvet calorimetry, differential scanning calorimetry (DSC), and variable-temperature X-ray powder diffraction. Several concomitant polymorphs (α, β, γ, and δ forms) were observed and studied. A continuous transformation to the stable α form was detected by DSC and monitored in detail using X-ray powder diffraction. A long-term coexistence of the stable crystalline form with the liquid phase was observed. The vapor pressure measurements of both compounds were performed using two static apparatus over a temperature range from 274 K to 363 K. Condensed-phase heat capacities were measured by adiabatic and Tian-Calvet calorimetry in the wide temperature interval from 5 K to 368 K. Experimental data of L- and DL-menthol are compared mutually as well as with available literature results. The thermodynamic functions of crystalline and liquid L-menthol between 0 K and 370 K were calculated from the calorimetric results. The thermodynamic properties in the ideal-gas state were obtained by combining statistical thermodynamics and quantum chemical calculations based on a thorough conformational analysis. Calculated ideal-gas heat capacities and experimental data on vapor pressure and condensed-phase heat capacity were treated simultaneously to obtain a consistent thermodynamic description. Based on the obtained results, the phase diagrams of L-menthol and DL-menthol were suggested.
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Affiliation(s)
- Vojtěch Štejfa
- Department of Physical Chemistry, University of Chemistry and Technology, Prague, Technická 5, CZ-166 28 Prague 6, Czech Republic
| | - Ala Bazyleva
- Applied Chemicals and Materials Division, National Institute of Standards and Technology, Boulder, CO 80305-3337, USA
| | - Michal Fulem
- Department of Physical Chemistry, University of Chemistry and Technology, Prague, Technická 5, CZ-166 28 Prague 6, Czech Republic
| | - Jan Rohlíček
- Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, 182 21 Praha 8, Czech Republic
| | - Eliška Skořepová
- Department of Chemical Engineering, University of Chemistry and Technology Prague, Technická 3, 16628, Prague 6, Czech Republic
| | - Květoslav Růžička
- Department of Physical Chemistry, University of Chemistry and Technology, Prague, Technická 5, CZ-166 28 Prague 6, Czech Republic
| | - Andrey V. Blokhin
- Chemistry Faculty, Belarusian State University, Leningradskaya 14, 220030 Minsk, Belarus
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Lim HW, Kim DH, Kim SH, Lee JM, Chon JW, Song KY, Bae D, Kim J, Kim H, Seo KH. Antimicrobial Effect of Mentha piperita (Peppermint) Oil against Bacillus cereus, Staphylococcus aureus, Cronobacter sakazakii, and Salmonella Enteritidis in Various Dairy Foods: Preliminary Study. ACTA ACUST UNITED AC 2018. [DOI: 10.22424/jmsb.2018.36.3.146] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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20
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Abstract
Chiroptical spectroscopy techniques for the differentiation of enantiomers in the condensed phase are based on an established paradigm that relies on symmetry breaking using circularly polarized light. We review a novel approach for the study of chiral molecules in the gas phase using broadband rotational spectroscopy, namely microwave three-wave mixing, which is a coherent, nonlinear, and resonant process. This technique can be used to generate a coherent molecular rotational signal that can be detected in a manner similar to that in conventional Fourier transform microwave spectroscopy. The structure (and thermal distribution of conformations), handedness, and enantiomeric excess of gas-phase samples can be determined unambiguously by employing tailored microwave fields. We discuss the theoretical and experimental aspects of the method, the significance of the first demonstrations of the technique for enantiomer differentiation, and the method's rapid advance into a robust choice to study molecular chirality in the gas phase. Very recently, the microwave three-wave mixing approach was extended to enantiomer-selective population transfer, an important step toward spatial enantiomer separation on the fly.
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Affiliation(s)
- Sérgio R. Domingos
- Deutsches Elektronen-Synchrotron, 22607 Hamburg, Germany
- Christian-Albrechts-Universität zu Kiel, Institut für Physikalische Chemie, 24118 Kiel, Germany
- Max Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany
| | - Cristóbal Pérez
- Deutsches Elektronen-Synchrotron, 22607 Hamburg, Germany
- Christian-Albrechts-Universität zu Kiel, Institut für Physikalische Chemie, 24118 Kiel, Germany
- Max Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany
| | - Melanie Schnell
- Deutsches Elektronen-Synchrotron, 22607 Hamburg, Germany
- Christian-Albrechts-Universität zu Kiel, Institut für Physikalische Chemie, 24118 Kiel, Germany
- Max Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany
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21
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Domingos SR, Pérez C, Medcraft C, Pinacho P, Schnell M. Flexibility unleashed in acyclic monoterpenes: conformational space of citronellal revealed by broadband rotational spectroscopy. Phys Chem Chem Phys 2018; 18:16682-9. [PMID: 27298210 DOI: 10.1039/c6cp02876d] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Conformational flexibility is intrinsically related to the functionality of biomolecules. Elucidation of the potential energy surface is thus a necessary step towards understanding the mechanisms for molecular recognition such as docking of small organic molecules to larger macromolecular systems. In this work, we use broadband rotational spectroscopy in a molecular jet experiment to unravel the complex conformational space of citronellal. We observe fifteen conformations in the experimental conditions of the molecular jet, the highest number of conformers reported to date for a chiral molecule of this size using microwave spectroscopy. Studies of relative stability using different carrier gases in the supersonic expansion reveal conformational relaxation pathways that strongly favour ground-state structures with globular conformations. This study provides a blueprint of the complex conformational space of an important biosynthetic precursor and gives insights on the relation between its structure and biological functionality.
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Affiliation(s)
- Sérgio R Domingos
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany. and Center for Free-Electron Laser Science, Luruper Chaussee 149, 22761 Hamburg, Germany and The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Cristóbal Pérez
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany. and Center for Free-Electron Laser Science, Luruper Chaussee 149, 22761 Hamburg, Germany and The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Chris Medcraft
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany.
| | - Pablo Pinacho
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany. and Department of Physical Chemistry and Inorganic Chemistry, Universidad de Valladolid, Valladolid, Spain
| | - Melanie Schnell
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany. and Center for Free-Electron Laser Science, Luruper Chaussee 149, 22761 Hamburg, Germany and The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
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22
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Krin A, Pérez C, Pinacho P, Quesada-Moreno MM, López-González JJ, Avilés-Moreno JR, Blanco S, López JC, Schnell M. Structure Determination, Conformational Flexibility, Internal Dynamics, and Chiral Analysis of Pulegone and Its Complex with Water. Chemistry 2017; 24:721-729. [DOI: 10.1002/chem.201704644] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Indexed: 11/10/2022]
Affiliation(s)
- Anna Krin
- Deutsches Elektronen-Synchrotron; Notkestrasse 85 22607 Hamburg Germany
- Max-Planck Institut für Struktur und Dynamik der Materie; Luruper Chaussee 149 22761 Hamburg Germany
- Christian-Albrechts-Universität zu Kiel, Institute of Physical Chemistry; Max-Eyth-Str. 1 24118 Kiel Germany
| | - Cristóbal Pérez
- Deutsches Elektronen-Synchrotron; Notkestrasse 85 22607 Hamburg Germany
- Max-Planck Institut für Struktur und Dynamik der Materie; Luruper Chaussee 149 22761 Hamburg Germany
- Christian-Albrechts-Universität zu Kiel, Institute of Physical Chemistry; Max-Eyth-Str. 1 24118 Kiel Germany
| | - Pablo Pinacho
- Departamento de Química Física y Química Inorgánica; Universidad de Valladolid; Paseo Belen 7 47011 Valladolid Spain
| | - María Mar Quesada-Moreno
- Departamento de Química Física y Analítica; Universidad de Jaén; Campus Las Lagunillas E-23071 Jaen Spain
| | - Juan Jesús López-González
- Departamento de Química Física y Analítica; Universidad de Jaén; Campus Las Lagunillas E-23071 Jaen Spain
| | - Juan Ramón Avilés-Moreno
- Departamento de Sistemas Físicos, Químicos y Naturales; Universidad Pablo de Olavide Sevilla; Carretera de Utrera Km 1 E-41013 Seville Spain
| | - Susana Blanco
- Departamento de Química Física y Química Inorgánica; Universidad de Valladolid; Paseo Belen 7 47011 Valladolid Spain
| | - Juan Carlos López
- Departamento de Química Física y Química Inorgánica; Universidad de Valladolid; Paseo Belen 7 47011 Valladolid Spain
| | - Melanie Schnell
- Deutsches Elektronen-Synchrotron; Notkestrasse 85 22607 Hamburg Germany
- Max-Planck Institut für Struktur und Dynamik der Materie; Luruper Chaussee 149 22761 Hamburg Germany
- Christian-Albrechts-Universität zu Kiel, Institute of Physical Chemistry; Max-Eyth-Str. 1 24118 Kiel Germany
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23
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Loru D, Bermúdez MA, Sanz ME. Structure of fenchone by broadband rotational spectroscopy. J Chem Phys 2017; 145:074311. [PMID: 27544109 DOI: 10.1063/1.4961018] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The bicyclic terpenoid fenchone (C10H16O, 1,3,3-trimethylbicyclo[2.2.1]heptan-2-one) has been investigated by chirped pulse Fourier transform microwave spectroscopy in the 2-8 GHz frequency region. The parent species and all heavy atom isotopologues have been observed in their natural abundance. The experimental rotational constants of all isotopic species observed have been determined and used to obtain the substitution (rs) and effective (r0) structures of fenchone. Calculations at the B3LYP, M06-2X, and MP2 levels of theory with different basis sets were carried out to check their performance against experimental results. The structure of fenchone has been compared with those of norbornane (bicyclo[2.2.1]heptane) and the norbornane derivatives camphor (1,7,7-trimethylbicyclo[2.2.1]heptan-2-one) and camphene (3,3-dimethyl-2-methylenebicyclo[2.2.1]heptane), both with substituents at C2. The structure of fenchone is remarkably similar to those of camphor and camphene. Comparison with camphor allows identification of changes in ∠CCC angles due to the different position of the methyl groups. All norbornane derivatives display similar structural changes with respect to norbornane. These changes mainly affect the bond lengths and angles of the six-membered rings, indicating that the substituent at C2 drives structural adjustments to minimise ring strain after its introduction.
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Affiliation(s)
- Donatella Loru
- Department of Chemistry, King's College London, London SE1 1DB, United Kingdom
| | - Miguel A Bermúdez
- Department of Chemistry, King's College London, London SE1 1DB, United Kingdom
| | - M Eugenia Sanz
- Department of Chemistry, King's College London, London SE1 1DB, United Kingdom
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24
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Loru D, Quesada-Moreno MM, Avilés-Moreno JR, Jarman N, Huet TR, López-González JJ, Sanz ME. Conformational Flexibility of Limonene Oxide Studied By Microwave Spectroscopy. Chemphyschem 2016; 18:274-280. [DOI: 10.1002/cphc.201600991] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 11/17/2016] [Indexed: 01/11/2023]
Affiliation(s)
- Donatella Loru
- Department of Chemistry; King's College London; London United Kingdom
| | - María Mar Quesada-Moreno
- University of Jaen; Department of Physical and Analytical Chemistry; Campus Las Lagunillas E-23071 Jaen Spain
- PhLAM, UMR8523 CNRS-; Université Lille 1; Bâtiment P5 F-59655 Villeneuve D'Ascq Cedex France
| | | | - Natasha Jarman
- Department of Chemistry; King's College London; London United Kingdom
| | - Thérèse R. Huet
- PhLAM, UMR8523 CNRS-; Université Lille 1; Bâtiment P5 F-59655 Villeneuve D'Ascq Cedex France
| | - Juan Jesús López-González
- University of Jaen; Department of Physical and Analytical Chemistry; Campus Las Lagunillas E-23071 Jaen Spain
| | - M. Eugenia Sanz
- Department of Chemistry; King's College London; London United Kingdom
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25
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Calabrese C, Gou Q, Maris A, Melandri S, Caminati W. Conformational Equilibrium and Internal Dynamics of E-Anethole: A Rotational Study. J Phys Chem B 2016; 120:6587-91. [PMID: 27341010 DOI: 10.1021/acs.jpcb.6b04883] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The rotational spectra of the two conformers of E-anethole have been investigated using the free jet broadband millimeter-wave spectroscopic technique combined with theoretical calculations. Anti and syn conformers differ for the relative orientation of the propenyl and methoxy chains, with all heavy atoms coplanar to the benzene ring. Relative intensity measurements prove that the anti form is the global minimum, about 2.0(5) kJ mol(-1) lower in energy with respect to the syn conformer, solving the contrasting results supplied by different theoretical methods. For both conformers, the barriers to internal rotation of the propenyl -CH3 group are low enough to generate fully resolved A-E splittings of the rotational transitions. The corresponding V3 barriers have been determined to be 7.080(5) and 6.978(4) kJ mol(-1), respectively.
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Affiliation(s)
- Camilla Calabrese
- Dipartimento di Chimica "G. Ciamician" dell'Università , Via Selmi 2, I-40126 Bologna, Italy
| | - Qian Gou
- Dipartimento di Chimica "G. Ciamician" dell'Università , Via Selmi 2, I-40126 Bologna, Italy
| | - Assimo Maris
- Dipartimento di Chimica "G. Ciamician" dell'Università , Via Selmi 2, I-40126 Bologna, Italy
| | - Sonia Melandri
- Dipartimento di Chimica "G. Ciamician" dell'Università , Via Selmi 2, I-40126 Bologna, Italy
| | - Walther Caminati
- Dipartimento di Chimica "G. Ciamician" dell'Università , Via Selmi 2, I-40126 Bologna, Italy
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26
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Shubert VA, Schmitz D, Pérez C, Medcraft C, Krin A, Domingos SR, Patterson D, Schnell M. Chiral Analysis Using Broadband Rotational Spectroscopy. J Phys Chem Lett 2016; 7:341-350. [PMID: 26745342 DOI: 10.1021/acs.jpclett.5b02443] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
broadband microwave spectroscopy is a proven tool to precisely determine molecular properties of gas-phase molecules. Recent developments make it applicable to investigate chiral molecules. Enantiomers can be differentiated, and the enantiomeric excess and, indirectly, the absolute configuration can be determined in a molecule-selective manner. The resonant character and high resolution of rotational spectroscopy provide a unique mixture compatibility. Future directions, such as extending the technique to chemical analysis, are discussed.
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Affiliation(s)
- V Alvin Shubert
- Max-Planck-Institut für Struktur und Dynamik der Materie , Luruper Chaussee 149, D-22761 Hamburg, Germany
- Center for Free-Electron Laser Science , Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - David Schmitz
- Max-Planck-Institut für Struktur und Dynamik der Materie , Luruper Chaussee 149, D-22761 Hamburg, Germany
- Center for Free-Electron Laser Science , Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Cristóbal Pérez
- Max-Planck-Institut für Struktur und Dynamik der Materie , Luruper Chaussee 149, D-22761 Hamburg, Germany
- Center for Free-Electron Laser Science , Luruper Chaussee 149, D-22761 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg , Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Chris Medcraft
- Max-Planck-Institut für Struktur und Dynamik der Materie , Luruper Chaussee 149, D-22761 Hamburg, Germany
- Center for Free-Electron Laser Science , Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Anna Krin
- Max-Planck-Institut für Struktur und Dynamik der Materie , Luruper Chaussee 149, D-22761 Hamburg, Germany
- Center for Free-Electron Laser Science , Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Sérgio R Domingos
- Max-Planck-Institut für Struktur und Dynamik der Materie , Luruper Chaussee 149, D-22761 Hamburg, Germany
- Center for Free-Electron Laser Science , Luruper Chaussee 149, D-22761 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg , Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - David Patterson
- Department of Physics, Harvard University , Cambridge, Massachusetts 02138, United States
| | - Melanie Schnell
- Max-Planck-Institut für Struktur und Dynamik der Materie , Luruper Chaussee 149, D-22761 Hamburg, Germany
- Center for Free-Electron Laser Science , Luruper Chaussee 149, D-22761 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg , Luruper Chaussee 149, D-22761 Hamburg, Germany
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27
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Reinscheid F, Reinscheid U. Stereochemical analysis of menthol and menthylamine isomers using calculated and experimental optical rotation data. J Mol Struct 2016. [DOI: 10.1016/j.molstruc.2015.09.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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28
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Schmitz D, Shubert VA, Patterson D, Krin A, Schnell M. Phase Dependence of Double-Resonance Experiments in Rotational Spectroscopy. J Phys Chem Lett 2015; 6:1493-1498. [PMID: 26263157 DOI: 10.1021/acs.jpclett.5b00494] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We here report on double-resonance experiments using broadband chirped pulse Fourier transform microwave spectroscopy that can facilitate spectral assignment and yield information about weak transitions with high resolution and sensitivity. Using the diastereomers menthone and isomenthone, we investigate the dependence of pumping a radio frequency transition on both the amplitude and phase of the signal from a microwave transition with which it shares a common rotational level. We observe a strong phase change when scanning the radio frequency through molecular resonance. The direction of the phase change depends on the energy level arrangement, that is, if it is progressive or regressive. The experimental results can be simulated using the three-level optical Bloch equations and described with the AC Stark effect, giving rise to an Autler-Townes splitting.
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Affiliation(s)
- David Schmitz
- †Max-Planck-Institut für Struktur und Dynamik der Materie, Luruper Chaussee 149, D-22761 Hamburg, Germany
- ‡Center for Free-Electron Laser Science, Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - V Alvin Shubert
- †Max-Planck-Institut für Struktur und Dynamik der Materie, Luruper Chaussee 149, D-22761 Hamburg, Germany
- ‡Center for Free-Electron Laser Science, Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - David Patterson
- ¶Department of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Anna Krin
- †Max-Planck-Institut für Struktur und Dynamik der Materie, Luruper Chaussee 149, D-22761 Hamburg, Germany
- ‡Center for Free-Electron Laser Science, Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Melanie Schnell
- †Max-Planck-Institut für Struktur und Dynamik der Materie, Luruper Chaussee 149, D-22761 Hamburg, Germany
- ‡Center for Free-Electron Laser Science, Luruper Chaussee 149, D-22761 Hamburg, Germany
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