Gas Phase Ion-Molecule Chemistry. I. Ion Cyclotron Resonance Investigations of Organophosphorus Compounds. II. Reactions of Aluminum Ions with Alkyl Halides

Citation

Hodges, Ronald Vernon (1978) Gas Phase Ion-Molecule Chemistry. I. Ion Cyclotron Resonance Investigations of Organophosphorus Compounds. II. Reactions of Aluminum Ions with Alkyl Halides. Dissertation (Ph.D.), California Institute of Technology. https://resolver.caltech.edu/CaltechTHESIS:06232025-170342003

Abstract

The properties and reactions of a series of phosphate and phosphite esters have been studied using the techniques of ion cyclotron resonance spectroscopy. The positive and negative ion chemistry of these species has been examined and their gas phase base strengths (proton affinities) and adiabatic ionization potentials measured. Effects of constrained geometry on the base strengths of phosphites are explored by comparing a series of cyclic phosphites with acyclic analogs. Axial and equatorial phosphorus lone pairs in six membered phosphite rings differing only by inversion of configuration at phosphorus are shown to have significantly different base strengths. A linear correlation exists between the proton affinities and first adiabatic ionization potentials of all tervalent phosphorus compounds for which data are available. This has implications for the electronic structure of these species, strongly suggesting that the highest occupied molecular orbital is the phosphorus lone pair. The results of these experiments are useful in the design of schemes for chemical ionization mass spec trometric analysis of phosphorus esters, which include widely used pesticides.

An ion beam apparatus is used to study the gas phase reactions of aluminum ions with a series of alkyl halides. The variation of product distributions with collision energy is reported. The observed reactivity of aluminum ions is discussed in terms of the electronic structure of aluminum, the reaction thermodynamics and proposed reaction mechanisms.

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