Electron Transfer Dissociation of Doubly Charged Ions with Different Cationizing Agents

2015 ◽  
Vol 21 (5) ◽  
pp. 713-723 ◽  
Author(s):  
Xiumin Liu ◽  
Chrys Wesdemiotis
Keyword(s):  
Electron Transfer ◽  
Electron Transfer Dissociation ◽  
Doubly Charged Ions ◽  
Doubly Charged ◽  
Charged Ions

Electron transfer dissociation of a melectin peptide: correlating the precursor ion structure with peptide backbone dissociations

2011 ◽  
Vol 76 (4) ◽  
pp. 295-309 ◽  
Author(s):  
Christopher L. Moss ◽  
Thomas W. Chung ◽  
Václav Čeřovský ◽  
František Tureček
Keyword(s):  
Electron Transfer ◽  
Density Functional ◽  
Electron Transfer Dissociation ◽  
Electron Attachment ◽  
Point Energy ◽  
Doubly Charged Ions ◽  
Fragment Ions ◽  
Gradient Optimization ◽  
Doubly Charged ◽  
Charged Ions

Electron transfer dissociation (ETD) of doubly and triply charged ions from the amphipathic N-terminal decapeptide GFLSILKKVL-NH2 segment of melectin gave different distributions of fragment ions. The triply charged ions generated extensive series of fragment ions of c and z type that covered the entire sequence from both the N and C termini. In contrast, electron transfer to the doubly charged ions caused backbone cleavages that occurred at residues close to the N and C termini. Attachment of a free low-energy electron to the doubly charged ions caused primary dissociations close to the N and C termini that were followed by consecutive dissociations of z ions. The structure of gaseous doubly charged ions from the melectin peptide was elucidated by a combination of exhaustive conformational search by force-field molecular dynamics, large-scale gradient optimization using the semiempirical PM6 method, and density functional theory single-point energy and gradient optimization calculations. The most stable doubly charged ions were found to be protonated at the lysine ε-amino groups and have globular conformations. The backbone cleavages in ETD correlated with the electronic structure of cation-radicals produced by electron attachment to the most stable conformers. The charged lysine ammonium groups direct the incoming electron to the π* orbitals at the proximate amide groups at Phe, Leu, Lys and Val residues that show the highest spin densities. Electron attachment at these amide groups weakens the N–Cα bonds between the Phe-Leu, Leu-Ser, Lys-Lys and Lys-Val residues and causes backbone dissociations.

A collisionally activated dissociation (CAD) and computational investigation of doubly and singly charged DMSO complexes of Cu2+

2005 ◽  
Vol 83 (11) ◽  
pp. 1921-1935 ◽  
Author(s):  
John A Stone ◽  
Timothy Su ◽  
Dragic Vukomanovic
Keyword(s):  
Electron Transfer ◽  
Collision Energy ◽  
Nbo Analysis ◽  
Computational Investigation ◽  
Doubly Charged Ions ◽  
Collisionally Activated Dissociation ◽  
The Difference ◽  
Singly Charged ◽  
Doubly Charged ◽  
Charged Ions

The singly and doubly charged Cu(II)–DMSO complexes formed by electrospray have been examined by CAD and computation. The CAD spectra were obtained as a function of collision energy. The doubly charged ions, [Cu(DMSO)n]2+, were observed only for n ≥ 2. For n = 3, dissociation leads mainly to [Cu(DMSO)2]+ + DMSO+, with only a trace of [Cu(DMSO)2]2+. Although [Cu(DMSO)]2+ was never detected, computation shows that the n = 1 complex exists in a potential well. Loss of DMSO+ is computed to be exothermic for n = 1–3, the exothermicity decreasing as n increases. The singly charged complexes in the ESI spectra were [CuX(DMSO)n]+ (X = Cl, Br, NO3, HSO4, n = 1 or 2). The CAD spectra showed competition between electron transfer from anion to metal followed by loss of X and loss of DMSO+. Experiment and computation show that for [CuX(DMSO)]+, loss of X is the preferred decomposition at low collision energy. NBO analysis shows that electron transfer to Cu from DMSO decreases in [Cu(DMSO)n]2+ as n increases, the bonding becoming more electrostatic and less covalent. In [CuX(DMSO)n]+, the negative charge on X is much less than unity with most of the difference appearing on the DMSO ligand(s).Key words: copper–DMSO complexes, electrospray, CAD, structures.

ELECTRON TRANSFER TO MULTIPLY CHARGED IONS OF Ar, N2, N, AND O2

1967 ◽  
Vol 45 (4) ◽  
pp. 1451-1467 ◽  
Author(s):  
J. William McGowan ◽  
Larkin Kerwin
Keyword(s):  
Electron Transfer ◽  
Cross Sections ◽  
Large Scatter ◽  
Single Charge ◽  
Doubly Charged Ions ◽  
Multiply Charged ◽  
Double Electron ◽  
Doubly Charged ◽  
Charged Ions ◽  
Small Scatter

Cross sections for the transfer of one and of two electrons to fast doubly charged ions of Ar, O, N2, N, and to the triply charged ion of Ar are presented. The 20/02 reaction of Ar++ in Ar is resonant and smaller than that for Ar+ in Ar. The nonresonant, single-charge transfer process 20/11, even though it is exothermic, required that 12.5 ± 2.0 eV be transferred to the reaction from the kinetic energy of the projectile for the reaction to go. Consequently, the scatter of the fast Ar+ products is very large. Similarly, large scatter is observed for the double-electron transfer to Ar+++ as the ion traverses an argon target. Unlike the above, however, single- and double-electron transfer to O++ from O2 and to N2++ from N2, double transfer from Ar to Ar++, and single and triple transfer from Ar to Ar+++ show but small scatter.

REACTIONS OF DOUBLY CHARGED IONS WITH VARIOUS NEUTRALS

1979 ◽  
Vol 40 (C7) ◽  
pp. C7-21-C7-22
Author(s):  
K. Peska ◽  
E. Alge ◽  
H. Villinger ◽  
H. Störi ◽  
W. Lindinger
Keyword(s):  
Doubly Charged Ions ◽  
Doubly Charged ◽  
Charged Ions

Triatomic molecules

2018 ◽  
Author(s):  
John H. D. Eland ◽  
Raimund Feifel
Keyword(s):  
Degrees Of Freedom ◽  
Normal Modes ◽  
Electronic States ◽  
Triatomic Molecules ◽  
Doubly Charged Ions ◽  
Spectral Bands ◽  
Valence Electrons ◽  
Doubly Charged ◽  
Charged Ions ◽  
Double Ionisation

Double ionisation of the triatomic molecules presented in this chapter shows an added degree of complexity. Besides potentially having many more electrons, they have three vibrational degrees of freedom (three normal modes) instead of the single one in a diatomic molecule. For asymmetric and bent triatomic molecules multiple modes can be excited, so the spectral bands may be congested in all forms of electronic spectra, including double ionisation. Double photoionisation spectra of H2O, H2S, HCN, CO2, N2O, OCS, CS2, BrCN, ICN, HgCl2, NO2, and SO2 are presented with analysis to identify the electronic states of the doubly charged ions. The order of the molecules in this chapter is set first by the number of valence electrons, then by the molecular weight.

Doubly-charged ions in desorption mass spectrometry

1983 ◽  
Vol 55 (8) ◽  
pp. 1310-1313 ◽  
Author(s):  
David N. Heller ◽  
James. Yergey ◽  
Robert J. Cotter
Keyword(s):  
Mass Spectrometry ◽  
Desorption Mass Spectrometry ◽  
Doubly Charged Ions ◽  
Doubly Charged ◽  
Charged Ions
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