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Determining the gas‐phase properties and reactivities of multiply charged ions
Author(s) -
Gronert Scott
Publication year - 1999
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/(sici)1096-9888(199908)34:8<787::aid-jms847>3.0.co;2-o
Subject(s) - chemistry , ion , charged particle , proton , kinetic energy , reactivity (psychology) , electrostatics , chemical physics , nucleophilic substitution , charge (physics) , computational chemistry , atomic physics , organic chemistry , medicine , physics , alternative medicine , pathology , quantum mechanics
Approaches for analyzing kinetic and thermochemical data from the reactions of multiply charged ions are presented. A method for estimating the electrostatic repulsion in a multiply charged ion is described followed by examples of the potential energy surfaces for two representative reactions of multiply charged ions, proton transfer and nucleophilic substitution ( S N 2). The effect of electrostatic repulsion on reaction barriers is discussed and approaches for extracting thermochemical data from kinetic results are described. For reactions with small intrinsic barriers (i.e. proton transfer), considerable internal electrostatic repulsion is released at the transition state and multiply charged ions exhibit much greater reactivity than singly charged analogs. In contrast, relatively little electrostatic repulsion is released at the transition states of reactions with large intrinsic barriers (i.e. S N 2) and multiply charged ions with moderate charge separations (>10 Å) can exhibit reactivity that is very similar to that of singly charged analogs. Copyright © 1999 John Wiley & Sons, Ltd.