Gas-Phase Tyrosine-to-cysteine Radical Migration in Model Systems

2015 ◽  
Vol 21 (3) ◽  
pp. 589-597 ◽  
Author(s):  
Michael Lesslie ◽  
Sandra Osburn ◽  
Michael J van Stipdonk ◽  
Victor Ryzhov
Keyword(s):  
Gas Phase ◽  
Model Systems ◽  
Radical Migration

Gas-Phase Anionic Metal Clusters are Model Systems for Surface Oxidation: Kinetics of the Reactions of Mn– with O2 (M = V, Cr, Co, Ni; n = 1–15)

2021 ◽  
Vol 125 (10) ◽  
pp. 2069-2076
Author(s):  
Brendan C. Sweeny ◽  
David C. McDonald ◽  
Nicholas S. Shuman ◽  
Albert A. Viggiano ◽  
Juergen Troe ◽  
...  
Keyword(s):  
Gas Phase ◽  
Oxidation Kinetics ◽  
Metal Clusters ◽  
Surface Oxidation ◽  
Model Systems ◽  
Kinetics Of

The use of a silica-based heat sink to “uncouple” the matrix-assisted laser desorption/ionization (MALDI) mechanism

2011 ◽  
Vol 89 (4) ◽  
pp. 446-460 ◽  
Author(s):  
E. Lourantos ◽  
O. M. Ramirez ◽  
A. E. Giannakopulos ◽  
K. A. Beran ◽  
Peter J. Derrick ◽  
...  
Keyword(s):  
Gas Phase ◽  
Heat Sink ◽  
Model System ◽  
Model Systems ◽  
Laser Desorption Ionization ◽  
System A ◽  
The Matrix ◽  
Pass Through ◽  
Maldi Mechanism ◽  
Silicon Based

The relationships between ion yield(s) as a function of desorption alone and (or) ionization was investigated using two model systems. In the first model system, a carbohydrate (2,3,6-tri-O-methyl-β-cyclodextrin, TMBCD), which could be directly laser desorbed, was analyzed with and without a silicon-based heat sink compound (HSC). The HSC allowed heat to pass through but obstructed the flow of charge. In the second model system, a peptide (substance P), which ccould not be laser desorbed, was analyzed under similar conditions. The ion yield of TMBCD under either system of heat conductivity was similar, whereas the ion yield of the peptide with the heat sink was negligible. Compounds that are predominately cationized either in the gas phase or preformed in solution give an ion yield that is not dependent upon the surface conditions, whereas compounds that are not ordinarily cationized are affected by the emission of electrons from the metal surface.

β-sheet model systems in the gas phase: Structures and vibrations of Ac–Phe–NHMe and its dimer (Ac–Phe–NHMe)2

2004 ◽  
Vol 6 (10) ◽  
pp. 2682-2690 ◽  
Author(s):  
M. Gerhards ◽  
C. Unterberg ◽  
A. Gerlach ◽  
A. Jansen
Keyword(s):  
Gas Phase ◽  
Model Systems ◽  
Phase Structures ◽  
Β Sheet

Clusters of a protected amino acid with pyrazole derivatives: -sheet model systems in the gas phase

2002 ◽  
Vol 20 (3) ◽  
pp. 543-550 ◽  
Author(s):  
C. Unterberg ◽  
A. Gerlach ◽  
T. Schrader ◽  
M. Gerhards
Keyword(s):  
Amino Acid ◽  
Gas Phase ◽  
Model Systems ◽  
Pyrazole Derivatives ◽  
Protected Amino Acid

B-DNA model systems in non-terran bio-solvents: implications for structure, stability and replication

2017 ◽  
Vol 19 (26) ◽  
pp. 16969-16978 ◽  
Author(s):  
Trevor A. Hamlin ◽  
Jordi Poater ◽  
Célia Fonseca Guerra ◽  
F. Matthias Bickelhaupt
Keyword(s):  
Density Functional Theory ◽  
Gas Phase ◽  
Density Functional ◽  
Model Systems ◽  
Structure Stability ◽  
Implicit Solvation ◽  
Base Pairs ◽  
Functional Theory ◽  
Dna Base ◽  
Dna Base Pairs

We have computationally analyzed a comprehensive series of Watson–Crick and mismatched B-DNA base pairs, in the gas phase and in several solvents, including toluene, chloroform, ammonia, methanol and water, using dispersion-corrected density functional theory and implicit solvation.

Gas Phase Model Systems for Catalysis

2019 ◽  
Vol 233 (6) ◽  
pp. 755-758
Author(s):  
Sandra M. Lang
Keyword(s):  
Gas Phase ◽  
Model Systems ◽  
Phase Model

Effect of Intramolecular Hydrogen Bonds on the Gas-Phase Basicity of Guanidines

2014 ◽  
Vol 67 (7) ◽  
pp. 1056 ◽  
Author(s):  
Zoran Glasovac ◽  
Mirjana Eckert-Maksić
Keyword(s):  
Hydrogen Bond ◽  
Gas Phase ◽  
Model Systems ◽  
Chain Model ◽  
Open Chain ◽  
Independent Variables ◽  
Wide Range ◽  
Intramolecular Hydrogen ◽  
Gas Phase Basicities ◽  
Two Independent Variables

Three series of novel trisubstituted guanidines containing at least one hydrogen bond accepting (HBA) group were modelled using B3LYP/6–311+G(2df,p)//B3LYP/6–31G(d) calculations. Their structure was modified by incorporating a variety of different HBA groups covering a wide range of hydrogen bond strengths. Calculated gas-phase basicities (GBs) ranged from 1035 to 1181 kJ mol–1 depending on the nature of the substituent. To rationalise changes in the GB, a correlation of GB against two independent variables (pKHB and σ4B) was conducted where pKHB served as the descriptor of the hydrogen bond strength and σ4B was introduced to describe changes in the GBs in the open-chain model systems, i.e. in the absence of intramolecular hydrogen bond (IMHB), caused by the electronic effect of the propyl-HBA substituent. A very good correlation of the calculated gas-phase basicities against these two independent variables was established for all three sets of the bases.

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