scholarly journals Effects of Gas-Phase Basicity on the Proton Transfer between Organic Bases and Trifluoroacetic Acid in the Gas Phase:  Energetics of Charge Solvation and Salt Bridges†

2000 ◽  
Vol 104 (45) ◽  
pp. 10271-10279 ◽  
Author(s):  
Eric F. Strittmatter ◽  
Richard L. Wong ◽  
Evan R. Williams
Keyword(s):  
Proton Transfer ◽  
Gas Phase ◽  
Trifluoroacetic Acid ◽  
Salt Bridges ◽  
Organic Bases ◽  
Charge Solvation

Probing the Stability and Structure of Metalloporphyrin Complexes with Basic Peptides by Mass Spectrometry

2005 ◽  
Vol 11 (1) ◽  
pp. 65-72 ◽  
Author(s):  
Emily E. Jellen ◽  
Victor Ryzhov
Keyword(s):  
Gas Phase ◽  
Metal Ion ◽  
Basic Amino Acid ◽  
Quadrupole Ion Trap ◽  
Model Systems ◽  
Central Metal ◽  
Salt Bridges ◽  
Charge Solvation ◽  
The Stability ◽  
Basic Peptides

The stability and structure of non-covalent complexes of various peptides contatining basic amino acid residues (Arg, Lys) with metalloporphyrins were studied in a quadrupole ion trap mass spectrometer. The complexes of heme and three other metalloporphyrins with a variety of basic peptides and model systems were formed via electrospray ionization (ESI) and their stability was probed by energy-variable collision-induced dissociation (CID). A linear dependence for basic peptides and model compounds/metalloporphyrin complexes was observed in the plots of stability versus degrees of freedom and was used to evaluate relative bond strength. These results were then compared with previous data obtained for complexes of metalloporphyrins with His-containing peptides and peptides containing no basic amino acids. The binding strengths of Lys-containing peptide complexes in the gas phase was found to be almost as strong as that of Arg-containing complexes. Both systems showed stronger binding than His-containing peptides studied previously. To probe the structure of Arg and Lys non-covalent complexes (charge solvation versus salt bridges), two techniques, CID and ion–molecule reactions, were used. CID experiments indicate that the gas-phase complexes are most likely formed by charge solvation of the central metal ion in the metalloporphyrin by basic side chains of Arg or Lys. Results from the ion–molecule reaction studies are consistent with the charge solvation structure as well.

Structural effects on the iodine cation basicity of organic bases in the gas phase

1989 ◽  
Vol 111 (24) ◽  
pp. 8960-8961 ◽  
Author(s):  
Jose Luis M. Abboud ◽  
Rafael Notario ◽  
Lucia Santos ◽  
Carmen Lopez-Mardomingo
Keyword(s):  
Gas Phase ◽  
Structural Effects ◽  
Organic Bases

An experimental study of the reactivity of the hydroxide anion in the gas phase at room temperature, and its perturbation by hydration

1981 ◽  
Vol 59 (11) ◽  
pp. 1615-1621 ◽  
Author(s):  
Scott D. Tanner ◽  
Gervase I. Mackay ◽  
Diethard K. Bohme
Keyword(s):  
Experimental Study ◽  
Proton Transfer ◽  
Gas Phase ◽  
Rate Constants ◽  
Room Temperature ◽  
Gas Phase Reactions ◽  
Flowing Afterglow ◽  
Hydroxide Anion

Flowing afterglow measurements are reported which provide rate constants and product identifications at 298 ± 2 K for the gas-phase reactions of OH− with CH3OH, C2H5OH, CH3OCH3, CH2O, CH3CHO, CH3COCH3, CH2CO, HCOOH, HCOOCH3, CH2=C=CH2, CH3—C≡CH, and C6H5CH3. The main channels observed were proton transfer and solvation of the OH−. Hydration with one molecule of H2O was observed either to reduce the rate slightly and lead to products which are the hydrated analogues of the "nude" reaction, or to stop the reaction completely, k ≤ 10−12 cm3 molecule−1 s−1. The reaction of OH−•H2O with CH3—C≡CH showed an uncertain intermediate behaviour.

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.

Vibrational Signature of Charge Solvation vs Salt Bridge Isomers of Sodiated Amino Acids in the Gas Phase

2004 ◽  
Vol 126 (6) ◽  
pp. 1836-1842 ◽  
Author(s):  
Catherine Kapota ◽  
Joël Lemaire ◽  
Philippe Maître ◽  
Gilles Ohanessian
Keyword(s):  
Amino Acids ◽  
Gas Phase ◽  
Salt Bridge ◽  
Charge Solvation

scholarly journals Reactions between neutral molecules and cation-radicals in the gas-phase: Can protonation occur without proton transfer?

2015 ◽  
Vol 390 ◽  
pp. 39-48
Author(s):  
Yury V. Vasil’ev ◽  
Douglas F. Barofsky ◽  
Joseph S. Beckman ◽  
Benjamin J. Bythell
Keyword(s):  
Proton Transfer ◽  
Gas Phase ◽  
Cation Radicals

Collision-induced elimination of alkenes from deprotonated unsaturated ethers in the gas phase. Reactions involving specific .beta.-proton transfer

1990 ◽  
Vol 112 (7) ◽  
pp. 2537-2541 ◽  
Author(s):  
Russell J. Waugh ◽  
Roger N. Hayes ◽  
Peter C. H. Eichinger ◽  
K. M. Downard ◽  
John H. Bowie
Keyword(s):  
Proton Transfer ◽  
Gas Phase ◽  
Gas Phase Reactions
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