1
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Hartwig B, Schnell M, Suhm MA, Obenchain DA. Weak hydrogen bonding to halogens and chirality communication in propanols: Raman and microwave spectroscopy benchmark theory. Phys Chem Chem Phys 2024; 26:9432-9452. [PMID: 38446207 DOI: 10.1039/d3cp04911f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2024]
Abstract
Constitutional and conformational isomers of bromopropanol are vibrationally and rotationally characterised with parallels drawn to the structural chlorine analogues. A previous microwave spectroscopic study of the chloropropanols is re-examined and all systems are explored by Raman jet spectroscopy. For bromine, the entire nuclear quadrupole coupling tensors are accurately determined and compared to their chlorine counterparts. Tensor asymmetry parameters are determined and linked with the hydrogen bond strength as indicated by the downshift of the OH-stretching frequency. The spectroscopic constants derived from the observed transitions are used as benchmarks for a large variety of electronic structure methods followed by harmonic and anharmonic rovibrational treatments. The CCSD(T) electronic structure calculations provide the best performance, in particular once anharmonic and relativistic corrections are applied or implied. Standard DFT approaches vary substantially with respect to their systematic error cancellation across the investigated species, and cost-effective compromises for the different observables are proposed.
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Affiliation(s)
- Beppo Hartwig
- Institut für Physikalische Chemie, Tammannstrasse 6, 37077 Göttingen, Germany.
| | - Melanie Schnell
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
- Institute of Physical Chemistry, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Straße 1, 24118 Kiel, Germany
| | - Martin A Suhm
- Institut für Physikalische Chemie, Tammannstrasse 6, 37077 Göttingen, Germany.
| | - Daniel A Obenchain
- Institut für Physikalische Chemie, Tammannstrasse 6, 37077 Göttingen, Germany.
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2
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Meyer KAE, Nejad A. CC-stretched formic acid: isomerisation, dimerisation, and carboxylic acid complexation. Phys Chem Chem Phys 2021; 23:17208-17223. [PMID: 34350923 DOI: 10.1039/d1cp02700j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The cis-trans-isomerism of the propiolic acid monomer (HC[triple bond, length as m-dash]C-COOH) is examined with linear Raman jet spectroscopy, yielding the first environment-free vibrational band centres of a higher-energy cis-rotamer beyond formic acid (HCOOH) in addition to all fundamentals and a large number of hot and combination/overtone bands of the trans-conformer. Two near-isoenergetic trans-fundamentals of different symmetry (CC[double bond, length as m-dash]O bend and OH torsion) prove to be a sensitive benchmarking target, as their energetic order is susceptible to the choice of electronic structure method, basis set size, and inclusion of vibrational anharmonicity. For the infrared- and Raman-active C[double bond, length as m-dash]O stretching fundamentals of the cyclic (C2h) trans-propiolic acid dimer, resonance couplings are found that in part extend to the Cs-symmetric heterodimer of trans-propiolic and trans-formic acid. Exploratory vibrational perturbation theory (VPT2) calculations show that all perturbing states involve displacements of the OH moieties located on the doubly hydrogen bonded ring. The comparison of the infrared spectra of the propiolic acid dimer and its heterodimer with formic acid to that of several other carboxylic acid dimers from the literature reveals a notable similarity regarding a non-fundamental dimer band around 1800 cm-1, which in most cases is so far unassigned. VPT2 calculations and a simple harmonic model suggest an assignment to a combination vibration of the symmetric and antisymmetric OH torsion.
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Affiliation(s)
- Katharina A E Meyer
- Institute of Physical Chemistry, University of Göttingen, Tammannstr. 6, 37077 Göttingen, Germany.
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3
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Gawrilow M, Suhm MA. Quantifying Conformational Isomerism in Chain Molecules by Linear Raman Spectroscopy: The Case of Methyl Esters. Molecules 2021; 26:molecules26154523. [PMID: 34361676 PMCID: PMC8348275 DOI: 10.3390/molecules26154523] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/19/2021] [Accepted: 07/20/2021] [Indexed: 02/01/2023] Open
Abstract
The conformational preferences of the ester group have the potential to facilitate the large amplitude folding of long alkyl chains in the gas phase. They are monitored by Raman spectroscopy in supersonic jet expansions for the model system methyl butanoate, after establishing a quantitative relationship with quantum-chemical predictions for methyl methanoate. This requires a careful analysis of experimental details, and a simulation of the rovibrational contours for near-symmetric top molecules. The technique is shown to be complementary to microwave spectroscopy in quantifying coexisting conformations. It confirms that a C-O-C(=O)-C-C chain segment can be collapsed into a single all-trans conformation by collisional cooling, whereas alkyl chain isomerism beyond this five-membered chain largely survives the jet expansion. This sets the stage for the investigation of linear alkyl alkanoates in terms of dispersion-induced stretched-chain to hairpin transitions by Raman spectroscopy.
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4
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Garvey CJ, Impéror-Clerc M, Rouzière S, Gouadec G, Boyron O, Rowenczyk L, Mingotaud AF, Ter Halle A. Molecular-Scale Understanding of the Embrittlement in Polyethylene Ocean Debris. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:11173-11181. [PMID: 32808772 DOI: 10.1021/acs.est.0c02095] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The fate of plastic waste is a pressing issue since it forms a visible and long-lived reminder of the environmental impact of consumer habits. In this study, we examine the structural changes in the lamellar arrangements of semicrystalline polyethylene (PE) packaging waste with the aim of understanding the physical mechanisms of embrittlement in PE exposed to the marine environment. PE microplastics and macroplastics from identifiable PE packaging were collected in the Atlantic Ocean and compared to new PE boxes. Several experimental techniques interrogate the effects of environmental exposure on their bulk and surface properties. Size exclusion chromatography determines the molecular weight distribution of the PE polymer chains and differential scanning calorimetry gives the crystallinity. Small- and wide-angle X-ray scattering examines the packing of PE chains into semicrystalline lamellae. Longitudinal acoustic mode Raman spectroscopy provides a complementary measurement of the length of PE polymer chains extending through the crystalline lamellar domains. While there is a high degree of uncertainty in the time scale for the changes, the overall picture at the molecular scale is that although PE becomes more crystalline with environmental exposure, the lamellar order present in new packing boxes is disrupted by the weathering process. This process has important implications for embrittlement and subsequent degradation.
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Affiliation(s)
- Christopher J Garvey
- Laboratoire de Physique des Solides, UMR 8502, CNRS, Université Paris Saclay, 91400 Orsay, France
- Lund Institute for Advanced Neutron and X-ray Science, 223 70 Lund, Sweden
- Biofilm-Research Center for Biointerfaces and Biomedical Science Department, Faculty of Health and Society, Malmö University, 211 19 Malmö, Sweden
- Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Marianne Impéror-Clerc
- Laboratoire de Physique des Solides, UMR 8502, CNRS, Université Paris Saclay, 91400 Orsay, France
| | - Stéphan Rouzière
- Laboratoire de Physique des Solides, UMR 8502, CNRS, Université Paris Saclay, 91400 Orsay, France
| | - Gwenaël Gouadec
- Laboratoire MONARIS, Sorbonne Université, CNRS, c49, 75252 Paris, France
| | - Olivier Boyron
- C2P2-LCPP Group, UMR CNRS 5265, Université de Lyon, ESCPE Lyon, Bat 308F, 43 Bd du 11 novembre 1918, 69616 Villeurbanne, France
| | - Laura Rowenczyk
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Paul Sabatier, 118, route de Narbonne, F-31062 Toulouse, Cedex 09, France
| | - Anne Françoise Mingotaud
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Paul Sabatier, 118, route de Narbonne, F-31062 Toulouse, Cedex 09, France
| | - Alexandra Ter Halle
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Paul Sabatier, 118, route de Narbonne, F-31062 Toulouse, Cedex 09, France
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5
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Gawrilow M, Suhm MA. 2-Methoxyethanol: harmonic tricks, anharmonic challenges and chirality-sensitive chain aggregation. Phys Chem Chem Phys 2020; 22:15303-15311. [PMID: 32626860 DOI: 10.1039/d0cp02488k] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The Raman spectrum of jet-cooled, nearly monoconformational 2-methoxyethanol reveals a strong, aggregation-sensitive resonance in the backbone stretching region and pronounced chirality-dependent dimerisation effects in the OH stretching region. These effects are disentangled by a dual-detection scheme which simultaneously probes the two spectral regions. The performance of mass-scaled harmonic wavenumber predictions and of vibrational perturbation theory in reproducing these spectral features is explored.
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Affiliation(s)
- Maxim Gawrilow
- Institut für Physikalische Chemie, Georg-August-Universität Göttingen, Tammannstr. 6, 37077 Göttingen, Germany.
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6
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Hartwig B, Lange M, Poblotzki A, Medel R, Zehnacker A, Suhm MA. The reduced cohesion of homoconfigurational 1,2-diols. Phys Chem Chem Phys 2020; 22:1122-1136. [DOI: 10.1039/c9cp04943f] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Homochiral encounters of vicinal diols are blocked from relaxing to the heterochiral global minimum dimer structure in supersonic jet expansions.
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Affiliation(s)
- Beppo Hartwig
- Institut für Physikalische Chemie
- Universität Göttingen
- 37077 Göttingen
- Germany
| | - Manuel Lange
- Institut für Physikalische Chemie
- Universität Göttingen
- 37077 Göttingen
- Germany
| | - Anja Poblotzki
- Institut für Physikalische Chemie
- Universität Göttingen
- 37077 Göttingen
- Germany
| | - Robert Medel
- Institut für Physikalische Chemie
- Universität Göttingen
- 37077 Göttingen
- Germany
| | - Anne Zehnacker
- Institut des Sciences Moléculaires d'Orsay
- CNRS
- Université Paris-Sud
- Université Paris-Saclay
- Orsay
| | - Martin A. Suhm
- Institut für Physikalische Chemie
- Universität Göttingen
- 37077 Göttingen
- Germany
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7
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Meyer KAE, Suhm MA. Stretching of cis-formic acid: warm-up and cool-down as molecular work-out. Chem Sci 2019; 10:6285-6294. [PMID: 31341581 PMCID: PMC6598513 DOI: 10.1039/c9sc01555h] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Accepted: 05/15/2019] [Indexed: 01/17/2023] Open
Abstract
A new technique to rotationally simplify and Raman-probe conformationally and vibrationally excited small molecules is applied to the cis-trans isomerism of formic acid. It quintuples the previously available gas phase vibrational data base on this excited form of a strongly anharmonic planar molecule despite its limited spectral resolution. The newly determined cis-formic acid fundamentals allow for a balanced vibrational benchmark on both rotamers of formic acid. Assuming the adequacy of vibrational perturbation theory, it reveals weaknesses of standard methods for these systems like B3LYP-D3(BJ)/aVQZ VPT2 or PBE0-D3(BJ)/aVQZ VPT2. The functionals ωB97-XD and M06-2X additionally suffer from severe integration grid size and symmetry dependencies. The vibrational benchmark suggests B2PLYP-D3(BJ)/aVQZ VPT2 and MP2/aVQZ VPT2 as partially competitive and in any case efficient alternatives to computationally demanding coupled cluster vibrational configuration interaction calculations. Whether this is due to fortuitous compensation between electronic structure and vibrational perturbation error remains to be explored.
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Affiliation(s)
- Katharina A E Meyer
- Institut für Physikalische Chemie , Georg-August-Universität Göttingen , Tammannstr. 6 , 37077 Göttingen , Germany . ; ; Tel: +49 55139 33111
| | - Martin A Suhm
- Institut für Physikalische Chemie , Georg-August-Universität Göttingen , Tammannstr. 6 , 37077 Göttingen , Germany . ; ; Tel: +49 55139 33111
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8
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Shakirov T, Paul W. Folded alkane chains and the emergence of the lamellar crystal. J Chem Phys 2019; 150:084903. [PMID: 30823774 DOI: 10.1063/1.5087640] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The competition between chain stiffness and chain collapse gives rise to complex low temperature morphologies of single polymer chains, in our case alkanes. These structures are characterized by specific sequences of dihedral angles along the chain, i.e., dihedral angle correlations extending beyond local steric effects. To describe and classify these morphologies, one can transfer concepts from protein science, where this creation of dihedral angle correlations underlies the formation of α-helices and β-sheets. We show here by means of flat-histogram Monte Carlo simulations that, although lacking in primary structure being simple homopolymers, short alkane chains fold into non-trivial ground states (tertiary structure) consisting of chain segments of defined secondary structures. The folded lamellar crystal typical for polyethylene chains requires a minimum chain length to occur as the ground state folded structure, which we identify to be around 150 repeat units.
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Affiliation(s)
- T Shakirov
- Institute of Physics, Martin Luther University, 06099 Halle, Germany
| | - W Paul
- Institute of Physics, Martin Luther University, 06099 Halle, Germany
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9
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Forsting T, Zischang J, Suhm MA, Eckhoff M, Schröder B, Mata RA. Strained hydrogen bonding in imidazole trimer: a combined infrared, Raman, and theory study. Phys Chem Chem Phys 2019; 21:5989-5998. [DOI: 10.1039/c9cp00399a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This is not how three imidazole molecules prefer to arrange, as a combined IR, Raman and computational analysis unambiguously shows.
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Affiliation(s)
- Thomas Forsting
- Institut für Physikalische Chemie
- Universität Göttingen
- 37077 Göttingen
- Germany
| | - Julia Zischang
- Institut für Physikalische Chemie
- Universität Göttingen
- 37077 Göttingen
- Germany
| | - Martin A. Suhm
- Institut für Physikalische Chemie
- Universität Göttingen
- 37077 Göttingen
- Germany
| | - Marco Eckhoff
- Institut für Physikalische Chemie
- Universität Göttingen
- 37077 Göttingen
- Germany
| | - Benjamin Schröder
- Institut für Physikalische Chemie
- Universität Göttingen
- 37077 Göttingen
- Germany
| | - Ricardo A. Mata
- Institut für Physikalische Chemie
- Universität Göttingen
- 37077 Göttingen
- Germany
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10
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Loru D, Vigorito A, Santos AFM, Tang J, Sanz ME. The axial/equatorial conformational landscape and intramolecular dispersion: new insights from the rotational spectra of monoterpenoids. Phys Chem Chem Phys 2019; 21:26111-26116. [DOI: 10.1039/c9cp05264j] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using rotational spectroscopy and quantum chemistry calculations, we show that intramolecular dispersion stabilises the axial conformers of monoterpenoids, and that an accurate account of these interactions is challenging for theoretical methods.
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Affiliation(s)
- Donatella Loru
- Department of Chemistry
- King's College London
- SE1 1DB London
- UK
| | | | | | - Jackson Tang
- Department of Chemistry
- King's College London
- SE1 1DB London
- UK
| | - M. Eugenia Sanz
- Department of Chemistry
- King's College London
- SE1 1DB London
- UK
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11
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Poblotzki A, Gottschalk HC, Suhm MA. Tipping the Scales: Spectroscopic Tools for Intermolecular Energy Balances. J Phys Chem Lett 2017; 8:5656-5665. [PMID: 29094953 DOI: 10.1021/acs.jpclett.7b02337] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Intermolecular energy balances are supramolecular complexes with a nearly degenerate bistable docking structure and low barriers in between, which can be tuned by chemical substitution to prefer one or the other site. The docking preference can be probed by forming the complexes in a supersonic jet expansion and by measuring their spectroscopic signature. Linear spectroscopies are shown to be well suited for this purpose, in particular when they are assisted by more sensitive techniques and by approximate computed photon interaction cross sections. Molecular analogues of conventional beam balances, seesaw balances, and torsional balances are discussed, all based on noncovalent interactions. The discrimination of energy differences down to the sub-kJ/mol level is demonstrated. The correspondence to intramolecular torsional balances in NMR spectroscopy is outlined. Besides highlighting conformational preferences, the results of intermolecular balance experiments can serve as critical benchmarks for an accurate description of intermolecular forces and zero-point vibrational energies.
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Affiliation(s)
- Anja Poblotzki
- Institut für Physikalische Chemie, Universität Göttingen , Tammannstraße 6, 37077 Göttingen, Germany
| | - Hannes C Gottschalk
- Institut für Physikalische Chemie, Universität Göttingen , Tammannstraße 6, 37077 Göttingen, Germany
| | - Martin A Suhm
- Institut für Physikalische Chemie, Universität Göttingen , Tammannstraße 6, 37077 Göttingen, Germany
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12
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Bocklitz S, Suhm MA. Polymer Segments at the Folding Limit: Raman Scattering for the Diglyme Benchmark. Chemphyschem 2017; 18:3570-3575. [DOI: 10.1002/cphc.201701169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Sebastian Bocklitz
- Institut für Physikalische Chemie; Georg-August-Universität Göttingen; Tammannstraße 6 37077 Göttingen Germany
| | - Martin A. Suhm
- Institut für Physikalische Chemie; Georg-August-Universität Göttingen; Tammannstraße 6 37077 Göttingen Germany
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13
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Barkley DA, Jiang N, Sen M, Endoh MK, Rudick JG, Koga T, Zhang Y, Gang O, Yuan G, Satija SK, Kawaguchi D, Tanaka K, Karim A. Chain Conformation near the Buried Interface in Nanoparticle-Stabilized Polymer Thin Films. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b01187] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
| | | | | | | | | | | | | | - Oleg Gang
- Department
of Chemical Engineering and Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
| | - Guangcui Yuan
- Center for
Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Sushil K. Satija
- Center for
Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | | | | | - Alamgir Karim
- College of
Polymer Science and Polymer Engineering, The University of Akron, Akron, Ohio 44325-0301, United States
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14
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Mata RA, Suhm MA. Benchmarking Quantum Chemical Methods: Are We Heading in the Right Direction? Angew Chem Int Ed Engl 2017; 56:11011-11018. [PMID: 28452424 PMCID: PMC5582598 DOI: 10.1002/anie.201611308] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 12/20/2016] [Indexed: 11/15/2022]
Abstract
Theoreticians and experimentalists should work together more closely to establish reliable rankings and benchmarks for quantum chemical methods. Comparison to carefully designed experimental benchmark data should be a priority. Guidelines to improve the situation for experiments and calculations are proposed.
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Affiliation(s)
- Ricardo A. Mata
- Institut für Physikalische ChemieUniversität GöttingenTammannstrasse 637077GöttingenGermany
| | - Martin A. Suhm
- Institut für Physikalische ChemieUniversität GöttingenTammannstrasse 637077GöttingenGermany
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15
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Putaux JL, Lancelon-Pin C, Legrand FX, Pastrello M, Choisnard L, Gèze A, Rochas C, Wouessidjewe D. Self-Assembly of Amphiphilic Biotransesterified β-Cyclodextrins: Supramolecular Structure of Nanoparticles and Surface Properties. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:7917-7928. [PMID: 28492333 DOI: 10.1021/acs.langmuir.7b01136] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A series of β-cyclodextrin (βCD) amphiphilic derivatives with varying degrees of substitution were prepared by acylating βCDs on their secondary face using thermolysin to catalyze the transesterification. After dissolution in acetone, the βCD-Cn derivatives (n = 8, 10, 12, 14) were nanoprecipitated in water, where they self-organized into structured particles that were characterized using cryo-transmission electron microscopy (cryo-TEM) images and small-angle X-ray scattering (SAXS) data. Two types of morphologies and ultrastructures were observed depending on the total degree of substitution (TDS) of the parent derivative. The molecules with TDS < 5 formed nanospheres with a multilamellar organization, whereas those with TDS > 5 self-assembled into barrel-like (n = 8, 10, 12) or more tortuous (n = 14) particles with a columnar inverse hexagonal structure. In particular, faceted βCD-C14 particles (TDS = 7) appeared to be composed of several domains with different orientations that were separated by sharp interfaces. Ultrastructural models were proposed on the basis of cryo-TEM images and the analysis of the contrast distribution in different projections of the lattice. Complementary compression isotherm experiments carried out at the air-water interface also suggested that differences in the molecular conformation of the series of derivatives existed depending on whether TDS was lower or higher than 5.
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Affiliation(s)
| | | | - François-Xavier Legrand
- Institut Galien Paris-Sud, CNRS UMR 8612, Univ. Paris-Sud, Univ. Paris-Saclay , 5 Rue Jean-Baptiste Clément, F-92296 Châtenay-Malabry, France
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16
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Hewett DM, Bocklitz S, Tabor DP, Sibert Iii EL, Suhm MA, Zwier TS. Identifying the first folded alkylbenzene via ultraviolet, infrared, and Raman spectroscopy of pentylbenzene through decylbenzene. Chem Sci 2017; 8:5305-5318. [PMID: 30510673 PMCID: PMC6223349 DOI: 10.1039/c7sc02027a] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 05/22/2017] [Indexed: 01/19/2023] Open
Abstract
The shortest possible single-chain alkylbenzene to exist in a folded conformation is determined using spectroscopic and theoretical techniques.
The conformational preferences of pentyl- through decylbenzene are studied under jet-cooled conditions in the gas phase. Laser-induced fluorescence excitation spectra, fluorescence-dip infrared spectra in the alkyl CH stretch region, and Raman spectra are combined to provide assignments for the observed conformers. Density functional theory calculations at the B3LYP-D3BJ/def2TZVP level of theory provide relative energies and normal mode vibrations that serve as inputs for an anharmonic local mode theory introduced in earlier work on alkylbenzenes with n = 2–4. This model explicitly includes anharmonic mixing of the CH stretch modes with the overtones of scissors/bend modes of the CH2 and CH3 groups in the alkyl chain, and is used to assign and interpret the single-conformation IR spectra. In octylbenzene, a pair of LIF transitions shifted –92 and –78 cm–1 from the all-trans electronic origin have unique alkyl CH stretch transitions that are fit by the local model to a g1g3g4 conformation in which the alkyl chain folds back over the aromatic ring π cloud. Its calculated energy is only 1.0 kJ mol–1 above the all-trans global minimum. This fold is at an alkyl chain length less than half that of the pure alkanes (n = 18), consistent with a smaller energy cost for the g1 dihedral and the increased dispersive interaction of the chain with the π cloud. Local site frequencies for the entire set of conformers from the local mode model show ‘edge effects’ that raise the site frequencies of CH2(1) and CH2(2) due to the phenyl ring and CH2(n – 1) due to the methyl group. The g1g3g4 conformer also shows local sites shifted up in frequency at CH2(3) and CH2(6) due to interaction with the π cloud.
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Affiliation(s)
- Daniel M Hewett
- Department of Chemistry , Purdue University , West Lafayette , IN 47907 , USA .
| | - Sebastian Bocklitz
- Institut für Physikalische Chemie , Universität Göttingen , Göttingen , Germany
| | - Daniel P Tabor
- Department of Chemistry , University of Wisconsin-Madison , Madison , WI 53706 , USA .
| | - Edwin L Sibert Iii
- Department of Chemistry , University of Wisconsin-Madison , Madison , WI 53706 , USA .
| | - Martin A Suhm
- Institut für Physikalische Chemie , Universität Göttingen , Göttingen , Germany
| | - Timothy S Zwier
- Department of Chemistry , Purdue University , West Lafayette , IN 47907 , USA .
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17
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Mata RA, Suhm MA. Quantenchemische Methoden im Leistungsvergleich: Stimmt die Richtung noch? Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201611308] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Ricardo A. Mata
- Institut für Physikalische Chemie; Universität Göttingen; Tammannstraße 6 37077 Göttingen Deutschland
| | - Martin A. Suhm
- Institut für Physikalische Chemie; Universität Göttingen; Tammannstraße 6 37077 Göttingen Deutschland
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18
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Tabor DP, Hewett DM, Bocklitz S, Korn JA, Tomaine AJ, Ghosh AK, Zwier TS, Sibert EL. Anharmonic modeling of the conformation-specific IR spectra of ethyl, n-propyl, and n-butylbenzene. J Chem Phys 2016; 144:224310. [PMID: 27306010 DOI: 10.1063/1.4953181] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Daniel P. Tabor
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Daniel M. Hewett
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - Sebastian Bocklitz
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - Joseph A. Korn
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - Anthony J. Tomaine
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - Arun K. Ghosh
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - Timothy S. Zwier
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - Edwin L. Sibert
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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19
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Samuel AZ, Zhou M, Ando M, Mueller R, Liebert T, Heinze T, Hamaguchi HO. Determination of Percent Crystallinity of Side-Chain Crystallized Alkylated-Dextran Derivatives with Raman Spectroscopy and Multivariate Curve Resolution. Anal Chem 2016; 88:4644-50. [DOI: 10.1021/acs.analchem.5b04075] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Ashok Zachariah Samuel
- Department
of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, 1001 Ta-Hsueh Road, Hsinchu 30010, Taiwan
| | - Mengbo Zhou
- Institute
of Organic Chemistry and Macromolecular Chemistry, Friedrich Schiller University of Jena, Humboldtstrasse 10, D-07743 Jena, Germany
| | - Masahiro Ando
- Waseda University, Consolidated Research Institute
for Advanced Science and Medical Care, 513 Wasedatsurumaki-cho, Shinjuku-ku, Tokyo 162-0041, Japan
| | - Robert Mueller
- Leibniz Institute of Photonic Technology e.V. (IPHT), Postfach 100239, D-07702 Jena, Germany
| | - Tim Liebert
- Institute
of Organic Chemistry and Macromolecular Chemistry, Friedrich Schiller University of Jena, Humboldtstrasse 10, D-07743 Jena, Germany
| | - Thomas Heinze
- Institute
of Organic Chemistry and Macromolecular Chemistry, Friedrich Schiller University of Jena, Humboldtstrasse 10, D-07743 Jena, Germany
| | - Hiro-o Hamaguchi
- Department
of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, 1001 Ta-Hsueh Road, Hsinchu 30010, Taiwan
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20
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Gottschalk HC, Altnöder J, Heger M, Suhm MA. Ringmethylierung kontrolliert die Wasserstoffbrücken-Andockstelle bei Anisol. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201508481] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Hannes C. Gottschalk
- Institut für Physikalische Chemie; Georg-August-Universität Göttingen; Tammannstraße 6 37077 Göttingen Deutschland
| | - Jonas Altnöder
- Institut für Physikalische Chemie; Georg-August-Universität Göttingen; Tammannstraße 6 37077 Göttingen Deutschland
| | - Matthias Heger
- Institut für Physikalische Chemie; Georg-August-Universität Göttingen; Tammannstraße 6 37077 Göttingen Deutschland
| | - Martin A. Suhm
- Institut für Physikalische Chemie; Georg-August-Universität Göttingen; Tammannstraße 6 37077 Göttingen Deutschland
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21
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Gottschalk HC, Altnöder J, Heger M, Suhm MA. Control over the Hydrogen-Bond Docking Site in Anisole by Ring Methylation. Angew Chem Int Ed Engl 2015; 55:1921-4. [DOI: 10.1002/anie.201508481] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 10/31/2015] [Indexed: 11/06/2022]
Affiliation(s)
- Hannes C. Gottschalk
- Institut für Physikalische Chemie; Georg-August-Universität Göttingen; Tammannstraße 6 37077 Göttingen Deutschland
| | - Jonas Altnöder
- Institut für Physikalische Chemie; Georg-August-Universität Göttingen; Tammannstraße 6 37077 Göttingen Deutschland
| | - Matthias Heger
- Institut für Physikalische Chemie; Georg-August-Universität Göttingen; Tammannstraße 6 37077 Göttingen Deutschland
| | - Martin A. Suhm
- Institut für Physikalische Chemie; Georg-August-Universität Göttingen; Tammannstraße 6 37077 Göttingen Deutschland
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22
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Heger M, Altnöder J, Poblotzki A, Suhm MA. To π or not to π – how does methanol dock onto anisole? Phys Chem Chem Phys 2015; 17:13045-52. [DOI: 10.1039/c5cp01545f] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Supersonic jet spectroscopy reveals that methanol opts against aromatic docking onto anisole despite a very close competition.
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Affiliation(s)
- Matthias Heger
- Institut für Physikalische Chemie
- Georg-August-Universität Göttingen
- D-37077 Göttingen
- Germany
| | - Jonas Altnöder
- Institut für Physikalische Chemie
- Georg-August-Universität Göttingen
- D-37077 Göttingen
- Germany
| | - Anja Poblotzki
- Institut für Physikalische Chemie
- Georg-August-Universität Göttingen
- D-37077 Göttingen
- Germany
| | - Martin A. Suhm
- Institut für Physikalische Chemie
- Georg-August-Universität Göttingen
- D-37077 Göttingen
- Germany
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23
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Heger M, Otto KE, Mata RA, Suhm MA. Bracketing subtle conformational energy differences between self-solvated and stretched trifluoropropanol. Phys Chem Chem Phys 2015; 17:9899-909. [DOI: 10.1039/c4cp05868b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The interconversion landscape between stretched and folded trifluoropropanol conformations is characterized by Raman jet spectroscopy and theory.
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Affiliation(s)
- Matthias Heger
- Institut für Physikalische Chemie
- Universität Göttingen
- 37077 Göttingen
- Germany
| | - Katharina E. Otto
- Institut für Physikalische Chemie
- Universität Göttingen
- 37077 Göttingen
- Germany
| | - Ricardo A. Mata
- Institut für Physikalische Chemie
- Universität Göttingen
- 37077 Göttingen
- Germany
| | - Martin A. Suhm
- Institut für Physikalische Chemie
- Universität Göttingen
- 37077 Göttingen
- Germany
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24
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Drawe P, Lüttschwager N, Suhm M. The elastic modulus of isolated polytetrafluoroethylene filaments. SCIENCEOPEN RESEARCH 2014. [DOI: 10.14293/s2199-1006.1.sor-matsci.aka0j6.v2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We report vibrational Raman spectra of small extended perfluoro-n-alkanes (C{n}F{2n+2} with n=6, 8-10, 12-14) isolated in supersonic jet expansions and use wavenumbers of longitudinal acoustic vibrations to extrapolate the elastic modulus of cold, isolated polytetrafluoroethylene filaments. The derived value E = 209(10) GPa defines an upper limit for the elastic modulus of the perfectly crystalline, non-interacting polymer at low temperatures and serves as a benchmark for quantum chemical predictions.
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25
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The elastic modulus of isolated polytetrafluoroethylene filaments. SCIENCEOPEN RESEARCH 2014. [DOI: 10.14293/a2199-1006.01.sor-matsci.ka0j6.v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We report vibrational Raman spectra of small extended perfluoro-n-alkanes (C{n}F{2n+2} with n=6, 8-10, 12-14) isolated in supersonic jet expansions and use wavenumbers of longitudinal acoustic vibrations to extrapolate the elastic modulus of cold, isolated polytetrafluoroethylene filaments. The derived value E = 209(10) GPa defines an upper limit for the elastic modulus of the perfectly crystalline, non-interacting polymer at low temperatures and serves as a benchmark for quantum chemical predictions.
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