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Wu G, Dai Y, Hung I, Gan Z, Terskikh V. 1H/ 17O Chemical Shift Waves in Carboxyl-Bridged Hydrogen Bond Networks in Organic Solids. J Phys Chem A 2024; 128:4288-4296. [PMID: 38748612 PMCID: PMC11840671 DOI: 10.1021/acs.jpca.4c01866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
We report solid-state 1H and 17O NMR results for four 17O-labeled organic compounds each containing an extensive carboxyl-bridged hydrogen bond (CBHB) network in the crystal lattice: tetrabutylammonium hydrogen di-[17O2]salicylate (1), [17O4]quinolinic acid (2), [17O4]dinicotinic acid (3), and [17O2]Gly/[17O2]Gly·HCl cocrystal (4). The 1H isotropic chemical shifts found for protons involved in different CBHB networks are between 8.2 and 20.5 ppm, which reflect very different hydrogen-bonding environments. Similarly, the 17O isotropic chemical shifts found for the carboxylate oxygen atoms in CBHB networks, spanning a large range between 166 and 341 ppm, are also remarkably sensitive to the hydrogen-bonding environments. We introduced a simple graphical representation in which 1H and 17O chemical shifts are displayed along the H and O atomic chains that form the CBHB network. In such a depiction, because wavy patterns are often observed, we refer to these wavy patterns as 1H/17O chemical shift waves. Typical patterns of 1H/17O chemical shift waves in CBHB networks are discussed. The reported 1H and 17O NMR parameters for the CBHB network models examined in this study can serve as benchmarks to aid in spectral interpretation for CBHB networks in proteins.
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Affiliation(s)
- Gang Wu
- Department of Chemistry, Queen’s University, 90 Bader Lane, Kingston, Ontario, K7L 3N6, Canada
| | - Yizhe Dai
- Department of Chemistry, Queen’s University, 90 Bader Lane, Kingston, Ontario, K7L 3N6, Canada
| | - Ivan Hung
- National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, USA
| | - Zhehong Gan
- National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, USA
| | - Victor Terskikh
- Metrology, National Research Council Canada, Ottawa, K1A 0R6, Canada
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Hydrogen Bonds: Raman Spectroscopic Study. Int J Mol Sci 2021; 22:ijms22105380. [PMID: 34065358 PMCID: PMC8161095 DOI: 10.3390/ijms22105380] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/14/2021] [Accepted: 05/18/2021] [Indexed: 11/26/2022] Open
Abstract
The work outlines general ideas on how the frequency and the intensity of proton vibrations of X–H···Y hydrogen bonding are formed as the bond evolves from weak to maximally strong bonding. For this purpose, the Raman spectra of different chemical compounds with moderate, strong, and extremely strong hydrogen bonds were obtained in the temperature region of 5 K–300 K. The dependence of the proton vibrational frequency is schematically presented as a function of the rigidity of O-H···O bonding. The problems of proton dynamics on tautomeric O–H···O bonds are considered. A brief description of the N–H···O and C–H···Y hydrogen bonds is given.
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Wu G, Hung I, Gan Z, Terskikh V, Kong X. Solid-State 17O NMR Study of Carboxylic Acid Dimers: Simultaneously Accessing Spectral Properties of Low- and High-Energy Tautomers. J Phys Chem A 2019; 123:8243-8253. [DOI: 10.1021/acs.jpca.9b07224] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Gang Wu
- Department of Chemistry, Queen’s University, 90 Bader Lane, Kingston, Ontario K7L 3N6, Canada
| | - Ivan Hung
- Center of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Zhehong Gan
- Center of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Victor Terskikh
- Department of Chemistry, Queen’s University, 90 Bader Lane, Kingston, Ontario K7L 3N6, Canada
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Xianqi Kong
- Department of Chemistry, Queen’s University, 90 Bader Lane, Kingston, Ontario K7L 3N6, Canada
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Abstract
The Raman spectra of polycrystalline samples of ( RS)-2-(4-isobutylphenyl)-propionic acid of the common name ibuprofen have been measured in the temperature range 5-300 K. In the low-frequency spectrum of the normal C12H17(COOH) and deuterated C12H17(COOD) species, modes with ∼103 and ∼95 cm-1 wavenumbers were detected, which corresponded to translational vibrations of O-H(D)···O hydrogen bonds of two different tautomers: left L and right R , respectively. At temperatures below 150 K, only the L-tautomer is found, and at T ≥ 150 K, both tautomers are observed. The energy difference Δ E of the ground vibrational state of potential minima for L- and R-tautomers is ∼80 meV for COOH and ∼70 meV for COOD. At T ≥ 150 K, the vibrational frequency of the C═O bond in the COOH moiety exhibits an unusual temperature dependence.
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Affiliation(s)
- Artem G Demkin
- A.V. Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences , Novosibirsk 630090 , Russia
| | - Boris A Kolesov
- A.V. Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences , Novosibirsk 630090 , Russia.,Faculty of Physics , Novosibirsk National Research State University , Novosibirsk 630090 , Russia
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Kolesov BA. Unusual behavior of benzoic acid at low temperature: Raman spectroscopic study. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2015; 142:320-323. [PMID: 25706602 DOI: 10.1016/j.saa.2015.02.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 01/13/2015] [Accepted: 02/04/2015] [Indexed: 06/04/2023]
Abstract
The Raman spectra of benzoic acid single crystals have been measured in the temperature range of 5-300K. At T<60K the spectra show at least two anomalous features, one of which is of direct relevance to intensity changes of the lattice modes in the low-wavenumber region. The intensity of modes at ∼86 and ∼146cm(-1) tends to zero at T→0K. It is associated with appearance of two H-bonds of different length in the same l-tautomer, and with the loss of the inversion center in the dimer. The modes at ∼86 and ∼146cm(-1) are assigned to symmetric stretching intra-dimer vibrations of the OH⋯O hydrogen bonds of the first and second order, respectively. The assignment is based on the measurements of spectral parameters as function of temperature. The other anomaly is that the series of weak and narrow bands arises in the high-wavenumber region of 2500-3700cm(-1). The bands are assigned to combination tones of O-H hydrogen bonded stretching vibration and intramolecular modes. This effect results from a low-temperature transition of a conventional two wells potential of short H-bond in the l-tautomer to asymmetrical single well potential, and is due to a strong coupling of intramolecular vibrations to O-H stretching.
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Affiliation(s)
- Boris A Kolesov
- Institute of Inorganic Chemistry SB RAS, Novosibirsk, Russia; Novosibirsk State University, Physical Department, Novosibirsk, Russia.
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Frantsuzov I, Johnson MR, Trommsdorff HP, Horsewill AJ. Proton tunnelling in the hydrogen bonds of the benzoic acid dimer: (18)O substitution and isotope effects of the heavy atom framework. J Phys Chem B 2014; 118:7777-84. [PMID: 24428637 DOI: 10.1021/jp410889x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Field-cycling (1)H NMR relaxometry has been used to measure the rate of concerted double proton transfer in the hydrogen bonds of (16)O and (18)O isotopologues of benzoic acid dimers. The experiments have been conducted in the solid state at low temperature 13.3 ≤ T ≤ 80 K where the dynamics are dominated by incoherent proton tunnelling. The low temperature tunnelling rate in the (16)O isotopologue is observed to be approximately 15% faster than in the (18)O isotopologue. The difference is attributed to an isotope effect of the heavy atom framework of the benzoic acid dimer resulting from displacements of the oxygen atoms that accompany the proton transfer. Sources of systematic uncertainty have been minimized in the design of the experimental protocols and the experiments are critically appraised in formally assigning the measured differences to an effect of mass on the tunnelling dynamics.
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Affiliation(s)
- I Frantsuzov
- School of Physics & Astronomy, University of Nottingham , Nottingham NG7 2RD, U.K
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Ueda K, Oguni M. Effect of p-tert-Butyl Group Substitution on the Quantum Tunneling Rate in Quadruple Proton Rearrangement of Calix[4]arene. J Phys Chem B 2013; 117:14157-62. [DOI: 10.1021/jp409280s] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kouhei Ueda
- Department of Chemistry, Graduate School
of Science and Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Masaharu Oguni
- Department of Chemistry, Graduate School
of Science and Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551, Japan
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Kong X, Shan M, Terskikh V, Hung I, Gan Z, Wu G. Solid-State 17O NMR of Pharmaceutical Compounds: Salicylic Acid and Aspirin. J Phys Chem B 2013; 117:9643-54. [DOI: 10.1021/jp405233f] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xianqi Kong
- Department
of Chemistry, Queen’s University, 90 Bader Lane, Kingston,
Ontario, K7L 3N6, Canada
| | - Melissa Shan
- Department
of Chemistry, Queen’s University, 90 Bader Lane, Kingston,
Ontario, K7L 3N6, Canada
| | - Victor Terskikh
- Department
of Chemistry, Queen’s University, 90 Bader Lane, Kingston,
Ontario, K7L 3N6, Canada
- National Research Council Canada, 100 Sussex Drive, Ottawa, Ontario, K1A
0R6, Canada
| | - Ivan Hung
- Center of Interdisciplinary
Magnetic
Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United
States
| | - Zhehong Gan
- Center of Interdisciplinary
Magnetic
Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United
States
| | - Gang Wu
- Department
of Chemistry, Queen’s University, 90 Bader Lane, Kingston,
Ontario, K7L 3N6, Canada
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Biliškov N, Kojić-Prodić B, Mali G, Molčanov K, Stare J. A Partial Proton Transfer in Hydrogen Bond O−H···O in Crystals of Anhydrous Potassium and Rubidium Complex Chloranilates. J Phys Chem A 2011; 115:3154-66. [DOI: 10.1021/jp112380f] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Nikola Biliškov
- Rudjer Bošković Institute, POB 180, HR-10002 Zagreb, Croatia
| | | | - Gregor Mali
- National Institute of Chemistry, Hajdrihova 19, 1001 Ljubljana, Slovenia
- EN-FIST Centre of Excellence, Dunajska c. 156, SI-1000 Ljubljana
| | | | - Jernej Stare
- National Institute of Chemistry, Hajdrihova 19, 1001 Ljubljana, Slovenia
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Amiri S, Reisenauer HP, Schreiner PR. Electronic Effects on Atom Tunneling: Conformational Isomerization of Monomeric Para-Substituted Benzoic Acid Derivatives. J Am Chem Soc 2010; 132:15902-4. [DOI: 10.1021/ja107531y] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Shadi Amiri
- Institute for Organic Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany
| | - Hans Peter Reisenauer
- Institute for Organic Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany
| | - Peter R. Schreiner
- Institute for Organic Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany
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Stability and molecular dynamics of solid lasamide (API of diuretic and antivirial drugs) studied by 1H NMR spectroscopy and DFT methods. J Mol Struct 2009. [DOI: 10.1016/j.molstruc.2009.05.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Latanowicz L. Complex methyl group and hydrogen-bonded proton motions in terms of the Arrhenius and Schrödinger equations. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2008; 34:93-104. [PMID: 18023155 DOI: 10.1016/j.ssnmr.2007.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2007] [Accepted: 10/03/2007] [Indexed: 05/25/2023]
Abstract
Equations for the temperature dependence of the spectral densities J(is)(m)(momega(I) +/-omega(T)), where m=1, 2, omega(I) and omega(T) are the resonance and tunnel splitting angular frequencies, in the presence of a complex motion, have been derived. The spin pairs of the protons or deuterons of the methyl group perform a complex motion consisting of three component motions. Two of them involve mass transportation over the barrier and through the barrier. They are characterized by k((H)) (Arrhenius) and k((T)) (Schrödinger) rate constants, respectively. The third motion causes fluctuations of the frequencies (nomega(I)+/-omega(T)) and it is related to the lifetime of the methyl spin at the energy level influenced by the rotor-bath interactions. These interactions induce rapid transitions, changing the symmetry of the torsional sublevels either from A to E or from E(a) to E(b). The correlation function for this third motion (k((omega)) rate constant) has been proposed by Müller-Warmuth et al. The spectral densities of the methyl group hindered rotation (k((H)), k((T)) and k((omega)) rate constants) differ from the spectral densities of the proton transfer (k((H)) and k((T)) rate constants) because three compound motions contribute to the complex motion of the methyl group. The recently derived equation [Formula: see text] , where [Formula: see text] and [Formula: see text] are the fraction and energy of particles with energies from zero to E(H), is taken into account in the calculations of the spectral densities. This equation follows from Maxwell's distribution of thermal energy. The spectral densities derived are applied to analyse the experimental temperature dependencies of proton and deuteron spin-lattice relaxation rate in solids containing the methyl group. A wide range of temperatures from zero Kelvin up to the melting point is considered. It has been established that the motion characterized by k((omega)) influences the spin-lattice relaxation up to the temperature T(tun) only. This temperature is directly determined by the equation C(p)T=E(H) (thermal energy=activation energy), where C(p) is the molar heat capacity. Probably the cessation of the third motion is a result of the de Broglie wavelength related to this motion becoming too short. As shown recently, the potential barrier can be an obstacle for the de Broglie wave. The theoretical equations derived in this paper are compared to those known in the literature.
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Affiliation(s)
- L Latanowicz
- Faculty of Biological Sciences, University of Zielona Góra, Szafrana 1, 5-516 Zielona Góra, Poland.
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Filarowski A, Koll A, Lipkowski P, Pawlukojć A. Inelastic neutron scattering and vibrational spectra of 2-(N-methyl-α-iminoethyl)-phenol and 2-(N-methyliminoethyl)-phenol: Experimental and theoretical approach. J Mol Struct 2008. [DOI: 10.1016/j.molstruc.2007.11.045] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Wilson CC. The evolution of hydrogen atom parameters under changing external conditions by time-of-flight single crystal neutron diffraction. CRYSTALLOGR REV 2007. [DOI: 10.1080/08893110701565913] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Latanowicz L, Medycki W. Application of Schrödinger Equation to Study the Tunnelling Dynamics of Proton Transfer in the Hydrogen Bond of 2,5-Dinitrobenzoic Acid: Proton T1, T1ρ, and Deuteron T1 Relaxation Methods. J Phys Chem A 2007; 111:1351-7. [PMID: 17263515 DOI: 10.1021/jp0648442] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Temperature measurements of proton T1 (24.7 MHz), deuteron (deuterated hydroxyl group) T1 (55.2 MHz), and proton T1(rho) (B1 = 9 G) spin-lattice relaxation times of 2,5-dinitrobenzoic acid have been performed. An analysis of present experimental data together with previously published proton T1 (55.2 MHz) data has revealed the following molecular motions: proton/deuteron transfer in the hydrogen bond and two-site hopping of the whole dimer. It is shown that the proton-transfer dynamics are characterized by two correlation times tau(ov) and tau(tu), describing two fundamentally different motional processes, namely, thermally activated jumps over the barrier and tunneling through the barrier. The temperature dependence of 1/tau(tu) is the solution of Schrödinger's equation, which also yields the temperature T(tun), where begins the tunnel pathway for proton transfer. A new equation for the spectral density function of complex motion consisting of the three motions is derived. The third motion (two-site hopping of the whole dimer characterized by tau(lib) correlation time) is responsible for a proton T1(rho) minimum in high temperatures, just below the melting point. Such a minimum is not reached by T1 temperature dependencies. The minimum of T1(rho) assigned to the classical hopping of a hydrogen-bonded proton occurs in the same low-temperature regime in which the flattening of the temperature dependencies of T1 points to the dominance of incoherent tunneling. This experimental fact denies the known theories predicting the intermediate temperature regime where a smooth transition between classical and quantum tunneling dynamics is expected. The fit of the derived theoretical equations to the experimental data T1(rho) and T1 is satisfactory. The correlation times obtained for deuterons indicate deuteron-transfer dynamics much slower than proton-transfer dynamics. It is concluded that the classical proton transfer takes place over the whole temperature regime, while the incoherent tunneling occurs below 46.5 (hydrogen) or 87.2 K (deuterium) only.
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Affiliation(s)
- L Latanowicz
- Institute of Biotechnology and Environmental Sciences, University of Zielona Góra, Szafrana 1, 65-516 Zielona Góra, Poland.
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Middlemiss DS, Facchini M, Morrison CA, Wilson CC. Small energy differences in molecular crystals: A first principles study of tautomerism and dynamics in benzoic acid derivatives. CrystEngComm 2007. [DOI: 10.1039/b703181e] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Horsewill A. Reply to the Comment on ‘The correspondence between quantum and classical mechanics: An experimental demonstration of the smooth transition between the two regimes’ [Chem. Phys. Lett. 402 (2005) 519]. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2006.11.083] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Latanowicz L, Reynhardt E. Comment on ‘The correspondence between quantum and classical mechanics: An experimental demonstration of the smooth transition between the two regimes’ [Chem. Phys. Lett. 402 (2005) 519]. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2006.11.082] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Latosińska J, Latosińska M, Medycki W, Osuchowicz J. Molecular dynamics of solid furosemide (4-chloro-2-furfurylamino-5-sulfamoyl-benzoic acid) studied by NMR and DFT methods. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.08.080] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Xue Q, Horsewill AJ, Johnson MR, Trommsdorff HP. Isotope effects associated with tunneling and double proton transfer in the hydrogen bonds of benzoic acid. J Chem Phys 2006; 120:11107-19. [PMID: 15268141 DOI: 10.1063/1.1738644] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The isotope effects associated with double proton transfer in the hydrogen bonds of benzoic acid (BA) dimers have been measured using field-cycling (1)H NMR relaxometry and quasielastic neutron scattering. By studying mixed isotope (hydrogen and deuterium) samples, the dynamics of three isotopologues, BA-HH, BA-HD, and BA-DD, have been investigated. Low temperature measurements provide accurate measurements of the incoherent tunneling rate, k(0). This parameter scales accurately with the mass number, m, according to the formula k(0)=(E/m)e(-Fm) providing conclusive evidence that the proton transfer process is a strongly correlated motion of two hydrons. Furthermore, we conclude that the tunneling pathway is the same for the three isotopologue species. Measurements at higher temperatures illuminate the through barrier processes that are mediated via intermediate or excited vibrational states. In parallel with the investigation of proton transfer dynamics, the theoretical and experimental aspects of studying spin-lattice relaxation in single crystals of mixed isotope samples are investigated in depth. Heteronuclear dipolar interactions between (1)H and (2)H isotopes contribute significantly to the overall proton spin-lattice relaxation and it is shown that these must be modeled correctly to obtain accurate values for the proton transfer rates. Since the sample used in the NMR measurements was a single crystal, full account of the orientation dependence of the spin-lattice relaxation with respect to the applied B field was incorporated into the data analysis.
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Affiliation(s)
- Q Xue
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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Wilson CC, Xu X, Florence AJ, Shankland N. Temperature dependence of proton transfer in 4-chlorobenzoic acid. NEW J CHEM 2006. [DOI: 10.1039/b601123c] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Wu W, Noble DL, Owers-Bradley JR, Horsewill AJ. A 13C field-cycling NMR relaxometry investigation of proton tunnelling in the hydrogen bond: dynamic isotope effects, the influence of heteronuclear interactions and coupled relaxation. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2005; 175:210-21. [PMID: 15908247 DOI: 10.1016/j.jmr.2005.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2005] [Revised: 04/06/2005] [Accepted: 04/06/2005] [Indexed: 05/02/2023]
Abstract
Concerted double proton transfer in the hydrogen bonds of a carboxylic acid dimer has been studied using 13C field-cycling NMR relaxometry. Heteronuclear 13C-1H dipolar interactions dominate the 13C spin-lattice relaxation which is significantly influenced by the polarisation state of the 1H Zeeman reservoir. The methodology of field-cycling experiments for such heteronuclear spin-coupled systems is studied experimentally and theoretically, including an investigation of various saturation-recovery and polarisation-recovery pulse sequence schemes. A theoretical model of the spin-lattice relaxation of this coupled system is presented which is corroborated by experiment. Spectral density components with frequencies omega(C), omega(C) + omega(H), and omega(C) - omega(H) are mapped out experimentally from the magnetic field dependence of the 13C and 1H spin-lattice relaxation and the proton transfer rate at low temperature is determined from their widths. Any dynamic isotope effect on the proton tunnelling in the hydrogen bond arising from 13C enrichment in the skeletal framework of the dimer is found to be smaller than experimental uncertainties (approximately 5%).
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Affiliation(s)
- W Wu
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
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25
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Intramolecular proton transfer and tunnelling reactions of hydroxyphenylbenzoxazole derivatives in Xenon at 15 K. Chem Phys 2005. [DOI: 10.1016/j.chemphys.2004.11.039] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Wu W, Noble D, Horsewill A. The correspondence between quantum and classical mechanics: an experimental demonstration of the smooth transition between the two regimes. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2004.12.080] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Tautermann CS, Voegele AF, Liedl KR. The ground-state tunneling splitting of various carboxylic acid dimers. J Chem Phys 2004; 120:631-7. [PMID: 15267897 DOI: 10.1063/1.1630565] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Carboxylic acid dimers in gas phase reveal ground-state tunneling splittings due to a double proton transfer between the two subunits. In this study we apply a recently developed accurate semiclassical method to determine the ground-state tunneling splittings of eight different carboxylic acid derivative dimers (formic acid, benzoic acid, carbamic acid, fluoro formic acid, carbonic acid, glyoxylic acid, acrylic acid, and N,N-dimethyl carbamic acid) and their fully deuterated analogs. The calculated splittings range from 5.3e-4 to 0.13 cm(-1) (for the deuterated species from 2.8e-7 to 3.3e-4 cm(-1)), thus indicating a strong substituent dependence of the splitting, which varies by more than two orders of magnitude. One reason for differences in the splittings could be addressed to different barriers heights, which vary from 6.3 to 8.8 kcal/mol, due to different mesomeric stabilization of the various transition states. The calculated splittings were compared to available experimental data and good agreement was found. A correlation could be found between the tunneling splitting and the energy barrier of the double proton transfer, as the splitting increases with increased strength of the hydrogen bonds. From this correlation an empirical formula was derived, which allows the prediction of the ground-state tunneling splitting of carboxylic acid dimers at a very low cost and the tunneling splittings for parahalogen substituted benzoic acid dimers is predicted.
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Affiliation(s)
- Christofer S Tautermann
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 52a, A-6020 Innsbruck, Austria
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