ISSN:
0030-493X
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Ionization and appearance potentials have been determined for apparently competing [M — CH3] cleavage and [M — CH2O] rearrangement reactions in a series of m- and p-X substituted anisoles. Approximate activation energies AP-IP for most substituents are found not to differ by more than approximately 0.20 eV for m- and p-X compounds with the same substituent. This finding implies either common rearranged molecular ions and/or transition states for the [M — CH3] and [M — CH2O] reactions; or simply rather similar activation energies in unrearranged molecular ions. Assuming no rearrangment, we have found plots of AP-IP against σ+ to give reasonable linear correlations of positive slope for both reactions. To account for this, it is suggested that in the activated complexes for both cleavage and rearrangement, an additional degree of positive charge is developed at the reaction site, and concordant mechanisms are proposed. These conclusions have been compared to those obtained by application of peak relative intensity methods such as Z-values and their modifications.
Additional Material:
11 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/oms.1210040153