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Pem B, Brkljača Z, Philippe A, Schaumann GE, Vazdar M, Bakarić D. FTIR spectroscopy and molecular level insight of diluted aqueous solutions of acetic acid. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 302:123135. [PMID: 37454436 DOI: 10.1016/j.saa.2023.123135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 06/27/2023] [Accepted: 07/10/2023] [Indexed: 07/18/2023]
Abstract
Aqueous solutions of acetic acid (AA) have been intensively explored for decades with a particular attention addressed to the hydrogen bond network generated by COOH group at different concentrations. In majority of studies conducted so far the envelope originated from νCO is decomposed into two bands assigned to differently hydrated monomers: the one presumably to AA···H2O, and another one to AA···(H2O)2. In order to examine if species other than the mentioned monomers produce this spectral signature, we performed computational and FTIR spectroscopic study of AA in aqueous solutions. Dilute solutions of deuterated acetic acid (CD3COOD) in D2O and in C2Cl4 as a reference were prepared (c0 = 0.001, 0.01 and 0.1 mol dm-3) as well as of deuterated sodium acetate (CD3COONa) in D2O. CD3COOD in 0.1 mol dm-3 solution in D2O displays a feature that separated in two signals with maxima at 1706 cm-1 and 1687 cm-1. A combined DFT and molecular dynamics study performed in this work showed the assignation of those spectral bands to be a more complex problem than previously thought, with syn-anti isomerism and hydration contributing to the experimentally observed broad νCO envelope.
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Affiliation(s)
- Barbara Pem
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
| | - Zlatko Brkljača
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia; Selvita d.o.o. Prilaz baruna Filipovića 29, 10000 Zagreb, Croatia
| | - Allan Philippe
- University of Koblenz-Landau, iES Landau-Institute for Environmental Sciences, Group of Environmental and Soil Chemistry, Fortstraße 7, D-76829 Landau, Germany
| | - Gabriele E Schaumann
- University of Koblenz-Landau, iES Landau-Institute for Environmental Sciences, Group of Environmental and Soil Chemistry, Fortstraße 7, D-76829 Landau, Germany
| | - Mario Vazdar
- Department of Mathematics, Informatics and Cybernetics, University of Chemistry and Technology, 166 28 Prague, Czech Republic
| | - Danijela Bakarić
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia; University of Koblenz-Landau, iES Landau-Institute for Environmental Sciences, Group of Environmental and Soil Chemistry, Fortstraße 7, D-76829 Landau, Germany.
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2
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Venianakis T, Siskos MG, Papamokos G, Gerothanassis IP. Structural Studies of Monounsaturated and ω-3 Polyunsaturated Free Fatty Acids in Solution with the Combined Use οf NMR and DFT Calculations-Comparison with the Liquid State. Molecules 2023; 28:6144. [PMID: 37630396 PMCID: PMC10459368 DOI: 10.3390/molecules28166144] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 08/14/2023] [Accepted: 08/18/2023] [Indexed: 08/27/2023] Open
Abstract
Molecular structures, in chloroform and DMSO solution, of the free fatty acids (FFAs) caproleic acid, oleic acid, α-linolenic acid, eicosapentanoic acid (EPA) and docosahexaenoic acid (DHA) are reported with the combined use of NMR and DFT calculations. Variable temperature and concentration chemical shifts of the COOH protons, transient 1D NOE experiments and DFT calculations demonstrate the major contribution of low molecular weight aggregates of dimerized fatty acids through intermolecular hydrogen bond interactions of the carboxylic groups, with parallel and antiparallel interdigitated structures even at the low concentration of 20 mM in CDCl3. For the dimeric DHA, a structural model of an intermolecular hydrogen bond through carboxylic groups and an intermolecular hydrogen bond between the carboxylic group of one molecule and the ω-3 double bond of a second molecule is shown to play a role. In DMSO-d6 solution, NMR and DFT studies show that the carboxylic groups form strong intermolecular hydrogen bond interactions with a single discrete solvation molecule of DMSO. These solvation species form parallel and antiparallel interdigitated structures of low molecular weight, as in chloroform solution. This structural motif, therefore, is an intrinsic property of the FFAs, which is not strongly affected by the length and degree of unsaturation of the chain and the hydrogen bond ability of the solvent.
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Affiliation(s)
| | | | - George Papamokos
- Section of Organic Chemistry and Biochemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece; (T.V.); (M.G.S.)
| | - Ioannis P. Gerothanassis
- Section of Organic Chemistry and Biochemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece; (T.V.); (M.G.S.)
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3
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Han Y, Wang Z, Qiao R, Cheng J, Jiang C, Wang H. Study on depolymerization kinetics of formic acid dimers in binary mixture. Phys Chem Chem Phys 2023. [PMID: 37378660 DOI: 10.1039/d3cp01876h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
In this study, polarization Raman spectra were collected for binary mixtures of formic acid/methanol and formic acid/acetonitrile with different volume fractions. The broad band of formic acid in the CO vibration region was divided into four vibration peaks, corresponding to CO symmetric and anti-symmetric stretching vibration from cyclic dimer, CO stretching from open dimer, and CO stretching from the free monomer. The experiments showed that as the volume fraction of formic acid in the binary mixture decreased, the cyclic dimer gradually converted to the open dimer, and at a volume fraction of 0.1, fully depolymerized into monomer form (free monomer, solvated monomer, and hydrogen bonding monomer clusters with solvent). The contribution percentage of the total CO stretching intensity of each structure at different concentrations was quantitatively calculated using high resolution infrared spectroscopy, and the results were consistent with the conclusions predicted by polarization Raman spectroscopy. Concentration-triggered 2D-COS synchronous and asynchronous spectra also confirmed the kinetics of formic acid diluted in acetonitrile. This work provides a spectroscopic method for studying the structure of organic compounds in solution and concentration-triggering kinetics in mixtures.
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Affiliation(s)
- Yufei Han
- Hangzhou Institute of Advanced Studies, College of chemistry and life sciences, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China.
- Department of Chemistry, College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Zian Wang
- Department of Chemistry, College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Ru Qiao
- Hangzhou Institute of Advanced Studies, College of chemistry and life sciences, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China.
| | - Jianwen Cheng
- Hangzhou Institute of Advanced Studies, College of chemistry and life sciences, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China.
| | - Caiying Jiang
- Department of Chemistry, College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Huigang Wang
- Hangzhou Institute of Advanced Studies, College of chemistry and life sciences, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China.
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4
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Venianakis T, Siskos M, Papamokos G, Gerothanassis IP. NMR and DFT studies of monounsaturated and ω-3 polyunsaturated free fatty acids in the liquid state reveal a novel atomistic structural model of DHA. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
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5
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Sangeetha T, Naganandhini SP, Shanmugam R, Arivazhagan G. FTIR Spectral Signatures of Formamide + Propionic/Acetic Acid Solutions. J SOLUTION CHEM 2022. [DOI: 10.1007/s10953-022-01139-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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6
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Berry DBG, Clegg I, Codina A, Lyall CL, Lowe JP, Hintermair U. Convenient and accurate insight into solution-phase equilibria from FlowNMR titrations. REACT CHEM ENG 2022. [DOI: 10.1039/d2re00123c] [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
Solution phase titrations are made easy by multi-nuclear FlowNMR spectroscopy with automated, continuous titre addition to give accurate insights into Brønsted acid/base, hydrogen bonding, Lewis acid/base and metal/ligand binding equilibria under native conditions.
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Affiliation(s)
- Daniel B. G. Berry
- Department of Chemistry, University of Bath, Claverton Down, BA2 7AY Bath, UK
- Dynamic Reaction Monitoring Facility, University of Bath, Claverton Down, BA2 7AY Bath, UK
| | - Ian Clegg
- Bruker UK Ltd, Banner Lane, CV4 9GH Coventry, UK
| | - Anna Codina
- Bruker UK Ltd, Banner Lane, CV4 9GH Coventry, UK
| | - Catherine L. Lyall
- Department of Chemistry, University of Bath, Claverton Down, BA2 7AY Bath, UK
- Dynamic Reaction Monitoring Facility, University of Bath, Claverton Down, BA2 7AY Bath, UK
| | - John P. Lowe
- Department of Chemistry, University of Bath, Claverton Down, BA2 7AY Bath, UK
- Dynamic Reaction Monitoring Facility, University of Bath, Claverton Down, BA2 7AY Bath, UK
| | - Ulrich Hintermair
- Department of Chemistry, University of Bath, Claverton Down, BA2 7AY Bath, UK
- Dynamic Reaction Monitoring Facility, University of Bath, Claverton Down, BA2 7AY Bath, UK
- Centre for Sustainable and Circular Technologies, University of Bath, Claverton Down, BA2 7AY Bath, UK
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Lengvinaitė D, Kvedaraviciute S, Bielskutė S, Klimavicius V, Balevicius V, Mocci F, Laaksonen A, Aidas K. Structural Features of the [C4mim][Cl] Ionic Liquid and Its Mixtures with Water: Insight from a 1H NMR Experimental and QM/MD Study. J Phys Chem B 2021; 125:13255-13266. [PMID: 34806880 PMCID: PMC8667039 DOI: 10.1021/acs.jpcb.1c08215] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 11/09/2021] [Indexed: 01/05/2023]
Abstract
The 1H NMR chemical shift of water exhibits non-monotonic dependence on the composition of an aqueous mixture of 1-butyl-3-methylimidazolium chloride, [C4mim][Cl], ionic liquid (IL). A clear minimum is observed for the 1H NMR chemical shift at a molar fraction of the IL of 0.34. To scrutinize the molecular mechanism behind this phenomenon, extensive classical molecular dynamics simulations of [C4mim][Cl] IL and its mixtures with water were carried out. A combined quantum mechanics/molecular mechanics approach based on the density functional theory was applied to predict the NMR chemical shifts. The proliferation of strongly hydrogen-bonded complexes between chloride anions and water molecules is found to be the reason behind the increasing 1H NMR chemical shift of water when its molar fraction in the mixture is low and decreasing. The model shows that the chemical shift of water molecules that are trapped in the IL matrix without direct hydrogen bonding to the anions is considerably smaller than the 1H NMR chemical shift predicted for the neat water. The structural features of neat IL and its mixtures with water have also been analyzed in relation to their NMR properties. The 1H NMR spectrum of neat [C4mim][Cl] was predicted and found to be in very reasonable agreement with the experimental data. Finally, the experimentally observed strong dependence of the chemical shift of the proton at position 2 in the imidazolium ring on the composition of the mixture was rationalized.
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Affiliation(s)
- Dovilė Lengvinaitė
- Institute
of Chemical Physics, Faculty of Physics, Vilnius University, Vilnius LT-10257, Lithuania
| | | | - Stasė Bielskutė
- Institute
of Chemical Physics, Faculty of Physics, Vilnius University, Vilnius LT-10257, Lithuania
| | - Vytautas Klimavicius
- Institute
of Chemical Physics, Faculty of Physics, Vilnius University, Vilnius LT-10257, Lithuania
| | - Vytautas Balevicius
- Institute
of Chemical Physics, Faculty of Physics, Vilnius University, Vilnius LT-10257, Lithuania
| | - Francesca Mocci
- Università
di Cagliari, Dipartimento di Scienze Chimiche e Geologiche, Cittadella
Universitaria di Monserrato, Cagliari I-09042, Monserrato, Italy
| | - Aatto Laaksonen
- Energy Engineering,
Division of Energy Science, Luleå
University of Technology, Luleå 97181, Sweden
- Division
of Physical Chemistry, Department of Materials and Environmental Chemistry,
Arrhenius Laboratory, Stockholm University, Stockholm 10691, Sweden
- Center of
Advanced Research in Bionanoconjugates and Biopolymers, “Petru Poni” Institute of Macromolecular
Chemistry, Iasi 700469, Romania
- State
Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Kęstutis Aidas
- Institute
of Chemical Physics, Faculty of Physics, Vilnius University, Vilnius LT-10257, Lithuania
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8
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Lengvinaitė D, Klimavičius V, Balevicius V, Aidas K. Computational NMR Study of Ion Pairing of 1-Decyl-3-methyl-imidazolium Chloride in Molecular Solvents. J Phys Chem B 2020; 124:10776-10786. [PMID: 33183008 PMCID: PMC7735725 DOI: 10.1021/acs.jpcb.0c07450] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 10/09/2020] [Indexed: 01/14/2023]
Abstract
The 1H NMR spectra of 10-5 mole fraction solutions of 1-decyl-3-methyl-imidazolium chloride ionic liquid in water, acetonitrile, and dichloromethane have been measured. The chemical shift of the proton at position 2 in the imidazolium ring of 1-decyl-3-methyl-imidazolium (H2) is rather different for all three samples, reflecting the shifting equilibrium between the contact pairs and free fully solvated ions. Classical molecular dynamics simulations of the 1-decyl-3-methyl-imidazolium chloride contact ion pair as well as of free ions in water, acetonitrile, and dichloromethane have been conducted, and the quantum mechanics/molecular mechanics methods have been applied to predict NMR chemical shifts for the H2 proton. The chemical shift of the H2 proton was found to be primarily modulated by hydrogen bonding with the chloride anion, while the influence of the solvents-though differing in polarity and capabilities for hydrogen bonding-is less important. By comparing experimental and computational results, we deduce that complete disruption of the ionic liquid into free ions takes place in an aqueous solution. Around 23% of contact ion pairs were found to persist in acetonitrile. Ion-pair breaking into free ions was predicted not to occur in dichloromethane.
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Affiliation(s)
- Dovilė Lengvinaitė
- Institute
of Chemical Physics, Faculty of Physics, Vilnius University, Saulėtekio al. 3, LT-10257 Vilnius, Lithuania
| | - Vytautas Klimavičius
- Institute
of Chemical Physics, Faculty of Physics, Vilnius University, Saulėtekio al. 3, LT-10257 Vilnius, Lithuania
- Eduard-Zintl
Institute for Inorganic and Physical Chemistry, University of Technology Darmstadt, D-64287 Darmstadt, Germany
| | - Vytautas Balevicius
- Institute
of Chemical Physics, Faculty of Physics, Vilnius University, Saulėtekio al. 3, LT-10257 Vilnius, Lithuania
| | - Kęstutis Aidas
- Institute
of Chemical Physics, Faculty of Physics, Vilnius University, Saulėtekio al. 3, LT-10257 Vilnius, Lithuania
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9
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Benlahouès A, Brissault B, de Anda AR, Penelle J. Synthesis, Characterization, and Solid-State Properties of (CH 2–CH 2–C(COOH) 2) n: A Highly Symmetrical, Semicrystalline Carbon-Chain Poly(carboxylic acid). Macromolecules 2020. [DOI: 10.1021/acs.macromol.9b02665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Antoine Benlahouès
- Institut de Chimie et des Matériaux Paris-Est (East Paris Institute for Chemistry & Materials Science), Université Paris-Est and CNRS, 2-8 rue H. Dunant, F-94320 Thiais, France
| | - Blandine Brissault
- Institut de Chimie et des Matériaux Paris-Est (East Paris Institute for Chemistry & Materials Science), Université Paris-Est and CNRS, 2-8 rue H. Dunant, F-94320 Thiais, France
| | - Agustin Rios de Anda
- Institut de Chimie et des Matériaux Paris-Est (East Paris Institute for Chemistry & Materials Science), Université Paris-Est and CNRS, 2-8 rue H. Dunant, F-94320 Thiais, France
| | - Jacques Penelle
- Institut de Chimie et des Matériaux Paris-Est (East Paris Institute for Chemistry & Materials Science), Université Paris-Est and CNRS, 2-8 rue H. Dunant, F-94320 Thiais, France
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10
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Socha O, Dračínský M. Dimerization of Acetic Acid in the Gas Phase-NMR Experiments and Quantum-Chemical Calculations. Molecules 2020; 25:molecules25092150. [PMID: 32375390 PMCID: PMC7248931 DOI: 10.3390/molecules25092150] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/28/2020] [Accepted: 04/30/2020] [Indexed: 11/24/2022] Open
Abstract
Due to the nature of the carboxylic group, acetic acid can serve as both a donor and acceptor of a hydrogen bond. Gaseous acetic acid is known to form cyclic dimers with two strong hydrogen bonds. However, trimeric and various oligomeric structures have also been hypothesized to exist in both the gas and liquid phases of acetic acid. In this work, a combination of gas-phase NMR experiments and advanced computational approaches were employed in order to validate the basic dimerization model of gaseous acetic acid. The gas-phase experiments performed in a glass tube revealed interactions of acetic acid with the glass surface. On the other hand, variable-temperature and variable-pressure NMR parameters obtained for acetic acid in a polymer insert provided thermodynamic parameters that were in excellent agreement with the MP2 (the second order Møller–Plesset perturbation theory) and CCSD(T) (coupled cluster with single, double and perturbative triple excitation) calculations based on the basic dimerization model. A slight disparity between the theoretical dimerization model and the experimental data was revealed only at low temperatures. This observation might indicate the presence of other, entropically disfavored, supramolecular structures at low temperatures.
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Affiliation(s)
- Ondřej Socha
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 166 10 Prague, Czech Republic;
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 166 10 Prague, Czech Republic
| | - Martin Dračínský
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 166 10 Prague, Czech Republic;
- Correspondence: ; Tel./Fax: +42-02-2018-3139
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