Doctoral Dissertations

Huimin Luo

Date of Award

12-1992

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Chemistry

Major Professor

James L. Adcock

Committee Members

Ronald M. Magid, Richard M. Pagni, Engin H. Serpersu

Abstract

A series of novel perfluorinated diamondoid compounds has been synthesized utilizing the aerosol direct fluorination method. Aerosol direct fluorination of the hydrocarbon analogues produced directly the following perfluorinated diamondoid compounds: F-diamantane, F-adamantanone, 1-chloro-F-adamantane, 2-chloro-F-adamantane, 1,2-dichloro-F-adamantane, 1,3-dichloro-F-adamantane, 1,3,5-trichloro-F-adamantane, 1,3,5,7-tetrachloro-F-adamantane, 1-chloro-F-norbomane, F-4-oxahomoadamantan-5-one, and F-4-protoadamantanone. The first documented 1,3-chlorine shift is observed during aerosol fluorination of 2,2-dichloroadamantane producing 2,4-dichloro-F-adamantane in addition to 2,2-dichloro-F-adamantane. Unlike some cyclic perfluoroketones, F-adamantanone was found to be nonhygroscopic but reversibly forms hemiketals with alcohols. The concentration, temperature and steic effects on the equilibrium between F-adamantanone and its hemiketals with different alcohols have been studied. UV irradiation of F-adamantanone and F-4-protoadamantanone produced the same decarbonylized compound, F-noradamantane, in near quantitative yield its first reported synthesis. It was found that changes of β-fluorine and γ-fluorine chemical shifts in a series of 1-halo-F-adamantanes with different halogen substituents are in contradiction to those predicted by the inductive effect. The possible origin of this effect is discussed. 1-Lithio-F-adamantane was synthesized from the corresponding 1-hydryl-F-adamantane by metallation with methyllithium. 1-Lithio-F-adamantane can also be generated from 1-chloro-F-adamantane and tert-butyllithium or n-butyllithium. It appears that 1-lithio-F-adamantane is stable as long as no other reactive species is present. 19F NMR indicates that the reaction of 2-hydryl-F-adamantane and methyllithium initially gives 2-lithio-F-adamantane which rearranges to 1-lithio-F-adamantane over 2 hours. A possible mechanism is discussed. UV irradiation of F-adamantyl halides in methanol produced only radical substitution products. This provides a facile way to make hydrofluorocarbons from chlorofluorocarbons. By controlling the irradiation time, polychloro-F-adamantanes can be reduced in a stepwise manner.

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