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Double Proton Tautomerism via Intra- or Intermolecular Pathways? The Case of Tetramethyl Reductic Acid Studied by Dynamic NMR: Hydrogen Bond Association, Solvent and Kinetic H/D Isotope Effects. Molecules 2021; 26:molecules26144373. [PMID: 34299648 PMCID: PMC8304075 DOI: 10.3390/molecules26144373] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/29/2021] [Accepted: 06/30/2021] [Indexed: 11/17/2022] Open
Abstract
Using dynamic liquid-state NMR spectroscopy a degenerate double proton tautomerism was detected in tetramethyl reductic acid (TMRA) dissolved in toluene-d8 and in CD2Cl2. Similar to vitamin C, TMRA belongs to the class of reductones of biologically important compounds. The tautomerism involves an intramolecular HH transfer that interconverts the peripheric and the central positions of the two OH groups. It is slow in the NMR time scale around 200 K and fast at room temperature. Pseudo-first-order rate constants of the HH transfer and of the HD transfer after suitable deuteration were obtained by line shape analyses. Interestingly, the chemical shifts were found to be temperature dependent carrying information about an equilibrium between a hydrogen bonded dimer and a monomer forming two weak intramolecular hydrogen bonds. The structures of the monomer and the dimer are discussed. The latter may consist of several rapidly interconverting hydrogen-bonded associates. A way was found to obtain the enthalpies and entropies of dissociation, which allowed us to convert the pseudo-first-order rate constants of the reaction mixture into first-order rate constants of the tautomerization of the monomer. Surprisingly, these intrinsic rate constants were the same for toluene-d8 and CD2Cl2, but in the latter solvent more monomer is formed. This finding is attributed to the dipole moment of the TMRA monomer, compensated in the dimer, and to the larger dielectric constant of CD2Cl2. Within the margin of error, the kinetic HH/HD isotope effects were found to be of the order of 3 but independent of temperature. That finding indicates a stepwise HH transfer involving a tunnel mechanism along a double barrier pathway. The Arrhenius curves were described in terms of the Bell–Limbach tunneling model.
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Alkorta I, Elguero J, Del Bene JE. Perturbing the O-H …O Hydrogen Bond in 1-oxo-3-hydroxy-2-propene. Molecules 2021; 26:3086. [PMID: 34064185 PMCID: PMC8196739 DOI: 10.3390/molecules26113086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/06/2021] [Accepted: 05/12/2021] [Indexed: 11/16/2022] Open
Abstract
Ab initio MP2/aug'-cc-pVTZ calculations have been carried out to identify and characterize equilibrium structures and transition structures on the 1-oxo-3-hydroxy-2-propene: Lewis acid potential energy surfaces, with the acids LiH, LiF, BeH2, and BeF2. Two equilibrium structures, one with the acid interacting with the C=O group and the other with the interaction occurring at the O-H group, exist on all surfaces. These structures are separated by transition structures that present the barriers to the interconversion of the two equilibrium structures. The structures with the acid interacting at the C=O group have the greater binding energies. Since the barriers to convert the structures with interaction occurring at the O-H group are small, only the isomers with interaction occurring at the C=O group could be experimentally observed, even at low temperatures. Charge-transfer energies were computed for equilibrium structures, and EOM-CCSD spin-spin coupling constants 2hJ(O-O), 1hJ(H-O), and 1J(O-H) were computed for equilibrium and transition structures. These coupling constants exhibit a second-order dependence on the corresponding distances, with very high correlation coefficients.
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Affiliation(s)
- Ibon Alkorta
- Instituto de Química Médica, CSIC, Juan de la Cierva, 3, E-28006 Madrid, Spain;
| | - José Elguero
- Instituto de Química Médica, CSIC, Juan de la Cierva, 3, E-28006 Madrid, Spain;
| | - Janet E. Del Bene
- Department of Chemistry, Youngstown State University, Youngstown, OH 44555, USA
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3
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Marín-Luna M, Claramunt RM, López C, Pérez-Torralba M, Sanz D, Reviriego F, Alkorta I, Elguero J. A GIPAW versus GIAO-ZORA-SO study of 13C and 15N CPMAS NMR chemical shifts of aromatic and heterocyclic bromo derivatives. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2020; 108:101676. [PMID: 32640403 DOI: 10.1016/j.ssnmr.2020.101676] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 06/04/2020] [Accepted: 06/04/2020] [Indexed: 06/11/2023]
Abstract
Theoretical simulation of NMR parameters in compounds bearing heavy atoms generally requires the application of relativistic corrections. We report herein the theoretical characterization of 13C and 15N CPMAS NMR of known bromo-derivative crystals by using both the GIPAW and the combined GIAO-ZORA-SO approximation methods. Several statistical analyses were performed to compare both approaches, with non-relativistic GIPAW method being more useful to predict the 13C and 15N chemical shifts. The problem of applying GIPAW to crystal structures showing static or dynamic crystalline disorder of the special class resulting in half-protons will be discussed in detail.
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Affiliation(s)
- Marta Marín-Luna
- Departamento de Química Orgánica, Facultad de Química, Universidad de Murcia, Regional Campus of International Excellence "Campus Mare Nostrum", E-30100, Murcia, Spain.
| | - Rosa M Claramunt
- Departamento de Química Orgánica y Bio-Orgánica, Facultad de Ciencias, UNED, Paseo Senda del Rey, 9, E-28040, Madrid, Spain
| | - Concepción López
- Departamento de Química Orgánica y Bio-Orgánica, Facultad de Ciencias, UNED, Paseo Senda del Rey, 9, E-28040, Madrid, Spain
| | - Marta Pérez-Torralba
- Departamento de Química Orgánica y Bio-Orgánica, Facultad de Ciencias, UNED, Paseo Senda del Rey, 9, E-28040, Madrid, Spain
| | - Dionisia Sanz
- Departamento de Química Orgánica y Bio-Orgánica, Facultad de Ciencias, UNED, Paseo Senda del Rey, 9, E-28040, Madrid, Spain
| | - Felipe Reviriego
- Instituto de Ciencia y Tecnología de Polímeros, CSIC, Juan de la Cierva, 3, E-28006, Madrid, Spain
| | - Ibon Alkorta
- Instituto de Química Médica, CSIC, Juan de la Cierva, 3, E-28006, Madrid, Spain
| | - José Elguero
- Instituto de Química Médica, CSIC, Juan de la Cierva, 3, E-28006, Madrid, Spain
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4
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Kumar V, Pilati T, Quici S, Chierotti MR, Nervi C, Gobetto R, Resnati G. Proton in a Confined Space: Structural Studies of H + ⊂Crypt-111 Iodide and Some Halogen-Bonded Derivatives. Chemistry 2017; 23:14462-14468. [PMID: 28657685 DOI: 10.1002/chem.201701699] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2017] [Revised: 06/27/2017] [Indexed: 11/06/2022]
Abstract
Experimental observations and modeling data are reported on the solid-state structural features of crypt- 111⋅HI (1) and the three-component co-crystals that 1 forms with α,ω-diiodoperfluoroalkanes 2 a-d. X-ray analyses indicate that, in all five systems and at low temperature, the caged proton is covalently bonded to a single nitrogen atom and is involved in a network of intramolecular hydrogen bonds. In contrast, room-temperature, solid-state 15 N NMR spectroscopy suggests magnetic equivalency of the two N atoms of crypt-111 in both 1 and co-crystals of 1 with diiodoperfluoroalkanes. Computational modelling confirms that the acidic hydrogen inside the cavity preferentially sits along the internitrogen axis and is covalently bonded to one nitrogen. The computed energy barriers suggest that the hopping of the encapsulated proton between the two N atoms of the cage can occur in the halogen-bonded co-crystals of 1⋅2, but it is hardly possible in the pure H+ ⊂crypt-111 iodide 1. These different pictures of the proton position and dynamics obtained by using different techniques and conditions confirm the unique characteristics of the confined space within the cavity of crypr-111 and the distinctive features of processes occurring therein.
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Affiliation(s)
- Vijith Kumar
- Nanostructured Fluorinated Materials Laboratory (NFMLab), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Via L. Mancinelli 7, 20131, Milan, Italy
| | - Tullio Pilati
- Nanostructured Fluorinated Materials Laboratory (NFMLab), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Via L. Mancinelli 7, 20131, Milan, Italy
| | - Silvio Quici
- CNR, Istituto di Scienze e Tecnologie Molecolari, Via C. Golgi 19, 20133, Milan, Italy
| | - Michele R Chierotti
- Department of Chemistry and NIS, University of Turin, Via P. Giuria 7, 10125, Turin, Italy
| | - Carlo Nervi
- Department of Chemistry and NIS, University of Turin, Via P. Giuria 7, 10125, Turin, Italy
| | - Roberto Gobetto
- Department of Chemistry and NIS, University of Turin, Via P. Giuria 7, 10125, Turin, Italy
| | - Giuseppe Resnati
- Nanostructured Fluorinated Materials Laboratory (NFMLab), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Via L. Mancinelli 7, 20131, Milan, Italy
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Mahmudov KT, Pombeiro AJL. Resonance-Assisted Hydrogen Bonding as a Driving Force in Synthesis and a Synthon in the Design of Materials. Chemistry 2016; 22:16356-16398. [PMID: 27492126 DOI: 10.1002/chem.201601766] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Indexed: 11/08/2022]
Abstract
Resonance-assisted hydrogen bonding (RAHB), a concept introduced by Gilli and co-workers in 1989, concerns a kind of intramolecular H-bonding strengthened by a conjugated π-system, usually in 6-, 8-, or 10-membered rings. This Review highlights the involvement of RAHB as a driving force in the synthesis of organic, coordination, and organometallic compounds, as a handy tool in the activation of covalent bonds, and in starting moieties for synthetic transformations. The unique roles of RAHB in molecular recognition and switches, E/Z isomeric resolution, racemization and epimerization of amino acids and chiral amino alcohols, solvatochromism, liquid-crystalline compounds, and in synthons for crystal engineering and polymer materials are also discussed. The Review can provide practical guidance for synthetic chemists that are interested in exploring and further developing RAHB-assisted synthesis and design of materials.
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Affiliation(s)
- Kamran T Mahmudov
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisboa, Portugal. .,Department of Chemistry, Baku State University, Z. Xalilov Str. 23, Az 1148, Baku, Azerbaijan.
| | - Armando J L Pombeiro
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisboa, Portugal.
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Mitsumi M, Ezaki K, Komatsu Y, Toriumi K, Miyatou T, Mizuno M, Azuma N, Miyazaki Y, Nakano M, Kitagawa Y, Hanashima T, Kiyanagi R, Ohhara T, Nakasuji K. Proton Order-Disorder Phenomena in a Hydrogen-Bonded Rhodium-η(5)-Semiquinone Complex: A Possible Dielectric Response Mechanism. Chemistry 2015; 21:9682-96. [PMID: 26032896 DOI: 10.1002/chem.201500796] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Indexed: 11/06/2022]
Abstract
A newly synthesized one-dimensional (1D) hydrogen-bonded (H-bonded) rhodium(II)-η(5)-semiquinone complex, [Cp*Rh(η(5)-p-HSQ-Me4)]PF6 ([1]PF6; Cp* = 1,2,3,4,5-pentamethylcyclopentadienyl; HSQ = semiquinone) exhibits a paraelectric-antiferroelectric second-order phase transition at 237.1 K. Neutron and X-ray crystal structure analyses reveal that the H-bonded proton is disordered over two sites in the room-temperature (RT) phase. The phase transition would arise from this proton disorder together with rotation or libration of the Cp* ring and PF6(-) ion. The relative permittivity εb' along the H-bonded chains reaches relatively high values (ca., 130) in the RT phase. The temperature dependence of (13)C CP/MAS NMR spectra demonstrates that the proton is dynamically disordered in the RT phase and that the proton exchange has already occurred in the low-temperature (LT) phase. Rate constants for the proton exchange are estimated to be 10(-4)-10(-6) s in the temperature range of 240-270 K. DFT calculations predict that the protonation/deprotonation of [1](+) leads to interesting hapticity changes of the semiquinone ligand accompanied by reduction/oxidation by the π-bonded rhodium fragment, producing the stable η(6)-hydroquinone complex, [Cp*Rh(3+)(η(6)-p-H2Q-Me4)](2+) ([2](2+)), and η(4)-benzoquinone complex, [Cp*Rh(+)(η(4)-p-BQ-Me4)] ([3]), respectively. Possible mechanisms leading to the dielectric response are discussed on the basis of the migration of the protonic solitons comprising of [2](2+) and [3], which would be generated in the H-bonded chain.
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Affiliation(s)
- Minoru Mitsumi
- Department of Material Science, Graduate School of Material Science, University of Hyogo and, Research Center for New Functional Materials, Graduate School of Material Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297 (Japan).
| | - Kazunari Ezaki
- Department of Material Science, Graduate School of Material Science, University of Hyogo and, Research Center for New Functional Materials, Graduate School of Material Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297 (Japan)
| | - Yuuki Komatsu
- Department of Material Science, Graduate School of Material Science, University of Hyogo and, Research Center for New Functional Materials, Graduate School of Material Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297 (Japan)
| | - Koshiro Toriumi
- Department of Material Science, Graduate School of Material Science, University of Hyogo and, Research Center for New Functional Materials, Graduate School of Material Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297 (Japan)
| | - Tatsuya Miyatou
- Department of Chemistry, Graduate School of Natural Science & Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192 (Japan)
| | - Motohiro Mizuno
- Department of Chemistry, Graduate School of Natural Science & Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192 (Japan).
| | - Nobuaki Azuma
- Research Center for Structural Thermodynamics, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan)
| | - Yuji Miyazaki
- Research Center for Structural Thermodynamics, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan).
| | - Motohiro Nakano
- Research Center for Structural Thermodynamics, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan)
| | - Yasutaka Kitagawa
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan).
| | - Takayasu Hanashima
- Research Center for Neutron Science and Technology, CROSS Tokai, Ibaraki 319-1106 (Japan)
| | - Ryoji Kiyanagi
- J-PARC center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan)
| | - Takashi Ohhara
- J-PARC center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan).
| | - Kazuhiro Nakasuji
- School of Materials Science, Fukui University of Technology, 3-6 Gakuen, Fukui 910-8505 (Japan)
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8
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Masuda Y, Mori Y, Sakurai K. Effects of Counterion and Solvent on Proton Location and Proton Transfer Dynamics of N–H···N Hydrogen Bond of Monoprotonated 1,8-Bis(dimethylamino)naphthalene. J Phys Chem A 2013; 117:10576-87. [DOI: 10.1021/jp4061297] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yuichi Masuda
- Department of Chemistry,
Faculty of Science, Ochanomizu University, Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
| | - Yukie Mori
- Department of Chemistry,
Faculty of Science, Ochanomizu University, Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
| | - Kazumi Sakurai
- Department of Chemistry,
Faculty of Science, Ochanomizu University, Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
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9
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Fita P, Ciacka P, Czerski I, Pietraszkiewicz M, Radzewicz C, Waluk J. Double Hydrogen Transfer in Low Symmetry Porphycenes. ACTA ACUST UNITED AC 2013. [DOI: 10.1524/zpch.2013.0372] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract
The rate constants of intramolecular double hydrogen transfer have been determined for of tert-butyl-substituted porphycenes: 2-tert-butyl-, 2,7-di-tert-butyl-, 2,7,12-tri-tert-butyl-, and 2,7,12,17-tetra-tert-butylporphycene using femtosecond pump-probe polarization spectroscopy. The rates increase monotonically with the number of substituents. As is the case for other porphycenes studied so far, the tautomerization becomes slower after excitation to the lowest excited singlet state. The potential for the trans-trans self-exchange reaction is symmetrical in di- and tetra-tert-butyl substituted derivatives, but not for the singly and triply substituted ones. Our studies enabled determination of the relative populations of nonequivalent tautomers and thus of the equilibrium constants in S0 and S1 states, as well as estimation of ground and excited state activation energies for the tautomerization process.
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Affiliation(s)
- Piotr Fita
- University of Warsaw, Faculty of Physics, Warsaw, Polen
| | - Piotr Ciacka
- University of Warsaw, Faculty of Physics, Warsaw, Polen
| | - Igor Czerski
- Polish Academy of Sciences, Institute of physical Chemistry, Warsaw, Polen
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10
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Ueda K, Oguni M. Quantum Tunneling in the Quadruple Proton Rearrangement on a Hydroxyl Hydrogen Bond Ring in Calix[4]arene. J Phys Chem B 2012; 116:14470-6. [DOI: 10.1021/jp304689z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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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11
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Torres V, Lopez JM, Langer U, Buntkowsky G, Vieth HM, Elguero J, Limbach HH. Kinetics of Coupled Double Proton and Deuteron Transfer in Hydrogen-Bonded Ribbons of Crystalline Pyrazole-4-carboxylic Acid. ACTA ACUST UNITED AC 2012. [DOI: 10.1524/zpch.2012.0305] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract
The proton tautomerism of pyrazole-4-carboxylic acid (PCA) has been studied by a combination of 15N CPMAS and 2H NMR spectroscopy and relaxometry. Down to 250 K, PCA forms a hydrogen bonded ribbon where adjacent carboxylic and pyrazole groups are linked by an OH···N and an O···HN hydrogen bond, forming either the tautomeric state A or B. Down to about 250 K, the tautomerism is fast on the NMR timescale and degenerate, corresponding to a phase exhibiting dynamic proton disorder. At lower temperatures, a transition to an ordered phase is observed with localized protons, assigned to an all-syn conformation adopting the sequence of tautomeric states ..ABABA.. The longitudinal 15N relaxation times T
1 of PCA-15N2 have been measured at 9.12 MHz (2.1 T). Because of the low field, a chemical shift anisotropy mechanism could be neglected, and the data were analyzed in terms of a dipolar 1H-15N relaxation mechanism, yielding the rate constants k
HH. The rate constants k
HD and k
DD were obtained from the measurement and analysis of the 2H T
1 values of PCA-15N1-d0.9 and PCA-15N1-d0.1 measured at 46.03 MHz. Within the margin of error, no kinetic isotope effects could be detected, in contrast to previous results reported for the very fast tautomerism of solid benzoic acid dimers and the much slower tautomerism of solid 3,5-diphenyl-4-brompyrazole (DPBrP) dimers. The Arrhenius curves of all three systems were simulated using the Bell–Limbach tunneling model. Evidence for a major heavy atom motion for the tautomerism of PCA is obtained, associated with small angle reorientation of PCA molecules around the molecular axis. The observed proton order-disorder transition and the mechanism of the observed rate process are discussed in terms of a coupling of adjacent tautomeric states.
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Affiliation(s)
- Verónica Torres
- Freie Universität Berlin, Institut für Chemie und Biochemie, Berlin, Deutschland
| | - Juan-Miguel Lopez
- Freie Universität Berlin, Institut für Chemie und Biochemie, Berlin, Deutschland
| | - Uwe Langer
- Freie Universität Berlin, Institut für Chemie und Biochemie, Berlin, Deutschland
| | - Gerd Buntkowsky
- Technische Universität Darmstadt, Eduard-Zintl-Institut für Anorganische und, Darmstadt, Deutschland
| | - Hans-Martin Vieth
- Freie Universität Berlin, Institut für Experimentalphysik, Berlin, Deutschland
| | - José Elguero
- CSIC, Instituto de Quimica Medica, Madrid, Spanien
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13
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Nakano T, Masuda Y. Application of Nuclear Magnetic Relaxation To Elucidate Proton Location and Dynamics in N···H···O Hydrogen Bonds. J Phys Chem A 2012; 116:8409-18. [DOI: 10.1021/jp303297c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tomoko Nakano
- Department of Chemistry, Faculty
of Science, Ochanomizu University, Bunkyo-ku,
Tokyo 112-8610, Japan
| | - Yuichi Masuda
- Department of Chemistry, Faculty
of Science, Ochanomizu University, Bunkyo-ku,
Tokyo 112-8610, Japan
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14
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Mori Y, Takano K. Location of protons in N–H⋯N hydrogen-bonded systems: a theoretical study on intramolecular pyridine–dihydropyridine and pyridine–pyridinium pairs. Phys Chem Chem Phys 2012; 14:11090-8. [DOI: 10.1039/c2cp41425b] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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15
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Enchev V, Angelova S, Rogojerov M, Monev V, Wawer I, Tkaczyk M, Kostova K. Solid-state tautomerism in 2-carboxyindan-1,3-dione. J Phys Chem A 2011; 115:2026-34. [PMID: 21338100 DOI: 10.1021/jp1100973] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The structure of 2-carboxyindan-1,3-dione was investigated using a combination of quantum-chemical calculations and solid-state NMR and IR spectroscopy. Due to poor solubility of the compound in different solvents, no single crystals could be obtained. Two dimeric structures formed from the tautomers of 2-carboxyindan-1,3-dione are likely to coexist in the solid state. The dimers interconvert via intramolecular proton transfer in one of the tautomeric forms constituting the dimers. The energy barrier of the intramolecular proton transfer reaction is calculated as 5.82 kcal mol(-1) at the MP2/6-31++G level of theory.
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Affiliation(s)
- Venelin Enchev
- Institute of Organic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria.
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16
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Schriever C, Lochbrunner S, Ofial AR, Riedle E. The origin of ultrafast proton transfer: Multidimensional wave packet motion vs. tunneling. Chem Phys Lett 2011. [DOI: 10.1016/j.cplett.2010.12.087] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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17
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Perrin CL, Karri P. Position-Specific Secondary Deuterium Isotope Effects on Basicity of Pyridine. J Am Chem Soc 2010; 132:12145-9. [DOI: 10.1021/ja105331g] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Charles L. Perrin
- Department of Chemistry & Biochemistry, University of California—San Diego, La Jolla, California 92093-0358
| | - Phaneendrasai Karri
- Department of Chemistry & Biochemistry, University of California—San Diego, La Jolla, California 92093-0358
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18
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Enk B, Eisenstecken D, Kopacka H, Wurst K, Müller T, Pevny F, Winter RF, Bildstein B. Doubly N-Functionalized Pentafulvenes and Redox-Responsive [N,N]- and [N,C,N]-Pincer Bis(imidoyl)pentamethylruthenocene Metalloligands. Organometallics 2010. [DOI: 10.1021/om100458h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Barbara Enk
- Institute of General, Inorganic and Theoretical Chemistry, Faculty of Chemistry and Pharmacy, University of Innsbruck, Innrain 52a, 6020 Innsbruck, Austria
| | - Daniela Eisenstecken
- Institute of General, Inorganic and Theoretical Chemistry, Faculty of Chemistry and Pharmacy, University of Innsbruck, Innrain 52a, 6020 Innsbruck, Austria
| | - Holger Kopacka
- Institute of General, Inorganic and Theoretical Chemistry, Faculty of Chemistry and Pharmacy, University of Innsbruck, Innrain 52a, 6020 Innsbruck, Austria
| | - Klaus Wurst
- Institute of General, Inorganic and Theoretical Chemistry, Faculty of Chemistry and Pharmacy, University of Innsbruck, Innrain 52a, 6020 Innsbruck, Austria
| | - Thomas Müller
- Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Innsbruck, Innrain 52a, 6020 Innsbruck, Austria
| | - Florian Pevny
- Department of Chemistry, University of Konstanz, Universitätstrasse 10, D-78457 Konstanz, Germany
| | - Rainer F. Winter
- Department of Chemistry, University of Konstanz, Universitätstrasse 10, D-78457 Konstanz, Germany
| | - Benno Bildstein
- Institute of General, Inorganic and Theoretical Chemistry, Faculty of Chemistry and Pharmacy, University of Innsbruck, Innrain 52a, 6020 Innsbruck, Austria
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Lesnichin SB, Tolstoy PM, Limbach HH, Shenderovich IG. Counteranion-dependent mechanisms of intramolecular proton transfer in aprotic solution. Phys Chem Chem Phys 2010; 12:10373-9. [PMID: 20582365 DOI: 10.1039/c004499g] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using the freon mixture CDF(3)/CDClF(2) as solvent we have been able to measure the (1)H and (15)N NMR spectra of the doubly (15)N labeled 2,2'-bipyridinium cation (BpyH(+)) at temperatures down to 115 K. The obtained NMR parameters strongly depend on the type of counteranions indicating the formation of ion pairs. In the case of the bulky poorly coordinating tetrakis[3,5-bis(trifluoromethyl)phenyl]-borate as the counteranion a strong intramolecular NHN hydrogen bond was observed in BpyH(+) exhibiting a degenerate intramolecular proton transfer which is of the order of 10(6) s(-1) even at 120 K. By contrast, the weak hydrogen bond acceptor tetrafluoroborate favors a weak intermolecular FHN interaction and quenches the intramolecular proton transfer. The intramolecular proton transfer requires in this case a dissociation of the ion pair which is hindered by the Coulomb interaction. A slow intramolecular proton transfer was observed in the case of dichloroacetate which forms a strong intermolecular OHN hydrogen bond to BpyH(+). The mechanism of this transfer presumably involves a preliminary intermolecular proton transfer from nitrogen towards oxygen followed by a hydrogen bond switch to the neighboring nitrogen to which the proton is then transferred.
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Affiliation(s)
- Stepan B Lesnichin
- Institut für Chemie und Biochemie der Freien Universiät Berlin, Takustrasse 3, D-14195, Berlin, Germany
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20
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Limbach HH, Schowen KB, Schowen RL. Heavy atom motions and tunneling in hydrogen transfer reactions: the importance of the pre-tunneling state. J PHYS ORG CHEM 2010. [DOI: 10.1002/poc.1663] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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21
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Noble DL, Aibout A, Horsewill AJ. 1H-19F spin-lattice relaxation spectroscopy: proton tunnelling in the hydrogen bond studied by field-cycling NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2009; 201:157-164. [PMID: 19783187 DOI: 10.1016/j.jmr.2009.09.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Revised: 08/24/2009] [Accepted: 09/02/2009] [Indexed: 05/28/2023]
Abstract
Proton tunnelling in the hydrogen bonds of two fluorine substituted benzoic acid dimers has been investigated using field-cycling NMR relaxometry. The close proximity of the (19)F nuclei to the hydrogen bond protons introduces heteronuclear (19)F-(1)H dipolar interactions into the spin-lattice relaxation processes. This renders the (1)H magnetisation-recovery biexponential and introduces multiple spectral density components into the relaxation matrix characterised by frequencies that are sums and differences of the (19)F and (1)H Larmor frequencies. Using field-cycling NMR pulse sequences that measure the spin-lattice relaxation and cross-relaxation rates we demonstrate how some of these multiple spectral density components can be separately resolved. This leads to an accurate determination of the correlation times that characterise the proton tunnelling motion. A broad spectrum of relaxation behaviour is illustrated and explored in the chosen samples and the investigation is used to explore the theory and practise of field-cycling NMR relaxometry in cases where heteronuclear interactions are significant.
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Affiliation(s)
- D L Noble
- School of Physics & Astronomy, University of Nottingham, University Park, Nottingham, England NG7 2RD, UK
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22
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Coles MP, Khalaf MS, Claramunt RM, García MA, Alkorta I, Elguero J. Double proton transfer in crystals of 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a] pyrimidine (hppH): 13C and 15N CPMAS NMR study of (hppH)2. J PHYS ORG CHEM 2009. [DOI: 10.1002/poc.1636] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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23
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Alkorta I, Blanco F, Elguero J. A theoretical structural analysis of the factors that affect (1)J(NH), (1h)J(NH) and (2h)J(NN) in N-H...N hydrogen-bonded complexes. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2009; 47:249-256. [PMID: 19097158 DOI: 10.1002/mrc.2382] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Calculations of (1)J(NH), (1h)J(NH) and (2h)J(NN) spin-spin coupling constants of 27 complexes presenting N-H...N hydrogen bonds have allowed to analyze these through hydrogen-bond coupling as a function of the hybridization of both nitrogen atoms and the charge (+1, 0, - 1) of the complex. The main conclusions are that the hybridization of N atom of the hydrogen bond donor is much more important than that of the hydrogen bond acceptor. Positive and negative charges (cationic and anionic complexes) exert opposite effects while the effect of the transition states 'proton-in-the-middle' is considerable.
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Affiliation(s)
- Ibon Alkorta
- Instituto de Química Médica, CSIC, Juan de la Cierva, 3, E-28006 Madrid, Spain.
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24
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Johnson AL, Willcocks AM, Raithby PR, Warren MR, Kingsley AJ, Odedra R. Unprecedented double migratory insertion of phenyl isocyanide into cyclopentadienyl C–H bonds. Dalton Trans 2009:922-4. [DOI: 10.1039/b822337h] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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25
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Lopez del Amo JM, Langer U, Torres V, Pietrzak M, Buntkowsky G, Vieth HM, Shibl MF, Kühn O, Bröring M, Limbach HH. Isotope and Phase Effects on the Proton Tautomerism in Polycrystalline Porphycene Revealed by NMR. J Phys Chem A 2008; 113:2193-206. [DOI: 10.1021/jp8079414] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Juan Miguel Lopez del Amo
- Institut für Chemie und Biochemie, Takustrasse 3, Freie Universität Berlin, D-14195 Berlin, Germany, Institut für Physikalische Chemie der Friedrich-Schiller Universität, Helmholtzweg 4, D-07743 Jena, Germany, Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany, Fachbereich Chemie, Philipps Universität Marburg, Hans-Meerwein-Strasse, 35032 Marburg, Germany
| | - Uwe Langer
- Institut für Chemie und Biochemie, Takustrasse 3, Freie Universität Berlin, D-14195 Berlin, Germany, Institut für Physikalische Chemie der Friedrich-Schiller Universität, Helmholtzweg 4, D-07743 Jena, Germany, Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany, Fachbereich Chemie, Philipps Universität Marburg, Hans-Meerwein-Strasse, 35032 Marburg, Germany
| | - Verónica Torres
- Institut für Chemie und Biochemie, Takustrasse 3, Freie Universität Berlin, D-14195 Berlin, Germany, Institut für Physikalische Chemie der Friedrich-Schiller Universität, Helmholtzweg 4, D-07743 Jena, Germany, Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany, Fachbereich Chemie, Philipps Universität Marburg, Hans-Meerwein-Strasse, 35032 Marburg, Germany
| | - Mariusz Pietrzak
- Institut für Chemie und Biochemie, Takustrasse 3, Freie Universität Berlin, D-14195 Berlin, Germany, Institut für Physikalische Chemie der Friedrich-Schiller Universität, Helmholtzweg 4, D-07743 Jena, Germany, Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany, Fachbereich Chemie, Philipps Universität Marburg, Hans-Meerwein-Strasse, 35032 Marburg, Germany
| | - Gerd Buntkowsky
- Institut für Chemie und Biochemie, Takustrasse 3, Freie Universität Berlin, D-14195 Berlin, Germany, Institut für Physikalische Chemie der Friedrich-Schiller Universität, Helmholtzweg 4, D-07743 Jena, Germany, Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany, Fachbereich Chemie, Philipps Universität Marburg, Hans-Meerwein-Strasse, 35032 Marburg, Germany
| | - Hans-Martin Vieth
- Institut für Chemie und Biochemie, Takustrasse 3, Freie Universität Berlin, D-14195 Berlin, Germany, Institut für Physikalische Chemie der Friedrich-Schiller Universität, Helmholtzweg 4, D-07743 Jena, Germany, Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany, Fachbereich Chemie, Philipps Universität Marburg, Hans-Meerwein-Strasse, 35032 Marburg, Germany
| | - Mohamed F. Shibl
- Institut für Chemie und Biochemie, Takustrasse 3, Freie Universität Berlin, D-14195 Berlin, Germany, Institut für Physikalische Chemie der Friedrich-Schiller Universität, Helmholtzweg 4, D-07743 Jena, Germany, Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany, Fachbereich Chemie, Philipps Universität Marburg, Hans-Meerwein-Strasse, 35032 Marburg, Germany
| | - Oliver Kühn
- Institut für Chemie und Biochemie, Takustrasse 3, Freie Universität Berlin, D-14195 Berlin, Germany, Institut für Physikalische Chemie der Friedrich-Schiller Universität, Helmholtzweg 4, D-07743 Jena, Germany, Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany, Fachbereich Chemie, Philipps Universität Marburg, Hans-Meerwein-Strasse, 35032 Marburg, Germany
| | - Martin Bröring
- Institut für Chemie und Biochemie, Takustrasse 3, Freie Universität Berlin, D-14195 Berlin, Germany, Institut für Physikalische Chemie der Friedrich-Schiller Universität, Helmholtzweg 4, D-07743 Jena, Germany, Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany, Fachbereich Chemie, Philipps Universität Marburg, Hans-Meerwein-Strasse, 35032 Marburg, Germany
| | - Hans-Heinrich Limbach
- Institut für Chemie und Biochemie, Takustrasse 3, Freie Universität Berlin, D-14195 Berlin, Germany, Institut für Physikalische Chemie der Friedrich-Schiller Universität, Helmholtzweg 4, D-07743 Jena, Germany, Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany, Fachbereich Chemie, Philipps Universität Marburg, Hans-Meerwein-Strasse, 35032 Marburg, Germany
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