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Journal articles on the topic 'Proton transfer reactions'

Author: Grafiati

Published: 4 June 2021

Last updated: 26 January 2023

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1

Mijatović, Tea, Suzana Szilner, Lorenzo Corradi, Franco Galtarossa, Samuel Bakes, Daniele Brugnara, Gabriele Carozzi, et al. "Multinucleon transfer reactions and proton transfer channels." EPJ Web of Conferences 223 (2019): 01039. http://dx.doi.org/10.1051/epjconf/201922301039.

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Transfer reactions have always been of great importance for nuclear structure and reaction mechanism studies. So far, in multinucleon transfer studies, proton pickup channels have been completely identified in atomic and mass numbers at energies close to the Coulomb barrier only in few cases. We measured the multinucleon transfer reactions in the 40Ar+208Pb system near the Coulomb barrier, by employing the PRISMA magnetic spectrometer. By using the most neutron-rich stable 40Ar beam we could populate, besidesneutron pickup and proton stripping channels, also neutron stripping and proton pickup channels. Comparison ofcross sections between different systems with the 208Pb target and with projectiles going from neutron-poor to neutron-rich nuclei, as well as between the data and GRAZING calculations, was carried out.Finally, recent results concerning the measurement of the excitation function from the Coulomb barrier to far below for the 92Mo+54Fe system, where both proton stripping and pickup channels were populated with similar strength, will be discussed.

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2

Brzezinski, Peter, Joachim Reimann, and Pia Ädelroth. "Molecular architecture of the proton diode of cytochrome c oxidase." Biochemical Society Transactions 36, no. 6 (November 19, 2008): 1169–74. http://dx.doi.org/10.1042/bst0361169.

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CytcO (cytochrome c oxidase) is a membrane-bound multisubunit protein which catalyses the reduction of O2 to H2O. The reaction is arranged topographically so that the electrons and protons are taken from opposite sides of the membrane and, in addition, it is also linked to proton pumping across the membrane. Thus the CytcO moves an equivalent of two positive charges across the membrane per electron transferred to O2. Proton transfer through CytcO must be controlled by the protein to prevent leaks, which would dissipate the proton electrochemical gradient that is maintained across the membrane. The molecular mechanism by which the protein controls the unidirectionality of proton-transfer (cf. proton diode) reactions and energetically links electron transfer to proton translocation is not known. This short review summarizes selected results from studies aimed at understanding this mechanism, and we discuss a possible mechanistic principle utilized by the oxidase to pump protons.

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3

Pavošević, Fabijan, Sharon Hammes-Schiffer, Angel Rubio, and Johannes Flick. "Cavity-Modulated Proton Transfer Reactions." Journal of the American Chemical Society 144, no. 11 (March 10, 2022): 4995–5002. http://dx.doi.org/10.1021/jacs.1c13201.

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4

Brzezinski, Peter. "Proton-transfer reactions in bioenergetics." Biochimica et Biophysica Acta (BBA) - Bioenergetics 1458, no. 1 (May 2000): 1–5. http://dx.doi.org/10.1016/s0005-2728(00)00056-6.

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5

Pines, E., and D. Huppert. "Geminate recombination proton-transfer reactions." Chemical Physics Letters 126, no. 1 (April 1986): 88–91. http://dx.doi.org/10.1016/0009-2614(86)85121-1.

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6

Meot-Ner, Michael. "Entropy-driven proton-transfer reactions." Journal of Physical Chemistry 95, no. 17 (August 1991): 6580–85. http://dx.doi.org/10.1021/j100170a039.

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7

J�rgensen, Solvejg, and Kurt V. Mikkelsen. "Proton transfer reactions in solution." International Journal of Quantum Chemistry 77, no. 1 (2000): 221–39. http://dx.doi.org/10.1002/(sici)1097-461x(2000)77:1<221::aid-qua21>3.0.co;2-6.

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8

Kapral, Raymond, Styliani Consta, and Daniel Laria. "1996 Polanyi Award Lecture Proton reactions in clusters." Canadian Journal of Chemistry 75, no. 1 (January 1, 1997): 1–8. http://dx.doi.org/10.1139/v97-001.

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Reactions in mesoscopic, molecular clusters may proceed by mechanisms and with rates that differ from those in bulk solvents. Two examples of reactions in large, liquid-state, molecular clusters are described to illustrate the distinctive features of these reactions: acid dissociation and proton transfer in aprotic, polar solvents. Both of these reactions involve proton dynamics so methods for dealing with mixed quantum–classical systems must be utilized to investigate the reaction dynamics. Surface versus bulk solvation effects play an important role in determining the reaction mechanisms as do the strong cluster fluctuations. Mechanisms for proton transfer within clusters that have no bulk analogs will be described. Keywords: proton reactions, mesoscopic clusters.

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9

Schmickler, Wolfgang. "The transfer coefficient in proton transfer reactions." Journal of Electroanalytical Chemistry and Interfacial Electrochemistry 284, no. 2 (May 1990): 269–77. http://dx.doi.org/10.1016/0022-0728(90)85037-6.

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10

STUCHEBRUKHOV, ALEXEI A. "ELECTRON TRANSFER REACTIONS COUPLED TO PROTON TRANSLOCATION: CYTOCHROME OXIDASE, PROTON PUMPS, AND BIOLOGICAL ENERGY TRANSDUCTION." Journal of Theoretical and Computational Chemistry 02, no. 01 (March 2003): 91–118. http://dx.doi.org/10.1142/s0219633603000318.

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Cytochrome oxidase (COX) is the terminal component of electron transport chain of the respiratory system in mitochondria, and one of the key enzymes responsible for energy generation in cells. COX functions as a proton pump that utilizes free energy of oxygen reduction for translocation of protons across the mitochondrion membrane. The proton gradient created in the process is later utilized to drive synthesis of ATP. Although the structure of COX has been recently resolved, the molecular mechanism of proton pumping remains unknown. In this paper, general principles and possible molecular mechanisms of energy transformations in this enzyme will be discussed. The main question is how exactly chemical energy of oxygen reduction and water formation is transformed into a proton gradient; or, how exactly electron transfer reactions are utilized to translocate protons across the mitochondrion membrane against the electrochemical gradient. A key to the solution of this problem is in understanding correlated transport of electrons and protons. Here, theoretical models are discussed for coupled electron and proton transfer reactions in which an electron is tunneling over long distance between two redox cofactors, and a coupled proton is moving along a proton conducting channel in a classical, diffusion-like random walk fashion. Such reactions are typical for COX and other enzymes involved in biological energy transformations.

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11

Junge, W., S. Engelbrecht, C. Griwatz, and G. Groth. "THE CHLOROPLAST H+-ATPase: PARTIAL REACTIONS OF THE PROTON." Journal of Experimental Biology 172, no. 1 (November 1, 1992): 461–74. http://dx.doi.org/10.1242/jeb.172.1.461.

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This article reviews proton intake, charge transfer and proton release by F-ATPases, based in part on flash spectrophotometric studies on the chloroplast ATPase in thylakoid membranes, CF1Fo. The synthesis-coupled translocation of charges by CF1Fo (maximum rate <1500 s-1) and the dissipative flow through its exposed channel portion, CFo (rate >10 000 s-1), are extremely proton-specific (selectivity H+:K+>10(7):1). The proton-specific filter is located in CFo. Proton flow through exposed CFo can be throttled by adding subunit (&dgr;) or subunit &bgr; of CF1. These subunits thus may provide energy-transducing contacts between CF1 and CFo. Recently, we characterized two conditions where, in contrast to the above situation, proton intake by CF1Fo was decoupled from proton transfer across the main dielectric barrier: (a) CF1Fo structurally distorted by low ionic strength transiently trapped protons in a highly cooperative manner, but remained proton tight. This result has been interpreted in terms of Mitchell's proton well. (b) In the absence of nucleotides there is a proton slip. Addition of nucleotides (100 nmol l-1 ADP) abolished proton conduction but not proton intake by CF1Fo. These experiments functionally tag proton binding groups on CF1Fo that are located before the main dielectric barrier.

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12

KROLL, P., M. SCHÜRMANN, and W. SCHWEIGER. "EXCLUSIVE PHOTON-PROTON REACTIONS AT MODERATELY LARGE MOMENTUM TRANSFER." International Journal of Modern Physics A 06, no. 23 (September 30, 1991): 4107–32. http://dx.doi.org/10.1142/s0217751x91002021.

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The diquark model in which protons are viewed as being built up by quarks and diquarks (the latter are treated as quasi-elementary constituents at moderately large momentum transfer) is applied to Compton scattering off protons and combined with similar studies of the electromagnetic form factors of nucleons and of [Formula: see text]. It is demonstrated that the model is able to describe very well the data for these reactions at moderately large values of the momentum transfer with a common set of parameters. We also investigate the helicity dependence of the amplitudes. Very interesting and characteristic predictions for various observables are given. In particular a sizeable transversal polarization of the proton is obtained for Compton scattering.

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13

Formosinho, Sebastião J., and Luís G. Arnaut. "Excited-state proton transfer reactions II. Intramolecular reactions." Journal of Photochemistry and Photobiology A: Chemistry 75, no. 1 (October 1993): 21–48. http://dx.doi.org/10.1016/1010-6030(93)80158-6.

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14

Wang, Se, Zhuang Wang, and Ce Hao. "Role of intramolecular hydrogen bonding in the excited-state intramolecular double proton transfer (ESIDPT) of calix[4]arene: A TDDFT study." Open Physics 14, no. 1 (January 1, 2016): 602–9. http://dx.doi.org/10.1515/phys-2016-0067.

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AbstractThe time-dependent density functional theory (TDDFT) method was performed to investigate the excited-state intramolecular double proton transfer (ESIDPT) reaction of calix[4]arene (C4A) and the role of the intramolecular hydrogen bonds in the ESIDPT process. The geometries of C4A in the ground state and excited states (S1, S2 and T1) were optimized. Four intramolecular hydrogen bonds formed in the C4A are strengthened or weakened in the S2 and T1 states compared to those in the ground state. Interestingly, upon excitation to the S1 state of C4A, two protons H1 and H2 transfer along the two intramolecular hydrogen bonds O1-H1···O2 and O2-H2···O3, while the other two protons do not transfer. The ESIDPT reaction breaks the primary symmetry of C4A in the ground state. The potential energy curves of proton transfer demonstrate that the ESIDPT process follows the stepwise mechanism but not the concerted mechanism. Findings indicate that intramolecular hydrogen bonding is critical to the ESIDPT reactions in intramolecular hydrogen-bonded systems.

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15

Richard, John P. "Enzymatic catalysis of proton transfer and decarboxylation reactions." Pure and Applied Chemistry 83, no. 8 (July 8, 2011): 1555–65. http://dx.doi.org/10.1351/pac-con-11-02-05.

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Deprotonation of carbon and decarboxylation at enzyme active sites proceed through the same carbanion intermediates as for the uncatalyzed reactions in water. The mechanism for the enzymatic reactions can be studied at the same level of detail as for nonenzymatic reactions, using the mechanistic tools developed by physical organic chemists. Triosephosphate isomerase (TIM)-catalyzed interconversion of D-glyceraldehyde 3-phosphate (GAP) and dihydroxyacetone phosphate (DHAP) is being studied as a prototype for enzyme-catalyzed proton transfer, and orotidine monophosphate decarboxylase (OMPDC)-catalyzed decarboxylation of orotidine 5'-monophosphate (OMP) is being studied as a prototype for enzyme-catalyzed decarboxylation. 1H NMR spectroscopy is an excellent analytical method to monitor proton transfer to and from carbon catalyzed by these enzymes in D2O. Studies of these partial enzyme-catalyzed exchange reactions provide novel insight into the stability of carbanion reaction intermediates, which is not accessible in studies of the full enzymatic reaction. The importance of flexible enzyme loops and the contribution of interactions between these loops and the substrate phosphodianion to the enzymatic rate acceleration are discussed. The similarity in the interactions of OMPDC and TIM with the phosphodianion of bound substrate is emphasized.

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16

Cukier, R. I., and M. Morillo. "Solvent effects on proton‐transfer reactions." Journal of Chemical Physics 91, no. 2 (July 15, 1989): 857–63. http://dx.doi.org/10.1063/1.457137.

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17

Formosinho, Sebasti�o J. "Theoretical studies of proton-transfer reactions." Journal of the Chemical Society, Perkin Transactions 2, no. 1 (1987): 61. http://dx.doi.org/10.1039/p29870000061.

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18

Kalanderopoulos, Peter, and Keith Yates. "Intramolecular proton transfer in photohydration reactions." Journal of the American Chemical Society 108, no. 20 (October 1986): 6290–95. http://dx.doi.org/10.1021/ja00280a028.

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19

Stiller, W., R. Schmidt, and R. Schuster. "Proton-transfer reactions in ionized gases." Radiation Physics and Chemistry (1977) 26, no. 5 (January 1985): 571–73. http://dx.doi.org/10.1016/0146-5724(85)90212-2.

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20

Mui, Collin, Joseph H. Han, George T. Wang, Charles B. Musgrave, and Stacey F. Bent. "Proton Transfer Reactions on Semiconductor Surfaces." Journal of the American Chemical Society 124, no. 15 (April 2002): 4027–38. http://dx.doi.org/10.1021/ja0171512.

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21

Adamson, Aiko, Jean-Claude Guillemin, and Peeter Burk. "Proton transfer reactions of hydrazine-boranes." Journal of Physical Organic Chemistry 28, no. 4 (January 6, 2015): 244–49. http://dx.doi.org/10.1002/poc.3401.

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22

Li, Xiaoping, and John Alfred Stone. "The gas phase ion chemistry and proton affinity of hexamethyldisiloxane studied by high pressure mass spectrometry." Canadian Journal of Chemistry 65, no. 10 (October 1, 1987): 2454–60. http://dx.doi.org/10.1139/v87-410.

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The ion chemistry of hexamethyldisiloxane ((CH3)3SiOSi(CH3)3, HMDS) has been studied under chemical ionization conditions at ion source temperatures of 300–600 K and pressures of 2–4 Torr. Highly exothermic proton transfer to HMDS from CH5+ and C2H5+ leads mainly to loss of CH3 but with decreasing exothermicity the yield of HMDSH+ increases such that transfer from t-C4H9+ (ΔH0 = −7.5 kcal mol−1) yields almost exclusively HMDSH+. Although HMDSH+ transfers (CH3)3Si+ rather than a proton to most reference bases, the proton affinity of HMDS has been determined from van't Hoff plots using the equilibrium method with methylaromatics as reference bases. PA(HMDS) = 203.4 kcal mol−1 is in excellent accord with an earlier estimate of 203 kcal mol−1 obtained by the bracketing method. The rate constants for these proton transfer reactions show very large negative temperature coefficients in the exothermic directions which are consistent with the reactions of charge delocalized ions and/or reactions in which considerable loss of rotational freedom occurs along the reaction coordinate. The rate constants in the reverse directions have a positive temperature coefficient only when the endothermicity is significant (>2.5 kcal mol−1).

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23

Ramamurthy, V., P. Lakshminarasimhan, Clare P. Grey, and Linda J. Johnston. "Energy transfer, proton transfer and electron transfer reactions within zeolites." Chemical Communications, no. 22 (1998): 2411–24. http://dx.doi.org/10.1039/a803871f.

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24

Seabra, C. C., R. Linares, V. A. B. Zagatto, F. Cappuzzello, M. Cavallaro, D. Carbone, C. Agodi, and J. R. B. Oliveira. "Investigation of the transfer reactions induced by ¹⁶O in ²⁷Al and ²⁸Si at E_lab = 240 MeV." Journal of Physics: Conference Series 2340, no. 1 (September 1, 2022): 012037. http://dx.doi.org/10.1088/1742-6596/2340/1/012037.

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Abstract In this contribution, we present first experimental results for the deuteron pickup transfer in the 16O+28Si system at E lab. = 240 MeV. This reaction populates states in the 26Al target-like nucleus. In the same experimental campaign we have also measured the one-proton transfer 28Si(16O,17F)27Al and one-neutron transfer 27Al(16O,17O)26Al at the same beam energy. Comparison between the energy spectrum of these transfer reactions indicate that: i) the one-proton and one-neutron transfers favor the population of the low-lying states; ii) deuteron transfer to the ground state in 26Al is highly suppressed; iii) the cross-sections for deuteron transfer that populates low-lying states in 26Al are roughly 3 times less than the one-neutron transfer.

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25

Limbach, Hans-Heinrich, Ludger Meschede, and Gerd Scherer. "NMR Stratagems for the Study of Multiple Kinetic Hydrogen/Deuterium Isotope Effectsof Proton Exchange. Example: Di-p-fluorophenylformamidine/THF." Zeitschrift für Naturforschung A 44, no. 5 (May 1, 1989): 459–72. http://dx.doi.org/10.1515/zna-1989-0516.

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Stratagems are presented for the determination of kinetic isotope effects of proton exchange reactions by dynamic NMR spectroscopy. In such experiments, lineshape analyses and/or polarization transfer experiments are performed on the exchanging protons or deuterons as well as on remote spins, as a function of the deuterium fraction in the mobile proton sites. These methods are NMR analogs of previous proton inventory techniques involving classical kinetic methods. A theory is developed in order to derive the kinetic isotope effects as well as the number of transferred protons from the experimental NMR spectra. The technique is then applied to the problem of proton exchange in the system 15N,15N′-di-p-fluorophenylibrmamidine, a nitrogen analog of formic acid, dissolved in tetrahydrofuran-d8 (THF). DFFA forms two conformers in THF to which s-trans and s-cis structures have been assigned. Only the s-trans conformer is able to dimerize and exchange protons. Lineshape simulations and magnetization transfer experiments were carried out at 189,2 K, at a concentration of 0.02 mol l-1, as a function of the deuterium fraction D in the 1H-15N sites. Using 1H NMR spectroscopy, a linear dependence of the inverse proton lifetimes on D was observed. From this it was concluded that two protons are transported in the rate limiting step of the proton exchange. This result is expected for a double proton transfer in an s-trans dimer with a cyclic structure. The full kinetic HH/HD/DD isotope effects of 233:11:1 at 189 K were determined through 19F NMR experiments on the same samples. The deviation from the rule of geometric mean, although substantial, is much smaller than found in previous studies of intramolecular HH transfer reactions. Possible causes of this effect are discussed.

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26

Spesyvyi, Anatolii, David Smith, and Patrik Španěl. "Ion chemistry at elevated ion–molecule interaction energies in a selected ion flow-drift tube: reactions of H3O+, NO+ and O2+ with saturated aliphatic ketones." Physical Chemistry Chemical Physics 19, no. 47 (2017): 31714–23. http://dx.doi.org/10.1039/c7cp05795d.

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27

Fox, A., A. B. Raksit, S. Dheandhanoo, and D. K. Bohme. "Selected-ion flow tube studies of reactions of the radical cation (HC3N)+• in the interstellar chemical synthesis of cyanoacetylene." Canadian Journal of Chemistry 64, no. 2 (February 1, 1986): 399–403. http://dx.doi.org/10.1139/v86-064.

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The radical cation (HC3N)+• was produced in a Selected-Ion Flow Tube (SIFT) apparatus from cyanoacetylene by electron impact and reacted at room temperature in helium buffer gas with a selection of molecules including H2, CO, HCN, CH4, H2O, O2, HC3N, C2H2, OCS, C2H4, and C4H2. The observed reactions exhibited a wide range of reactivity and a variety of pathways including charge transfer, hydrogen atom transfer, proton transfer, and association. Association reactions were observed with CO, O2, HCN, and HC3N. With the latter two molecules association was observed to proceed close to the collision limit, which is suggestive of covalent bond formation perhaps involving azine-like N—N bonds. For HC3N an equally rapid association has been observed by Buckley etal. with ICR (Ion Cyclotron Resonance) measurements at low pressures and this is suggestive of radiative association. The hydrogen atom transfer reaction of ionized cyanoacetylene with H2 is slow while similar reactions with CH4 and H2O are fast. The reaction with CO fails to transfer a proton. These results have implications for synthetic schemes for cyanoacetylene as proposed in recent models of the chemistry of interstellar gas clouds. Proton transfer was also observed to be curiously unfavourable with all other molecules having a proton affinity higher than (C3N)•. Also, hydrogen-atom transfer was inefficient with the polar molecules HCN and HC3N. These results suggest that interactions at close separations may lead to preferential alignment of the reacting ion and molecule which is not suited for proton transfer or hydrogen atom transfer.

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28

Çakıcıoğlu-Özkan, Fehime, and İlker Polatoğlu. "Kinetics of proton transfer in the zeolitic tuff." Open Chemistry 7, no. 3 (September 1, 2009): 508–11. http://dx.doi.org/10.2478/s11532-009-0034-y.

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AbstractThe kinetics of a proton transfer into dilute acid solutions containing natural zeolitic tuff was studied by following the pH evolution of the liquid phase. Four different solutions with tuff contents of 9, 3, 1 and 0.5 (% wt) and three different particle size fractions (≤ 2000 μm) were studied. The proton concentration of the solution was decreased by increasing the zeolite amount and decreasing the particle size fraction. The proton transfer reaction was analyzed with chemical reactions and diffusion model equations. Analysis shows that the adsorption and/or ion exchange are possible mechanisms and are expressed by a second order reaction model.

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29

ARTEMOV, S. V., S. B. IGAMOV, A. A. KARAKHODZHAEV, G. K. NIE, R. YARMUKHAMEDOV, E. A. ZAPAROV, N. BURTEBAEV, and K. E. REHM. "ESTIMATES OF THE ASTROPHYSICAL S-FACTORS FOR PROTON RADIATIVE CAPTURE BY 10B AND 24Mg NUCLEI USING THE ANCs FROM PROTON TRANSFER REACTIONS." International Journal of Modern Physics E 19, no. 05n06 (June 2010): 1102–8. http://dx.doi.org/10.1142/s0218301310015540.

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The contribution of the direct radiative capture of protons by 10 B and 24 Mg nuclei at low energies to the astrophysical S -factors in the reactions 10 B (p,γ)11 C and 24 Mg (p,γ)25 Al have been calculated within the R-matrix formalism by using empirical proton asymptotical normalization coefficients (ANC). The ANCs for bound proton configurations {10 B +p} and {24 Mg +p} were obtained from the analysis of the reactions (3 He , d). The ANCs were also estimated from the values of the neutron ANCs in the mirror nucleus 25 Mg following the suggestion that the neutron and the proton in the mirror states have equivalent nuclear potentials. It has been found that the S -factor for the reaction 10 B (p,γ)11 C extrapolated to zero energy contributes ~100 keV b to the radiative capture to the ground state of 11 C . For the reaction 24 Mg (p,γ)25 Al the value S(0) gives 58 keV b with a direct capture contribution of 41 keV b .

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30

Chen, Chi-Lin, Yi-Ting Chen, Alexander P. Demchenko, and Pi-Tai Chou. "Amino proton donors in excited-state intramolecular proton-transfer reactions." Nature Reviews Chemistry 2, no. 7 (July 2018): 131–43. http://dx.doi.org/10.1038/s41570-018-0020-z.

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31

Reimers, Jeffrey R., Laura K. McKemmish, Ross H. McKenzie, and Noel S. Hush. "A unified diabatic description for electron transfer reactions, isomerization reactions, proton transfer reactions, and aromaticity." Physical Chemistry Chemical Physics 17, no. 38 (2015): 24598–617. http://dx.doi.org/10.1039/c5cp02236c.

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32

Cukier, R. I. "Mechanism for Proton-Coupled Electron-Transfer Reactions." Journal of Physical Chemistry 98, no. 9 (March 1994): 2377–81. http://dx.doi.org/10.1021/j100060a027.

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33

Szundi, Istvan, Tina L. Mah, James W. Lewis, Stefan Jäger, Oliver P. Ernst, Klaus Peter Hofmann, and David S. Kliger. "Proton Transfer Reactions Linked to Rhodopsin Activation†." Biochemistry 37, no. 40 (October 1998): 14237–44. http://dx.doi.org/10.1021/bi981249k.

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34

Hansel, A., W. Singer, A. Wisthaler, M. Schwarzmann, and W. Lindinger. "Energy dependencies of the proton transfer reactions." International Journal of Mass Spectrometry and Ion Processes 167-168 (November 1997): 697–703. http://dx.doi.org/10.1016/s0168-1176(97)00128-6.

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35

Buin, Andrei, and Radu Iftimie. "Molecular polarizabilities in aqueous proton transfer reactions." Journal of Chemical Physics 131, no. 23 (December 21, 2009): 234507. http://dx.doi.org/10.1063/1.3275963.

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36

Albery, W. John. "Isotope effects in double-proton-transfer reactions." Journal of Physical Chemistry 90, no. 16 (July 1986): 3774–83. http://dx.doi.org/10.1021/j100407a053.

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37

Pecina, O., and W. Schmickler. "A model for electrochemical proton-transfer reactions." Chemical Physics 228, no. 1-3 (March 1998): 265–77. http://dx.doi.org/10.1016/s0301-0104(97)00299-1.

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38

Wirz, J. "Kinetics of proton transfer reactions involving carbon." Pure and Applied Chemistry 70, no. 11 (November 30, 1998): 2221–32. http://dx.doi.org/10.1351/pac199870112221.

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39

Tognetti, Vincent, and Carlo Adamo. "Optimized GGA Functional for Proton Transfer Reactions†." Journal of Physical Chemistry A 113, no. 52 (December 31, 2009): 14415–19. http://dx.doi.org/10.1021/jp903672e.

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40

Rožman, Marko, Andrea Schneider, and Simon J. Gaskell. "Proton transfer reactions for improved peptide characterisation." Journal of Mass Spectrometry 46, no. 6 (June 2011): 529–34. http://dx.doi.org/10.1002/jms.1920.

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41

Wròblewski, T., L. Ziemczonek, and G. P. Karwasz. "Proton transfer reactions for ionized water clusters." Czechoslovak Journal of Physics 54, S3 (March 2004): C747—C752. http://dx.doi.org/10.1007/bf03166481.

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42

Petrie, Simon, and Diethard K. Bohme. "Proton transfer reactions of derivatized fullerene trications." Journal of the American Society for Mass Spectrometry 9, no. 2 (February 1998): 114–20. http://dx.doi.org/10.1016/s1044-0305(97)00234-1.

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43

Christov, S. G. "Theory of proton transfer reactions in solution." Chemical Physics 168, no. 2-3 (December 1992): 327–39. http://dx.doi.org/10.1016/0301-0104(92)87166-7.

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44

Sen Gupta, Susanta K. "Proton transfer reactions in apolar aprotic solvents." Journal of Physical Organic Chemistry 29, no. 5 (December 22, 2015): 251–64. http://dx.doi.org/10.1002/poc.3524.

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45

Abu-Saleh, Abd Al-Aziz A., Mansour H. Almatarneh, and Raymond A. Poirier. "Bimolecular reactions of carbenes: Proton transfer mechanism." Chemical Physics Letters 698 (April 2018): 36–40. http://dx.doi.org/10.1016/j.cplett.2018.03.001.

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46

Ishikita, Hiroshi, and Keisuke Saito. "Proton transfer reactions and hydrogen-bond networks in protein environments." Journal of The Royal Society Interface 11, no. 91 (February 6, 2014): 20130518. http://dx.doi.org/10.1098/rsif.2013.0518.

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In protein environments, proton transfer reactions occur along polar or charged residues and isolated water molecules. These species consist of H-bond networks that serve as proton transfer pathways; therefore, thorough understanding of H-bond energetics is essential when investigating proton transfer reactions in protein environments. When the p K a values (or proton affinity) of the H-bond donor and acceptor moieties are equal, significantly short, symmetric H-bonds can be formed between the two, and proton transfer reactions can occur in an efficient manner. However, such short, symmetric H-bonds are not necessarily stable when they are situated near the protein bulk surface, because the condition of matching p K a values is opposite to that required for the formation of strong salt bridges, which play a key role in protein–protein interactions. To satisfy the p K a matching condition and allow for proton transfer reactions, proteins often adjust the p K a via electron transfer reactions or H-bond pattern changes. In particular, when a symmetric H-bond is formed near the protein bulk surface as a result of one of these phenomena, its instability often results in breakage, leading to large changes in protein conformation.

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Lutz, Stephan, Ivan Tubert-Brohman, Yonggang Yang, and Markus Meuwly. "Water-assisted Proton Transfer in Ferredoxin I." Journal of Biological Chemistry 286, no. 27 (April 29, 2011): 23679–87. http://dx.doi.org/10.1074/jbc.m111.230003.

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The role of water molecules in assisting proton transfer (PT) is investigated for the proton-pumping protein ferredoxin I (FdI) from Azotobacter vinelandii. It was shown previously that individual water molecules can stabilize between Asp15 and the buried [3Fe-4S]0 cluster and thus can potentially act as a proton relay in transferring H+ from the protein to the μ2 sulfur atom. Here, we generalize molecular mechanics with proton transfer to studying proton transfer reactions in the condensed phase. Both umbrella sampling simulations and electronic structure calculations suggest that the PT Asp15-COOH + H2O + [3Fe-4S]0 → Asp15-COO− + H2O + [3Fe-4S]0 H+ is concerted, and no stable intermediate hydronium ion (H3O+) is expected. The free energy difference of 11.7 kcal/mol for the forward reaction is in good agreement with the experimental value (13.3 kcal/mol). For the reverse reaction (Asp15-COO− + H2O + [3Fe-4S]0H+ → Asp15-COOH + H2O + [3Fe-4S]0), a larger barrier than for the forward reaction is correctly predicted, but it is quantitatively overestimated (23.1 kcal/mol from simulations versus 14.1 from experiment). Possible reasons for this discrepancy are discussed. Compared with the water-assisted process (ΔE ≈ 10 kcal/mol), water-unassisted proton transfer yields a considerably higher barrier of ΔE ≈ 35 kcal/mol.

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Arnaut, Luís G., and Sebastião J. Formosinho. "Excited-state proton transfer reactions I. Fundamentals and intermolecular reactions." Journal of Photochemistry and Photobiology A: Chemistry 75, no. 1 (October 1993): 1–20. http://dx.doi.org/10.1016/1010-6030(93)80157-5.

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Ruttink, Paul J. A., Peter C. Burgers, and Johan K. Terlouw. "Proton and electron transfers in O•H•O and C•H•O hydrogen-bridged ions: their role in the dissociation chemistry of ionized acetol, CH3C(=O)CH2OH•+." Canadian Journal of Chemistry 74, no. 6 (June 1, 1996): 1078–87. http://dx.doi.org/10.1139/v96-121.

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Low-energy acetol ions CH3C(=O)CH2OH•+, 1, dissociate to CH3C(H)OH+ and HC=O• by a double hydrogen transfer (DHT), a common reaction among oxygen-containing radical cations. Recent experimental work has shown that the isotopologue CH3C(=O)CH2OD•+ specifically loses HC=O• to produce CH3C(D)OH+. This finding refutes an earlier postulated attractive mechanism based on the behaviour of 1 in ion-molecule reactions. Using ab initio MO calculations (at the CEPA//RHF/DZP level of theory complemented with valence bond (VB) methods), a low-energy pathway was traced that may explain all of the available experimental observations. It is shown that the unimolecular chemistry of 1 can be understood in terms of two proton transfers, taking place in intermediate O•H•O and C•H•O bonded hydrogen-bridged radical cations. The two protons originate from the same moiety and a charge transfer complex is therefore implicated and shown to be involved. These concepts of proton and charge transfer may well be more generally applicable and they do correctly predict the unimolecular chemistry of ionized acetoin, CH3C(=O)CH(CH3)OH•+ and related α-ketols. Key words: ab initio calculations, hydrogen-bridged ions.

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Wisudawati, Asih Widi, and Hans-Dieter Barke. "Proton Transfer: The First-Year Students’ Conceptual Understanding." JTK (Jurnal Tadris Kimiya) 7, no. 2 (December 31, 2022): 157–65. http://dx.doi.org/10.15575/jtk.v7i2.21029.

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Modern Chemistry education shows acid-base reactions by proton transfer with regard to Bronsted’s theory. Understanding how protons can be transferred by particles in solutions is quite challenging. The study aims to presents how university-first-year students are figuring out involved particles which take and give protons. Further, the enrolled participants in this study should explain how the process of proton transfer is running by selected particles but not by substances. Fifty-four students participated in this study that started from revealing participant’s experiences on their previous education at senior high school. Subsequently, researchers conducted a pretest, learning planning, and learning implementation, finally a posttest. Qualitative analysis is preferred to analyze students’ conceptions on particle level. The result shows us that there are two categories of participant’s difficulties. First is determining the involved particles either all particles or reacting particles. The difficulties dominate on mixing terminology of atoms, ions, and molecules, also on preferences of memorizing and calculating oxidation state for chemical equations. The subsequent difficulty is the proton transfer process that caused by participant’s failure on how they selected reacting particles. The systematic sequence on introducing and interpreting chemical equations has also presented as breakthrough.

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