The Secondary Isotope Effect on Proton Transfer from the Hydronium Ion in Aqueous Solution

1964 ◽  
Vol 86 (22) ◽  
pp. 5014-5016 ◽  
Author(s):  
A. J. Kresge ◽  
D. P. Onwood
Keyword(s):  
Aqueous Solution ◽  
Proton Transfer ◽  
Isotope Effect ◽  
Hydronium Ion

Kinetics of acid-catalyzed hydration in aqueous solution of 1-methoxy- and 1-methylthio-2-phenylethyne and some related acetylenes

1987 ◽  
Vol 65 (2) ◽  
pp. 441-444 ◽  
Author(s):  
N. Banait ◽  
M. Hojatti ◽  
P. Findlay ◽  
A. J. Kresge
Keyword(s):  
Aqueous Solution ◽  
Proton Transfer ◽  
Isotope Effect ◽  
Rate Constants ◽  
Acid Catalysis ◽  
The Other ◽  
Buffer Solutions ◽  
Hydronium Ion ◽  
Acid Catalyzed ◽  
Kinetics Of

The rates of conversion of C6H5C≡COCH3 to C6H5CH2CO2CH3 were measured in dilute HClO4/H2O, DCIO4/D2O, and H3PO4–H2PO2−/H2O buffer solutions, and the rates of conversion of C6H5C≡CSCH3 to C6H5CH2COSCH3, C6H5C≡CH to C6H5COCH3, 2,4,6-(CH3)3C6H2C≡CH to 2,4,6-(CH3)3C6H2COCH3, and p-CH3OC6H4C≡CCH3 to p-CH3OC6H4COCH2CH3 were measured in concentrated HClO4/H2O solutions, all at 25 °C. The reaction of C6H5C≡COCH3 showed general acid catalysis and gave the isotope effect [Formula: see text], which indicates that it proceeds through rate-determining proton transfer from catalyst to substrate. The hydronium ion catalytic coefficient for this reaction is [Formula: see text], and those for the other four, in the order given above, are [Formula: see text], and 8.5 × 10−6 M−1 s−1. Relative reactivities based on these rate constants are discussed.

Ketonization equilibria of phenol in aqueous solution

1999 ◽  
Vol 77 (5-6) ◽  
pp. 605-613 ◽  
Author(s):  
Marco Capponi ◽  
Ivo G Gut ◽  
Bruno Hellrung ◽  
Gaby Persy ◽  
Jakob Wirz
Keyword(s):  
Aqueous Solution ◽  
Proton Transfer ◽  
Isotope Effect ◽  
Kinetic Isotope Effect ◽  
Flash Photolysis ◽  
Equilibrium Constants ◽  
Thermodynamic Cycle ◽  
Acidity Constant ◽  
Kinetic Isotope ◽  
Carbon Acids

The two keto tautomers of phenol (1), cyclohexa-2,4-dienone (2) and cyclohexa-2,5-dienone (3), were generated by flash photolysis of appropriate precursors in aqueous solution, and the pH-rate profiles of their enolization reactions, 2 –> 1 and 3 –> 1, were measured. The rates of the reverse reactions, 1 –> 2 and 1 –> 3, were determined from the rates of acid-catalyzed hydron exchange at the ortho- and para-positions of 1; the magnitude of the kinetic isotope effect was assessed by comparing the rates of hydrogenation of phenol-2t and -2d. The ratios of the enolization and ketonization rate constants provide the equilibrium constants of enolization, pKE(2, aq, 25°C) = -12.73 ± 0.12 and pKE(3, aq, 25°C) = -10.98 ± 0.15. Combination with the acidity constant of phenol also defines the acidity constants of 2 and 3 through a thermodynamic cycle. These ketones are remarkably strong carbon acids: pKa(2) = -2.89 ± 0.12 and pKa(3) = -1.14 ± 0.15. They disappear by proton transfer to the solvent with lifetimes, τ(2) = 260 μs and τ(3) = 13 ms, that are insensitive to pH in the range from 3-10.Key words: proton transfer, tautomers, flash photolysis, kinetic isotope effect, pH-rate profiles.

The Isotope Effect on Acid-Catalyzed Slow Proton Transfer in Dilute Aqueous Solution

1962 ◽  
Vol 84 (20) ◽  
pp. 3976-3977 ◽  
Author(s):  
A. J. Kresge ◽  
Y. Chiang
Keyword(s):  
Aqueous Solution ◽  
Proton Transfer ◽  
Isotope Effect ◽  
Dilute Aqueous Solution ◽  
Acid Catalyzed

ChemInform Abstract: VINYL ETHER HYDROLYSIS. 9. ISOTOPE EFFECTS ON PROTON TRANSFER FROM THE HYDRONIUM ION

1978 ◽  
Vol 9 (5) ◽  
Author(s):  
A. J. KRESGE ◽  
D. S. SAGATYS ◽  
H. L. CHEN
Keyword(s):  
Proton Transfer ◽  
Vinyl Ether ◽  
Isotope Effects ◽  
Hydronium Ion

scholarly journals Base-enhanced catalytic water oxidation by a carboxylate–bipyridine Ru(II) complex

2015 ◽  
Vol 112 (16) ◽  
pp. 4935-4940 ◽  
Author(s):  
Na Song ◽  
Javier J. Concepcion ◽  
Robert A. Binstead ◽  
Jennifer A. Rudd ◽  
Aaron K. Vannucci ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Proton Transfer ◽  
Water Oxidation ◽  
Proton Acceptor ◽  
Half Time ◽  
X Ray ◽  
X Ray Crystallography ◽  
Buffer Base ◽  
Electron Proton Transfer ◽  
C Nmr

In aqueous solution above pH 2.4 with 4% (vol/vol) CH3CN, the complex [RuII(bda)(isoq)2] (bda is 2,2′-bipyridine-6,6′-dicarboxylate; isoq is isoquinoline) exists as the open-arm chelate, [RuII(CO2-bpy-CO2−)(isoq)2(NCCH3)], as shown by 1H and 13C-NMR, X-ray crystallography, and pH titrations. Rates of water oxidation with the open-arm chelate are remarkably enhanced by added proton acceptor bases, as measured by cyclic voltammetry (CV). In 1.0 M PO43–, the calculated half-time for water oxidation is ∼7 μs. The key to the rate accelerations with added bases is direct involvement of the buffer base in either atom–proton transfer (APT) or concerted electron–proton transfer (EPT) pathways.

Gas-phase proton-transfer reactions of the hydronium ion at 298 K

1979 ◽  
Vol 57 (12) ◽  
pp. 1518-1523 ◽  
Author(s):  
Gervase I. Mackay ◽  
Scott D. Tanner ◽  
Alan C. Hopkinson ◽  
Diethard K. Bohme
Keyword(s):  
Proton Transfer ◽  
Gas Phase ◽  
Rate Constants ◽  
Transfer Reactions ◽  
Flowing Afterglow ◽  
Hydronium Ion ◽  
Proton Transfer Reactions

Rate constants measured with the flowing afterglow technique at 298 ± 2 K are reported for the proton-transfer reactions of H3O+ with CH2O, CH3CHO, (CH3)2CO, HCOOH, CH3COOH, HCOOCH3, CH3OH, C2H5OH, (CH3)2O, and CH2CO. Dissociative proton-transfer was observed only with CH3COOH. The rate constants are compared with the predictions of various theories for ion–molecule collisions. The protonation is discussed in terms of the energetics and mechanisms of various modes of dissociation.

Deuterium isotope effect in proton transfer processes in a viscous medium

1990 ◽  
Vol 168 (5) ◽  
pp. 410-416 ◽  
Author(s):  
Alok Samanta ◽  
Swapan K. Ghosh ◽  
H.K. Sadhukhan
Keyword(s):  
Proton Transfer ◽  
Isotope Effect ◽  
Viscous Medium ◽  
Deuterium Isotope Effect ◽  
Transfer Processes

A water soluble ESIPT-based fluorescent chemodosimeter for the ratiometric detection of palladium ions in aqueous solution and its application in live-cell imaging

2018 ◽  
Vol 42 (19) ◽  
pp. 15587-15592 ◽  
Author(s):  
Jing Huang ◽  
Yu Ding ◽  
Hongyu Fu ◽  
Bo Chen ◽  
Yifeng Han
Keyword(s):  
Aqueous Solution ◽  
Excited State ◽  
Proton Transfer ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Intramolecular Proton Transfer ◽  
Live Cell ◽  
Water Soluble ◽  
Ratiometric Detection ◽  
Fluorescent Chemodosimeter

A new Excited State Intramolecular Proton Transfer (ESIPT) based water-soluble fluorescent chemodosimeter for the ratiometric detection of palladium ions has been rationally designed and developed.

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