134757-64-5Relevant academic research and scientific papers
Skeletal Rearrangements Preceding CO Loss from Metastable Phenoxymethylene Ions Derived from Phenoxyacetic Acid and Anisole
Molenaar-Langeveld, Tineke A.,Ingemann, Steen,Nibbering, Nico M. M.
, p. 1167 - 1178 (2007/10/02)
The loss of CHO2(.) from the molecular ion of phenoxyacetic acid and the expulsion of an H(.) atom from ionized anisole lead to phenoxymethylene ions, which fragment predominantly by CO loss on the microsecond time-scale.Carbon-13 labelling reveals that ca. 90percent of the CO molecules expelled from the metastable ions derived from phenoxyacetic acid incorporate the carbon atom from the 1-position of the phenyl group of the parent compound, whereas the residual CO molecules contain one of the other carbon atoms of the aromatic ring.The 2-fluoro- and 2-methylphenoxymethylene ions derived from the appropriate aryloxyacetic acids behave similarly, i.e. the carbon atom of the methylene group of the parent compound is not incorporated in the expelled CO molecules.In contrast, ca. 45percent of the CO molecules eliminated from the metastable phenoxymethylene ions formed from ionized anisole contain the carbon atom of the methyl group, while the remaining part contains the carbon atom from the 1-position of the phenyl ring of the parent compound.This result is taken as evidence for the occurrence of a skeletal rearrangement of the anisole molecular ion leading to an interchange between the carbon atom of the methyl group and the carbon atom at the 1-position of the ring.The elimination of CO from the metastable ions generated from either phenoxyacetic acid or anisole gives rise to a composite metastable peak.Conclusive evidence as to the formation of (+) isomers other than the phenoxymethylene ion is not obtained, indicating that the composite metastable peak is a result of two competing reactions both leading to CO loss.Possible mechanisms of these reactions are discussed together with the mechanism of the skeletal rearrangement of the molecular ion of anisole prior to H(.) loss.
Isotopomer Distributions of Neutral Products from a Doubly Labeled Cation in the Gas Phase. Interconversion of 1-Fluoro-1-propyl Cation and 1-Fluoroisopropyl Cation on the C3H6F+ Potential Energy Surface
Shaler, Thomas A.,Morton, Thomas Hellman
, p. 6771 - 6779 (2007/10/02)
The title cations CH3CH2CHF+ (3) and CH3CHCH2F+ (4) are formed as transient intermediates in the gas phase.These are labile on the millisecond timescale as free ions but can be intercepted in ion-neutral complexes.When 3 is generated as free cation by reaction of CF3+ with propionaldehyde, it rearranges to (CH3)2CF+ (1), as shown by recovery of 2-fluoropropene as a neutral product from its deprotonation in an EBFlow experiment.The same neutral product is recovered when 1 is produced directly by reaction of acetone with CF3+ in the EBFlow.Neutral productsindicative of 3 and 4 (allyl fluoride and 1-fluoropropene) are recovered when these cations are formed in + PhO.> ion-neutral complexes by electron bombardment of CH3CDFCH2OPh (6).Analysis of the isotopic distribution in the recovered neutrals from EBFlow radiolysis of CH3CDF*CH2OPh (where the asterisked carbon is 13C-labeled) allows an assessment of the primary rearrangement pathways.The distribution of label is assayed by using 19F NMR.Rearrangement of the R+ moiety to form deuterated 1 occurs in about half of the complexes formed.In the remainder, methyl transfer (to form deuterated 3) is 2-3 times faster than fluoride transfer (to form deuterated 4).Scrambling of deuterium in the neutral products provides evidence that 3 and 4 interconvert within the ion-neutral complexes.
