Steric and electronic effects of alkyl substituents in the naphthalene system
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
In order to obtain assessment of the relative substituent effects of the acenaphthene bridge, the 1-methyl, and the 1,8-dimethyl groups in naphthalene derivatives, the following series of acids has been prepared:- 1-methyl-2-maphthoic, 4-methyl-1-naphthoic, 1,8-dimethyl-2-naphthoic, 4,5-dimethyl-2-naphthoic, 4,5-dimethyl-1-naphthoic, and 3-, 4-, and 5-acenaphthoic acids. The dissociation constants of these acids, as well as those of 1-naphthoic, 2-naphthoic and 5-methyl-1-naphthoic acids, were determined in 20% (w/w) dioxin-water solutions at 25°, by an ultraviolet spectrophotometric method. In addition the ultraviolet spectra of those acids having the carboxyl group attached to the β-position of the naphthalene ring were determined over the range 3000-3600 Å, in the same solvent. 1-Methyl-2-dimethylaminonaphthalene and 3-dimethyl-aminoceneaphthene were prepared and their ultraviolet spectre, together with that of 2-dimethylaminonaphthalene, were determined with that of 2-dimethylaminonaphthalene, were determined over the range 2400-3600Å using hexane as the solvent. From the results obtained, conclusions have been drawn concerning the relative electron-releasing abilities and steric requirements of the three substituent groups.